Weighted index explained more variance in physical function than an additively scored functional comorbidity scale

Using the Functional Comorbidity Index with administrative workers' compensation data: Utility, validity, and caveats

BACKGROUND

Chronic health conditions impact worker outcomes but are challenging to measure using administrative workers' compensation (WC) data. The Functional Comorbidity Index (FCI) was developed to predict functional outcomes in community-based adult populations, but has not been validated for WC settings. We assessed a WC-based FCI (additive index of 18 conditions) for identifying chronic conditions and predicting work outcomes.

METHODS

WC data were linked to a prospective survey in Ohio (N = 512) and Washington (N = 2,839). Workers were interviewed 6 weeks and 6 months after work-related injury. Observed prevalence and concordance were calculated; survey data provided the reference standard for WC data. Predictive validity and utility for control of confounding were assessed using 6-month work-related outcomes.

RESULTS

The WC-based FCI had high specificity but low sensitivity and was weakly associated with work-related outcomes. The survey-based FCI suggested more comorbidity in the Ohio sample (Ohio mean = 1.38; Washington mean = 1.14), whereas the WC-based FCI suggested more comorbidity in the Washington sample (Ohio mean = 0.10; Washington mean = 0.33). In the confounding assessment, adding the survey-based FCI to the base model moved the state effect estimates slightly toward null (<1% change). However, substituting the WC-based FCI moved the estimate away from null (8.95% change).

CONCLUSIONS

The WC-based FCI may be useful for identifying specific subsets of workers with chronic conditions, but less useful for chronic condition prevalence. Using the WC-based FCI cross-state appeared to introduce substantial confounding. We strongly advise caution-including state-specific analyses with a reliable reference standard-before using a WC-based FCI in studies involving multiple states.

The one-year clinical course of back-related disability and the prognostic value of comorbidity among older adults with back pain in primary care

ABSTRACT

Back pain and comorbidity are common in older adults. Comorbidity is a promising prognostic factor for the clinical course of back-related disability, but confirmatory studies assessing its prognostic value are needed. Thus, the aims of this study were to describe the clinical course of back-related disability during 1-year follow-up in patients aged ≥55 years visiting primary care (general practitioner, physiotherapist, or chiropractor) with a new episode of back pain and assess the prognostic value of comorbidity on back-related disability during 1-year follow-up. A prospective cohort study was conducted, including 452 patients. The outcome measure was Roland-Morris Disability Questionnaire (RMDQ, range 0-24) measured at baseline and at 3-, 6-, and 12-month follow-up. The Self-Administered Comorbidity Questionnaire was used to assess comorbidity count (CC, range 0-15) and comorbidity burden (CB, range 0-45). The RMDQ scores improved from median (interquartile range) 9 (4-13) at baseline to 4 (1-9), 4 (0-9), and 3 (0-9) at 3, 6, and 12 months, respectively. Using linear mixed-effects models, we found that CC and CB were independently associated with RMDQ scores. A 1-point increase in CC was associated with an increase in RMDQ score of 0.76 points (95% confidence interval [0.48-1.04]) over the follow-up year, adjusted for known prognostic factors. A 1-point increase in CB was associated with an increased RMDQ score of 0.47 points (95% confidence interval [0.33-0.61]). In conclusion, the clinical course of back-related disability for older adults presenting in primary care was favorable, and increased comorbidity was an independent prognostic factor for increased disability levels.

The Lumbar Stenosis Prognostic Subgroups for Personalizing Care and Treatment (PROSPECTS) study: protocol for an inception cohort study

Background

Lumbar spinal stenosis (LSS) is a common degenerative condition that contributes to back and back-related leg pain in older adults. Most patients with symptomatic LSS initially receive non-operative care before surgical consultation. However, there is a scarcity of data regarding prognosis for patients seeking non-surgical care. The overall goal of this project is to develop and evaluate a clinically useful model to predict long-term physical function of patients initiating non-surgical care for symptomatic LSS.

Methods

This is a protocol for an inception cohort study of adults 50 years and older who are initiating non-surgical care for symptomatic LSS in a secondary care setting. We plan to recruit up to 625 patients at two study sites. We exclude patients with prior lumbar spine surgeries or those who are planning on lumbar spine surgery. We also exclude patients with serious medical conditions that have back pain as a symptom or limit walking. We are using weekly, automated data pulls from the electronic health records to identify potential participants. We then contact patients by email and telephone within 21 days of a new visit to determine eligibility, obtain consent, and enroll participants. We collect data using telephone interviews, web-based surveys, and queries of electronic health records. Participants are followed for 12 months, with surveys completed at baseline, 3, 6, and 12 months. The primary outcome measure is the 8-item PROMIS Physical Function (PF) Short Form. We will identify distinct phenotypes using PROMIS PF scores at baseline and 3, 6, and 12 months using group-based trajectory modeling. We will develop and evaluate the performance of a multivariable prognostic model to predict 12-month physical function using the least absolute shrinkage and selection operator and will compare performance to other machine learning methods. Internal validation will be conducted using k-folds cross-validation.

