PHYSICAL THERAPISTS are continuously challenged to

Transcription

1 1349 ORIGINAL ARTICLE Associations Between Treatment Processes, Patient Characteristics, and Outcomes in Outpatient Physical Therapy Practice Daniel Deutscher, MSc, PT, Susan D. Horn, PhD, Ruth Dickstein, DSc, PT, Dennis L. Hart, PhD, PT, Randall J. Smout, MS, Moshe Gutvirtz, MHA, BPT, Ilana Ariel, BPT ABSTRACT. Deutscher D, Horn SD, Dickstein R, Hart DL, Smout RJ, Gutvirtz M, Ariel I. Associations between treatment processes, patient characteristics, and outcomes in outpatient physical therapy practice. Arch Phys Med Rehabil 2009;90: Objective: To identify how treatment processes are related to functional outcomes for patients seeking treatment for musculoskeletal impairments while controlling for demographic and health characteristics at intake. Design: Prospective, observational cohort study. Treatment processes were not altered. Data were collected continuously from June 2005 to January Descriptive statistics were applied to compare patient characteristics, interventions, and outcomes between impairment categories. Ordinary leastsquares multiple regressions were used to examine associations between patient characteristics at intake, treatment processes, and functional outcomes. Setting: Fifty-four community-based outpatient physical therapy clinics of Maccabi Healthcare Services, a public health plan in Israel. Participants: A consecutive sample of 22,019 adult patients (mean age 51.2y, standard deviation 15.7, range 18 96, 58% women) seeking treatment due to lumbar spine, knee, cervical spine, or shoulder impairments with functional measurements at intake and discharge. Interventions: Not applicable. Main Outcome Measure: Functional status at discharge. Results: Explanatory power ranged from 30% to 39%. Better outcomes were associated with patient compliance with self-exercise and therapy attendance, application of therapeutic exercise and manual therapy, and completion of 3 or more functional surveys during the episode of care. Worse outcomes were associated with women, electrotherapy for pain management, and therapeutic ultrasound for shoulder impairments. Mixed results were found for group exercise programs. From the Physical Therapy Services, Maccabi Health Care Services HMO, Tel- Aviv (Deutscher, Gutvirtz), and Northern District Physical Therapy Services, Maccabi Health Care Services HMO, Haifa (Ariel); Department of Physical Therapy, Faculty of Social Welfare and Health Sciences, University of Haifa, Mount Carmel, Haifa (Dickstein), Israel; Institute for Clinical Outcomes Research, Salt Lake City, UT (Horn, Smout); and Consulting and Research, Focus On Therapeutic Outcomes Inc, White Stone, VA (Hart). Supported by Maccabi Healthcare Services HMO, Israel; and by the Maccabi Institute for Health Services Research, Israel. A commercial party having a direct financial interest in the results of the research supporting this article has conferred or will confer a financial benefit on the author or one or more of the authors. Hart is an employee of, and investor in, Focus On Therapeutic Outcomes Inc, a database management company, owner of the outcomes collection software used to collect function outcome for the study. Correspondence to Daniel Deutscher, MSc, PT, 27 Hamered St, Tel-Aviv 68125, Israel, Deutsch_d@mac.org.il. Reprints are not available from the author /09/ $36.00/0 doi: /j.apmr Conclusions: The study of associations between treatment processes, patient characteristics, and outcomes helps to describe practice and can be used to suggest ways to improve outcomes in outpatient physical therapy practice. Key Words: Database; Evidence-based practice; Musculoskeletal system; Rehabilitation; Therapy, physical (specialty) by the American Congress of Rehabilitation Medicine PHYSICAL THERAPISTS are continuously challenged to provide evidence of contribution to patients health. Desired outcomes of PT include enhanced physical and functional abilities and restored, maintained, or promoted optimal physical function, wellness, fitness, and optimal quality of life related to movement and health. 1 The World Confederation for PT promotes physical functioning as a primary goal of the profession, 2 emphasizing the importance of activities and participation components as defined in the International Classification of Functioning, Disability and Health. 3 Therefore, physical functioning, defined as a patient s ability to perform activities, 4,5 is an essential construct that should guide clinical reasoning when establishing treatment goals and assessing outcomes. Improvement in PT services and outcomes depends on the therapist s ability to identify treatment processes that are related to best outcomes, controlling for large variability in patient characteristics. To date, although research in PT is increasing, reports on associations between treatment processes, patient characteristics, and outcomes are limited. These associations can be investigated through experimental or observational studies, with the purpose of enhancing the ability to choose the right treatment for the right patient on the basis of the evidence. In observational studies, also called practice-based evidence studies, 6 evidence is based on daily medical practice without establishing a specific experimental environment. 7 Practicebased evidence studies are more available today as a result of computerization of medical services and formation of large clinical databases Within these databases, data on daily APTA BMI CAT EHR FS ICD-9 IRT PT List of Abbreviations American Physical Therapy Association body mass index computerized adaptive testing electronic health record functional status International Classification of Diseases, 9th Revision item response theory physical therapy

