Effect of administration of intestinal anthelmintic drugs on haemoglobin: systematic review of randomised controlled trials.

OBJECTIVE To evaluate the effect of routine administration of intestinal anthelmintic drugs on haemoglobin. DESIGN Systematic review of randomised controlled trials. DATA SOURCES Electronic databases and hand search of reviews, bibliographies of books, and abstracts and proceedings of international conferences. STUDY SELECTION Included studies were randomised or quasi-randomised controlled trials using an intestinal anthelmintic agent in the intervention group, in which haemoglobin was evaluated as an outcome measure. Trials in which treatment for schistosoma (praziquantel) was given exclusively to the intervention group were excluded. RESULTS The search identified 14 eligible randomised controlled trials. Data were available for 7829 subjects, of whom 4107 received an anthelmintic drug and 3722 received placebo. The pooled weighted mean difference (random effect model) of the change in haemoglobin was 1.71 (95% confidence interval 0.70 to 2.73) g/l (P<0.001; test for heterogeneity: Cochran Q=51.17, P<0.001; I(2)=61% (37% to 76%)). With the World Health Organization's recommended haemoglobin cut-offs of 120 g/l in adults and 110 g/l in children, the average estimated reduction in prevalence of anaemia ranged from 1.1% to 12.4% in adults and from 4.4% to 21.0% in children. The estimated reductions in the prevalence of anaemia increased with lower haemoglobin cut-offs used to define anaemia. CONCLUSIONS Routine administration of intestinal anthelmintic agents results in a marginal increase in haemoglobin (1.71 g/l), which could translate on a public health scale into a small (5% to 10%) reduction in the prevalence of anaemia in populations with a relatively high prevalence of intestinal helminthiasis.