Back pain exacerbations and lost productive time costs in United States workers.

STUDY DESIGN: Cross-sectional with follow-up case-control component. OBJECTIVES: To measure the prevalence of back pain (BP) and back pain exacerbations, describe BP features and functional impairment, estimate BP-related lost productive time (LPT) and costs, and assess the relation between pain exacerbations and lost productive time. SUMMARY OF BACKGROUND DATA: BP is associated with substantial lost work time. However, little is known about the extent to which BP with or without exacerbation explains lost work time. METHODS: A national telephone survey of the U.S. workforce identified 320 workers 40 to 65 years of age with BP defined by NHANES I criteria and 91 matched non-BP controls. Participants self-reported pain characteristics, lost productive time (absenteeism and presenteeism) in the previous 2 weeks, activity limitations, and demographics. A population-weighting adjustment was applied to estimates to account for selection bias and ensure that estimates of certain sample demographic subgroups' totals conformed to the Current Population Survey. RESULTS: The 2-week period prevalence of BP was 15.1%; 42% of workers with BP experienced pain exacerbations. BP prevalence was associated with demographic factors, but BP exacerbations were not. BP was reported by 42.6% of all workers. Workers with exacerbations reported more days with BP than those without exacerbations. Workers with exacerbations were significantly more likely than those without such exacerbations to report activity limitation (88.4% vs. 60.7%; P < 0.0001) and BP-related LPT (22.1% vs. 13.0%; P = 0.0259). BP in workers 40 to 65 years of age costs employers an estimated $7.4 billion/year. Workers with BP exacerbations account for 71.6% of this cost. CONCLUSIONS: Workers with BP exacerbations account for a disproportionate share of the cost of BP-related lost productive time.

Pain exacerbation as a major source of lost productive time in US workers with arthritis.

OBJECTIVE: To estimate the prevalence of arthritis and arthritis pain exacerbations in US workers including impact on functioning and lost productive work time (LPT). METHODS: The research was conducted as a nested case-control study of participants in the Caremark American Productivity Audit, a US national random-digit-dial survey of US workers. The sample included 329 workers ages 40-65 years meeting the First National Health and Nutrition Examination Survey criteria for arthritis, and 91 workers not meeting arthritis inclusion criteria. Participants completed a telephone interview to measure the prevalence of arthritis and pain exacerbations, LPT (in hours and dollars), functional disability using the Western Ontario and McMaster Universities Knee and Hip Osteoarthritis Index (WOMAC) and the Australian/Canadian Osteoarthritis Hand Index, and demographics. RESULTS: The prevalence of arthritis in US workers ages 40-65 years was 14.7% during the 2-week period. Pain exacerbation occurred among 38% of participants with arthritis. Workers with pain exacerbations were significantly more likely to have higher WOMAC scores (38.6 versus 29.6; P = 0.0041) and report arthritis-related LPT (24.4% versus 13.3%; P = 0.0118) than workers without exacerbations. Among those with LPT, average LPT did not differ (4.1 hours per week) between persons with and without exacerbations. The estimated annual LPT cost from arthritis in the US workforce was $7.11 billion, with 65.7% of this cost attributed to the 38% of workers with pain exacerbations. CONCLUSION: Workers with arthritis pain exacerbation account for a disproportionate share of the arthritis-related LPT cost. Stratifying workers for appropriate treatment management based on pain exacerbation status could significantly decrease arthritis-related LPT and offer employees and employers an effective return on health care use.

Validation of the work and health interview.

BACKGROUND: Instruments that measure the impact of illness on work do not usually provide a measure that can be directly translated into lost hours or costs. We describe the validation of the Work and Health Interview (WHI), a questionnaire that provides a measure of lost productive time (LPT) from work absence and reduced performance at work. METHOD: A sample (n = 67) of inbound phone call agents was recruited for the study. Validity of the WHI was assessed over a 2-week period in reference to workplace data (i.e. absence time, time away from call station and electronic continuous performance) and repeated electronic diary data (n = 48) obtained approximately eight times a day to estimate time not working (i.e. a component of reduced performance). RESULTS: The mean (median) missed work time estimate for any reason was 11 (8.0) and 12.9 (8.0) hours in a 2-week period from the WHI and workplace data, respectively, with a Pearson's (Spearman's) correlation of 0.84 (0.76). The diary-based mean (median) estimate of time not working while at work was 3.9 (2.8) hours compared with the WHI estimate of 5.7 (3.2) hours with a Pearson's (Spearman's) correlation of 0.19 (0.33). The 2-week estimate of total productive time from the diary was 67.2 hours compared with 67.8 hours from the WHI, with a Pearson's (Spearman's) correlation of 0.50 (0.46). CONCLUSION: At a population level, the WHI provides an accurate estimate of missed time from work and total productive time when compared with workplace and diary estimates. At an individual level, the WHI measure of total missed time, but not reduced performance time, is moderately accurate.

