The association between primary source of ambulatory care and access to and outcomes of treatment among AIDS patients.

OBJECTIVES: To examine the relationship between having a primary source of ambulatory care (PSAC), access to AIDS treatment and prophylaxis for opportunistic infection, and hospital and mortality outcomes among heterosexual men and women with AIDS.
METHODS: Using a linked AIDS Registry-Medicaid database, 366 adults were identified (1989-1991) with at least 1 year of continuous Medicaid enrollment before AIDS diagnosis, who survived 2 weeks after diagnosis, and with no antiretroviral use or Pneumocystis carinii pneumonia (PCP) prophylaxis during the pre-diagnosis year. Outcomes included times to zidovudine treatment, PCP prophylaxis, hospitalization and death following diagnosis. Multivariate proportional hazards models were used to estimate the effects of patients' PSAC status in the 12-month post-diagnosis period on outcomes, controlling for demographic and case-mix variables.
RESULTS: Study criteria preferentially included females, non-whites and enrollees eligible on the basis of aid to families with dependent children. A total of 49% of the patients had no PSAC. Patients with a PSAC were more likely to have received zidovudine [relative risk (RR) = 1.75, 95% confidence interval (CI) = 1.2, 2.2] or PCP prophylaxis (RR = 2.22, 95% CI = 1.5, 3.3). Regression models simultaneously examining association of the propensity to use zidovudine and PCP prophylaxis agents with death indicated that zidovudine-treated and PCP-prophylaxed patients were 64% and 51% less likely to die, respectively (RRdeath,zidovudine = (.36, 95% CI = 0.2, 0.4; RRdeath, PCP prophylaxis = 0.49, 95% CI = 0.3, 0.8).
CONCLUSIONS: Patients' underuse of zidovudine and PCP prophylaxis was systematically associated with not having a PSAC. Lack of PSAC, in turn, predicted shorter survival but not increased hospitalization. Female gender, injecting drug use, non-white race and earlier diagnosis year also predicted poorer outcomes.