Trends in disability duration and cost of workers' compensation low back pain claims (1988-1996)

Previously published epidemiologic studies of low back pain (LBP) have repo rted that the prevalence of low back disability has increased dramatically. These studies based their findings on either the number of disability clai ms filed, the disability duration, or both. This information was from count ries other than the United States or from the US Social Security Disability Insurance data, with findings reported only to the early 1980s. More recen t studies of US workers' compensation LBP claims reported a decrease in the incidence rate from the late 1980s to the mid-1990s. No studies have been found that report on the trends of disability duration for workers' compens ation LBP claims. This study examined recent trends in the length of disabi lity (LOD) for LBP claims and associated costs, using a large sample of cla ims from the privately insured US workers' compensation market. LOD and cos t information were derived for injuries from 1988, 1990, 1992, 1994, and 19 96. For each year, the distributions of LOD and cost were skewed, with the small percentage of claims that lasted more than one year (4.6%-8.8%, depen ding on the year) accounting for a large percentage of the total disability days (77.6%-90.1%) and cost (64.9%-84.7%). From 1988 to 1996, the average LOD decreased 60.9%, from 156 days to 61 days. The probability of being on disability for a long period of time has decreased over the years. Over the study period, the average cost of a claim decreased 41.4%, while the media n cost increased 19.7%. The most influential change in the LOD and cost dis tributions was a reduction in expensive claims with a long disability durat ion. The evolution of LOD and cost is also detailed for different disabilit y durations for the study period.