Pharmacy and medical claims data identified migraine sufferers with high specificity but modest sensitivity.

OBJECTIVE: Claims data are often used to identify and monitor individuals with particular conditions, but many health conditions are not easily recognizable from claims data alone. Patient characteristics routinely available in claims data were used to develop model-based claims signatures to identify migraineurs. STUDY DESIGN AND SETTING: A validated telephone interview was administered to 23,299 continuously enrolled managed care members aged 18-55 to identify 1,265 migraineurs and 1,178 controls. Responses were linked to medical and prescription claims. Claims variables were evaluated for sensitivity, specificity, and positive and negative predictive value in predicting migraine status. Regression models for predicting migraine status were developed. RESULTS: Regression-based claims signature models were successful in case-finding, as indicated by fairly sizable odds ratios (OR). In the full model (including demographic, medical, pharmacy, and comorbidity claims variables), a claim for a migraine drug, gender, and a claims-based headache diagnosis were strongly associated with migraine case status (OR=3.9, 3.2, and 3.0, respectively). CONCLUSION: Using either medical or pharmacy claims provided highly specific and moderately sensitive case-findings. Strategies that combined medical and pharmacy information improved sensitivity and may increase the usefulness of claims for identifying migraine and improving the quality of migraine care.

The medical care utilization and costs associated with migraine headache.

OBJECTIVE: To describe the medical care use and costs associated with migraine. DESIGN: Retrospective case-control design in which migraine case status was ascertained via validated telephone interview and linked with comprehensive claims data. Unadjusted and adjusted use and cost differences by migraine status were evaluated using exponential score tests and generalized estimating equations. SETTING AND PATIENTS: We interviewed 8,579 individuals to identify migraine cases (N = 1,265) and a random sample of nonmigraine controls (N = 1,178) among eligible health plan enrollees aged 18 to 55. MEASURES: Survey responses were used to categorize individuals meeting the International Headache Society's diagnostic criteria for migraine with or without aura as migraine cases and to collect information on comorbid psychiatric symptoms. Claims data were used to compile annual medical and pharmaceutical use and costs, presence of migraine diagnosis, and other diagnosed comorbidities. RESULTS: Interview-ascertained migraine cases used more outpatient visits (9.1 vs 6.8; P < .01), were more likely to be seen in the emergency department (20.7% vs 17.6%; P < .05), and were admitted to the hospital more (4.5% vs 2.8%; P < .05) compared to nonmigraine controls. Cases incurred significantly higher medical care costs ($2,761 vs $2,064; P < .01). Multivariable model results indicate that much of this increase in costs is due to the presence of major depressive symptoms as well as other diagnosed comorbidities that are more common among those with migraine. CONCLUSIONS: By combining validated telephone survey information to identify migraine cases and controls with comprehensive claims data, we found migraine cases incur higher medical care costs compared to controls. These increased costs are associated with the presence of psychiatric symptoms and other comorbidities.

Health-related lost productive time (LPT): recall interval and bias in LPT estimates.

We examined the effect of interview characteristics (ie, recall interval, interview version) on estimates of health-related lost productive work time (LPT). Three versions of a telephone interview were administered using 7-day and 4-week recall periods. In a population-based survey, 7674 workers randomly were assigned to one of six interviews at contact; 615 participants received a follow-up interview. We found strong evidence of under-reporting using a 4-week recall period and a not significant trend in over-reporting LPT using a 7-day recall period. Of the three interviews, version 3 could be administered most quickly, on average, and yielded the most discriminating estimates of LPT by health condition (ie, headache, allergic rhinitis, and cold/flu). Our data suggest that variation in relatively short recall periods influences estimates of health-related LPT. A 2-week recall period may be optimal for minimizing overall reporting error but requires additional research to verify.