An analysis of medication adherence and optimism-pessimism in a population of people living with HIV/AIDS Open Access
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The purpose of this research was to investigate and elucidate the relationship between medication adherence and optimism-pessimism in a population of people living with HIV/AIDS. The first aim was to assess the association between optimism-pessimism and two different measures of medication adherence via two different multivariable models. The first measure of adherence was a self-report measure of the frequency with which a person missed their medications for various reasons where a higher score denoted less adherence to their current medication regimen. A robust Poisson regression model was used as the primary mechanism to analyze this measure of adherence. The second measure of adherence was an ordinal-scaled question that inquired about level of confidence to take medication as prescribed by a health care provider. An ordered logit regression (proportional odds regression) was used to analyze this measure of adherence. In both analyses, the quantification of optimism-pessimism on medication adherence began with unadjusted univariate models then progressed to fully-adjusted multivariable models. The second aim was to determine whether the hypothesized association between optimism-pessimism and medication adherence followed from the expression of optimism-pessimism as a single, bipolar metric or as two distinct, unipolar metrics. Both expressions of optimism-pessimism -- the single continuum measure and the disaggregated unidimensional measures, respectively -- were included in the multivariable models proposed in the first aim. The data used in this project came from a randomized controlled trial conducted between December 2005 and January 2007 by the International Nursing Network for HIV/AIDS Research. The findings from this research indicated that optimism (both dispositional and disaggregated) was positively associated with medication adherence in unadjusted and partially adjusted models but not when depression, quality of life, and self-efficacy were adjusted for. An exploratory analysis that led to the stratification of the sample by the median age, 44, returned a positive association between optimism and medication adherence across all models among subjects <44 years of age. A similar pattern was observed for the association between optimism and confidence to take medications as directed. The analysis of optimism- pessimism as a single continuum or as two independent constructs suggested that optimism and pessimism are not opposite ends of the same continuum but represent two unipolar dimensions. Medication adherence is central to benefits realized at both the individual- and population-levels and these findings help to elucidate the relationship between adequate adherence and a not-yet-fully-understood psychological factor, optimism-pessimism.