Deborah Fulton-Kehoe

Early opioid prescription and subsequent disability among workers with back injuries: the Disability Risk Identification Study Cohort.

Study Design. Prospective, population-based cohort study. Objective. To examine whether prescription of opioids within 6 weeks of low back injury is associated with work disability at 1 year. Summary of Background Data. Factors related to early medical treatment have been little investigated as possible risk factors for development of long-term work disability among workers with back injuries. We have previously shown that about 1 of 3 of workers receive an opioid prescription early after a low back injury, and a recent study suggested that such prescriptions may increase risk for subsequent disability. Methods. We analyzed detailed data reflecting paid bills for opioids prescribed within 6 weeks of the first medical visit for a back injury among 1843 workers with lost work-time claims. Additional baseline measures included an injury severity rating from medical records, and demographic, psychosocial, pain, function, smoking, and alcohol measures from a worker survey conducted 18 days (median) after receipt of the back injury claim. Computerized database records of work disability 1 year after claim submission were obtained for the primary outcome measure. Results. Nearly 14% (254 of 1843) of the sample were receiving work disability compensation at 1 year. More than one-third of the workers (630 of 1843) received an opioid prescription within 6 weeks, and 50.7% of these (319 of 630) were received at the first medical visit. After adjustment for pain, function, injury severity, and other baseline covariates, receipt of opioids for more than 7 days (odds ratio = 2.2; 95% confidence interval, 1.5–3.1) and receipt of more than 1 opioid prescription were associated significantly with work disability at 1 year. Conclusion. Prescription of opioids for more than 7 days for workers with acute back injuries is a risk factor for long-term disability. Further research is needed to elucidate this association.

Worker recovery expectations and fear-avoidance predict work disability in a population-based workers' compensation back pain sample

Study Design. Prospective, population-based cohort study. Objectives. To examine whether worker demographic, pain, disability, and psychosocial variables, assessed soon after work-related back pain disability onset, predict 6-month work disability. Summary of Background Data. Greater age, pain, and physical disability, and certain psychosocial characteristics may be risk factors for prolonged back pain-related work disability, although many studies have been small, findings have been inconsistent, and some psychosocial variables have not been examined prospectively. Methods. Workers (N = 1,068) completed telephone interviews assessing demographic, pain, disability, and psychosocial variables 18 days (median) after submitting Workers’ Compensation back pain disability claims. Administrative measures of work disability 6 months after claim submission were obtained. Results. At 6 months, 196 workers (18.4%) were receiving work disability compensation. Age, race, education, and baseline pain and disability were significant predictors of 6-month disability. Adjusting for baseline demographics, pain, disability, and other psychosocial variables, high work fear-avoidance (odds ratio, 4.6; 95% confidence interval, 1.6–13.7) and very low recovery expectations (odds ratio, 3.1, 95% confidence interval, 1.5–6.5) were significant independent predictors. Conclusions. Among individuals with acute work-related back pain, high pain and disability, low recovery expectations, and fears that work may increase pain or cause harm are risk factors for chronic work disability.

MR nerve imaging in a prospective cohort of patients with suspected carpal tunnel syndrome

Objectives To evaluate the reliability and diagnostic accuracy of high-resolution MRI of the median nerve in a prospectively assembled cohort of subjects with clinically suspected carpal tunnel syndrome (CTS). Methods The authors prospectively identified 120 subjects with clinically suspected CTS from five Seattle-area clinics. All subjects completed a hand-pain diagram and underwent a standardized nerve conduction study (NCS). The reference standard for determining CTS status was a classic or probable hand pain diagram and NCS with a difference >0.3 ms between the 8-cm median and ulnar peak latencies. Readers graded multiple imaging parameters of the MRI on four-point scales. The authors also performed quantitative measurements of both the median nerve and carpal tunnel cross-sectional areas. NCS and MRI were interpreted without knowledge of the other study or the hand pain diagram. Results Intrareader reliability was substantial to near perfect (kappa = 0.76 to 0.88). Interreader agreement was lower but still substantial (kappa = 0.60 to 0.67). Sensitivity of MRI was greatest for the overall impression of the images (96%) followed by increased median nerve signal (91%); however, specificities were low (33 to 38%). The length of abnormal signal on T2-weighted images was significantly correlated with nerve conduction latency, and median nerve area was larger at the distal radioulnar joint (15.8 vs 11.8 mm2) in patients with CTS. A logistic regression model combining these two MR variables had a receiver operating characteristic area under the curve of 0.85. Conclusions The reliability of MRI is high but the diagnostic accuracy is only moderate compared with a research-definition reference standard.

