Statistical Analysis of. Manual Therapists Funded by ACC:

Transcription

1 Statistical Analysis of Manual Therapists Funded by ACC: Initial Referrals and Aspects of Patient Journey Prepared for Osteopathic Council of NZ by: Dr Carl Scarrott DRAFT REPORT statconsultancy.com

2 Executive Summary This study examines the type of treatment providers making the initial referrals of claimants and what type of treatment provider is sought on the subsequent visits. The variation in the claimant choices for initial referrals and subsequent visits over time (financial years / to /) and different injury types is also considered. Most of the report considers what providers the claimant sees on subsequent visits conditional on the initial treatment provider. The final section of the report considers the initial treatment provider of claims conditional on which provider is sought at subsequent visits. Key findings:. There is roughly a : split between the initial referrals being a manual therapist (acupuncturist, chiropractor, osteopath or physiotherapist) versus a GP, radiologist or professions in the Other category.. A higher proportion of initial referral are by osteopaths and chiropractors (at % and %) than is expected given the proportion of claims which include these visits to these professions in their claims (at % for both in Figure..) from Scarrott (a). Acupuncturists have far lower proportion of initial referrals at just.% compared to % of all claims which include acupuncturists. A slightly lower proportion of initial referrals are made by physiotherapists (at %) compared to across all claims (at %).. The manual therapy professions have different retention rates from the initial referral to subsequent visits (from second to fourth and later visits): in descending order physiotherapists (-%), chiropractors (-%), osteopaths (-%) and acupuncturists (-%).. As previously observed in Scarrott (b) of the manual therapy providers: osteopaths have the highest proportions if claims which finish with one or two visits (at % at two visits), followed by physiotherapists (%), chiropractors (%) and acupuncturists (%).. The claimants which visit both acupuncturist and osteopaths (or physiotherapists) are far more likely to visit an osteopath (or physiotherapist) first followed by the acupuncturist, rather than the other way around.. The higher propensity for claimants to combine osteopathy (or physiotherapy) and acupuncture noted in Scarrott (b) has also been highlighted here. However, this study also highlights a higher propensity for combinations of radiologist and chiropractor visits, compared to radiologist visits combined with any other manual therapy profession. A strong propensity for initial referrals by GP s followed by acupuncturists (and vice-versa) is also observed.. AveryhighproportionofsubsequentvisitstoacupuncturistswereinitiatedbyGP s(at -% across all subsequent visits) followed by -% for physiotherapists, compared to just -% for chiropractors, -% for osteopaths.. The proportion of claims initiated by osteopaths has substantially increased (by close to %) from % in / to % in / (though most of this increase was prior

3 to /). Correspondingly, the proportion initiated by physiotherapists has reduced from % to % over the same time period.. The retention of claimants from the initial visit to subsequent visits for each manual therapy profession have generally reduced slightly over time.. The choice of therapy providers in subsequent visits for claims initiated by GP s has substantially changed over time. Firstly, the proportion of claimants seeking each of physiotherapy, osteopathy or chiropody has decreased over time. However, there has been a notable increase in subsequent acupuncture visits at.% for second visit in / to.% in / and % to % for fourth or later visits. Some of the latter feature changes (but by no means all) could be explained by ethno-demographic changes over this time period as discussed in Scarrott (c).. The choice of therapy providers in subsequent visits for claims initiated by radiologist s has also substantially changed over time. The proportion of subsequent visits to osteopaths has increased over time (e.g. % for second visit in / to % in /) The picture for subsequent chiropractor visits is more mixed. The proportion of chiropractors visits at the second and third visits has decreased over time (e.g. % for second visit in / to % in /), whereas there does not appear to be any trend for the fourth and later visits.

4 Chapter Initial Referrals of ACC Claimants. Introduction This report is one of a series providing a statistical analysis of the manual therapy market funded by the Accident Compensation Commission (ACC) commissioned by the Osteopathic Council of New Zealand (OCNZ), see Scarrott (a, b and c) for previous reports. The main results of an exploratory data analysis of the ACC claims by the type of provider that made the initial referral, including claimant choices about type of provider accessed during follow-up visits and how these choices varied over recent years and across different injury types. The report commences with a description of the data in Section.. Section. shows the results of an exploratory analysis of distribution of treatment provider types chosen at the:. first visit;. second visit conditional on the type of first treatment provider;. third visit conditional on the type of first treatment provider;. fourth (and later) visits conditional on the type of first treatment provider. The second, third and fourth (and later) visits are referred to herein as the subsequent visits. This initial analysis essentially follows the claimants through their subsequent visits, considering how their choice of provider may vary according to the type of provider who initiated the claim. Section. considers how the type of treatment provider choice for the first and subsequent varies over time (financial years - until -) and by injury type/read code in Section.. An alternative viewpoint is considered in the final Section. where for each type of treatment provider used at the subsequent visits the type of initial treatment provider is considered. These results show the where the claimants using each type of provider came from (i.e. what type of provider initiated the claim). The OCNZ specified the injury types and treatment providers of interest and have provided some directions of interest to the analysis. The results presented are a fair representation of the information in the available data, following an extensive exploratory data analysis. statconsultancy.com

