Incidence and risk factor of major opportunistic infections after initiation of antiretroviral therapy between HIV-infected patients with baseline CD4 cell counts ≤50 cells/mm³ and >50 cells/mm³

Abstract number: 1733_153

Manosuthi W., Chaovavanich A., Tansuphaswadikul S., Inthong Y., Chottanapund S., Sittibusaya C., Moolasart V., Sungkanuparph S.

Objectives: To study incidence and risk factors for new episodes of major opportunistic infections (OIs) after antiretroviral therapy (ART) among HIV-infected patients.

Methods: A retrospective cohort study was conducted among naïve HIV-infected patients who were initiated ART between January 2001 and December 2003. Patients were categorised into two groups based on baseline CD4 cell counts: group A (≤50 cells/mm³) and group B (>50 cells/mm³). All patients were followed until 15 months after ART initiation.

Results: There were 793 patients with a mean age of 35.1±7.4 years and 56% male. Of 793 patients, 531 (67.0%) were in group A and 262 (33.0%) were in group B. Median (IQR) CD4 cell count was 13 (6–26) cells/mm³ in group A and 116 (78–167) cells/mm³ in group B. Median (IQR) baseline plasma HIV RNA was 300,500 (138,500–556,000) copies/mL and 185,000 (68,500–577,500) copies/mL in the corresponding groups (P < 0.05). Group A had a higher proportion of male, previous OIs, body weight, transaminase enzymes (P < 0.05). Incidence of major OIs (i.e., tuberculosis, cryptococcosis, pneumocystis pneumonia, histoplamosis and CMV disease) at 1, 3, 6, and 12 months after ART were 2.8%, 6.6%, 8.3% and 9.8% in group A; and 1.5%, 1.9%, 3.1% and 3.5% in group B (log rank test, P = 0.002). Cox's proportional hazard model showed that the patients with baseline CD4 cell count ≤50 copies/mL was associated with high incidence of OIs after initiation of ART (P = 0.018, HR = 4.292, 95%CI = 1.289–14.286).

Conclusions: HIV-infected patients who had baseline CD4 ≤50 cells/mm³ had a higher probability of the occurrence of major OIs after initiation of ART than those who had baseline CD4 >50 cells/mm³. Closed monitoring of clinical condition is strongly recommended after ART initiation in patients with low baseline CD4 cell counts.