Early effects of antiretroviral therapy on work performance: preliminary results from a cohort study of Kenyan agricultural workers

Objective: This paper estimates the impact of antiretroviral therapy (ART) on days harvesting tea per month for tea-estate workers in Kenya. Such information is needed to assess the potential economic benefits of providing treatment to working adults. Methods: Data for this analysis come from company payroll records for 59 HIV-infected workers and a comparison group of all workers assigned to the same work teams (reference group, n = 1992) for a period covering 2 years before and 1 year after initiating ART. Mean difference tests were used to obtain overall trends in days harvesting tea by month. A difference in difference approach was used to estimate the impact of HIV/AIDS on days working in the pre-ART period. Information on likely trends in the absence of the therapy was used to estimate the positive impacts on days harvesting tea over the initial 12 months on ART. Results: No significant difference existed in days plucking tea each month until the ninth month before initiating ART, when workers worked -2.79 fewer days than references (15% less). This difference grew to 5.09 fewer days (27% less) in the final month before initiating ART. After 12 months on ART, we conservatively estimate that workers worked at least twice as many days in the month than they would have in the absence of ART. Conclusions: Treatment had a large, positive impact on the ability of workers to undertake their primary work activity, harvesting tea, in the first year on ART. (C) 2008 Wolters Kluwer Health | Lippincott Williams & Wilkins.