5 All the analysis results are either included in the main text or in the Appendix for completeness. When discussing the key results a purely statistical interpretation is given (except where the causal factors are obvious and are therefore included in the main text), as the background contextual information will be provided in follow-up publications by the authors or the OCNZ. If further information, clarification or additional results are required for follow-up study then please contact the author at carl.scarrott@statsconsultancy.com.. Available Data The ACC claim data were kindly provided in a tabulated form by Peter Woods at ACC... Initial Referral Count Data ACC kindly provided the following five spreadsheets of data. The first spreadsheet is a count of the number of claims which see each of the following types of treatment provider: acupuncturist; chiropractor; osteopath; physiotherapist; general practitioner (GP); radiologist; other; aggregated for each financial year - to - ( years) and for each injury type/read code: S.. - Ankle sprain; S. - Coccyx sprain; S. - Lumbar sprain; S. - Neck sprain; S. - Sacroiliac ligament sprain; S. - Sprain of shoulder and upper arm; S. - Sprain wrist ligament; S. - Sprain, elbow joint, radial collateral ligament; S. - Thoracic sprain. Osteopathic Council NZ Technical Report

6 The second spreadsheet follows these claimants through to their second visit. The counts of claims by treatment provider for that visit are broken down by financial year and read code as for the first visit, as well as the type of treatment provider seen at the first visit. From the difference in the counts between the first and second visits the number of claimants who have finished their treatment under the ACC claim can be calculated. The third spreadsheet follows the claimant through to their third visit, with the same breakdown as with the second visit. The fourth spreadsheet provides similar counts for the fourth and later visits. However, the data are slightly more complex to interpret in great detail as a single claimant could see more than one type of provider for the fourth or later visits, so could be counted more than once. The fifth spreadsheet provides a total count of the number of claims included in the first to fourth spreadsheets, as a way to verify the data integrity. Adetailedanalysisofthecountsforthefourthandlatervisitsisrathertroublesomeasit is not possible to determine exactly: ) how many patients have stopped treatment at three visits or the number who have visited two or ) more types of treatment providers at the fourth and later visits. However, Scarrott (b) showed that just % of claimants visited more than one type of provider on their claim. So given that many claimants will visit a GP or radiologist in one of the first to third visits, we will ignore the possible duplicated contribution for a small number of claimants. However, the tentative nature of the conclusions drawn from the fourth (and later) visits will be highlighted in the discussion as appropriate.. Statistical Analysis The data provided by ACC consists,, claims over an eight year period for the nine read codes listed above. The magnitude of this data provides a strong basis for the conclusions drawn in thei report. However, under deep levels of disaggregation there is a possibility of small number of claims in certain cells leading to uncertainty in the results presented in these cases. Where the quantities of interest are based on a relatively small number of claims, this will be explicitly noted in the text of the report. An exploratory statistical analysis of the initial referrals and the early parts of patient journey under the ACC claim is carried out using simple graphical summaries. A fair and broad collection of aggregations are considered, with only minor directions on possible aggregations provided by OCNZ to ensure fairness. Statistical interpretations of the results are drawn (and obvious physical causes are mentioned where appropriate), but no formal statistical testing has been carried out.. Initial Referrals Figure. shows the distribution of claimant choice of type of treatment provider to initiate their claim in the uppermost pie chart. Claims from all the financial years and all read codes have been included. A consistent colour scheme has been used throughout this report to aid interpretation: acupuncturist = blue; statconsultancy.com

7 chiropractor = green; osteopath = red; physiotherapist = golden rod; general practitioner (GP) = grey; radiologist = orange; other = cyan. The manual therapy providers (first four in above list) are positioned together on the pie charts in the ordered specified. The other treatment providers (GP s, radiologist and Other ) are also positioned together for clarity. Consistent structures of the figures has also been used to aid interpretation. The subsequent rows of Figure. consider the distribution of claimant choice of type of treatment provider for the subsequent visits (second, third and then fourth and later), where the claims are considered separately (conditionally) based on the type of provider who initiated the claim. For example, the pie chart on the first row and first column, includes only claims at the second visit where the initiator s profession was an acupuncturist. The subsequent pie charts completely ignore claims which have been completed at an earlier visit (e.g. the acupuncturist pie chart for the second visit ignore patients who only claimed for a single session with an acupuncturist at the first visit and made NO subsequent visits to any provider). As noted above the interpretation of the bottom row of the pie charts is tentative due to the fact that a single claim can be included more than once (although the number of duplicates is known to be small from Scarrott, b). The distribution of claimant choice for the initial visit is broadly compatible with the results previously presented in Figure.. of Scarrott (a). The difference between the figures is due to the differences in the source data. The figure below considers only the first visit a claimant makes, whereas Figure.. of Scarrott (a) considers claims which include avisittotherelevanttreatmentprovideratleastonce. Furtherthepreviousreportdid not consider the Other category of provider. The upper pie chart in Figure. shows that there is roughly a : split between claims where the initial visit is to one of the manual therapists or the other providers (GP s, radiologists and Other). A small proportion of claims (%) are initiated by radiologists. A very large proportion of the claims (%) are initiated by GP s (so the pie charts in column of Figure. include a large number of claimants). Just.% of claims are initiated by an acupuncturist. A roughly equal number of claims (%) are initiated by osteopaths and chiropractors. As expected the manual therapy profession which initiates the most claims is physiotherapy at %. Section.. considers claimant choices of manual therapists only, ignoring GP, radiologist and Other visits. When considering the subsequent visit pie charts which condition on the type of initial referral provider it should be remembered that each pie chart represents a different total number of claims. For example, the column of acupuncturists pie charts includes just, claims, whereas for GP s it is,, claims (almost times as many claims). Osteopathic Council NZ Technical Report