Discussion

This study will be one of the largest cohorts of individuals with symptomatic LSS initiating new episodes of non-surgical care. The successful completion of this project will produce a cross-validated prognostic model for LSS that can be used to tailor treatment approaches for patient care and clinical trials.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-022-05598-x.

The Update on Instruments Used for Evaluation of Comorbidities in Total Hip Arthroplasty

INTRODUCTION

It is a well-established fact that concomitant diseases can affect the outcome of total hip arthroplasty (THA). Therefore, careful preoperative assessment of a patient's comorbidity burden is a necessity, and it should be a part of routine screening as THA is associated with a significant number of complications. To measure the multimorbidity, dedicated clinical tools are used.

METHODS

The article is a systematic review of instruments used to evaluate comorbidities in THA studies. To create a list of available instruments for assessing patient's comorbidities, the search of medical databases (PubMed, Web of Science, Embase) for indices with proven impact on revision risk, adverse events, mortality, or patient's physical functioning was performed by two independent researchers.

RESULTS

The initial search led to identifying 564 articles from which 26 were included in this review. The measurement tools used were: The Charlson Comorbidity Index (18/26), Society of Anesthesiology classification (10/26), Elixhauser Comorbidity Method (6/26), and modified Frailty Index (5/26). The following outcomes were measured: quality of life and physical function (8/26), complications (10/26), mortality (8/26), length of stay (6/26), readmission (5/26), reoperation (2/26), satisfaction (2/26), blood transfusion (2/26), surgery delay or cancelation (1/26), cost of care (1/26), risk of falls (1/26), and use of painkillers (1/26). Further research resulted in a comprehensive list of eleven indices suitable for use in THA outcomes studies.

CONCLUSION

The comorbidity assessment tools used in THA studies present a high heterogeneity level, and there is no particular system that has been uniformly adopted. This review can serve as a help and an essential guide for researchers in the field.

The Relationship of the Therapeutic Alliance to Patient Characteristics and Functional Outcome During an Episode of Physical Therapy Care for Patients With Low Back Pain: An Observational Study

OBJECTIVE

Research supports the relevance of the therapeutic alliance (TA) between patients and physical therapists on outcomes, but the impact of TA during routine physical therapist practice has not been quantified. The primary objective of this study was to examine the relationship between TA assessed during a physical therapy episode of care for patients with low back pain and functional outcome at the conclusion of care. The secondary objective was to examine psychometric properties of the Working Alliance Inventory-Short Revised (WAI-SR) form, a patient-reported TA measure.

METHODS

This study was a retrospective analysis of prospectively collected data from 676 patients (mean [SD] age = 55.6 [16.1] y; 55.9% female) receiving physical therapy for low back pain in 45 outpatient clinics from 1 health system in the United States. Participating clinics routinely collect patient-reported data at initial, interim, and final visits. The lumbar computer-adapted test (LCAT) was used to evaluate functional outcome. The TA was assessed from the patient's perspective at interim assessments using the WAI-SR, bivariate correlations were examined, and regression models were examined if interim WAI-SR scores explained outcome variance beyond a previously validated multivariate prediction model. Internal consistency and ceiling effects for the WAI-SR were examined.

RESULTS

Interim WAI-SR scores were not correlated with patient characteristics or initial LCAT, but they were correlated with final LCAT and LCAT change from initial to final assessment. WAI-SR total score (adjusted R2 = 0.36), and Task (adjusted R2 = 0.38) and Goal subscales (adjusted R2 = 0.35) explained additional variance in outcome beyond the base model (adjusted R2 = 0.33). Internal consistency was higher for WAI-SR total score (α = .88) than for subscales (α = .76-.82). Substantial ceiling effects were observed for all WAI-SR scores (27.2%-63.6%).

CONCLUSION

Findings support the importance of TA in physical therapist practice. Measurement challenges were identified, most notably ceiling effects.

IMPACT

This study supports the impact of the patient-physical therapist alliance on functional outcome. Results extend similar findings from controlled studies into a typical physical therapist practice setting. Better understanding of the role of contextual factors including the therapeutic alliance might be key to improving the magnitude of treatment effect for discrete physical therapist interventions and enhancing clinical outcomes of physical therapy episodes of care.

Development and Testing of Compatible Diagnosis Code Lists for the Functional Comorbidity Index: International Classification of Diseases, Ninth Revision, Clinical Modification and International Classification of Diseases, 10th Revision, Clinical Modification

BACKGROUND

The Functional Comorbidity Index (FCI) was developed for community-based adult populations, with function as the outcome. The original FCI was a survey tool, but several International Classification of Diseases (ICD) code lists-for calculating the FCI using administrative data-have been published. However, compatible International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) and ICD-10-CM versions have not been available.

