Incidence and risk factors for pneumonia in HIV infected and non-infected drug users.

OBJECTIVE

To study the incidence and risk factors for pneumonia in a cohort of HIV infected and non-infected drug users (DU).

DESIGN

A prospective epidemiological study.

SETTING AND PATIENTS

Injecting and non-injecting DU who attended the Municipal Health Service in Amsterdam for follow-up visits in the study.

MAIN RESULTS

203 HIV infected and 437 non-infected DU were followed for a total of 1749 person-years. HIV infected DU reported 111 episodes of pneumonia, which required hospitalization in 29 cases, and HIV negative DU reported 55 episodes, which required hospitalization in nine cases. The incidences among HIV positive and HIV negative DU were 0.19 and 0.05 per person-year respectively. With multivariate Poisson regression current injecting (RR 2.13), recent seroconversion (RR 3.92), asthmatic constitution (RR 2.72), CD4+ cell count between 200-500 (RR 1.67 compared to > 500), CD4+ cell count less than 200 (RR 2.23 compared to > 500) and a previous history of pneumonia (RR 2.43) were independently associated with self-reported pneumonia among HIV infected DU. Among HIV negative DU heroin smoking (RR 1.87), asthmatic constitution (RR 3.62) and a previous history of pneumonia (RR 2.84) were independently associated with self-reported pneumonia. Also a higher Quetelet Index (QI) appeared to be protective (QI > or = 21 RR 0.42, QI 19-21 RR 0.82 compared to QI < 19) among HIV negative DU. Risk factors for reported and hospitalized cases of pneumonia were comparable among HIV positive DU.

CONCLUSIONS

HIV infected DU are at increased risk for pneumonia and the rate increases with lower CD4 cell counts. Also behavioural characteristics, such as injecting drug use and smoking heroin, and clinical history variables, such as a history of pneumonia or an asthmatic constitution, are risk factors for pneumonia among DU. Pneumococcal vaccination should not only be focused on HIV positive DU but also on the identified risk groups among HIV negative DU.