Background: Highly active antiretroviral therapy (HAART) for people living with HIV/AIDS (PLWHA) has been generally accepted as the gold standard for the management of HIV patients but conflicting reports about the ability of HAART to improve upon the quality of life of HIV patients has cast doubts over the efficacy and the need for therapy.

Objective: This study was conducted to assess the efficacy and ability of HAART to resolve immunological and haematological abnormalities in HIV infected patients, existent sex variations in immunological and haematological parameters and CD4 predictive ability of the study parameters.

Methods: A total of 442 PLWHA consisting of 166 patients on HAART (28 males and 138 females) and 276 HAART-naïve patients (76 males and 200 females) were recruited for this study. Complete haemogram, immunological analysis (CD4 & CD3) and weight were measured for all the patients.

Results: HAART patients were older and heavier than their naïve counterparts. The incidence of anaemia (Hb less or equal to 10.5 (63%) and PCV < 30% (37.6%)) and lymphopoenia (16.7%) in HAART-naïve patients was significantly higher compared to their counterparts on HAART (46%, 15.2% and 5.3%) respectively. 70% of HAART-naïve females had anaemia in comparison to 44% in HAART-naïve males (P = 0.0001). The likelihood of developing microcytic hypochromic anaemia in HAART-naïve patients was 5 times more compared to those on HAART (P = 0.0002). Total lymphocyte count, haemoglobin, lymphocyte count and weight were significant predictors of CD4 counts and TLC values between 1.0 - 2.0 k µL(-1) was a significant predictor of CD4 <200 cells mm(-3).

Conclusion: HAART has the capability of reducing the incidence of anaemia and lymphopoenia which are associated with disease progression and death in HIV infected patients. Total lymphocyte count, haemoglobin and weight could also serve as useful predictive tools in the management and monitoring of HIV infected patients in resource limited settings.