OBJECTIVE

We developed ICD-9-CM and ICD-10-CM diagnosis code lists to optimize FCI concordance across ICD lexicons.

RESEARCH DESIGN

We assessed concordance and frequency distributions across ICD lexicons for the FCI and individual comorbidities. We used length of stay and discharge disposition to assess continuity of FCI criterion validity across lexicons.

SUBJECTS

State Inpatient Databases from Arizona, Colorado, Michigan, New Jersey, New York, Utah, and Washington State (calendar year 2015) were obtained from the Healthcare Cost and Utilization Project. State Inpatient Databases contained ICD-9-CM diagnoses for the first 3 calendar quarters of 2015 and ICD-10-CM diagnoses for the fourth quarter of 2015. Inpatients under 18 years old were excluded.

MEASURES

Length of stay and discharge disposition outcomes were assessed in separate regression models. Covariates included age, sex, state, ICD lexicon, and FCI/lexicon interaction.

RESULTS

The FCI demonstrated stability across lexicons, despite small discrepancies in prevalence for individual comorbidities. Under ICD-9-CM, each additional comorbidity was associated with an 8.9% increase in mean length of stay and an 18.5% decrease in the odds of a routine discharge, compared with an 8.4% increase and 17.4% decrease, respectively, under ICD-10-CM.

CONCLUSION

This study provides compatible ICD-9-CM and ICD-10-CM diagnosis code lists for the FCI.

Performance of the Functional Comorbidity Index (FCI) in Prognostic Models for Risk Adjustment in Patients With Back Pain

BACKGROUND

The Functional Comorbidity Index (FCI) is a comorbidity measure associated with physical function and may contribute to risk adjustment models in rehabilitation settings, but an International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) of the FCI has not been tested in outpatient settings.

OBJECTIVE

This study examines the ability of an ICD-9-CM- based FCI to predict function, health-related quality of life, and overall health care use.

DESIGN

Cohort study.

SETTING AND PARTICIPANTS

This was a secondary analysis of 5155 adults ≥65 years of age with a new back pain visit from the Back pain Outcomes using Longitudinal Data cohort study.

INDEPENDENT VARIABLES

We measured 18 comorbidities with an ICD-9-CM version of the FCI using diagnosis codes 12 months prior to an index visit.

MAIN OUTCOME MEASUREMENTS

Outcomes included the Roland Morris Disability Questionnaire (RMDQ, 0-24), health-related-quality-of-life (EQ5D, 0-1), and total health care use (sum of all relative value units [RVUs]) measured at baseline and 12 months after the index visit. Linear regression and generalized linear models estimated the association between the FCI and each outcome and to examine goodness of fit. We used a 10-fold cross-validation to develop and compare predictive models with and without the FCI.

RESULTS

There were 1398 participants (27%) with two or more comorbidities. Adjusted estimates show that for every one unit increase in FCI, RMDQ increased by 1.0 (95% confidence interval [CI] 0.8 to 1.1) and R² = 0.093; EQ5D decreased by 0.023 (95% CI -0.028 to -0.019) and R² = 0.076; and mean total RVUs increased by 13% (95% CI 1.09 to 1.17). Cross-validation showed that FCI contributed to small improvements in the performance of predictive models.

CONCLUSION

An ICD-9-CM version of the FCI is associated with long-term function, health-related quality of life, and total health care use among older adults with back pain; however, it explains only a small proportion of the variance.

Impact of Risk Adjustment on Provider Ranking for Patients With Low Back Pain Receiving Physical Therapy

Background The impact of risk adjustment on clinic quality ranking for patients treated in physical therapy outpatient clinics is unknown. Objectives To compare clinic ranking, based on unadjusted versus risk-adjusted outcomes for patients with low back pain (LBP) who are treated in physical therapy outpatient clinics. Methods This retrospective cohort study involved a secondary analysis of data from adult patients with LBP treated in outpatient physical therapy clinics from 2014 to 2016. Patients with complete outcomes data at admission and discharge were included to develop the risk-adjustment model. Clinics with complete outcomes data for at least 50% of patients and at least 10 complete episodes of care per clinician per year were included for ranking assessment. The R² shrinkage and predictive ratio were used to assess overfitting. Agreement between unadjusted and adjusted rankings was assessed with percentile ranking by deciles or 3 distinct quality ranks based on uncertainty assessment. Results The primary sample included 414 125 patients (mean ± SD age, 57 ± 17 years; 60% women) treated by 12 569 clinicians from 3048 clinics from all US states; 82% of patients from 2107 clinics were included in the ranking assessment. The R² shrinkage was less than 1%, with a predictive ratio of 1. Risk adjustment impacted ranking for 70% or 31% of clinics, based on deciles or 3 distinct quality levels, respectively. Conclusion Important changes in ranking were found after adjusting for basic patient characteristics of those admitted to physical therapy for treatment of LBP. Risk-adjustment profiling is necessary to more accurately reflect quality of care when treating patients with LBP. Level of Evidence Therapy, level 2b. J Orthop Sports Phys Ther 2018;48(8):637-648. Epub 22 May 2018. doi:10.2519/jospt.2018.7981.

