Associations between HIV infection status, psychosocial factors, and adjuvant endocrine therapy adherence among South African women with early-stage breast cancer.

Abstract

We aimed to evaluate for associations between HIV status, psychosocial factors, and adjuvant endocrine therapy (AET) adherence in South African (SA) women with estrogen receptor positive (ER+) breast cancer (BC). We enrolled South African women with early-stage ER + BC in remission and prescribed tamoxifen or an aromatase inhibitor to the prospective observational study. We performed AET pill counts at enrollment, 12 weeks, and 24 weeks, and calculated adherence ratios of pills consumed between visits to days between visits. Women completed questionnaires on social support, attitude towards medication, health literacy, self-efficacy, mental health, and AET toxicity. We collected household wealth data. We used hierarchical linear (HLM) and structural equation modelling (SEM) to compare adherence ratios between women with and without HIV while adjusting for psychosocial factors. We collected adherence data from 239 women, 63 (26.4%) with co-morbid HIV. Comparing women with and without HIV, median AET adherence ratio was 0.88 vs 0.89, respectively (HLM p = 0.31). In our SEM model for the full cohort, mental health, healthcare savvy, and side effect burden latent variables were not significantly associated with adherence. In the subgroup of women living with HIV, lower SES quintile (β 0.04, SE 0.02, p = 0.08) and poorer mental health (β -0.02, SE 0.01, p = 0.10) showed trends toward association with adherence. HIV status is not predictive of AET adherence among SA women with ER + BC, though decreasing SES status and increasing mental health symptoms are marginally associated with adherence in women with BC and HIV.