Haematological changes and infectious complications in anorexia nervosa: a case-control study

To determine the prevalence of haematological abnormalitiesin patients with anorexia nervosa (AN), and assess the relationshipsbetween these changes, the severity of AN and the propensityto infections, we retrospectively studied 67 patients who metthe DSM-III-R diagnostic criteria for AN. We recorded physicalfindings and routine haematological data on admission, and infectiousevents during hospitalization. The patients were compared with67 normal controls matched for age and sex. Mean haemoglobin(Hb) was normal but lower in AN patients than in controls (131± 1 9 vs. 137 + 11 g/l, p=0.03) and the prevalence ofanaemia (Hb<120 g/l) was higher in the AN group (27% vs.1.5%, p<0.0001). Patients had a lower leucocyte count (4.94+ 1.9 vs. 6.78 + 2.4 x10⁹/ l , p< 0.0001), and increasedprevalence of leucopenia ( < 4 x 10 ⁹ cells/l)(36% vs. 1.5%,p<0.0001), neutropenia (<1500x10⁶ cells/l)(17% vs. 0%,p=0.0015)and thrombocytopenia (<150x109 / l ) (10% vs. 0%, p = 0.03).Only 2 patients (3%) had pancytopenia, but 9/17 patients withanaemia (53%) also had leucopenia. There was a slight but significantcorrelation between body-mass index (BMI) and total leucocyte,neutrophil and red blood cell counts. Severe infectious complicationsoccurred in 9% of AN patients vs. 0% in controls (p = 0.01);they were more frequent with neutropenia (relative risk, 15.1:95% Cl, 10–20.2) or low (<12) BMI (relative risk, 11.6:95% Cl, 6.6–16.6) on admission. Compared with controls,AN patients thus had an increased prevalence of anaemia, leucopeniaand thrombocytopenia. The severity of AN, as assessed by BMI,correlated with leucocyte, neutrophil and red blood cell countsbut not with platelet count The risk for subsequently developingsevere infections was significantly increased when low BMI orneutropenia was found on admission.