2 1350 PRACTICE-BASED EVIDENCE IN PHYSICAL THERAPY, Deutscher practice provided to all patients are captured, enabling the study of relationships between treatments and outcomes. Patient characteristics are accounted for by multivariate statistics, in which many variables can be considered simultaneously and covariates can be identified and controlled to evaluate intervention effects. The practice-based evidence design (initially called clinical practice improvement study design) 11,12 allows nonstandardized treatment protocols to be included, so data reflect real-world clinical environments. Practice-based evidence studies have few selection criteria for participation, thus enhancing generalizability of findings (external validity). 11 For example, patients with comorbidities are commonly excluded from randomized, controlled trials but are included in practicebased evidences, thus extending generalizability of findings to the targeted population. 13 Practice-based evidence studies require comprehensive, complex databases including detailed patient demographic and health descriptions, characterizations of rehabilitation treatments, and recordings of valid outcomes measures. 13 If the data set is large enough and if factors influencing distributions of both interventions and outcomes of interest are measured and controlled, treatment effects can be identified from observational data. 7 A practice-based evidence design is not valid for identification of cause and effect but can identify associations between treatments and outcome variables, which then can be used to develop future before/after studies or randomized, controlled trials. Of the 114,953 episodes of care provided to 101,310 patients who received PT services during 2007 in outpatient clinics of a medical service in Israel (Maccabi Healthcare Services), 93% were initiated as a result of musculoskeletal disorders, which are known to be associated with high treatment costs. 8,9,14-17 The 4 most frequently affected body parts were the lumbar spine (21%), knee (14%), cervical spine (15%), and shoulder (13%), which is similar to the incidence in outpatient clinics in the United States. 15 Therefore, we included in our study patients receiving PT treatments in Maccabi for these 4 impairments groups. The current study, which is based on a practicebased evidence design of a large clinical data set, seeks to identify those treatment processes that were related to functional outcomes, controlling for patient characteristics. METHODS Design We conducted a prospective, observational cohort study. Treatment processes were not altered. Data were collected prospectively from June 2005 to January 2008 from all patients referred to PT who met the inclusion criteria described below. Subjects The study was conducted in the PT service of Maccabi, a public health maintenance organization responsible for providing health care for approximately 1.8 million people in Israel. Patients were Israeli born and new immigrants, including people whose primary language was Hebrew, Russian, Arabic, English, or Spanish. The study population included all adult patients (at least 18 years of age) who were treated with PT. Some had more than 1 episode of care. We analyzed each episode separately; therefore, we refer in the text to episodes of care as patients. This study was approved by the Institutional Review Board for the Protection of Human Subjects of Maccabi Healthcare Services HMO, Israel. Patients were selected for analyses if they had a musculoskeletal disorder related to 1 of the 4 impairment categories described above and had FS measurements at intake (first visit) and discharge (last visit). The study population came from a larger group of patients that had similar characteristics, including patients who either completed the treatment episode without completing a functional survey at discharge (incomplete protocol), or dropped out of treatment during the episode of care. Given the possibility for patient selection bias for patients with complete data, a comparison of patient demographic and health characteristics was made between the 2 groups of patients: those with complete and those with incomplete data for characteristics known to be related to functional outcomes, eg, age, days from onset of symptoms (acuity), and FS at intake. 15,17-19 Clinics and Therapists Outpatient rehabilitation clinics were defined operationally as clinics where patients with neuromusculoskeletal impairments not requiring hospitalization were treated. 16 Patients were managed by 386 physical therapists (aged 36 10y, range 22 63y, 72% women) employed in 54 clinics (2 20 therapists per clinic) located in 50 cities throughout Israel. All therapists held a bachelor s degree in PT, and 10% had also earned a master s degree. The average number of years of clinical experience standard deviation was 10 9 years. Data were collected during routine practice where electronic outcomes were integrated into an EHR system. 8 Patient Characteristics and Treatment Process Data Collection Patient characteristics and treatment process data were collected by the Maccabi EHR system, as described elsewhere. 