Impact of co-morbidities on resource use and adherence to guidelines among commercially insured adults with new visits for back pain

RATIONALE, AIMS AND OBJECTIVES

To assess if co-morbidity is associated with higher use of back-related care and adherence to back pain guidelines.

METHODS

We conducted a retrospective cohort study using administrative claims data from 2007-2011. We included individuals ≥18 years with an index visit for back pain. Co-morbidities were measured 12 months prior to index. Co-morbidity burden was measured using Quan's Co-morbidity Index. Co-morbidities categories were measured using chronic condition indicators from the Agency for Healthcare Research and Quality. Total lumbar spine-related resource use for three years was ascertained using procedure codes. A clustering algorithm identified higher long-term utilizer. We identified initial use from day 0-42 for several categories of spine-related care. We used logistic regression to test the association between co-morbidities and resource use.

RESULTS

Greater co-morbidity burden was associated with higher long-term spine-related resource use. Those with ≥2 on Quan's Co-morbidity Index had 29% higher odds of being a high back-specific resource user compared to those with no co-morbidities [Odds Ratio (OR): 1.29, 95% Confidence Interval (CI): 1.23-1.35]. Greater co-morbidity burden was associated with more frequent initial use of imaging, emergency visits, injections, and opioid fills; and less frequent initial use of medical and physical therapy visits. Co-morbid musculoskeletal conditions had the strongest association with being a high utilizer of long-term back-specific resources (OR: 1.53, 95% CI: 1.50-1.57).

CONCLUSIONS

Co-morbidity burden and the presence of specific chronic conditions, such as musculoskeletal conditions, were associated with high long-term use of back-related care and care inconsistent with guidelines.

Association of Early Outpatient Rehabilitation With Health Service Utilization in Managing Medicare Beneficiaries With Nontraumatic Knee Pain: Retrospective Cohort Study

BACKGROUND

Nontraumatic knee pain (NTKP) is highly prevalent in adults 65 years of age and older. Evidence-based guidelines recommend early use of rehabilitation; however, there is limited information comparing differences in health care utilization when rehabilitation is included in the management of NTKP.

OBJECTIVES

To describe the overall health care utilization associated with the management of NTKP; estimate the proportion of people who receive outpatient rehabilitation services; and evaluate the timing of outpatient rehabilitation and its association with other health care utilization.

DESIGN

Rretrospective cohort study was conducted using a random 10% sample of 2009-2010 Medicare claims. The sample included 52,504 beneficiaries presenting within the ambulatory setting for management of NTKP.

METHODS

Exposure to outpatient rehabilitative services following the NTKP index ambulatory visit was defined as 1) no rehabilitation; 2) early rehabilitation (1-15 days); 3) intermediate rehabilitation (16-120 days); and 4) late rehabilitation (>120 days). Logistic regression models were fit to analyze the association of rehabilitation timing with narcotic analgesic use, utilization of nonsurgical invasive procedure, and knee surgery during a 12-month follow-up period.

RESULTS

Only 11.1% of beneficiaries were exposed to outpatient rehabilitation services. The likelihood of using narcotics, nonsurgical invasive procedures, or surgery was significantly less (adjusted odds ratios; 0.67, 0.50, 0.58, respectively) for those who received early rehabilitation when compared to no rehabilitation. The exposure-outcome relationships were reversed in the intermediate and late rehabilitation cohorts.

LIMITATIONS

This was an observational study, and residual confounding could affect the observed relationships. Therefore, definitive conclusions regarding the causal effect of rehabilitation exposure and reduced utilization of more aggressive interventions cannot be determined at this time.

CONCLUSIONS

Early referral for outpatient rehabilitation may reduce the utilization of health services that carry greater risks or costs in those with NTKP.

Effect of Adding McKenzie Syndrome, Centralization, Directional Preference, and Psychosocial Classification Variables to a Risk-Adjusted Model Predicting Functional Status Outcomes for Patients With Lumbar Impairments

