Acta Tropica 113 (2010) 155–161 Contents lists available at ScienceDirect Acta Tropica journal homepage: www.elsevier.com/locate/actatropica Factors contributing to anaemia after uncomplicated Plasmodium falciparum malaria in children Akintunde Sowunmi ∗ , Grace O. Gbotosho, Christian T. Happi, Babasola A. Fateye Department of Pharmacology & Therapeutics, Institute for Medical Research and Training, University of Ibadan, Ibadan, Nigeria article info Article history: Received 23 January 2009 Received in revised form 15 June 2009 Accepted 20 October 2009 Available online 27 October 2009 Keywords: Malaria Anaemia Children Nigeria abstract The factors contributing to anaemia in falciparum malaria were characterized in 1261 prospectively stud- ied children in an endemic area of southwestern Nigeria. Of these, 487 (39%) presented with anaemia (haematocrit <30%). The following were found to be independent risk factors for anaemia at presen- tation: age <5 years, history of illness >3 days before presentation, presence of fever, a palpable liver, >parasitaemia 10,000/l blood, and gametocytaemia. The mean maximum fractional fall in haematocrit (FFH) after treatment was 13.8% (95% confidence interval [CI] 13–14.6) of the baseline value. This occurred 3 days after treatment began and correlated positively with enrolment haematocrit. In children whose haematocrit was >30% at enrolment, the following were found to be independent risk factors associated with subsequent development of anaemia during follow-up: age <5 years and parasitaemia ≥100,000 parasites/l. Haematological recovery was usually complete by 4–5 weeks, but was slower in children who were anaemic at enrolment and in those with recrudescence of their infections. Half of the children with recrudescence were still anaemic at 4 weeks. These findings have implications for the control of the burden of malarial anaemia in children in sub-Saharan African countries. © 2009 Elsevier B.V. All rights reserved. 1. Introduction Plasmodium falciparum malaria contributes significantly to the prevalence and severity of anaemia in malaria endemic coun- tries (Hedberg et al., 1993; Kitua et al., 1997; Cornet et al., 1998; Schellenberg et al., 1999; Crawley, 2004; Nkuo-Akenji et al., 2006). In these countries, anaemia is an important cause of childhood morbidity, and when it is severe, mortality in acute falciparum infections (Premji et al., 1995; Marsh et al., 1995; Newton et al., 1997; English, 2000; Murphy and Breman, 2001). In these children, particularly in young children, both clinical and sub-clinical infec- tions contribute to the anaemia associated with malaria (Kitua et al., 1997; Mockenhaupt et al., 1999, 2003; May et al., 2000). In West African children the prevalence of malaria-associated anaemia may range from 17 to 50% (Mockenhaupt et al., 1999; Ronald et al., 2006; Sowunmi et al., 2009). Despite this high prevalence, the factors that identify patients at risk of develop- ing anaemia during malaria have been infrequently studied in the region. Studies from the western border of Thailand (Price et al., 2001), an area of lesser intensity of malaria transmission (Luxemburger et al., 1996) than Nigeria (Salako et al., 1990), indi- ∗ Corresponding author at: Department of Clinical Pharmacology, University Col- lege Hospital, Ibadan, Nigeria. Tel.: +234 80 233 59390; fax: +234 2 2411843. E-mail address: akinsowunmi@hotmail.com (A. Sowunmi). cate that an age <5 years, a duration of illness >2 days, a palpable spleen or liver, female gender and recrudescent infections are independent predictors of anaemia in uncomplicated malaria. In addition, patients with drug-resistant infections were at risk of developing anaemia. With respect to drug resistance, it has also been reported that drug resistance could not be implicated in the pathogenesis of severe malaria (Quashie et al., 2006). It is unclear whether these factors, alone or in addition to others, are associated with the anaemia of acute malaria infections in Nigerian children. The pathogenesis of malarial anaemia is complex and, is due in part, to increased red blood cell destruction and reduced red blood cell production (Menendez et al., 2000; Eckvall et al., 2001; Price et al., 2001). In addition, the interaction between malarial anaemia and nutrition is complex; both may produce anaemia and lead to growth disturbance (Verhoef et al., 2002; Ronald et al., 2006; Sowunmi et al., 2007a) and both malaria and nutritional deficien- cies are common in areas of intense transmission. Few studies have examined the factors contributing to anaemia in falciparum malaria in Nigeria. In a study of Nigerian children with asymptomatic parasitaemias, May et al. (2000) identified polyclonal infections, a palpable spleen and the presence of - thalassaemia as predictors of anaemia. However, there is need to evaluate the factors contributing to anaemia in uncomplicated fal- ciparum infections in children because these infections are a major cause of morbidity and mortality and are more commonly encoun- tered in the health care setting than asymptomatic parasitaemias. 0001-706X/$ – see front matter © 2009 Elsevier B.V. All rights reserved. doi:10.1016/j.actatropica.2009.10.011