Setting The setting was secondary care. The economic study was carried out in the USA.

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1 A prospective, randomized trial of intrathecal injection vs. epidural infusion in the selection of patients for continuous intrathecal opioid therapy Anderson V C, Burchiel K J, Cooke B Record Status This is a critical abstract of an economic evaluation that meets the criteria for inclusion on NHS EED. Each abstract contains a brief summary of the methods, the results and conclusions followed by a detailed critical assessment on the reliability of the study and the conclusions drawn. Health technology Patients with chronic non-malignant pain, considered suitable for continuous intrathecal opioid therapy, were given morphine either by intrathecal injection (IN) or by epidural infusion (CE). Type of intervention Treatment. Economic study type Cost-effectiveness analysis. Study population The study population consisted of patients who had suffered from non-malignant pain for at least 6 months, who had not responded to medical and/or surgical treatments, and who had experienced sensory loss in an anatomic distribution. The patients would have had a diagnostic scan consistent with the diagnosis and no contraindications to surgery. In order to be admitted to the trial, the patients had to undergo psychological testing and interviewing to ensure their suitability. Setting The setting was secondary care. The economic study was carried out in the USA. Dates to which data relate The effectiveness and resource use evidence related to 1997 to No price year was given. Source of effectiveness data The effectiveness data were derived from a single study. Link between effectiveness and cost data The same patients who provided the effectiveness data also provided the cost data. It was unclear whether the costing had been carried out retrospectively or prospectively. Study sample The study was powered to detect a cost difference rather than an effect difference. Power calculations showed that, with 17 patients in each group, the study would have 80% power to detect a difference at the 5% significance level. This assumed that the estimated difference in costs between the two systems was $3,000 and the standard deviation was $3,000. Page: 1 / 5

2 Initially, there were 86 patients who appeared to meet the inclusion criteria. However, 28 patients were excluded due to the lack of baseline data, for not finally meeting the inclusion criteria, or for other reasons. Of the remaining 58 patients, 18 declined randomisation. This left 40 suitable patients who gave their consent, of which 3 (all randomised) were then refused cover by their insurer and did not continue in the trial. Thus, 18 were randomised to IN and 19 to CE. Of the 37 patients who completed the initial trial period, 10 reported less than 50% pain relief and withdrew from the treatment. Twenty-seven patients continued with the treatment. Study design This was a randomised, controlled trial that was carried out in a single centre. Randomisation was based on a simple (1:1) randomisation table. Neither the patients nor the investigators were blinded to the group assignments. The followup was at 3 and 6 months. The withdrawals included 10 patients who reported less than 50% pain relief during the trial. Analysis of effectiveness The analysis was based only on those patients who reported more than 50% pain relief during the trial. The primary health outcomes were change in pain and function after 6 months. Several side effects were also measured. The primary outcomes were measured using the following instruments: pain medication use (the Medication Quantification Scale), a 100-mm visual analog scale (VAS) of average pain intensity over the past week, a quality of life VAS, the McGill Pain Questionnaire (MPQ), the Profile of Mood States (POMS), and the short-form of the Sickness Impact Profile (s-sip). Comparisons of the patients at baseline showed no significant differences between the two patient groups. Effectiveness results The effectiveness results were reported as the mean value (+/- standard deviation, SD). The VAS pain measure went in 6 months from 80 (+/- 9) to 34 (+/- 21) for the IN group, and from 82 (+/- 11) to 43 (+/- 21) for the CE group. There was no significant difference between the groups. The MPQ went from 33 (+/- 9) to 21 (+/- 19) for the IN group, and from 32 (+/- 14) to 17 (+/- 9) for the CE group. There was no significant difference between the groups. Sixty per cent (6 out of 10) of the IN group and 64% (9 out of 14) of the CE group experienced at least a 50% pain reduction. The quality of life VAS improved from 91 (+/- 11) to 50 (+/- 25) for the IN group, and from 86 (+/- 15) to 48 (+/- 27) for the CE group. There was no significant difference between the groups. The s-sip changed from 16 (+/- 3) to 12 (+/- 6) for the IN group, and from 14 (+/- 5) to 7 (+/- 5) for the CE group. The POMS changed from 90 (+/- 34) to 75 (+/- 29) for the IN group, and from 94 (+/- 22) to 67 (+/- 22) for the CE group. The biggest difference in side effects was in the incidence of vomiting, which was more than twice as common in the IN group than the CE group. Page: 2 / 5