The association between pain and disability

&NA; A clearer understanding of how pain intensity relates to disability could have important implications for pain treatment goals and definitions of treatment success. The objectives of this study were to determine the optimal pain intensity rating (0–10 scale) cutpoints for discriminating disability levels among individuals with work‐related carpal tunnel syndrome (CTS) and low back (LB) injuries, whether these cutpoints differed for these conditions and for different disability measures, and whether the relationship between pain intensity and disability was linear in each injury group. Approximately 3 weeks after filing work injury claims, 2183 workers (1059 CTS; 1124 LB) who still had pain completed pain and disability measures. In the LB group, pain intensity rating categories of 1–4, 5–6, and 7–10 optimally discriminated disability levels for all four disability measures examined. In the CTS group, no pain intensity rating categorization scheme proved superior across all disability measures. For all disability measures examined, the relationship between pain intensity and disability level was linear in the CTS group, but nonlinear in the LB group. Among study participants with work‐related back injuries, when pain level was 1–4, a decrease in pain of more than 1‐point corresponded to clinically meaningful improvement in functioning, but when pain was rated as 5–10, a 2‐point decrease was necessary for clinically meaningful improvement in functioning. The findings indicate that classifying numerical pain ratings into categories corresponding to levels of disability may be useful in establishing treatment goals, but that classification schemes must be validated separately for different pain conditions.

ISSLS Prize Winner: Early Predictors of Chronic Work Disability : A Prospective, Population-Based Study of Workers With Back Injuries

Study Design. Prospective population-based cohort study. Objective. To identify early predictors of chronic work disability after work-related back injury. Summary of Background Data. Identification of early predictors of prolonged disability after back injury could increase understanding concerning the development of chronic, disabling pain, and aid in secondary prevention. Few studies have examined predictors across multiple domains in a large, population-based sample. Methods. Workers (N = 1885) were interviewed 3 weeks (average) after submitting a lost work-time claim for a back injury. Sociodemographic, employment-related, pain and function, clinical, health care, administrative/legal, health behavior, and psychological domain variables were assessed via worker interviews, medical records, and administrative databases. Logistic regression analyses identified early predictors of work disability compensation 1 year after claim submission. Results. Significant baseline predictors of 1-year work disability in the final multidomain model were injury severity (rated from medical records), specialty of the first health care provider seen for the injury (obtained from administrative data), and worker-reported physical disability (Roland-Morris disability questionnaire), number of pain sites, “very hectic” job, no offer of a job accommodation (e.g., light duty), and previous injury involving a month or more off work. The model showed excellent ability to discriminate between workers who were/were not disabled at 1 year (area under the receiver operating characteristic curve = 0.88, 95% CI = 0.86–0.90). Conclusion. Among workers with new lost work-time back injury claims, risk factors for chronic disability include radiculopathy, substantial functional disability, and to a lesser extent, more widespread pain and previous injury with extended time off work. The roles of employers and health care providers also seem important, supporting the need to incorporate factors external to the worker in models of the development of chronic disability and in disability prevention efforts.

Lumbar fusion outcomes in Washington State workers' compensation.

