Anaemia in a rural Ugandan HIV cohort: prevalence at enrolment, incidence, diagnosis and associated factors.

OBJECTIVES

To determine the prevalence and incidence of anaemia in HIV-positive and negative individuals; to identify risk factors for anaemia, prior to the introduction of HAART; and to determine the validity of the clinical diagnosis of anaemia.

METHODS

Between 1990 and 2003, we followed a rural population based cohort of HIV-infected and uninfected participants. Prevalence and incidence of anaemia were determined clinically and by laboratory measurements. The sensitivity, specificity and predictive values of clinical diagnosis were calculated.

RESULTS

The prevalence of anaemia at enrolment was 18.9% among HIV-positive and 12.9% among HIV-negative participants (P = 0.065). Incidence of anaemia increased with HIV disease progression, from 103 per 1000 person-years of observation among those with CD4 counts >500 to 289 per 1000 person-years of observation among those with CD4 counts <200. Compared to laboratory diagnosis, the clinical diagnosis of anaemia had a sensitivity of 17.8%, specificity of 96.8%, a positive predictive value of 50.6% and a negative predictive value of 86.4%. Being female, low CD4 cell counts, HIV-positive, wasting syndrome, WHO stage 3 or 4, malaria, fever, pneumonia and oral candidiasis were associated with prevalent anaemia.

CONCLUSIONS

Anaemia prevalence and incidence were higher among HIV-positive than negative participants. Compared to laboratory diagnosis, clinical detection of anaemia had a low sensitivity. Clinicians working in settings with limited laboratory support must be conscious of the risk of anaemia when managing HIV/AIDS patients, particularly when using antiretroviral drugs which by themselves may cause anaemia as a side effect. We recommend that haemoglobin should be measured before starting ART and monthly for the first three months.