Findings:
Using nationwide Medicaid claims data from 2001-2012, this population-based, retrospective study compared prevalence rates of retention in HIV care of persons with HIV (PWH) and schizophrenia with a control group of PWH without a diagnosis of schizophrenia or other major psychiatric disorder. Key findings included significantly lower prevalence of retention in care among PWH and schizophrenia compared to controls, 29.9% vs 38.5%, respectively. In subgroup analysis of demographic characteristics, men were less likely than women with HIV and schizophrenia to be retained in care, and White PWH and schizophrenia had lower retention rates compared to Blacks and Hispanics. In stratified analysis by substance use disorders, lower retention remained significantly more prevalent in PHW and schizophrenia compared to controls among those with alcohol, psychostimulant, sedative-hypnotic, and cannabis use disorders. Opioid use disorder was not associated with poorer retention in care. The association between medical comorbidities and lower retention varied by condition, Diabetes and hypertension were associated with lower rates of retention while dyslipidemia, hepatitis C, and other sexually transmitted infections conferred a greater likelihood of retention in care in PHW and schizophrenia, compared to controls. There was an overall decrease in disparity in retention in PWH with schizophrenia, compared to controls, over time.

Strengths and limitations:
This study’s strengths comprised its population-based sample of PWH, large size, nationwide scope, its use of both primary and secondary outcome measures, and several definitions of retention in care including CDC and US Health Resources and Services Administration definitions. The study was limited by lack of laboratory results, namely viral suppression, which is the gold standard for HIV quality of care. The data used was pooled from 45 states, and given the between-state heterogeneity observed, may not generalize to all states. Results may also not apply to other countries. The use of Medicaid data, and its delay in availability, may result in age of research findings. The introduction of the Affordable Care Act, after the study period, does not make it possible to assess the impact of this major national healthcare policy on HIV quality of care. Participants dually eligible for Medicare and Medicaid, which may represent a more medically and psychiatrically ill cohort, were excluded from involvement in the study. Thus, this study may underestimate the disparity in magnitude of association between schizophrenia and retention in HIV care.

Relevance:
Serious mental illness, such as schizophrenia is a risk factor for HIV, and the prevalence of schizophrenia in PWH exceeds that found in the general population. Schizophrenia alone is associated with higher morbidity and mortality and lower HIV testing rates, and confers an additional risk of early mortality in PWH and schizophrenia. Despite these known disparities along the full HIV continuum of HIV, there are only a limited number of studies examining retention in care among PWH with and without schizophrenia. This is the first nationally representative US study to assess the impact of schizophrenia on retention in HIV care. Study findings provide evidence for the utility of integration of care for patients “triply diagnosed” with HIV, major mental illness, and substance use disorders. Future research is needed to evaluate the effects of integrated care on treatment outcomes and retention in not only PWH, but also the “triply diagnosed” subpopulation.