Ocular opportunistic infection incidences among patients who are HIV positive compared to patients who are HIV negative

Objective: The purpose of the study was to examine the incidence of ocular opportunistic infections among patients who are human immunodeficiency virus (HIV) positive compared to patients who are HIV negative. Design: The study design was a retrospective cohort study. Participants: All patients were recruited from 1984 until 1995 at the San Francisco General Hospital. Intervention: Incidences for numerous diagnoses were compared among the exposure group (HIV positive) and nonexposed control group (HIV negative). Main Outcome Measures: The diagnoses studied were cytomegalovirus (CMV) retinitis, herpes zoster ophthalmicus, Pneumocystis carinii choroidopathy, herpes simplex keratitis, Toxoplasma retinitis, fungal retinitis, ocular syphilis, and ocular lymphoma. Results: Among the HIV-positive pool, there were 1800 patient visits with a total of 5200 person-years of follow-up. Among the HIV-negative control pool, there were 48,200 patient visits with a total of 30,100 person-years of follow-up. Incidence rates were calculated using the product-limit method, and risk ratios were calculated using the Cox proportional hazards model. Incidence rate differences were calculated using the incidence density method. Among the outcomes studied, only CMV retinitis, herpes zoster ophthalmicus, and, to a lesser extent, Toxoplasma retinitis showed both an elevated risk ratio and rate difference among patients who were HIV positive compared to patients who were HIV negative. Of the other outcomes studied, either the risk ratio, rate difference, or both were similar among patients who were HIV positive compared to patients who were HIV negative. Conclusions: Not all ocular infections seen in patients who are HIV positive should be considered opportunistic, because many occur with similar incidence among patients who are HIV negative. The biologic reasons for this will require further study.