TRIMETHOPRIM-SULFAMETHOXAZOLE FOR PNEUMOCYSTIS JIROVECII PNEUMONIA PROPHYLAXIS AMONG HIV-POSITIVE PATIENTS IN THE ERA OF EARLY ANTIRETROVIRAL THERAPY INITIATION

Background: Trimethoprim-Sulfamethoxazole (TMP-SMX) is currently recommended for the primary prevention of Pneumocystis jirovecii pneumonia (PCP) among HIV-positive patients whose CD4 count is less than 200 cells/mm3. However, adverse drug reactions (ADR) have been reported among some patients. In the era of early antiretroviral therapy (ART) initiation, the prevalence of PCP has gradually decreased. Therefore, to avoid unnecessary ADR, TMP-SMX might be less beneficial when the patient receives early ART initiation.
 Objectives: The study aimed to evaluate the incidence of PCP, all-cause mortality, CD4 count at 6 months after ART, other opportunistic infections (OIs), and ADRs among HIV-positive patients receiving early ART initiation with and without TMP-SMX for PCP prophylaxis.
 Methods: This retrospective cohort study was conducted in Ratchaburi Hospital between January 2014 and February 2022. HIV-positive patients with an initial CD4 count <200 cells/mm3 or <14% and receiving early ART initiation within 2 weeks after HIV diagnosis were investigated. Patients with and without TMP-SMX prophylaxis were analyzed in terms of baseline characteristics, the incidence of PCP, all-cause mortality, other OIs and ADRs from TMP-SMX. The ratio of TMP-SMX vs. no TMP-SMX groups was 2:1.
 Results: In total, 230 HIV-positive patients presenting an initial CD4 count <200 cells/mm3 or <14% were included in this study. All patients received early ART initiation within 2 weeks after HIV diagnosis and showed good adherence. The incidence of PCP in the TMP-SMX prophylaxis group was 2 of 153 cases (1.31%) and in the no prophylaxis group was 3 of 77 cases (3.89%), OR 0.329; 95% CI, (0.053 – 1.998); p=0.226. CD4 count at 6 months after ART initiation significantly increased in the no prophylaxis group (277.4 vs. 179.5 cells/mm3; mean difference 97.92; 95% CI of difference, (65.15-130.69); p <0.001). All-cause mortality and other bacterial and OIs did not differ between the two groups. All adverse events from TMP-SMX were minor rashes, 13 of 153 cases (8.5%).
 Conclusion: Among HIV-positive patients receiving early ART initiation, the incidence of PCP revealed no difference between with and without TMP-SMX prophylaxis. All-cause mortality and rate of OI were also comparable between the 2 groups.