Study Design Retrospective cohort. Background Patient-classification subgroupings may be important prognostic factors explaining outcomes. Objectives To determine effects of adding classification variables (McKenzie syndrome and pain patterns, including centralization and directional preference; Symptom Checklist Back Pain Prediction Model [SCL BPPM]; and the Fear-Avoidance Beliefs Questionnaire subscales of work and physical activity) to a baseline risk-adjusted model predicting functional status (FS) outcomes. Methods Consecutive patients completed a battery of questionnaires that gathered information on 11 risk-adjustment variables. Physical therapists trained in Mechanical Diagnosis and Therapy methods classified each patient by McKenzie syndromes and pain pattern. Functional status was assessed at discharge by patient-reported outcomes. Only patients with complete data were included. Risk of selection bias was assessed. Prediction of discharge FS was assessed using linear stepwise regression models, allowing 13 variables to enter the model. Significant variables were retained in subsequent models. Model power (R(2)) and beta coefficients for model variables were estimated. Results Two thousand sixty-six patients with lumbar impairments were evaluated. Of those, 994 (48%), 10 (<1%), and 601 (29%) were excluded due to incomplete psychosocial data, McKenzie classification data, and missing FS at discharge, respectively. The final sample for analyses was 723 (35%). Overall R(2) for the baseline prediction FS model was 0.40. Adding classification variables to the baseline model did not result in significant increases in R(2). McKenzie syndrome or pain pattern explained 2.8% and 3.0% of the variance, respectively. When pain pattern and SCL BPPM were added simultaneously, overall model R(2) increased to 0.44. Although none of these increases in R(2) were significant, some classification variables were stronger predictors compared with some other variables included in the baseline model. Conclusion The small added prognostic capabilities identified when combining McKenzie or pain-pattern classifications with the SCL BPPM classification did not significantly improve prediction of FS outcomes in this study. Additional research is warranted to investigate the importance of classification variables compared with those used in the baseline model to maximize predictive power. Level of Evidence Prognosis, level 4. J Orthop Sports Phys Ther 2016;46(9):726-741. Epub 31 Jul 2016. doi:10.2519/jospt.2016.6266.

Comorbidity Indices Versus Function as Potential Predictors of 30-Day Readmission in Older Patients Following Postacute Rehabilitation

BACKGROUND

Information regarding the association of comorbidity indices with readmission risk for older adults receiving postacute care is limited. The purpose of this study was to compare the discriminatory ability of five comorbidity indices in predicting 30-day all-cause hospital readmission following discharge to the community from postacute inpatient rehabilitation facilities (IRF).

METHODS

The sample included Medicare fee-for-service beneficiaries with stroke, lower extremity joint replacement, and fracture, discharged from IRF in 2011 (N = 75,582). Logistic regression models were used to predict 30-day all-cause readmission. Impairment-specific base models included demographic characteristics and length of stay. Subsequent models included individual comorbidity indices: Tier, Charlson, Elixhauser, functional comorbidity index (FCI), and the hierarchical condition category (HCC). We then added discharge functional status to each model. Results were compared using C-statistics.

RESULTS

Thirty-day readmission rates following discharge from an IRF ranged from 6.5% (joint replacement) to 14% (stroke). The C-statistics were 0.53, 0.56, and 0.55 for the base models in the stroke, joint replacement, and fracture groups, respectively. Adding the Tier, Charlson, FCI, or Elixhauser variables increased the C-statistics by 0.03-0.07 across the three impairment categories. Adding the HCC increased the C-statistics by 0.06-0.09. With the addition of discharge functional status in the model, the C-statistics further increased by 0.06-0.09.

CONCLUSIONS

Comorbidity indices were weakly associated with 30-day readmission in older adults discharged from postacute inpatient rehabilitation. Adding patient-level functional status to the comorbidity indices further improved the discriminatory ability to predict readmission in our sample.

Examining the Association Between Comorbidity Indexes and Functional Status in Hospitalized Medicare Fee-for-Service Beneficiaries

BACKGROUND

Medicare data from acute hospitals do not contain information on functional status. This lack of information limits the ability to conduct rehabilitation-related health services research.

OBJECTIVE

The purpose of this study was to examine the associations between 5 comorbidity indexes derived from acute care claims data and functional status assessed at admission to an inpatient rehabilitation facility (IRF). Comorbidity indexes included tier comorbidity, Functional Comorbidity Index (FCI), Charlson Comorbidity Index, Elixhauser Comorbidity Index, and Hierarchical Condition Category (HCC).

DESIGN

This was a retrospective cohort study.

METHODS

Medicare beneficiaries with stroke, lower extremity joint replacement, and lower extremity fracture discharged to an IRF in 2011 were studied (N=105,441). Data from the beneficiary summary file, Medicare Provider Analysis and Review (MedPAR) file, and Inpatient Rehabilitation Facility-Patient Assessment Instrument (IRF-PAI) file were linked. Inpatient rehabilitation facility admission functional status was used as a proxy for acute hospital discharge functional status. Separate linear regression models for each impairment group were developed to assess the relationships between the comorbidity indexes and functional status. Base models included age, sex, race/ethnicity, disability, dual eligibility, and length of stay. Subsequent models included individual comorbidity indexes. Values of variance explained (R(2)) with each comorbidity index were compared.