Study Design. Retrospective population-based cohort study. Objective. To evaluate the influence of lumbar intervertebral fusion devices on clinical and disability outcomes among Washington State compensated workers with chronic back pain. Summary of Background Data. The efficacy of lumbar fusion for chronic low back pain remains controversial. Recent randomized controlled trials have shown results of fusion to be equivalent to those of structured exercise and cognitive intervention. Lumbar fusion rates, however, continue to increase nationally, fueled, in part, by introduction of new fusion devices, including intervertebral cages in 1996. It is not known whether these newer devices have improved outcomes, and particularly in compensated workers. Methods. In this population-based retrospective cohort study, we identified Washington State injured workers who underwent lumbar fusion between 1994 and 2001 from Washington State Workers’ Compensation system administrative database. All the data for this study were obtained from either the claims or medical bill payment databases. Multiple logistic regression analyses were used to examine the association between the surgical technique (interbody cages and/or instrumentation) and the risk of disability, reoperation, and complications following lumbar fusion. Results. Among the 1,950 eligible subjects, fusions with cages increased from 3.6% in 1996 to 58.1% in 2001. Overall disability rate at 2 years after fusion was 63.9%, reoperation rate 22.1%, and rate for other complications 11.8%. Use of cages or instrumentation was associated with increased complication risk compared with bone-only fusions without improving disability or reoperation rates. Legal, work-related, and psychologic factors predicted worse disability. Discography and multilevel fusions predicted greater reoperation risk. Degenerative disc disease and concurrent decompression procedures predicted lower reoperation risk. Conclusions. Use of intervertebral fusion devices rose rapidly after their introduction in 1996. This increased use was associated with an increased complication risk without improving disability or reoperation rates.

Opioid use for chronic low back pain: A prospective, population-based study among injured workers in Washington state, 2002-2005.

ObjectivesTo determine (1) the natural history of prescription opioid use, (2) the predictors of long-term opioid use, and (3) the association between opioid dose and pain and function in a large cohort of workers with recent back injuries. MethodsProspective cohort of workers with back injuries (N=1883) interviewed 18 days (median) and 1 year after claim submission. Detailed pharmacy data were obtained from computerized records of paid bills. ResultsForty-two percent of workers (781/1843) received an opioid in the year after injury, most (694/781, 89%) at or shortly after the first medical visit for the injury. Of these, most (410/694, 59%) received opioids only within the first quarter after injury, whereas 16% (111/694) received opioids for 4 quarters. Among these long-term users, total morphine equivalent dose (MED) increased significantly (P<0.01) from the first (mean, 2364 mg; standard deviation, 4019 mg) to the fourth (mean, 3824 mg; standard deviation, 5998 mg) quarter. Improvement by at least 30% in pain and function measure scores occurred in only 26% (95% confidence interval 18%-36%) and 16% (95% confidence interval 10%-25%), respectively, of long-term users. Opioid doses increased substantially over time in all but those in whom function improved. After adjustment for baseline pain, function, and injury severity, the strongest predictor of longer term opioid prescription was total MED in the first quarter. Workers receiving at least 40 mg MED per day in the first quarter had 6-fold odds of receiving longer-term opioids. DiscussionsFor the small group of workers with compensable back injuries who receive opioids longer-term (111/1843, 6%), opioid doses increase substantially and only a minority shows clinically important improvement in pain and function. The amount of prescribed opioid received early after injury strongly predicts long-term use. More research is needed to understand clinical decisions to continue or increase opioid therapy after back injury.

Comparison of the Roland–morris Disability Questionnaire and Generic Health Status Measures: A Population-based Study of Workers’ Compensation Back Injury Claimants

