Incidence and risk factors of bacterial pneumonia requiring hospitalization in HIV-infected patients started on a protease inhibitor-containing regimen

Objectives To describe the incidence and risk factors of bacterial pneumonia occurring in patients treated with antiretrovirals. Methods In the ongoing APROCO (Anti-proteases) cohort, 1281 patients at the initiation of a protease inhibitor (PI)-containing antiretroviral regimen were enrolled from 1997-1999. All events requiring hospitalization during follow up are recorded. Of these, bacterial pneumonia was defined as the occurrence of a new pulmonary infiltrate with fever and either evidence of a bacteriological cause (definite cases) or favourable outcome with antimicrobial therapy (presumptive cases). Risk factors of bacterial pneumonia were studied using survival analyses. Results During a median follow up of 43 months, 29 patients had at least one episode of bacterial pneumonia, giving an incidence of 0.8/100 patient years. The 11 definite cases were attributable to Streptococcus pneumoniae (n=9), Legionella pneumophila (n=1) and Haemophilus influenzae (n=1). In multivariate analysis, bacterial pneumonia was significantly more frequent in older patients, injecting drug users, patients having a CD4 cell count > 500 cells/mu L at baseline and patients who initiated PI therapy with nonboosted saquinavir. It was significantly less frequent in nonsmokers. The occurrence of bacterial pneumonia was also associated with lower self-reported adherence to antiretroviral therapy and to higher plasma HIV-1 RNA levels during follow-up. Conclusions Bacterial pneumonia occurs rarely in patients treated with a PI-containing regimen and may be associated with virological failure.