8 Briefly, the EHR was developed to standardize data collection related to all medical encounters for all Maccabi members, including medical data regarding treatments, patient responses, and clinical assessment. Detailed documentation of medical encounters was accomplished by using standardized data screens with each patient related to a single central medical therapy file that is accessible from any Maccabi facility throughout the country. The system provides online patient characteristics and treatment process data in real time for all clinicians. Data entered into the central data file for each therapy visit include patient personal identification number, age, sex, visit dates and time, treatment duration, clinician and clinic identification, episode identification, type of care (eg, orthopedic, neurologic), type of payer, referring doctor information, diagnosis based on ICD-9 coding, 20 physical therapist s classification, treatments used, and information on falls for elderly patients. Data including reason for discharge, goal achievement, attendance and exercise compliance, and capacity to return to previous activities are entered by therapists at discharge from therapy. Data generated from the EHR system are regularly imported to the Maccabi PT database. A thorough data validation process was conducted each month during 2004 and first half of 2005 when the EHR system was implemented, and it was validated by a random electronic file selection process to compare imported and original data. Whenever inconsistencies or inaccuracies were found, EHR programming or import procedures were modified until data were validated. Data entered by clinicians to the EHR were checked for inaccuracies during monthly educational sessions conducted between each clinician and their clinic manager. Outcomes Data Collection Patient-centered FS outcomes data were collected via CAT 4,5,21-31 based on IRT. 32,33 The use of CATs to collect outcomes data in routine clinical work is a relatively new

3 PRACTICE-BASED EVIDENCE IN PHYSICAL THERAPY, Deutscher 1351 concept, 4,5,23,24,29-31 but small and large-scale 8,15 applications have been described. Primary benefits of CAT are efficient data collection (eg, reduced respondent burden) with little loss of measurement precision 4,5,15,24-29,31,34-37 and ability to integrate data collection with an EHR in an automated manner. The FS outcomes data were integrated with the EHR data into a comprehensive database. 8 Manual verifications were conducted to ensure patient EHR data and outcomes data were merged accurately. We used 4 body part specific CATs 38 to estimate patientspecific FS measures: cervical spine, 15 shoulder, 4 lumbar spine, 29 and knee. 5,39 FS was defined as the patient s perception of his or her ability to perform functional tasks described in the FS items 4,5,15,29 and represents the activity dimension of the International Classification of Functioning, Disability and Health. 3 Briefly, CATs were developed by calibrating items into scales using the Andrich rating scale IRT model. 40 Results from previous studies 4,5,15,29 suggested data fit the IRT model, items represented unidimensional scales with adequate local independence, and thus supported the FS measures were interval scaled. Measures of FS generated by IRT mathematics and applied with CAT methods 38 were transformed to a range from 0 to 100 (low [0] to high [100] functioning) on a linear metric. 4,5,15,29 Although each CAT is transformed to a 0 to 100 FS metric, the 4 body part specific FS scales were not equated, 41 so all regressions were performed separately for the body part specific scales. Each CAT was developed to assess FS for patients with a specific type of impairment. Therefore, the item bank for each CAT is different (different items and item calibrations). However, all CATs use a specific starting item, the same item selection routine, estimate FS with the same technique with similar 0 to 100 linear metrics, and apply the same stopping rules. Specifics of each CAT have been published. 4,5,15,29 Studies describing sensitivity to change, 39,42,43 responsiveness, 39,42,43 and clinical interpretation 44 of FS measures estimated using the CATs are starting to be published, all of which support the notion that CAT FS measures have sound psychometric properties and can be interpreted in clinically meaningful ways. We used Patient Inquiry version 5.0 software 45,a to collect functional outcomes data. The software was customized by translating the original English surveys into Hebrew, Russian, and Arabic. Spanish surveys were available from the original Patient Inquiry software. Because outcomes data were collected using CATs, each clinic had at least 1 computer survey stand, including a touch screen connected to the Maccabi network for survey administration and data capture. Electronic Database Preparation We integrated 2 data sets (the functional outcomes database and existing EHR database) to form a PT database. 