Mandatory HIV screening of United States Air Force (USAF) personnel every two years effectively identifies incident cases, however testing frequency limits the ability to detect early HIV infection. Identifying clinical indicators of HIV in the USAF population is necessary to develop a supplemental provider-based targeted testing strategy. We conducted a matched case-control study of male active duty USAF personnel with a new HIV diagnosis (n = 452) between 1996 and 2011 matched to five randomly selected controls (n = 2176). The relationship between clinical diagnoses, determined by ICD-9 codes, and HIV infection was assessed using conditional logistic regression. In unadjusted analyses of ICD-9 codes ever and within the last two years before HIV diagnosis, the conditional odds of HIV infection were greater in those with clinical signs and symptoms of HIV (cOR 5.05, 95% CI 4.00-6.39), mental health diagnoses (cOR 2.61, 95% CI 1.86-3.67), and STI diagnoses (cOR 2.33, 95% CI 1.50-3.60). Compared to those with ≤10 medical encounters in the two years prior to HIV diagnosis, individuals with 11-35 medical encounters (cOR 2.19, 95% CI 1.73-2.79) and >35 medical encounters (cOR 4.15, 95% CI 2.69-6.39) had a higher odds of HIV acquisition. In multivariate analyses, clinical signs and symptoms of HIV within the last two years of HIV diagnosis (cOR 4.10, 95% CI 3.22-5.22) and ever having a mental health diagnosis (cOR 1.97, 95% CI 1.44-2.70) remained significant (p < .01). Clinical encounters, particularly those featuring clinical signs and symptoms of HIV or a history of mental health complaints, provide an opportunity for targeted testing as a supplement to mandated testing at two-year intervals. Provider education to increase HIV testing in persons at risk would enhance early HIV diagnosis and potentially reduce forward transmission in the USAF population.
Keywords: HIV; USAF; mental health; risk factors; targeted testing.