8 Therefore, we expect larger variability in the subsequent pie charts with a small number of claims (in particular for acupuncturists and radiologists). It is interesting to note that the distribution of type of treatment providers on subsequent visits for claims which are initiated by osteopaths and chiropractors are fairly similar. There are three notable differences: chiropractors have a higher retention of claimants through second, third and later visits (at, and % compared to, and % for osteopaths); claimants who visit chiropractors for the first visit are more likely to visit a radiologist in the second and third visits compared to those that initially visited an osteopath. However, for later visits the converse is true (but only a very slight difference in observed); claimants who visit osteopaths for the first visits are more likely to visit acupuncturists for subsequent visits compared to chiropractors (at % compare to % for fourth and later visits). Averysubstantialdifferenceinthedistributionoftreatmentchoicesisobservedforclaims initiated by acupuncturists (compared to that for osteopath/chirpractor initiated claims) in second row and first column of Figure.. In particular, a relatively high percentage of claimants see a GP for the second visit (at %, compared to /% for osteopath/chiropractor and % for physiotherapist initiated claims), with a larger (but less notable) percentage also visiting GP s for third and later visits compared to all the other manual therapists. In contrast, the percentage of claimants initiated by acupuncturists whom subsequently visit a radiologist is much less than for all the other manual therapists for the second and third visits, and is just less than for claims initiated by osteopaths/chirporactors and notably less than that for those initiated by physiotherapists. Overall the retention of claimants by acupuncturists is far less for claims initiated by acupuncturists (, and % for second, third and later visits) compared to all the other manual therapists, which also implies claimants are generally more likely to visits other manual therapists at subsequent visits (or other treatment providers). The proportion of claim initiated by physiotherapists is the highest amongst the the manual therapy providers (at %). Therefore, the pie charts for this group of claimants can be relied on due to the large sample size. Interestingly, a much higher percentage of physiotherapist initiated claims visit a GP (at %) in the second visit compared to those initiated by osteopaths/chiropractors at -% (though less than for acupuncturists at %). Figure. shows that a high percentage of claims initiated by GP s visited an acupuncturist at subsequent visits (at -%) than might be expected given the percentage in the first row pie chart (.%) in Figure. and Figure.. of Scarrott () of claims involving acupuncturists (%). The percentage of physiotherapist initiated claims which subsequently visit an osteopath or chiropractor is broadly consistent across all subsequent visits (at -%). Arelativelylargepercentageofsubsequentvisits(forGPinitiatedclaims)visitaGP,radiologist or Other treatment provider at subsequent visits compared to claims initiated by all the manual therapists. statconsultancy.com

9 Later Third Second First Chiropractor Acupuncturist % % Other % Radiologist % Osteopath % GP % Physiotherapist % Acupuncturist Chiropractor Osteopath Physiotherapist GP Radiologist Other Figure.: Distribution of claimants choice of type of treatment provider at first visit, followed by provider choice at second and fourth (and later) visits conditional on provider type that initiated the claim. Claims have been aggregated over all financial years and injury types. Claims finalised on prior visits are ignored. Osteopathic Council NZ Technical Report