8 The PT database was integrated with a third database stored on the Maccabi central computer that contains information on comorbidities based on ICD-9 codes, 20 or by attribution to disease-specific registries, chronic use of medication (based on prescribed pharmaceutical purchasing database), and appointment scheduling. Data Analysis Descriptive statistics were used to examine frequencies of categorical patient and treatment variables, and average and amount of variation with standard deviation for continuous measures. We compared patients with complete or incomplete outcomes collection protocol, as well as patient characteristics, therapy interventions, and outcomes between patients with lumbar spine, cervical spine, shoulder, and knee impairments. Chi-square tests were used for analysis of categorical data, and t tests or analyses of variance were used for continuous data. The was set at.05. We used ordinary least-squares multiple regression to examine associations between variables describing demographic and health characteristics at intake and treatment process variables with each patient s functional outcome at discharge. Use of CAT estimated measures of functional outcomes are not common in regression models of health data, but we thought that the interval nature of the FS measures based on a rating scale IRT model was appropriate for regression techniques that assume linearity of continuous data. 49 Only variables with frequencies of 2% or more of the sample were allowed to enter regression models. Stepwise R 2 selection procedure for ordinary least-squares regressions allowed independent variables to enter and leave each model. We created the most parsimonious model for each outcome by allowing only significant variables to remain in the model. 50 Variables were entered if the significance level of its T value was less than.05 (entry value) and removed if significance was greater than 0.1 (removal value). The importance of each predictor was determined by its T value. Variables entering regression models were checked for multicollinearity; no correlations were greater than 0.6. All analyses were performed with SPSS statistical software, version 15. b Data on age, intake FS, number of comorbidities, number of disease specific registries, number of visits per treatment episode, duration in days of treatment episode, and number of procedural interventions throughout the episode of care were allowed to enter the regression models as continuous measures. For categorical data, we created a dummy variable for each category to be used as independent variables in the regression models. Each category was represented as a binary predictor coded 1 if present and 0 if absent. All categories that were allowed to enter as dummy variables into the regression models are described in tables 1 through 4. For example, we used dummy variables to represent the attribution of each specific comorbidity, each disease specific registry, and each specific chronic medication use. RESULTS Subjects Intake surveys were administered for 57,008 patients. There were 17,485 patients (31%) who completed treatment but who did not complete a functional survey at discharge (incomplete protocol), and 17,504 patients (31%) who dropped out of treatment during the episode of care. That left 22,019 patients with intake and discharge measures, a 39% completion rate. 8 Descriptive data of these patients are provided in tables 1 through 5. The definitions of variables and categories described in tables are in appendix 1. Comparison of patient s age, acuity, and FS at intake between patients with complete versus incomplete outcomes collection protocols suggested no difference in age ( y and y, respectively, P.97), slight differences in sex frequency (58.0% and 59.5%, respectively, P.02), and a statistically significant but clinically identical difference in FS at intake ( and , respectively, P.02). However, the percentage of patients with a chronic condition at intake (conditions existing for 90 days as perceived by the patient) was higher in the incomplete protocol group than in the complete protocol group (51% and 47%, respectively, P), as was the average number of comorbidities ( and , respectively, P).

4 1352 PRACTICE-BASED EVIDENCE IN PHYSICAL THERAPY, Deutscher Table 1: Patient Characteristics Variables* Total (N 22,019) Lumbar Spine (n 7216) Knee (n 4394) Cervical Spine (n 5157) Shoulder (n 5252) P Patient Demographic Characteristics Age Age groups (%) Over Sex (%).003 Male Female Payer (%) Maccabi MVA Work Others Daily activity (%) Office Physical Combined Language (%) Hebrew Russian English Arabic Spanish Health and Functional Status Data at Intake Intake FS Acuity (%) Acute Sub acute Chronic Medication use at intake (%) Yes No No. of related surgeries (%) None or more Physical activity (%) None /wk or more NOTE. Values are mean SD unless otherwise noted. *Refer to Appendix 1 for variable operational definitions. Age is described both as continuous data and in categories but is allowed to enter the regression models only as continuous data. Patient Demographic and Health Data Patient demographic and general health characteristics at intake are described in table 1. Patients with lumbar and cervical spine impairments were younger than patients treated for knee and shoulder impairments. Nearly half of all patients were referred to treatment for chronic conditions existing at least 3 months, and 51% were not involved in any weekly physical activity before onset of the condition being treated. Most patients answered the surveys in Hebrew, and 27% of patients answered in Russian. For 19% of patients, the payer was motor vehicle insurance due to a motor vehicle accident. The rate of motor vehicle accident payer among cervical spine impairments was more than double that for the full sample. Patient comorbid conditions or attribution to disease registries are described in table 2. The highest number of comorbidities was usually found in patients with shoulder impairments, followed by knee impairments. Patients with cervical spine impairments had the largest frequency of tobacco use or women registered in the fertility registry, and patients with knee impairments had the highest rate of overweight or obesity. No significant differences between impairment groups were found for frequencies of hypothyroidism, asthma or other lung diseases, and depressive disorders.

