798 Low Incidence of Communitiy-acquired Pneumonia in Patients Discontinuing Antibiotic Primary Prophylaxis Against Pneumocystis Pneumonia H. Furrer*1, C. Eigenmann1, M. Flepp2, E. Bernasconi3, V. Schiffer4, A. Telenti5, H. Bucher6, T. Wagels7, M. Egger1, Swiss HIV Cohort Study8 1Univ Hosp, Berne, Switzerland; 2Univ Hosp, Zurich, Switzerland; 3Cantonal Hosp Lugano, Switzerland; 4Univ Hosp, Geneva, Switzerland; 5Univ Hosp, Lausanne, Switzerland; 6Univ Hosp, Basel, Switzerland; 7Cantonal Hosp, St Gallen, Switzerland; and 8Lausanne, Switzerland
Background: Discontinuation of primary prophylaxis against Pneumocystis Pneumonia (PcP) is possible in patients (pts) with immunologic response to antiretroviral therapy without relevant risk of PcP. However, discontinuation of antibiotic prophylaxis with Trimethoprim/Sulfamethoxazole (TMP/SMX) may be associated with a higher risk of community acquired pneumonia.
Methods: Within the Swiss HIV Cohort Study, we performed a large prospective observational study that proved safety of discontinuation of primary PcP prophylaxis in pts with sustained increase of CD4 cell count above 200/mul. We compared the incidence of bacterial pneumonia in 336 pts who discontinued TMP/SMX as PCP prophylaxis within this study (group I) to the incidence in 75 pts (group II) that fulfilled the criteria for discontinuation in the same time period but kept on taking prophylaxis.
Results: During a total follow of 472 person-yrs in group 1, there were 12 cases of bacterial pneumonia in pts discontinuing TMP/SMX based PCP prophylaxis, corresponding to an incidence of 2.5 events per 100 person-yrs. In 75 pts continuing prophylaxis, there was 1 pneumonia diagnosed during a follow-up of 77 person-yrs corresponding to an incidence rate of 1.3 events per 100 person-yrs. The difference in incidence rates of 1.2 event per 100 person-yrs was not statistically significant (95 confidence interval of difference -1.6-4.1 events per 100 person-yrs).
Conclusions: Discontinuation of TMP/SMX-based primary prophylaxis against PCP is not associated with a significant increase in incidence bacterial pneumonia in pts with a sustained increase in CD4 counts above 200 cells per microliter. However, a minor increase in risk cannot be excluded and has to be weighted against the negative effects of taking long-term antibiotic prophylaxis.