10 A relatively high percentage of claims initiated by GP s subsequently visited a physiotherapist (, % and % for second, third and later visits), compared to the other manual therapy provider. In the following section we consider only subsequent visits to a manual therapy provider, which will shed more light on the subsequent visits of claimants where the claim was initiated by a GP. Strong conclusions are difficult to draw from the pie charts for claims initiated by radiologists, due to the relatively small number of claims (% initiated by radiologists). A relatively high proportion of such claims of subsequent claims (-%) visited a chiropractor, compared to only -% for osteopaths and -% for acupuncturists. Similarly, strong conclusions are difficult to draw from claims initiated by treatment providers within the Other category due to the varied nature of providers within this category... Subsequent Manual Therapist Visits Only Figure. has the same structure as Figure. but only considers the claims which visits a manual therapist (acupuncturist, chiropractor, osteopath or physiotherapist) on the that particular visits (or visits). Therefore, each pie chart in Figure. consists less claims than in Figure.. This Figure permits consideration of claimants which are receiving actual manual therapy treatment, and gives a better feel for retention of claimants within one type of manual therapy profession. The pie chart of initiating profession on the first row can be compared to Figure.. of Scarrott (a) which considers all claims which visit a manual therapists at least once. The proportion of claims initiated by acupuncturists is low (at %) compared to those that visit an acupuncturist at least once on a claim. The reason for this feature is likely due to the higher propensity for claimants to use acupuncturists in combination with other types of manual therapy, in particular osteopaths as noted in Scarrott (b). The supposition is that many of these claimants who use multiple modalities (including acupuncturists) will see the other provider first, followed by an acupuncturist on later visits. Some support for this supposition is provided by the high proportion of claims (%) which saw an osteopath on the first visit and on the fourth or later visits visited an acupuncturist (shown in bottom row and third column of Figure.. Another potential contribution to the low percentage of claims initiated by acupuncturists is also that these claimants may visit a GP, radiologist or Other provider on the first visit. Support for this suggestion is provided by the relatively large proportion of the claims initiated by a GP or Other provider (note that % of all claims see a GP first, so this is a large number of claim) which visit an acupuncturist at the second, third and fourth (and later) visits (at -%, -% and -% respectively). The proportion of claims initiated by osteopaths or chiropractors in Figure. is also slightly higher (at and % respectively) than we might expect and correspondingly low proportion for physiotherapists, compared to the corresponding Figure.. (at %) of Scarrott (a) which considers all claims where they visited one of these therapists at least once. The low proportion of acupuncturist initiated claims noted above does not fully explain the differences, though it does account for much of the discrepancy between the proportion of claims initiated by osteopaths. The remaining discrepancy for the chiropractors and physiotherapists is unexplained. statconsultancy.com

11 Later Third Second First Acupuncturist % Chiropractor % Osteopath % Physiotherapist % Acupuncturist Chiropractor Osteopath Physiotherapist GP Radiologist Other Figure.: Distribution of claimants choice of type of manual therapy provider (ONLY) at first visit, followed by manual therapy provider choice at second and fourth (and later) visits conditional on provider type that initiated the claim. Claims have been aggregated over all financial years and injury types. Claims finalised on prior visits are ignored. Osteopathic Council NZ Technical Report

12 The following discussion will separately consider the proportion of claims which remain with the same type of provider on subsequent visits and those which change the type of treatment provider. Physiotherapists have the highest proportion of patients retained for the second, third and fourth (and later) visits (at, and %), closely followed by chiropractors (at, and %). Osteopaths have a slightly lower retention rate (at, and % respectively). Acupuncturist have the lowest retention rate (at, and %), the retention rate at the second visit notably lower than all the other manual therapy professions. If claimants have changed type of manual therapy treatment provider since the initial visit then it worthwhile comparing the relative proportions compared to that expected under the treatment choices made across the whole population of claims. A notable difference in the relative proportions of alternative manual therapy providers is shown by the pie charts for claims initiated by acupuncturists. A relatively high proportion of claims initiated by acupuncturists will subsequently visit an osteopath (particularly at the second visit) and conversely a relatively low proportion will subsequently visit a chiropractor. The opposite features are observed for claims initiated by an osteopath (i.e. much higher proportion of claims subsequently visit an acupuncturists compared to that expected). Of those claims initiated by physiotherapists, a relatively high proportion subsequently visit an acupuncturist with relatively low proportion visiting chiropractors and osteopaths. A slightly higher proportion of claimants who initiate claims with a chiropractor will subsequently visit an acupuncturist than might be expect, and correspondingly a slightly lower proportion subsequently visit a physiotherapist/osteopath. The above conclusions drawn about claimant choices when changing the type of manual therapist is consistent with that highlighted in the analysis of claims under multiple modalities by Scarrott (b). Interestingly the distribution of manual therapy choices in subsequent visits of claims initiated by GP s or Other professions are broadly consistent. However, you will notice that the distribution is very different to that for manual therapy initiated claims in the first row of Figure. and Figure.. of Scarrott (a). Of particular note is the relatively high proportion of claims who subsequently visit an acupuncturist (-%) compared to just % for claim initiators and % over all claims. A somewhat higher relative proportion also subsequently visit a physiotherapist (at -%) compared to % for claim initiators and % over all claims. Consequently, a relatively low proportion of claimants subsequently visit a chiropractor or osteopath (at -%) compared to /% for claim initiators and % over all claims. The distribution of manual therapy choices in subsequent visits of claims initiated by radiologist is very different to that for GP s and profession in the Other category. The most notable feature of these distributions is that the proportion of claimants who subsequently visit a chiropractor is far higher than expected given the distribution observed for the initial visit and amongst the population of claims (e.g. being three times larger than for osteopathic treatment). statconsultancy.com