5 PRACTICE-BASED EVIDENCE IN PHYSICAL THERAPY, Deutscher 1353 Table 2: Patient Comorbidities or Attribution to Disease Registries Comorbidity/Medical Registry Total (N 22,019) Lumbar Spine (n 7216) Knee (n 4394) Cervical Spine (n 5157) Shoulder (n 5252) P Comorbidities* Comorbidities groups (%) None or more Registry count* Registry count groups (%) None or more Asthma or other lung disease (%) Cardiovascular registry (%) CVA/TIA (%) NA NA NA NA 2.0 Depressive disorder (%) Diabetes registry (%) Fertility registry (%) Heart disease (%) Hyper cholesterol (%) Hyper tension registry (%) Hypothyroidism (%) Oncology registry (%) Osteoporosis (%) Overweight or obesity (%) Tobacco use disorder (%) NOTE. Values are mean SD unless otherwise noted. Abbreviations: CVA, cerebral vascular accident; NA, not applicable; TIA, transient ischemic attack. *Comorbidities and registry count are described both as continuous data and in categories but are allowed to enter the regression models only as continuous data. Frequencies 2%. Data on chronic use of medication are described in table 3. Patients treated for shoulder impairments usually used more medications than patients in the other groups. Yet patients with spinal impairments (mainly cervical spine) used more antipsychotic and antimigraine medication than patients with shoulder and knee problems. No substantial differences among impairment groups were found for frequencies of chronic use of sedatives, antidepressants, asthma medications, corticosteroid drugs, and hormone replacement therapy. Table 3: Chronic Use of Medication Condition Treated/Medication Group Total (N 22,019) Lumbar Spine (n 7216) Knee (n 4394) Cervical Spine (n 5157) Shoulder (n 5252) P Anticonvulsant Antidepressant Antineoplastic NA* NA* NA* NA* 2.0 Antipsychotic NA* 2.4 NA*.195 Antithrombotic Asthma Cardiovascular Corticosteroids Diabetes Hormone replacement therapy Hyperlipidemic Hypothyroidism Migraine Osteoporosis Prostate Sedatives NOTE. Values are percentage of N. Abbreviation: NA, not applicable. *Frequencies 2%.

6 1354 PRACTICE-BASED EVIDENCE IN PHYSICAL THERAPY, Deutscher Table 4: Treatment-Related Variables Variables* Total (N 22,019) Lumbar Spine (n 7216) Knee (n 4394) Cervical Spine (n 5157) Shoulder (n 5252) P No. of visits Duration (d) Referring doctor specialty (%) General practitioner Orthopedic Other Waiting days from referral Waiting days from referral categories (%) 0 to to to Over Mean appointment time (min) Mean appointment time categories (%) 0 to to to or more Attendance compliance (%) Good Moderate Not good Irrelevant Home exercise compliance (%) Good Moderate Not good Irrelevant No. of surveys during episode of care (%) or more NOTE. Values are mean SD unless otherwise noted. *Refer to Appendix 1 for variable operational definitions. Continuous variables of waiting days from referral to start of therapy and mean appointment time were allowed to enter regression models as categorical variables for ease of clinical interpretation, but they are also described as continuous data. Irrelevant attendance compliance refers to cases with a very small number of visits. Irrelevant home exercise compliance refers to cases where no self-exercises were prescribed. Treatment Process Variables related to treatment process are described in table 4. Number of visits per treatment episode, attendance compliance, and home exercise compliance were higher in patients with knee and shoulder compared with patients with lumber and cervical spine impairments. In all categories, most referrals were from orthopedic surgeons, with the highest rate for patients with knee impairments. The longest appointment length of time was scheduled for patients with spinal impairments. The lowest rate of patients completing at least 1 survey during the treatment episode in addition to the surveys completed at intake and discharge was in the knee impairment group. There were no differences between impairment groups in waiting days from referral to first visit. PT procedural interventions, intervention groups as defined in the guide to PT practice, 1 and FS outcome measures are described in table 5. The data in the table represent the average number of times each intervention was used during the overall episode of care. Exercises performed in the clinic were recorded more than twice as much for knee and shoulder than for lumbar and cervical spine impairments. Self-exercise education also was recorded more frequently in patients with knee and shoulder impairments than in spinal impairments, as was the case for the aggregated therapeutic exercise code. Group exercise was most frequent in patients with cervical spine impairments, and joint mobilization was least frequent for patients with knee impairments. Shortwave therapy was applied most frequently for knee impairments, and therapeutic ultrasound was applied most frequently for shoulder impairments. Associations Between Patient Characteristics, Process of Care, and Outcomes Multiple regression analyses for the 4 impairment categories are presented in table 6. The table has 2 sections. The first section (6A) includes significant associations between patient demographic and health characteristics at intake and FS at discharge (outcome). The second section (6B) includes significant associations between treatment process variables and functional outcome at discharge, controlling for patient characteristics. The explanatory power of the 4 regression models