Study Design. Workers’ compensation back injury claimants completed baseline and follow-up telephone interviews in a prospective population-based cohort study. Objective. To compare the Roland–Morris Disability Questionnaire (RDQ) to widely used generic health status measures in a sample of workers with recent work-related back injuries in terms of validity, reliability, responsiveness to change, and floor and ceiling effects. Summary of Background Data. Little research has directly compared the validity and responsiveness of the RDQ to that of the Short-Form 12 or Short-Form 36 health status measures among individuals with back pain. Furthermore, there is little information concerning the validity, reliability, and responsiveness of the RDQ as a measure of functional outcomes for workers with back injuries. Methods. Approximately 8 weeks (median) after filing low back injury claims, 309 workers completed the RDQ, Short-Form 12, and Short-Form 36 scales and gave information about their work status in computer-assisted telephone interviews. An average of 5 months later, 284 workers (91.9%) completed the measures again. Results. The RDQ demonstrated excellent internal consistency and validity through correlations with other measures of physical functioning, ability to discriminate between those working and those not working, and much more responsiveness to change than the Short-Form 12 and Short-Form 36 scales. However, 15% of the sample did not answer one or more RDQ items. Conclusions. The RDQ is a valid measure of physical disability among workers with back injuries. Its greater responsiveness to change suggests its superiority to the Short-Form 12 and Short-Form 36 as an outcome measure in this population.

Magnetic resonance imaging compared with electrodiagnostic studies in patients with suspected carpal tunnel syndrome: predicting symptoms, function, and surgical benefit at 1 year.

OBJECT The goal in this study of patients with clinical carpal tunnel syndrome (CTS) was to compare the usefulness of magnetic resonance (MR) imaging with that of electrodiagnostic studies (EDSs) for the following purposes: 1) prediction of 1-year outcomes and 2) identification of patients who are likely to benefit from surgical treatment. METHODS The authors prospectively enrolled 120 patients with clinically suspected CTS. The participants were tested using standardized EDSs, MR imaging, and a battery of questionnaires, including the Carpal Tunnel Syndrome Assessment Questionnaire, a well-validated 5-point score of symptoms and function. The EDSs and MR images were each interpreted independently. Patients were reevaluated after 1 year. The decision to treat patients conservatively or by carpal tunnel release was made by the individual surgeon, who had access to the initial EDS but not MR imaging results. Univariate and multivariate analyses were used to determine associations between 1-year outcomes and baseline diagnostic tests. RESULTS The authors recontacted 105 of 120 participants at 12 months. Of these, 30 patients had had surgery and 75 had not. Patients who had undergone surgery showed greater improvement at 1 year than those who had not had surgery. The length of the abnormal T2-weighted nerve signal on MR imaging and median-ulnar sensory latency difference were the strongest predictors of surgical benefit. There was a clear patient preference for the MR imaging over EDSs. CONCLUSIONS The findings obtained with MR imaging of the carpal tunnel predict surgical benefit independently of nerve conduction studies.

A case-control study of physical activity and non-insulin dependent diabetes mellitus (NIDDM). The San Luis Valley Diabetes Study

PURPOSE The purpose of this study was to examine the association between physical activity and non-insulin dependent diabetes mellitus (NIDDM). METHODS We conducted a population-based case-control study in Hispanic and non-Hispanic white men and women, ages 20-74. A total of 167 cases with NIDDM and 1100 controls with normal glucose tolerance were included. All subjects completed an oral glucose tolerance test. RESULTS Persons with recently diagnosed NIDDM reported significantly lower levels of physical activity than control subjects. For total metabolic units, the odds ratio for subjects in the highest tertile compared to those in the lowest tertile was 0.60 (95% confidence interval (CI) = 0.37-0.98) after adjusting for age, sex, ethnicity, and family history of diabetes. The adjusted odds ratio for persons reporting high levels of vigorous activity (at least three times per week for 20 minutes) was also less than 1, but was not statistically significant (odds ratio (OR) = 0.73, 95% CI = 0.47-1.14). Similar adjusted odds ratios were observed for high versus low levels of self-assessed work activity (OR = 0.50, 95% CI = 0.34-0.74) and leisure time physical activity (OR = 0.62, 95% CI = 0.44-0.90). Further adjustments for body mass index attenuated the strength of the association between physical activity and NIDDM. This is consistent with the hypothesis that obesity is one consequence of physical inactivity that puts individuals at increased risk for NIDDM. The association of physical activity and NIDDM was stronger in Hispanic than in non-Hispanic white subjects, although this difference was not statistically significant. CONCLUSIONS High levels of physical activity are associated with lower odds of NIDDM and this relationship may be stronger in Hispanic subjects.