13 .. Small Number of Visits per Claim Figure. should be compared to Figure. where the former now includes the proportion of claimants which have finalised their treatment before the second and third visits (shown by white slices of pies). Unfortunately, this information is not available for the fourth and later visits, as individual claims can be counted more than once in this data if the claimant uses more than one type of treatment providers for the fourth or later visits. Note that the proportion of claimants who have finished their claim increases from the second the third visits, as the total number who have finalised since the initial visit are included. Of all the manual therapy providers claims initiated by osteopaths have the highest proportion of claims finalised at both the first and second visits (at and %). This is expected given the distribution of number of visits per claim analysed in Scarrott (b), with osteopaths having the lowest average number of visits per claim. Physiotherapists have the second highest proportion of claims finished at one and two visits (at % and % respectively). Acupuncturists have the lowest number of claims which are finalised after one or two visits (at % and % respectively). Almost % of claims initiated by a GP are finalised after two visits, with a similar percentage for those initiated by professions in the Other category (at %). A relatively low proportion of radiologist initiated claimants (at %) finalise their claim after one visit, with a similar proportion finalising after two visits (at -=%) to those that initially visited a profession in the Other category. Osteopathic Council NZ Technical Report

14 Later Third Second First Chiropractor Acupuncturist % % Other % Radiologist % Osteopath % GP % Physiotherapist % Acupuncturist Chiropractor Osteopath Physiotherapist GP Radiologist Other Figure.: Distribution of claimants choice of type of treatment provider at first visit, followed by treatment provider choice at second and fourth (and later) visits conditional on provider type that initiated the claim. Claims have been aggregated over all financial years and injury types. Claims finalised on previous visits included in second and third visits. statconsultancy.com

15 Chapter Variation in Claimant Choices Over Time and Injury Type This Chapter explores how claimant choices of provider type vary over the financial years available (- to -) and injury read codes. The variation in choice of manual therapy providers is discussed in the main text accompanied by the relevant graphs. The corresponding graphs for all the treatment providers (i.e. including GP s, radiologist and Other professions) are included in the Appendix for completeness. Only a small number of key features are drawn from the graphs in the Appendix.. Time Variation Figure. shows how the distribution of claimant choice of manual therapist at the first and second visits varies over the financial years - to -. Essentially the time variation in the pie charts presented in the first and second rows of Figure. are shown, which are aggregated over all the financial years. The corresponding graphs for the third and fourth (and later) visits are shown in Figures. and.. Firstly, lets consider the time variation in the distribution of patient choice of manual therapist for initial visit. The proportion of claimants initiated with acupuncturist has barely changed over time ranging from.-.%. The proportion of claims initiated with chiropractors reduced from.% in / to.% in / followed by a slight increase to.% in /. The proportion of claims initiated by physiotherapist has also decreased from.% in / to % in /. The proportion of claims initiated by osteopaths has substantially increased (by roughly % overall) from.% in / to.% in / (though has only slightly risen since /). The following discussion will consider how the claimant choice of manual therapist varies conditionally on the initiating type of treatment provider. The distribution for claims initiated by acupuncturists varies substantially in time. In the financial years / to /, the retention of the claimants to further acupuncture sessions were the highest, and notably drop in / and /, followed by a general increase through / with a notable increase again in /. The (relative) proportion of claimants who switch to each of the other types of manual therapists has changed slightly over time. However, caution must be

16 ACC Claim Initial Referrals Analysis Oth Rad GP Phy Ost Chi Acu First % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % Figure.: Distribution of claimants choice of type of manual therapist at first visit, followed by manual therapist choice at second visit conditional on provider type that initiated the claim. Distributions are compared over each financial year. Claims have been aggregated over all injury types. Claims finalised on prior visits are ignored. statconsultancy.com

17 ACC Claim Initial Referrals Analysis Oth Rad GP Phy Ost Chi Acu First % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % Figure.: Distribution of claimants choice of type of manual therapist at first visit, followed by manual therapist choice at third visit conditional on provider type that initiated the claim. Distributions are compared over each financial year. Claims have been aggregated over all injury types. Claims finalised on prior visits are ignored. Osteopathic Council NZ Technical Report

18 Oth Rad GP Phy Ost Chi Acu First % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % Figure.: Distribution of claimants choice of type of manual therapist at first visit, followed by manual therapist choice at fourth and later visits conditional on provider type that initiated the claim. Distributions are compared over each financial year. Claims have been aggregated over all injury types. Claims finalised on prior visits are ignored. statconsultancy.com