7 PRACTICE-BASED EVIDENCE IN PHYSICAL THERAPY, Deutscher 1355 Table 5: Physical Therapy Procedural Interventions and Outcome Measure Variables* Total (N 22,019) Lumbar Spine (n 7216) Knee (n 4394) Cervical Spine (n 5157) Shoulder (n 5252) P Physical Therapy Procedural Interventions As Recorded in the EHR Actsit_mob NA NA Assit_ex NA NA NA NA Assupron_ex NA NA NA NA Bike_ex NA NA NA NA Back_sch NA NA NA Clinic_ex Cold_pack NA NA NA NA Consult DFM Electro_pain Ergonomic NA Function_ex NA NA NA NA Gait_ex NA NA NA NA Group_ex Hot_pack Joint_mob MET NA NA Neural_mob NA Passup_mob Proprio_ex NA NA NA NA Reassess Self_ex Shortwave Softis_mob Stabil_ex NA Stretch_ex Strength_ex NA NA Supron_ex Thermas NA NA NA NA Ultrasound Physical Therapy Procedural Interventions as Defined in the Guide to PT Practice 1 Electro APTA Man_ther APTA Pamm APTA Therap_ex APTA Outcome Measure FS at discharge FS change NOTE. Values are mean SD of average number of times each code was used during the episode of care. Abbreviation: NA, not applicable. *Refer to Appendix 1 for variable operational definitions. Frequencies 2%. (1 model per patient group), described by R 2 values, ranged from 30% to 39%. The R 2 value did not change when allowing 4 aggregated procedural intervention variables (Electro APTA, Man_ther APTA, Pamm APTA, Therap_ex APTA ) 1 to enter models, compared with allowing specific process variables. Therefore, we selected specific process variables for the 4 regression models because they are more informative than aggregated intervention variables from a clinical perspective. B coefficients indicated the amount of expected change in discharge FS given a 1-unit change in the value of the respective predictor variable, given that all other variables in the model are held constant. T values indicated the importance of each independent variable on predicting discharge FS (dependent variable). For all models, patient variables explained most of the variation in outcomes (ie, in discharge functional score), with intake FS score being positively associated with outcomes and the strongest predictor. For clarity, we note that variables associated with poorer or better outcomes refer to poorer or better than their reference group for example, acute compared with not acute, or women compared with not women. Older age, chronic conditions, and greater use of antidepressant medications were associated with poorer outcomes, whereas acute conditions and regular Maccabi payer (ie, regular health insurance as opposed to workers compensation or car insurance coverage) were associated with better outcomes. In all models except for the lumbar spine impairment group, women were associated with poorer outcomes, and in all models except for patients with shoulder impairments, no physical activity before onset of the condition was associated with poorer outcomes. Across all models, good home exercise compliance (reference is moderate or poor compliance) was the strongest process

8 1356 PRACTICE-BASED EVIDENCE IN PHYSICAL THERAPY, Deutscher Table 6A: Multiple Regression Analyses by Impairment Categories: Patient Characteristics Dependent Variable Lumbar Spine Cervical Spine Impairment Knee Impairment Impairment Shoulder Impairment Discharge FS (n 7216; R ) (n 4394; R ) (n 5157; R ) (n 5252; R ) Predictors B* T P B* T P B* T P B* T P Constant Demographic Age Daily activity office Female Language Hebrew Language Russian Payer Maccabi Payer Work Health Acuity acute Acuity chronic Intake functional status Medication use at intake No. of related surgeries 1 or more Physical activity 1 2/week Physical activity none Comorbidities No. of comorbidities No. of medical condition registries Cardiovascular registry Tobacco use disorder Chronic medication use Antidepressant Asthma Migraine Osteoporosis *B indicates the coefficient that represents the amount of expected change in discharge FS given a 1-unit change in the value of the variable, given that all other variables in the model are held constant. T indicates values representing the importance of each independent variable on predicting discharge FS (dependent variable). variable associated with better outcomes and was 1 of 3 second most predictive variables overall, along with symptom acuity and age. In addition, poor home exercise compliance was associated with poorer outcomes, and good visit attendance compliance was associated with better outcomes. In all models except for knee impairments, completion of at least 1 functional survey during the episode of care in addition to intake and discharge surveys (labeled 3 surveys or more with reference being 2 surveys only at intake and discharge) was associated with better outcomes. In models for spinal impairments (lumbar and cervical spine), a high number of visits per episode of care was associated with poorer outcomes. Patients with lumbar or cervical spine impairments who were referred by general practitioners were associated with better outcomes compared with referral by an orthopedic surgeon. For lumbar spine and knee impairments, longer waiting days from referral to admission were associated with poorer outcomes. Greater use of electrotherapeutic modalities for pain management was associated with poorer outcomes in all models except for a cervical spine impairments model. In models for patients with knee and cervical spine impairments, manual joint mobilization was associated with better outcomes. Additionally, in all models, higher frequencies of personal active exercise interventions were associated with better outcomes. The only active intervention that had mixed associations with outcomes was group exercise, with negative associations for knee and shoulder impairments and positive associations for cervical spine impairments. DISCUSSION Our purpose was to identify associations between FS outcomes during PT, patient characteristics, and treatment processes for patients with lumbar spine, knee, cervical spine, or shoulder musculoskeletal impairments. Many associations were identified. For brevity, we discuss only some of these associations, which characterize our findings and emphasize benefits of practice-based evidence studies to outpatient therapy clinical practice. Patient Demographic and General Health Demographic variables and health characteristics are considered outcome confounders. 7,11,51-55 Intake FS, age, acuity level, payer, the existence of various comorbidities, chronic use of antidepressant medication, and exercise history were associated with functional outcomes across all 4 regression models. The 4 strongest predictors of outcomes were intake FS, age, acuity levels, and payer. These have been reported by others, 15,39,42,54 a finding that emphasizes the importance of controlling for these factors when studying associations between treatment processes and outcomes in PT.

