Malaria as a cause of morbidity and mortality in children with homozygous sickle cell disease on the coast of Kenya

Abstract

Background: To date, it has been widely assumed that malaria is a common cause of morbidity and mortality in children with sickle cell disease (SCD) in malaria-endemic countries, and as a result, malarial prophylaxis is commonly recommended. Nevertheless, few data are available that support this practice.

Methods: We conducted a retrospective analysis of the data collected prospectively from children aged 0-13 years who were admitted to Kilifi District Hospital during the period from July 1998 through June 2005. We studied the prevalence, clinical features, and outcome of malarial infections in these children, stratified by SCD status.

Results: Although we estimated the prevalence of SCD in children to be only 0.8% (71 of 8531 children) during the period from August 2006 through September 2008 in the community surrounding the hospital, 555 (1.6%) of 34,529 children admitted to the hospital during the study period (i.e., from July 1998 through June 2005) were children with SCD; in fact, a total of 309 children with SCD were admitted 555 times. The prevalence of Plasmodium falciparum parasitemia was lower among children with SCD than it was among children without SCD (86 [15.6%] of 551 children vs. 13,835 [41.3%] of 33,500 children; P < .001). Similarly, among those infected with P. falciparum parasites, the mean parasite density was significantly lower among children with SCD than it was among children without SCD (2205 vs. 23,878 parasites/microL; P < .001). Fourteen (16.3%) of 86 parasitemic patients with SCD had features consistent with severe malaria, compared with 3424 (24.7%) of 13,835 parasitemic patients without SCD (odds ratio, 0.59; P < .07). We found no association between malarial parasitemia and death.

Conclusions: We found no evidence to support the conclusion that the risk of malaria is higher among children with SCD than it is among children without SCD in a rural area on the coast of Kenya. Further studies should be undertaken to help policy makers develop appropriate guidelines regarding malarial prophylaxis for patients with SCD in malaria-endemic regions.

Figure 1

Parasite densities among patients with and without sickle cell disease (SCD), by age group. Densities were calculated from the ratio of parasites to white blood cells or from the ratio of parasites to red blood cells for more severe infections.

Figure 2

Prevalence of malaria among patients with and without sickle cell disease (SCD), by year of hospital admission.

Figure 3

Odds ratios (ORs) and 95% confidence intervals (CIs) for malarial parasitemia among 2 subgroups of patients with sickle cell disease (SCD; i.e., clinic attender and clinic nonattenders), by age group. ORs were derived by generalized estimating equation analysis.