RESULTS

Base models explained 7.7% of the variance in motor function ratings for stroke, 3.8% for joint replacement, and 7.3% for fracture. The R(2) increased marginally when comorbidity indexes were added to base models for stroke, joint replacement, and fracture: Charlson Comorbidity Index (0.4%, 0.5%, 0.3%), tier comorbidity (0.2%, 0.6%, 0.5%), FCI (0.4%, 1.2%, 1.6%), Elixhauser Comorbidity Index (1.2%, 1.9%, 3.5%), and HCC (2.2%, 2.1%, 2.8%).

LIMITATION

Patients from 3 impairment categories were included in the sample.

CONCLUSIONS

The 5 comorbidity indexes contributed little to predicting functional status. The indexes examined were not useful as proxies for functional status in the acute settings studied.

Risk Adjustment for Lumbar Dysfunction: Comparison of Linear Mixed Models With and Without Inclusion of Between-Clinic Variation as a Random Effect

BACKGROUND

Valid comparison of patient outcomes of physical therapy care requires risk adjustment for patient characteristics using statistical models. Because patients are clustered within clinics, results of risk adjustment models are likely to be biased by random, unobserved between-clinic differences. Such bias could lead to inaccurate prediction and interpretation of outcomes.

PURPOSE

The purpose of this study was to determine if including between-clinic variation as a random effect would improve the performance of a risk adjustment model for patient outcomes following physical therapy for low back dysfunction.

DESIGN

This was a secondary analysis of data from a longitudinal cohort of 147,623 patients with lumbar dysfunction receiving physical therapy in 1,470 clinics in 48 states of the United States.

METHODS

Three linear mixed models predicting patients' functional status (FS) at discharge, controlling for FS at intake, age, sex, number of comorbidities, surgical history, and health care payer, were developed. Models were: (1) a fixed-effect model, (2) a random-intercept model that allowed clinics to have different intercepts, and (3) a random-slope model that allowed different intercepts and slopes for each clinic. Goodness of fit, residual error, and coefficient estimates were compared across the models.

RESULTS

The random-effect model fit the data better and explained an additional 11% to 12% of the between-patient differences compared with the fixed-effect model. Effects of payer, acuity, and number of comorbidities were confounded by random clinic effects.

LIMITATIONS

Models may not have included some variables associated with FS at discharge. The clinics studied may not be representative of all US physical therapy clinics.

CONCLUSIONS

Risk adjustment models for functional outcome of patients with lumbar dysfunction that control for between-clinic variation performed better than a model that does not.

Physical therapists' level of McKenzie education, functional outcomes, and utilization in patients with low back pain

STUDY DESIGN

Longitudinal, prospective, observational cohort.

OBJECTIVE

To examine associations between McKenzie training, functional status (FS) at discharge, and number of physical therapy visits (utilization) in patients receiving physical therapy for low back pain.

BACKGROUND

The McKenzie method is commonly used in treating patients with low back pain.

METHODS

A McKenzie postgraduate educational program was initiated in a large outpatient physical therapy service. Functional status data were collected at intake and at discharge. Separate hierarchical linear mixed models were used to examine associations between physical therapists' McKenzie training level (none; Parts A, B, C, and D; and credentialed), FS score at discharge, and utilization, controlling for patient risk factors.

RESULTS

The final data set included 20 882 patients (mean ± SD age, 51 ± 16 years; 57% women) who completed FS surveys at both admission and discharge. Patients treated by physical therapists with any McKenzie training had better outcomes (additional 0.7 to 1.3 FS points; P<.05 to <.001) and fewer visits (0.6 to 0.9, P<.001) compared to patients treated by physical therapists with no training. For patients treated by therapists with no versus some McKenzie education, 65% versus 70% achieved at least the minimal clinically important improvement, respectively. There were no significant differences in outcomes or utilization by level of McKenzie training.

CONCLUSION

There was a slightly greater improvement of 0.7 to 1.3 points in FS at discharge in patients receiving physical therapy for low back pain by physical therapists who underwent McKenzie training. This difference was clinically important for an additional 5% of patients who achieved the minimal clinically important improvement when treated by therapists with some McKenzie training. Reduction in physical therapy utilization was 0.6 to 0.9 visits, with the fewest visits utilized by patients of physical therapists at the McKenzie Part D and credentialed levels. Together, these findings suggest improved cost-effectiveness at advanced McKenzie training levels. Ways to improve ongoing education and patient outcomes were proposed.

Lumbar computerized adaptive test and Modified Oswestry Low Back Pain Disability Questionnaire: relative validity and important change

STUDY DESIGN

Retrospective analysis of longitudinal, observational cohort data.

OBJECTIVES

To compare discriminating ability and minimal clinically important improvement (MCII) calculated using functional status (FS) measures estimated from the lumbar computerized adaptive test (LCAT) and Modified Oswestry Low Back Pain Disability Questionnaire (ODQ).

BACKGROUND

The LCAT and ODQ are commonly used to estimate FS in patients seeking outpatient therapy but have not been compared directly.

