The current study extends earlier findings of short-term improvements in physical wellbeing among HIV-positive tea plantation workers after initiating ART in western Kenya (Larson et al., 2008
). We have demonstrated that initial improvements in physical wellbeing among 222 individuals were sustained over two years on ART even after adjustment for confounding. We noted substantial declines in reports of most negative symptoms of physical wellbeing over two years. In some cases the declines were dramatic, from approximately 41% of subjects reporting fatigue often at ART initiation to about 15% at two years. These gains in physical wellbeing are encouraging and should be recognized as part of the overall benefit of ART.
Our results are consistent with previous findings in this cohort which showed that initiating ART coincided with substantial increases in days worked compared to their pre-ART working patterns, and to levels similar, though somewhat lower than the general population (Larson et al., 2008
). The current study demonstrates that these productivity gains are accompanied by improvements in physical wellbeing. We cannot distinguish the direction of the effects from our data—that is, whether ART improves physical wellbeing which leads to an improved ability to work, or ART improves the ability to work, which then leads to improvements in physical wellbeing. We speculate, however, that the first relationship is more likely.
While we estimated substantial reductions in the frequency of having symptoms often overtime, we did not detect significant continual improvements over time. For example, outcomes after one year on ART were not statistically different from two years on ART. Future research in larger cohorts is needed to determine if gains on ART continue to increase over time.
Our findings are also consistent with earlier evidence from a clinical trial in Uganda (Stangl, Wamai, Mermin, Awor, & Bunnell, 2007
) and data from South Africa (Jelsma, Maclean, Hughes, Tinise, & Darder, 2005c) which showed significant decreases in reports of negative symptoms after one year on ART. Our findings extend these earlier results by showing that gains are largely sustained over the second year on ART.
We did note, however, some increased reporting of bodily pain and skin rash at two years compared to levels reported at earlier time points. It is encouraging to note that in all cases levels of these symptoms at two years were still below what was observed at ART initiation. If real, however, these increases are troubling and may warn of problems as treatment programs mature, particularly if these increases are markers for ART treatment failure. Two-year attrition rates from ART programs have been shown to be as high as 40% (Rosen, Fox, & Gill, 2007
), and attrition is likely affected by patients experiencing symptoms while on ART. Long-term monitoring of patient welfare will therefore be needed to ensure that treatment programs continue to generate benefits for patients and families. If these late upward trends are substantiated or continue to increase after two years, program resources will likely need to be targeted at dealing with negative changes in wellbeing.
Our study should be considered in light of several limitations. First, because our study was nested within a larger cohort study, our data do not come from patients all enrolled at the time of ART initiation. Many patients were already on ART at enrollment and we therefore have no pre-ART baseline comparison. However, assuming subjects do represent a random sample of all ART patients in the program, the medians and proportions calculated over time will still be valid estimates of the impact of ART.
Second, there may be some selection bias in our study. Sicker patients would be more likely to leave care before study enrollment began. Sicker patients might also have been less likely to enroll if experiencing significant problems during their clinic visits. Thus, the tea pluckers enrolled were likely to be healthier than the general population of tea pluckers on ART during enrollment. Once enrolled in the overall study, however, productivity records show that study subjects continued to be employed and experienced substantial improvements in work outcomes after one year on ART. Thus the results presented here may underestimate the average populationlevel improvements from ART if patients remain in care. Our findings should be interpreted as being conditional on remaining in care for two years.
Although this study is being conducted in a plantation setting, plucking tea is physically demanding outdoor work like much agricultural work in Africa. Pluckers walk substantial distances to fields, stand for hours, carry heavy packs to weighing stations, and are constantly reaching, plucking, and tossing tea leaf in their basket. Many of the characteristics of tea plucking are thus similar to other types of labor commonly found in rural Kenya, such as family labor on one’s own farm.
Third, our measures of physical wellbeing were based on self-report and reflect subjects’ recall ability over the previous seven or thirty days. Recall bias is possible, particularly if symptoms are more likely to be remembered by patients who have been on treatment for shorter or longer periods of time. If time since treatment initiation leads to a decrease in reports of symptoms, rather than an actual decrease, then the declines we observed will overestimate the impact of ART on wellbeing.
Fourth, tea pluckers are generally not as poor as the surrounding rural population and generally have good access to high quality health care. Barriers to accessing and adhering to ART within this setting are probably as low as possible. Cash transportation costs to the ART clinic are zero (the company provides transportation) and travel times are modest. If long term adherence to ART is substantially worse among the general rural population, the potential positive socio-economic impacts of ART among rural populations will be muted.
Finally, we had no data on treatment adherence, and thus were not able to adjust for differences in adherence over time. If patients were not adhering to their medications, symptoms might be observed that are not directly related to medication, but rather to the underlying illness. This increase in symptoms would likely occur well after the initiation of treatment as patients either began experiencing side effects or treatment fatigue. This may explain why reports of symptoms increase approaching two years, though our data cannot discern this.
In conclusion, we found substantial improvements in physical wellbeing over the two years since ARV initiation. Improvements were largest in the first few months after initiating treatment but were generally sustained over two years. These gains are important in sustaining long-term adherence to ART and as such the long-term success of HIV treatment programs, but future research should be targeted at determining predictors of wellbeing on ART. We did note some increases in reports of negative symptoms near two years on treatment and these changes will need to be monitored to make sure improvements in wellbeing are not reversed with long-term care.