19 applied in interpretation of the relative proportions who changed manual therapist in / and / as these consist only and claims respectively (whereas the numbers have increased from in / to in /). Of the claimants who initiated their claim with an acupuncturist and then changed to another type of manual therapist, the relative proportion of claimants who subsequently visited a chiropractor has barely changed over time. Whereas the relative proportion who have subsequently visited an osteopath has reduced (e.g. from % in / to % in / for second visit) for the second, third and fourth (and later) visits, with correspondingly the relative proportion subsequently visiting aphysiotherapistincreasingovertime(e.g.from%to%forsecondvisit). The retention of claimants who initially visit a chiropractor has only slightly reduced over time from % in / to % in /. However, the relative proportions of choice of alternative manual therapists in subsequent visits has changed notably over time. The relative proportion of these claimants who switch to an acupuncturist in subsequent visit has roughly doubled over / to /. In contrast the relative proportion who subsequently visit a physiotherapist has reduced (e.g. from % to % for second visit). The time variation for claimants changing to osteopathy is more complex. The relative proportion changing to an osteopath slightly increased from / to /, but has reduced slightly since this time (e.g. % in / to % in / to % in /). Similarly, the retention of claimants who initially visit an osteopath has slightly reduced over time from % in / to % in /. As with those claims initiated by chiropractors, the relative proportions of choice of alternative manual therapists in subsequent visits has changed notably over time. The relative proportion of claimants who switch from osteopaths in the first visit to physiotherapists or chiropractors in subsequent visits has reduced over time (e.g. from % in / to % in / at second visit for physiotherapist and correspondingly % to % for chiropractors). Therefore, the relative proportion of claimants who have switched to an acupuncturist in later visits has generally increased over time (e.g. from % to % for fourth and later visits), although the relative proportion switching to acupuncturists at the second visit reached a peak in / (at %) from % in / and then reduced to % in /. The retention of claimants who initially visited a physiotherapist has only slightly reduced over time from.% in / to.% in /. The relative proportion of those claims that were initiated by a physiotherapist and then changed to an acupuncturist in subsequent visits has increased substantially over time (e.g. from % in / to % in / for second visit and correspondingly % to % for fourth and later visits). In contrast the proportion of claims changing to a chiropractor has decreased over time. The time variation for these claimants who change to an osteopath is somewhat more complicated, generally the proportion increased from / to / followed by a decrease until / (e.g. % in / to % in / to % in / for the second visit). As noted above % of all claims are initiated by GP s so the time trends observed in the pie chart on the sixth row of Figures.-. involve a large number of claims. There are clear trends in the claimants choice of manual therapist for subsequent visits for claims initiated by GP s. Firstly, the proportion of claimants seeking each of physiotherapy, osteopathy and chiropody has decreased over time. There has been a substantial increase in the proportion of claims seeking acupuncture in subsequent visits (e.g..% for second visit in / to.% in / and correspondingly % to % for fourth and later visits). Similar time variations are observed for claims initiated by professions in the Other category. Osteopathic Council NZ Technical Report

20 The time variation in manual therapy choice for claims initiated by radiologists are a little more mixed, which will be partly due to the relatively small number of claims involved. The proportion of claimants using acupuncturists in subsequent visits has been increasing since / (e.g. from.% at second visit in / to.% in /). In contrast, the proportion of claimants who subsequently visit an osteopath has increased over time (e.g. from % in / for second visit to % in /). The proportion of claimants using chiropractors at the second and third visit has decreased over time (e.g. % for second visit in / to % in /), whereas there does not appear to be a trend in the proportion of claimants who visit chiropractors for the fourth and later visits. The proportion of claimants using physiotherapists at the second visit has increased over time (at % in / to % in /), whereas there does not appear to be a trend in the proportion of claimants who visit physiotherapists for the third, fourth and later visits. Figures.-. also included the subsequent visits to GP s, radiologist and Other professions. The proportion of claims initiated by acupuncturists which subsequently visit a GP do not appear to be following any particular trend. By contrast the proportion of claims initiated by physiotherapists, chiropractor or osteopaths which subsequently visit a GP has reduced over time (e.g. for physiotherapist initiated claims at fourth and later visits has reduced from % in / to % in / and correspondingly for osteopaths of % to %). The corresponding proportion of subsequent visits to radiologists has stayed fairly constant over time.. Injury Related Variation As in Section. the trends in the distribution of manual therapy choices across the different injury type or read codes is shown in Figures.-.. The read codes have be broadly grouped so that the most similar injury types are close together in the graphs. The first broadly defined group is shoulder, elbow, wrist and ankle with the other group of sacroiliac, neck, thoracic, lumbar and coccyx injuries. Henceforth, these two groups will be labelled the joints group and spinal group respectively. Thereareclearlyverystarkdifferencesin the treatment provider choices across the injury types, with strong similarities within these groups and few differences within these broad groups. In contrast to the time variation considered in Section. which focused on the choice of manual therapist, in this section we will consider all the types of provider and how choices amongst these vary over read codes. It is very clear in Figure. that a very high proportion of claimants for the joints group are initiated by a GP (at -%), whereas in the spinal group the proportion is mainly around % with the only exception being the coccyx injuries with a very high percentage of %. The joints group also have a relatively large proportion of claims (at -%) initiated by professions in the Other group compared to the spinal group (with most in range -%), although again the coccyx injuries within the spinal group are relatively high (at %). The coccyx injury claims also stand out in the spinal group due to the relatively high proportion of radiologist initiated claims (at % compared to just % for other spinal related injuries). Wrist injuries have the highest proportion of radiologist initiated claims (at %), closely followed by wrist (%) and elbow injuries (%) with shoulder injuries having the lowest at %. statconsultancy.com

21 ACC Claim Initial Referrals Analysis Oth Rad GP Phy Ost Chi Acu First % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % Shoulder Elbow Wrist Ankle Sacroiliac Neck Thoracic Lumbar Coccyx Figure.: Distribution of claimants choice of type of treatment provider at first visit, followed by treatment provider choice at second visit conditional on provider type that initiated the claim. Distributions are compared over each injury type. Claims have been aggregated over all financial years. Claims finalised on prior visits are ignored. Osteopathic Council NZ Technical Report