9 PRACTICE-BASED EVIDENCE IN PHYSICAL THERAPY, Deutscher 1357 Table 6B: Multiple Regression Analyses by Impairment Categories: Treatment Process Dependent Variable Lumbar Spine Cervical Spine Impairment Knee Impairment Impairment Shoulder Impairment Discharge FS (N 7216; R ) (N 4394; R ) (N 5157; R ) (N 5252; R ) Predictors B* T P B* T P B* T P B* T P Constant Process related Attendance compliance good Referring doctor s specialty general practitioner Referring doctor s specialty orthopedic Duration Home exercise compliance good Home exercise compliance not good Mean appointment time 30min or more No. of surveys 3 or more No. of visits Waiting days from referral Waiting days from referral Waiting days from referral 14.1 to Interventions Assupron_ex NA NA NA Cold_pack NA NA NA Consult Electro_pain Group_ex Joint_mob Neural_mob NA Passupro_mob Proprio_ex NA NA NA Reassess Shortwave Stabil_ex NA Stretch_ex Ultrasound *B indicates the coefficient that represents the amount of expected change in discharge FS given a 1-unit change in the value of the variable, given that all other variables in the model are held constant. T indicates values representing the importance of each independent variable on predicting discharge FS (dependent variable). NA (frequencies 2%). The presence of comorbid conditions was associated with poorer outcomes across all 4 regression models (see table 6). This supports use of comorbidity indices known to be predictive of functional outcomes. 39,42,43,56 However, although the highest rate of comorbidities usually found in patients with shoulder impairments, this group had the weakest associations between comorbidities and outcomes. This result has been reported previously, 57 suggesting that comorbidities may not have important negative effects on shoulder functional outcomes. Additionally, overweight, with highest frequency in patients with knee impairments, was not associated with functional outcomes in any model. Evidence exists supporting a BMI effect on incidence of knee osteoarthritis, particularly in women, although several studies failed to detect an effect of BMI on knee osteoarthritis progression. 58 Future analyses should perhaps identify smaller and more homogeneous subsets of patients with knee impairments that might show associations that are masked when all knee impairments are analyzed together. For example, if women with knee impairments were analyzed separately from men, or patients with knee osteoarthritis were analyzed separately from patients with knee internal derangements, associations between BMI and functional outcomes might emerge. Furthermore, we noted that rates of overweight and obesity in our study were much lower than rates reported in a recent survey in Israel. 59 This suggests possible underreporting of BMI measures in Maccabi records, which might have influenced our results. Chronic use of medication had a stronger association with poorer outcomes than comorbidities. This stronger association could result from the fact that the medication data being extracted from a database of purchased prescriptions are not affected by the comprehensiveness of doctors registration in the EHR. For example, for the total sample, only 2% of patients were labeled as experiencing a depressive disorder, but 13% purchased antidepression medication, which was the most predictive chronic medication use of poorer outcomes in all groups. This finding is supported by previous publications 60,61 and emphasizes the need to control for use of medications as well as to identify patients with depression when studying associations between treatments and outcomes in PT. From a clinical perspective, it is important to find ways to improve outcomes of patients with depression when seeking PT treatment. Previous studies have suggested integrating cognitive behavioral treatments to improve func-

10 1358 PRACTICE-BASED EVIDENCE IN PHYSICAL THERAPY, Deutscher tional and mental status, including depression in patients with low back pain. 62 Additional studies are required to study the contribution of these approaches. Lack of physical activity (defined as at least once a week for a duration of 20min or more) before the onset of the condition being treated was associated with poorer outcomes in lumbar spine, knee, and cervical spine impairments. Moderate physical activity (once to twice a week) was associated with better outcomes in shoulder impairments. Exercise history has been previously reported to be associated with functional outcomes, 39,42,43,54,63 which suggests that health promotion measures targeted to improve participation in routine physical activity could benefit patients attending PT. Sex was associated with outcomes in 3 of the 4 regression models. Women were associated with poorer outcomes for patients with knee, cervical spine and shoulder impairments. English-speaking men and women in the United States responded to FS items in similar ways, 5,29,64 suggesting that sex plays a role in how a person responds to PT. Previous evidence indicates that women are more likely to respond positively to multidisciplinary 65 and cognitive-behavioral treatments for chronic pain. 66,67 A recent study on sex differences for workdisabled people with chronic musculoskeletal pain found sex differences in the influence of sociodemographic and psychosocial factors on rehabilitation outcomes of functional health status. 