METHODS

Data from 8198 adult patients who completed the LCAT and ODQ at intake were analyzed, 3379 (41%) of whom completed both surveys at discharge. Global ratings of change data were available for 980 patients. Discriminating ability of FS estimates from the LCAT and ODQ was estimated using relative validity, calculated by dividing F values from LCAT and ODQ analyses of covariance for important risk-adjustment variables. MCII was estimated using receiver-operating-characteristic analyses by quartiles of intake FS values, and areas under the curves were compared.

RESULTS

Relative validity ratios favored the LCAT for age (3.7; 95% confidence interval [CI]: 2.0, 8.9), acuity (1.3; 95% CI: 1.1, 1.6), comorbidities (1.8; 95% CI: 1.3, 2.6), and surgical history (1.8; 95% CI: 1.2, 2.9). MCII cut scores per quartile favored the LCAT. Receiver-operating-characteristic areas under the curves were not different.

CONCLUSION

FS measures estimated by both questionnaires had similar psychometric characteristics. The LCAT FS estimates tended to be more discriminating than ODQ FS estimates. MCII cut scores by quartile of intake FS favored the LCAT. Given the need to be efficient and precise in estimating measures of FS, particularly in older patients, results favor the LCAT in busy, automated outpatient therapy clinics, which are increasingly serving an aging population.

Using intake and change in multiple psychosocial measures to predict functional status outcomes in people with lumbar spine syndromes: a preliminary analysis

BACKGROUND

Managing patients with lumbar spine syndromes who are seeking outpatient physical therapy represents a complex problem where psychosocial constructs such as fear-avoidance beliefs regarding physical activities or work activities, somatization, and depressive symptoms may affect functional status (FS) outcomes.

OBJECTIVE

The purpose of this study was to determine whether intake or changes in fear-avoidance beliefs regarding physical or work activities, somatization, and depressive symptoms assessed simultaneously affect FS outcomes prediction.

DESIGN

This study was a secondary analysis of prospectively collected, longitudinal, observational cohort data.

METHODS

Data analyzed were from adult patients (n=323) with lumbar syndromes classified as elevated versus not elevated on single-item screening instruments for fear-avoidance beliefs regarding physical or work activities, somatization, and depressive symptoms at intake and discharge. Prediction of minimal clinically important difference in FS was assessed separately for intake and change from intake to discharge classifications using logistic regression models controlling for important variables.

RESULTS

Intake and change models were strong (McFadden rho-squared values=.31 and .49, respectively). Patients classified as not elevated in fear-avoidance beliefs regarding physical activities but elevated in fear-avoidance beliefs regarding work activities, somatization, and depressive symptoms at intake were 5 out of 100 times less likely to report clinically important outcomes compared with being elevated in each measure. Patients not elevated in fear-avoidance beliefs regarding work activities and somatization at intake and discharge were 8 to 14 times more likely to report clinically important outcomes compared with being elevated in each measure.

LIMITATIONS

Sample size was limited. Data analyses were retrospective with no control of missing data.

CONCLUSIONS

Combinations of multiple psychosocial constructs were important predictors of FS outcomes and may assist patient management by: (1) identifying patients with elevated psychosocial constructs at intake and (2) tracking change in psychosocial variables for improved outcomes prediction. This model may prove helpful for future clinical and research applications to determine optimal psychosocial screening methods.

Change in psychosocial distress associated with pain and functional status outcomes in patients with lumbar impairments referred to physical therapy services

STUDY DESIGN

Prospective, longitudinal, observational cohort design.

OBJECTIVE

The primary aim was to examine the association between changes in psychosocial distress (PD), and functional status (FS) and pain intensity at discharge from physical therapy.

BACKGROUND

Patients with lumbar impairments seeking physical therapy commonly demonstrate elevated PD. However, it is not clear if PD changes that occur during physical therapy management are associated with improved clinical outcomes.

METHODS

Data from adults (n = 692) with lumbar impairment were analyzed. Patients were screened using the Symptom Checklist Back Pain Prediction Model questionnaire (SCL BPPM) to identify patients at intake and discharge into 3 levels of risk for persistent disability (high, intermediate, or low). SCL BPPM classifications allowed for 5 patterns of change in PD during therapy (decreased, stable low, stable intermediate, stable high, or increased). Associations between PD change patterns and discharge FS and pain intensity were assessed using multivariable linear regression models, controlling for selected risk-adjustment variables.

RESULTS

Proportions of patients classified by patterns of PD change for decreased, stable low, stable intermediate, stable high, and increased were 0.34, 0.52, 0.05, 0.06, and 0.03, respectively. Compared to the decreased PD group, (1) increased, stable high, and stable intermediate PD patterns were associated with worse discharge FS scores (-7.9 [95% CI: -13.5, -2.21], -10.9 [95% CI: -15.25, -6.49], and -8.9 [95% CI: -13.65, -4.21] units, respectively), and (2) stable high and stable intermediate PD patterns were associated with higher pain intensity (2.59 [95% CI: 1.81, 3.56] and 2.14 [95% CI: 1.25, 3.04] units, respectively).

