title: Clozapine and anemia: a 2-year follow-up study.
abstract: OBJECTIVE
  Clozapine's association with agranulocytosis led to the implementation of stringent and mandatory hematologic monitoring guidelines in most countries. Although other hematologic aberrations such as eosinophilia and neutropenia have been previously described, clozapine's impact on the erythroid lineage has not been studied. There is a suspicion that a higher rate of anemia is observed in patients receiving clozapine; therefore, we hypothesized that there would be a higher rate of anemia in patients receiving clozapine therapy.
  
  
  METHODS
  All individuals initiated on clozapine at our center from 2009 to 2010 were recruited. Information on age, gender, medical comorbidities, and smoking status was extracted from the medical records. Data from complete blood counts over a 2-year follow-up period were extracted, with anemia defined as a hemoglobin value below 120 g/L for women and 130 g/L for men. Time to anemia event was calculated and Cox regression was employed to identify predictors of anemia.
  
  
  RESULTS
  We found a high incidence of anemia in the first 2 years following clozapine initiation; of the 94 individuals (68 men, 26 women) recruited, 23 (24.5%) developed anemia. Higher baseline hemoglobin level (hazard ratio [HR] = 0.86, P = .002) and smoking status (HR = 0.21, P = .021) were identified as significant protective factors against anemia in men but not in women (HR = 0.92, P = .184, and HR = 0.52, P = .467 for baseline hemoglobin and smoking, respectively).
  
  
  CONCLUSIONS
  Although smoking appears to lower the risk of anemia, we believe this is due to smoking's up-regulation of hemoglobin levels. Further studies are warranted in light of the present findings; for example, we cannot exclude the possibility that anemia was an epiphenomenon, characterizing instead a population with severe mental illness.
authors: Schizophrenia Division, Centre for Addiction and Mental Health, 25 College St, Toronto, Ontario M5T 1R8 jimmy_lee@imh.com.sg.
authors: Jimmy
authors: J
authors: Lee
authors: Robert
authors: R
authors: Bies
authors: Amaal
authors: A
authors: Bhaloo
authors: Valerie
authors: V
authors: Powell
authors: Gary
authors: G
authors: Remington
mesh_terms: D000328:Adult; D000740:Anemia / Q000097:blood / Q000139:chemically induced* / Q000453:epidemiology; D014150:Antipsychotic Agents / Q000009:adverse effects* / Q000627:therapeutic use; D003024:Clozapine / Q000009:adverse effects* / Q000627:therapeutic use; D005260:Female; D005500:Follow-Up Studies; D006454:Hemoglobins / Q000378:metabolism*; D006801:Humans; D015994:Incidence; D008297:Male; D001523:Mental Disorders / Q000188:drug therapy; D012044:Regression Analysis; D012737:Sex Factors; D012907:Smoking; D013997:Time Factors
chemical_list: D014150:Antipsychotic Agents; D006454:Hemoglobins; D003024:Clozapine