68 Future studies are needed to identify ways to adapt treatment procedures to sex. Subset analyses by sex could help discover whether different treatment plans should be designed for women and men. Process-Related and Intervention Variables Compliance with self-exercise programs was one of the strongest predictors overall and the strongest predictor among process variables (see table 6B). Better outcomes were achieved when patients were more compliant with their exercise program. This result has important implications for clinicians. Ability to improve patient compliance is probably more of an educational skill than a clinical skill. One could perceive this as a marketing skill. Physical therapists need to know how to educate and persuade patients that what they are selling actually works. These persuasive skills are especially important because self-exercise programs are time-consuming and demand self-discipline and persistence. It is only when the patient is convinced that it is worth the time and effort that good compliance with exercise programs can be achieved. Another patient compliance issue is compliance with attending therapy. Again, better compliance was associated with better outcomes. These results suggest clinicians should strengthen their educating skills. Although similar recommendations were published recently, 69 the best ways to achieve this goal are yet to be determined. Interestingly, patients with spinal impairments had a lower rate of good home exercise compliance than patients with peripheral impairments. The same trend was observed for good attendance compliance. These differences may result from therapists clinical skills, which seem to be more persuasive when educating their patients to do exercises targeted to peripheral joint structures. Also, exercises for peripheral joints may be easier to understand and perform, and therefore they are related to higher compliance than exercises addressing spinal structures. Support for this claim is seen in the frequencies of therapeutic exercise use by impairment categories (see table 5, Therap_ex APTA ); therapeutic exercises were used more frequently per treatment episodes for peripheral compared with spinal impairments. We conjecture that physical therapists consider exercises for peripheral joints to be more effective and easier to perform than exercises for spinal joints, and therefore they are prescribed more often. Physical therapists may need more education regarding evidence-based knowledge on effectiveness of exercises for spinal impairments. An enhanced postgraduate educational program on methods that are supported scientifically can help therapists to better adjust exercises to their patients, be more persuasive, and improve patient compliance. Our data strongly suggest that if this happens, outcomes could be improved. For patients to comply with exercise programs, they first must be prescribed by their therapists. Active exercise variables that entered the regression models were associated with better outcomes. An exception was group exercise, which was associated with poorer outcomes for knee and shoulder impairments. For lumbar spine impairments, group exercise was not associated with outcomes, a result reported previously. 70 Only patients with cervical spine impairments, who had the highest frequency for use of group exercises, seemed to benefit from them. This result calls for further investigation of the specific contents of group exercise programs and their appropriateness for different musculoskeletal conditions. Joint mobilization was positively related to outcomes in cervical spine impairments and had borderline significance for knee impairments. Thus, in spite of little support in the literature for passive interventions, 71,72 the use of manual therapy (a passive intervention) is important. Further analyses are needed to identify more specific groups of patients that do or do not benefit from manual therapy techniques, as reported previously for spinal manipulation techniques However, electrotherapy, including shortwave therapy and therapeutic ultrasound, were always associated with poorer outcomes. Similar results have been reported in the past. 71,76-80 Nonetheless, there is some evidence to support that with knee osteoarthritis, transcutaneous electrical nerve stimulation was more effective than placebo 81 and that combined exercise therapy with physical agents increases the effectiveness of exercise. 82 This suggests the need for further investigation to detect groups of patients that might benefit from these interventions, and for reevaluation of electrotherapeutic modalities and therapeutic ultrasound, which in many cases may have little benefit in promoting functional outcomes. Interestingly, in all but knee impairments (where 3 or more surveys were least frequent), patients who took only the intake and discharge surveys had poorer outcomes than those who took 3 or more surveys. Three or more surveys indicate that a functional survey was completed at least once during the episode of care. This could have encouraged therapists to adjust treatment strategies when realizing that patients were not improving as expected. This suggests that therapists ought to initiate a wider use of functional measures during therapy in order for the process of care to be continuously based on outcomes. For treated patients with spinal impairments, poorer outcomes were associated with more visits per treatment episode. This finding needs careful interpretation. Because of the public nature of the Maccabi system, therapists reimbursement is not dependent on number of visits. Therefore, the main reason to prolong therapy is when a patient does not get better. Our data suggest that when outcomes improve during treatment of spinal impairments, the episode of care is usually shorter. When outcomes do not improve, the tendency of therapists might be to add visits, hoping that this will help improve outcomes, but simply doing more might not be beneficial. Further testing is needed to study whether