CONCLUSIONS

Lower FS and higher pain intensity outcomes were associated in similar but not identical patterns with patients whose SCL BPPM classification of PD increased, or remained at high or intermediate levels during physical therapy. Serial assessments of change in PD during rehabilitation are recommended as a possible treatment-monitoring tool.

Total number and severity of comorbidities do not differ based on anatomical region of musculoskeletal pain

STUDY DESIGN

Secondary analysis, cross-sectional study.

OBJECTIVES

To (1) compare differences in individual comorbidity rates among patients with cervical, lumbar, and extremity pain complaints and (2) compare rates based on total number and severity in these same patient groups.

BACKGROUND

Comorbidities can impact recovery, prognosis, and potentially hinder participation in rehabilitation. Few studies have compared comorbidity rates among patients with different anatomical region of pain, to determine whether specific screening is warranted in physical therapy settings.

METHODS

Included in the analyses were 2375 patients who reported complete demographic, clinical, and comorbidity information using Patient Inquiry software. Comorbidity data were collected from the Functional Comorbidity Index (18 items) and 6 additional comorbidities, to assess the presence of medical disease across multiple body systems. Comorbidities were further classified as "nonsevere" or "severe," based on inclusion in the Charlson Comorbidity Index. Chi-square analyses investigated differences in the rates of total number and severe comorbidities. Odds ratios (OR) and 95% confidence intervals (CIs) were calculated on rates with statistically significant differences (P<.001), using the lumbar spine as the reference group.

RESULTS

Of the 24 comorbid conditions included in this analysis, 3 nonsevere medical conditions (degenerative disc disease, obesity, and headache) had different rates among anatomical region. A lower rate for degenerative disc disease was associated with the extremity conditions (χ2 = 66.3; OR = 0.40; 95% CI: 0.32, 0.50). Higher rate of headache (χ2 = 115.3; OR = 3.01; 95% CI: 2.45, 3.70) and lower rate of obesity (χ2 = 16.2; OR = 0.64; 95% CI: 0.51, 0.80) were associated with cervical conditions. There were no differences among the 3 anatomical regions for total number or severe comorbidities.

CONCLUSION

Focused screening for degenerative disc disease, obesity, and headache may be warranted. However, the same strategy was not supported for total number or severe comorbidities, at least when considering comparative rates from this cohort. Physical therapists should consider the potential influence of total number and severe comorbidities equally for all anatomical regions of musculoskeletal pain.

LEVEL OF EVIDENCE

Differential diagnosis/symptom prevalence, level 3b.

Effect of fear-avoidance beliefs of physical activities on a model that predicts risk-adjusted functional status outcomes in patients treated for a lumbar spine dysfunction

STUDY DESIGN

Retrospective analysis of a prospective, longitudinal cohort study of 30 858 patients being treated for a lumbar spine dysfunction in outpatient physical therapy.

OBJECTIVES

To determine effect of adding a single-item screening variable classifying patients with elevated versus not-elevated scores of fear-avoidance beliefs of physical activities at intake, on a model predicting risk-adjusted functional status (FS) outcomes.

BACKGROUND

Outcomes must be risk-adjusted before making meaningful interpretations. Elevated fear-avoidance beliefs scores have been predictive of poor outcomes. But the importance of elevated fear-avoidance scores in a multivariable model predicting FS outcomes needs further study.

METHODS

Using retrospective analyses, predictive ability (R2) of multivariable linear regression models of discharge FS with and without classification by elevated versus not-elevated fear-avoidance scores were compared, while controlling for intake FS, age, symptom acuity, surgical history, gender, number of comorbidities, and payer. Percent variance controlled and beta coefficients (95% confidence intervals) of each variable in both models were compared. A split-half design was used for model cross-validation. Predictive ratios (predicted FS, divided by actual discharge FS) were assessed.

RESULTS

Adding fear-avoidance beliefs classification to the discharge FS model improved (P<.001) model predictive ability but only slightly (R2 without, and with, fear-avoidance classification, 0.2997 and 0.3010, respectively). Variables impacted models similarly (95% confidence intervals not different). Fear-avoidance classification added 0.2% data variance control to the existing model. Cross-validation was supported. Predictive ratios were 1.09 and 1.10, without and with fear-avoidance, respectively.

CONCLUSION

Although screening for elevated fear-avoidance beliefs of physical activities significantly improves the FS outcomes predictive model, the amount of additional meaningful interpretation of FS outcomes was minimal. Exploration of other clinically relevant variables designed to improve outcomes prediction is warranted.

LEVEL OF EVIDENCE

Prognosis, level 2c.