Childhood trauma and health outcomes in HIV-infected patients: an exploration of causal pathways

Abstract

Objective: Traumatic life histories are highly prevalent in people living with HIV/AIDS and predict sexual risk behaviors, medication adherence, and all-cause mortality. Yet the causal pathways explaining these relationships remain poorly understood. We sought to quantify the association of trauma with negative behavioral and health outcomes and to assess whether those associations were explained by mediation through psychosocial characteristics.

Methods: In 611 outpatient people living with HIV/AIDS, we tested whether trauma's influence on later health and behaviors was mediated by coping styles, self-efficacy, social support, trust in the medical system, recent stressful life events, mental health, and substance abuse.

Results: In models adjusting only for sociodemographic and transmission category confounders (estimating total effects), pasttrauma exposure was associated with 7 behavioral and health outcomes including increased odds or hazard of recent unprotected sex [odds ratio (OR) = 1.17 per each additional type of trauma, 95% confidence interval = 1.07 to 1.29], medication nonadherence (OR = 1.13, 1.02 to 1.25), hospitalizations (hazard ratio = 1.12, 1.04 to 1.22), and HIV disease progression (hazard ratio = 1.10, 0.98 to 1.23). When all hypothesized mediators were included, the associations of trauma with health care utilization outcomes were reduced by about 50%, suggesting partial mediation (eg, OR for hospitalization changed from 1.12 to 1.07), whereas point estimates for behavioral and incident health outcomes remained largely unchanged, suggesting no mediation (eg, OR for unprotected sex changed from 1.17 to 1.18). Trauma remained associated with most outcomes even after adjusting for all hypothesized psychosocial mediators.

Conclusions: These data suggest that past trauma influences adult health and behaviors through pathways other than the psychosocial mediators considered in this model.

Figures

Figure 1

Mediation analysis. Figure 1(a). Model estimating the total effect (path c) of lifetime trauma experience on health behaviors and outcomes, adjusted for confounders. Figure 1(b). Model estimating the remaining direct effect (path c') of lifetime trauma experience on health behaviors and outcomes, after adjusting for hypothesized mediators. If the mediators explain all of the causal pathways through which trauma affects outcomes, we would expect path c' to be null. If the mediators explain none of the effect of trauma on outcomes, we would expect path c' to approximately equal path c from Figure 1a. If the mediators explain part of the pathways through which trauma affects outcomes, we would expect path c' to be attenuated relative to path c but non-null.

Figure 1

Mediation analysis. Figure 1(a). Model estimating the total effect (path c) of lifetime trauma experience on health behaviors and outcomes, adjusted for confounders. Figure 1(b). Model estimating the remaining direct effect (path c') of lifetime trauma experience on health behaviors and outcomes, after adjusting for hypothesized mediators. If the mediators explain all of the causal pathways through which trauma affects outcomes, we would expect path c' to be null. If the mediators explain none of the effect of trauma on outcomes, we would expect path c' to approximately equal path c from Figure 1a. If the mediators explain part of the pathways through which trauma affects outcomes, we would expect path c' to be attenuated relative to path c but non-null.

Figure 2

Association of lifetime trauma exposure with (a) odds of any hospitalization in past 9 months and (b) odds of antiretroviral nonadherence in past week, and assessment of mediation by psychosocial characteristics. Path c represents the total effect adjusted for confounders; path c' represents the remaining direct effect after accounting for mediation by psychosocial characteristics.

Figure 2

Association of lifetime trauma exposure with (a) odds of any hospitalization in past 9 months and (b) odds of antiretroviral nonadherence in past week, and assessment of mediation by psychosocial characteristics. Path c represents the total effect adjusted for confounders; path c' represents the remaining direct effect after accounting for mediation by psychosocial characteristics.