Aim: Newborns admitted to neonatal units (NNUs) in resource-limited settings face a high risk of mortality, but the epidemiology of these deaths is poorly understood. We describe risk factors for NNU mortality in an area with high prevalence of human immunodeficiency virus (HIV).

Methods: We performed a prospective cohort study of infants admitted to the NNU at a public referral hospital in Gaborone, Botswana. The primary outcome was neonatal death, defined as death within 28 days of a live delivery. Cox proportional hazard models were used to evaluate risk factors for mortality.

Results: From October 2008 to April 2009, 449 neonates were admitted to the NNU. Cumulative mortality was 24.5% (110/449). Factors associated with increased risk of death included lack of enteral feeding (hazard ratio (HR) 18.8, 95% confidence interval (CI) 10.3, 34.2), gestational age <28 weeks (HR 2.0, 95% CI 1.1, 3.8) and Apgar score <7 at 10 min (HR 2.5, 95% CI 1.5, 4.2). Among 348 (78%) infants who were fed, there was no difference in mortality between infants who were breastfed compared with those who were formula fed or had mixed feeding (P = 0.76). There was no significant mortality difference by HIV exposure status; 35 (28%) of 128 HIV-exposed infants died compared with 55 (21%) of 272 HIV-unexposed infants (P = 0.19).

Conclusions: This study identified low Apgar scores, extreme prematurity and lack of enteral feeding as the most important risk factors for mortality in this NNU setting. HIV exposure and formula feeding were not significantly associated with death in neonates who were very ill.

Keywords: Botswana; HIV; feeding method; neonatal intensive care unit; neonatal mortality.