22 ACC Claim Initial Referrals Analysis Oth Rad GP Phy Ost Chi Acu First % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % Shoulder Elbow Wrist Ankle Sacroiliac Neck Thoracic Lumbar Coccyx Figure.: Distribution of claimants choice of type of treatment provider at first visit, followed by treatment provider choice at third visit conditional on provider type that initiated the claim. Distributions are compared over each injury type. Claims have been aggregated over all financial years. Claims finalised on prior visits are ignored. statconsultancy.com

23 ACC Claim Initial Referrals Analysis Oth Rad GP Phy Ost Chi Acu First % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % Shoulder Elbow Wrist Ankle Sacroiliac Neck Thoracic Lumbar Coccyx Figure.: Distribution of claimants choice of type of treatment provider at first visit, followed by treatment provider choice at fourth and later visits conditional on provider type that initiated the claim. Distributions are compared over each injury type. Claims have been aggregated over all financial years. Claims finalised on prior visits are ignored. Osteopathic Council NZ Technical Report

24 The distribution of manual therapy choices for the initial visit also varies substantially across the injury groups, which are most easily seen in Figures.-. in the Appendix where the non-manual therapists are ignored. Interestingly of the spinal group, the coccyx injuries stood out as unusual compared to the others in that group for GP, radiologist and Other providers, whereas when considering just the choice of manual therapist (shown in Figures.-. in the Appendix) for initial visit the injury which stands out is sacroiliac injuries. The proportion of claims initiated by acupuncturists (%) or chiropractors (-%) is very similar for neck, thoracic, lumbar and coccyx injuries, whereas the corresponding proportions for sacroiliac injuries is close to % and % respectively. However, the proportion of claims initiated by osteopaths varies across all spinal related injuries (from % for lumbar injuries to % for coccyx injuries). The proportion of physiotherapist initiated claims is similar for neck, thoracic and lumbar injuries (at -%), with % for coccyx injuries and % for sacroiliac injuries. Of the joints group almost all claims in the elbow, wrist and ankle injuries are initiated by physiotherapists (at -%). The proportion of the remaining claims initiated by osteopaths is much higher than for chiropractors (with a ratio of : respectively), which is very different to the proportions observed over all injury types. The distribution of treatment choice at the second visit conditional on the claim initiator is shown in Figure.. Of the claims initiated by acupuncturist, a high proportion of claimants (-% across all read codes) visit a GP at the second visit which is far higher than all other manual therapists. The retention rate varies somewhat over the read codes, with the lowest rate as % for sacroiliac injuries and % for elbow injuries. The proportions of second visits to the other manual therapy providers is broadly similar in the joints group, with the only exception of a higher proportion of claims visiting a physiotherapist for ankle injuries (at % compare to -% for other joint injuries) and relatively low proportion for this injury using osteopaths (% compared to -%). The proportion of claims using other manual therapist for coccyx injuries for coccyx injuries are very similar to those in the joints group. Of the other spinal injury types a relatively small proportion visit a chiropractor at the second visit (-%) and relatively high proportion visit an osteopath (ranging from -%). The standout injury type for claim initiated by chiropractors and osteopaths (at the second visit in Figure.) is the ankle injuries, which have the lowest retention rate and correspondingly the highest proportion visiting other treatment providers. A relatively high proportion of chiropractor initiated claims see a radiologist at the second visit, particular compared to those initiated by osteopaths, the only exceptions being ankle and coccyx injuries. The distribution of treatment choices at the second visit for claims initiated by physiotherapists are very similar for sacroiliac, neck, thoracic and lumbar injuries, whereas coccyx injuries have a relatively low retention rate with a comparatively high proportion visiting GP s and radiologists. There are some notable differences within the joints group for physiotherapist initiated claims. A relatively high proportion of shoulder claims see a GP for the second visit, with a similar proportion for wrist injuries. Wrist injuries also have a fairly high proportion of radiologist visits at the second visit, compared to the other injuries in the joints group. The distribution of treatment provider choices for GP initiated claims at the second visit are broadly similar within the spinal group, with only the coccyx injuries as a standout injury statconsultancy.com

