Performance decrements resulting from illness in the workplace: the effect of headaches

Studies on the impact of illness on work productivity are important to rationally allocate healthcare resources and to design programs to mitigate these effects. This investigation was conducted to develop and apply daily measures of illness episodes, and to collect subjective and objective data on work performance impacts. Medical bill reviewers completed daily responses to a questionnaire about headache manifestations, severity, and speed of work using interactive voice response (IVR). Of 134 eligible enrolled subjects, 117 (86%) provided at least 30 daily reports over 3 months. Their responses were matched to difficulty-adjusted objective measures: daily output, time on the system, and productivity. Respondents were clinically classified as migraineurs (n = 56), other headache disorders (n = 47), or having no headache disorder (n = 14). Each headache episode was classified as a migraine or nonmigraine headache based on reported manifestations.

The three groups were similar in a variety of demographic factors, and mean subject-specific measures of speed, output, and productivity. In a multivariate model using general estimating equations, only episode severity (not type of headache or person-specific diagnosis) was found to be associated with a significant decrement in speed or productivity. The self-reported decrement in speed (approximately 20%) was much greater than the actual measured effect on productivity (approximately 8%). Intensive daily diary collection by IVR on symptoms and work performance is feasible. However, analysis of detailed daily objective productivity data can be complex, with significant unmeasured sources of variance. Severity may be a more important determinant of headache effect on work performance than specific diagnosis. Future studies on illness episodes and work performance should measure informal accommodations that may enable employees to compensate for episodic illnesses.