3 There were fewer patients suffering complications at 6 months than at 3 months. Complications, in general, were more common in the IN group. Clinical conclusions The authors concluded that there was no major difference in effectiveness between the two kinds of continuous intrathecal opioid therapy. Any pain difference that did exist would have been likely to be less than 26 VAS units. The major difference detected lay in the incidence of adverse side effects, which the authors considered to be more prevalent in the IN group. Measure of benefits used in the economic analysis No summary measure of benefit was used. Thus, in effect, a cost-consequences analysis was conducted. Direct costs No discounting was carried out since the costs were incurred during less than 2 years. Complete cost data were available for 35 patients (18 IN patients and 17 CE patients). The quantities and the costs were not analysed separately. The health service costs were included. The costs were broken down into the costs of the trial period and the costs of the infusion system. The costs were estimated using actual data, taken from hospital, pharmacy and professional charges. No price year was given. Statistical analysis of costs No statistical analysis of the costs was carried out. Indirect Costs No indirect costs were calculated. Currency US dollars ($). Sensitivity analysis No sensitivity analysis was carried out. Estimated benefits used in the economic analysis See the 'Effectiveness Results' section. Cost results The mean cost was $21,461 (SD=3,172) in the IN group and $24,831 (SD=3,228) in the CE group. The costs were calculated for 6 months. It was unclear whether the costs of adverse effects were included in the cost calculations. Synthesis of costs and benefits Not relevant. Page: 3 / 5

4 Authors' conclusions Intrathecal injection (IN) was a cheaper form of pain relief but it was associated with more adverse side effects. CRD COMMENTARY - Selection of comparators The two treatments, morphine administered by CE or IN, were chosen because they were both considered to be effective treatments for chronic non-malignant pain in the authors' setting. You should decide if either of the comparators represents current practice in your own setting. Validity of estimate of measure of effectiveness The effectiveness data were derived from a single study. The study design was appropriate for the hypothesis, in that it was a randomised controlled trial with several measures of effectiveness. However, the numbers of patients who actually experienced the 6 months' treatment was very small, which meant that differences in effectiveness may not have been detected. The study was only powered to detect cost-differences. This meant that the authors did not establish whether or not there was a difference in effectiveness between the two treatments. The study sample was not necessarily representative of people suffering from chronic pain. For example, patients were excluded for psychological reasons and several patients did not wish to participate. The effectiveness evidence was only concerned with patients who had found the initial trial period satisfactory and who wished to proceed with the long-term treatment. Thus, an important group of patients was excluded and the effectiveness evidence only covered patients who had experienced a successful response to the initial trial period. The authors did not assess the results of side effects and complications systematically in order to compare the two kinds of treatment. Validity of estimate of measure of benefit The authors did not derive a summary measure of health benefit. In effect, a cost-consequences analysis was conducted. Validity of estimate of costs The indirect costs were not included. Although the authors reported the health care resource use as recorded by the patients, they did not cost them, so the only direct costs recorded were those taken from the hospital. The costs were not broken down into prices and quantities, which limits the generalisability of the results. There was no analysis of the prices or quantities and no price year was given. The cost data were calculated for 37 patients for 6 months, whereas the main effectiveness results were calculated for 24 patients. This means that the two sets of data cannot be fairly compared. Other issues The issue of generalisability was only dealt with in the sense that the authors reported that it may not be possible to reproduce exactly their techniques and results in other settings. The authors acknowledged that the patients in the study might not be representative of chronic pain patients, as they were initially evaluated by a neurosurgeon and a psychologist and then experienced a 50% pain reduction in the initial trial period. The authors did not present their results on side effects in a very clear manner, sometimes they were concerned with all the patients who embarked on the trial and sometimes only with patients who stayed with the treatment for 6 months. The authors also did not report the numbers of patients who were not eligible for treatment because of the initial psychological screening. Overall, their results could have been much better presented. The paper sometimes used IN and sometimes IT as an acronym for intrathecal injection, which was confusing for the reader. Implications of the study The authors did not present any implications beyond their conclusion. Page: 4 / 5

5 Powered by TCPDF ( Source of funding Funded by a grant from Medtronic, Inc. Bibliographic details Anderson V C, Burchiel K J, Cooke B. A prospective, randomized trial of intrathecal injection vs. epidural infusion in the selection of patients for continuous intrathecal opioid therapy. Neuromodulation 2003; 6(3): Indexing Status Subject indexing assigned by CRD MeSH Analgesics, Opioid /adverse effects /therapeutic use; Chronic Disease; Cost-Benefit Analysis; Drug Delivery Systems /economics; Injections, Epidural; Injections, Spinal; Morphine /adverse effects /therapeutic use; Pain Measurement; Pain, Intractable /drug therapy AccessionNumber Date bibliographic record published 30/06/2004 Date abstract record published 30/06/2004 Page: 5 / 5