25 type (having a relatively high proportion of radiologist visit and far smaller proportion of claims using a physiotherapist). The proportion of claims for joints related injuries using a GP at the second visit are fairly similar at -%, whereas the proportion of claims using aradiologistvarysubstantially(rangingfrom%forshoulderinjuriesto%forankle injuries). A relatively high proportion of GP initiated claims for shoulder and elbow injuries are visiting an acupuncturist at the second visit (at %) with almost none for wrist and ankle injuries. Interestingly, the proportion of GP initiated claims within the joints group who visit a physiotherapist at the second visit vary substantially (at % for wrist injuries to % for shoulder injuries). Figure. considers only the visit to manual therapists at the second visit. For GP initiated claims the proportion of claims visiting an acupuncturist is higher than might be expected (from proportions observed over all claims) at -% over all injury types (except ankle injuries at %). The proportion of claims visiting a physiotherapist is also higher than expected (at -% within the spinal group and -% in the joints group compared to Figure.. of Scarrott, b over all claims). These higher than expected proportions lead to a lower than expected proportion visiting chiropractors and osteopaths, with the spinal group somewhat lower than expect (at -%) and joints group (-%). The radiologist initiated claims within the joint group have a broadly similar distribution of treatment choices at the second visit, with the standout difference being for the shoulder injuries (which have a relatively low proportion visiting GP s and relatively high proportion visiting a radiologist). The treatment choice distribution for the second visit for the spinal group are also broadly similar with some notable differences. Coccyx injuries again standout as unusual compared to the others injuries in the spinal group, having a relatively low proportion visiting any manual therapist or radiologist, and relatively high proportion of GP and Other professions (i.e. % and % respectively). Sacroiliac and thoracic injuries have a relatively high proportion of claims visiting a radiologist (at -% compare to -% for neck and lumbar injuries) and relatively low proportion of GP visits (at - % compared to -%). There is also a relatively high proportion of claims who visit a chiropractor (at % for thoracic injuries and % for sacroiliac injuries). Consider only subsequent visits to manual therapists in Figure.. It is very clear that for radiologist initiated claims the proportion of claims visiting an chiropractor in the spinal group (excluding coccyx injuries) is far higher than might be expected (from proportions observed over all claims) at -% over all injury types (except coccyx injuries at %). The proportion of claims visiting a physiotherapist or acupuncturist is correspondingly lower than expected (at -% and -% respectively). However, the distribution is rather different within the joints group. The proportion of acupuncturists visited is similarly low compared to the spinal group. The proportion of claims who visit a physiotherapist at the second visit is higher than expected (at -%), with lower than expected proportion of chiropractor or osteopathic claims (at lowest for ankle injuries at and % respectively and highest for and % for shoulder injuries respectively). It is difficult to draw conclusions from the claims initiated by professions in the Other category, due to the varied nature of these providers. Similar conclusions can be drawn from the third and fourth (and later) visits to manual therapists only shown in Figures.-.. The key differences in the conclusion drawn arise from claimants who initially sought acupuncturists, osteopaths or chiropractors that in the later visit seek physiotherapy. Further it is clear in Figure. that claimants who initially visited Osteopathic Council NZ Technical Report

26 an osteopath within the joints group are more likely to subsequently visit an acupuncturist than if they had a spinal injury. Further, the converse is true for claimants who initially visited an acupuncturist for a spinal injury, in that they are more likely to subsequently see an osteopath whereas those with a joints injury are far less likely to visit an osteopath. It is clear from Figure. that the retention rates for claims initiated by physiotherapist for joints injuries (-%) are higher that for spinal injuries (at -%).. Where Did The Claimants Come From? Figure. takes a completely different viewpoint to all the other figures presented in this report. All the previous figure consider the distribution of subsequent treatment provider choices conditional on the initiating profession. Whereas this alternative viewpoint conditions on the type of treatment provider used in subsequent visits and considers the distribution of initiating profession (e.g. for all claimants visiting an osteopath on the second visit what is the distribution of professions who initiated these claims). The pie chart on the top row of Figure. is exactly the same as for Figure., only the distributions for the subsequent visits will change from the new viewpoint. Chiropractors have the highest proportion of patients on subsequent visits which were also initiated by chiropractors (i.e. highest retention rate from first visit at % by second visit to % by fourth and later visits). The chiropractors are closely followed by osteopaths having the second highest retentions rates from the first visit (at % by second visit to % by fourth and later visits). GP s were the next largest initiator of claims which subsequently visit an osteopath or chiropractor (at -% and -% respectively). Physiotherapists also initiated many claims that subsequently included visits (notably for visit four an beyond) to chiropractors and osteopaths (at % and % respectively for the fourth and later visits). For claims which subsequently visit a physiotherapist, the retention rate from the first visit is lower than for osteopaths and chiropractors (at % for second, % for third and % for fourth and later visits), but they have a far higher proportion of claims initiated by GP s (at -%). Professions in the Other category also initiated many of the claims that subsequently included visits a physiotherapist (at -%). Interestingly, despite the known propensity for claimants to combine acupuncture with osteopathy (or physiotherapy), the proportion of subsequent visits to osteopaths or physiotherapists where the claims were initiated by an acupuncturist is very (at less than.% for osteopaths and less than.% for physiotherapists). This result suggests that the claimants who seek treatment from both acupuncturists and osteopaths (or physiotherapists) are most likely to see an osteopath first, which is confirmed by the relatively high percentage of claims which included subsequent visits to an acupuncturist (column one) that were initiated by osteopaths (at -% and for physiotherapists at -%). The distribution of initiating professions for claims which include subsequent visits to an acupuncturist (column on Figure.) are notably different to those for the other manual therapists in columns -. Firstly, the majority of these claims were initiated by GP s (ranging from % for fourth and later visits to % for second visit). Acupuncturists have the lowest retention from the first visit, at % for second visit, % for third visit and % for fourth and later visits. Osteopaths and physiotherapists initiated many of such claims (as previously noted) at (-% for osteopaths and -% for chiropractors). Compared to statconsultancy.com