Compensation costs of work-related back disorders among union carpenters, Washington State 1989-2003

We measured resources used to provide medical care and to estimate lost productivity represented by payments for lost work time or impairment for work-related back injuries among a large cohort of union carpenters over 15 years.

Using administrative data we identified a cohort of carpenters, their hours worked, their workers' compensation claims and associated costs. After adjustment for inflation and discounting to 2006 dollars, yearly costs for injuries and payment rates based on hours worked were calculated. Using negative binomial regression, dollars paid per claim were modeled based on age, gender, union tenure, and predominant type of work of the carpenter and whether the injury resulted from overexertion or acute trauma.

Workers' compensation costs for back injuries exceeded $128 million dollars between 1998 and 2003, representing payments of $0.97 for each hour of work. Costs per hour of work declined substantively over time due largely to declining overexertion injury rates. Traumatic injuries, though less common than overexertion injuries, were more expensive. Costs increased with the number of prior back injuries and with increasing age, beginning as early as age 30.

Increasing costs even among relatively young carpenters likely reflect the heavy nature of their work rather than simply the effects of biological aging. Musculoskeletal back problems remain a common, and consequently costly, source of injury among these carpenters that needs to be addressed through engineering modifications; there are also clearly needs for prevention of the often more costly back injuries associated with acute trauma.