Metabolic syndrome in patients with schizophrenia and other nonaffective psychoses is associated with a higher total and differential white blood cell count, increased high-sensitivity C-reactive protein levels, and higher monocyte levels, a small cross-sectional study shows.
The study also found that high-sensitivity C-reactive proteins (hs-CRPs) predicted two of the criteria for metabolic syndrome: an increased waist circumference and increased triglycerides, and both monocytes and lymphocytes were associated with increased triglycerides (all P values under .05).
Past research already had shown that schizophrenia patients were at an increased risk for metabolic syndrome, a combination of multiple factors that increase a person’s risk of developing cardiovascular disease. CVD is a leading killer of patients with nonaffective psychoses. Both schizophrenia and metabolic syndrome are associated with increased inflammation, and several studies have found associations between white blood cell (WBC) counts and metabolic syndrome.
Therefore, Dr. Brian J. Miller and his associates at Georgia Health Sciences University in Augusta, examined "the relationship between total and differential WBC counts, hs-CRP, and the metabolic syndrome in patients with schizophrenia and related nonaffective psychosis and in controls." The findings were published online Sept. 11 ahead of print (Brain Behav. Immun. 2012 [doi:10.1016/j.bbi.2012.08.016]).
At baseline, 59 inpatients and outpatients, aged 18-70 years, and 22 controls with no history of schizophrenia or mood disorders were assessed for psychosis and mood disorders using the Structured Clinical Interview for DSM-IV disorders. Participants with a range of conditions – including pregnancy, alcohol withdrawal, diabetes, recent surgery, recent drug use or current use of immunomodulatory agents, lipid-lowering therapies or antibiotics – were excluded. The Positive and Negative Syndrome Scale (PANSS) was used to evaluate patient symptoms. While four raters did the interviews for the subjects, a 100% concordance was achieved during prior training to ensure inter-rater reliability.
Among the patients, 39 had schizophrenia, 15 had schizoaffective disorder, 1 had brief psychotic disorder, and 4 had psychotic disorders not otherwise specified. Measurements of all participants also were taken for height, weight, waist circumference, and hip circumference. Their vital signs and a morning blood draw (between 8 and 9 a.m. after a 10-hour fast) also were taken to gather complete blood counts, fasting serum glucose, and a lipid panels analysis.
A total of 32% of the patients and 23% of the control group had metabolic syndrome based on having three or more of the five criteria: a waist circumference greater than or equal to 102 cm in males and greater than or equal to 88 cm in females; fasting triglycerides greater than or equal to 150 mg/dL; fasting HDL less than 40 mg/dL in males or less than 50 mg/dL in females; blood pressure greater than or equal to 130/85 mmHg (or taking medication to manage a history of hypertension); and a fasting glucose over greater than or equal to 100 mg/dL (or taking medication for increased glucose levels).
Using binary logistic regression models, the authors calculated how predictive the participants’ WBC counts, hs-CRP levels, monocytes, and lymphocytes were of metabolic syndrome and its criteria. The associations they found remained after controlling for age, sex, race, smoking, parental history of diabetes, age at first hospitalization for psychosis, and current psychotropic medications. (Only four patients were not taking antipsychotics, and 27% were taking risperidone.) The link between WBC counts, hs-CRP, and monocytes with metabolic syndrome existed for the controls as well, but those results did not achieve statistical power because of the small sample size.
"Taken together, our results contribute to a growing body of evidence for an association between inflammation and the metabolic syndrome in nonaffective psychoses," the authors reported. Their findings were limited by the study’s small size, mix of inpatients and outpatients, and diversity in patient treatments.
Consensus guidelines from the American Psychiatric Association and the American Diabetes Association recommend metabolic monitoring of patients taking antipsychotics. Yet "monitoring rates in clinical practice remain alarmingly low," and the researchers suggest taking account of patients’ WBC counts and hs-CRP levels. If their findings are replicated through further research, the researchers said, the cardiovascular risk of patients with nonaffective psychoses such as schizophrenia might be reduced if the patients were prescribed statins or another anti-inflammatory drug.
Dr. Miller reported receiving grant support from several sources, including the National Institutes of Health and Oy H. Lundbeck Ab; consultancy fees on behalf of Genentech/Roche; and speaker fees from the Maryland Psychiatric Research Center.