Prevalence of the metabolic syndrome in patients with schizophrenia: baseline results from the Clinical Antipsychotic Trials of Intervention Effectiveness (CATIE) schizophrenia trial and comparison with national estimates from NHANES III
McEvoy JP, Meyer JM, Goff DC, Nasrallah HA, Davis SM, et al.;
Commented by , 22 Feb 2006
Aim of the study
In part due to the introduction of the new "atypical" antipsychotics, the issue of weight gain, obesity, metabolic syndrome in schizophrenia is currently hotly debated. Given the interest in this issue, it is, however, surprising that there is a relative dearth of pure epidemiologic studies that assess the extent of the problem from a global perspective.
The Clinical Antipsychotic Trials of Intervention Effectiveness (CATIE) Schizophrenia Trial was a large industry independent study that compared 4 atypical antipsychotics with perphenazine. The inclusion criteria were relatively broad allowing generalisability of the findings. The baseline data of this study were used for an assessment of the prevalence of metabolic syndrome in schizophrenia.
Methods
The prevalence of metabolic syndrome in two samples was compared. The schizophrenia sample were the baseline data of the participants from the CATIE study. These numbers were compared with a randomly selected sample from the US National Health and Nutrition Examination Survey (NHANES III).
Patients were matched according to age, gender and race/ethnicity. The criteria for metabolic syndrome were those of a) the National Cholesterol Education Program (NCEP), and b) those of the American Heart Association (AHA) which uses a lower fasting glucose threshold of 100 mg/dl.
Inclusion criteria for the current analysis were sufficient patient characteristic data, data on diabetes medication, data on use of antihypertensive drugs, and fasting glucose and lipid values (defined as >8 h after last meal).
Results
689 of 1460 CATIE patients met the inclusion criteria.The prevalence of metabolic syndrome was 40.9% according to NCEP and 42.7% according to AHA criteria. The prevalence was higher in women (51.6% and 54.2% according to NCEP and AHA) than in men (36.0%, p = .0002; and 36.6%, p = .0003).
When the CATIE patients were compared with the matched sample of the NHANES study using logistic regression with age, race and ethnicity as covariates, the CATIE men were 138% more likely to have MS, and the CATIE women were 251% more likely to have MS.
Dr Leucht's comments
The discussion around the atypical antipsychotics has stimulated research in the problem of medical illnesses in people with schizophrenia. Interestingly, the problem of obesity and associated problems is not new, but was already prevalent in the preatypical era (ref. 1).
Especially the so-called low potency antipsychotics such as chlorpromazine or thioridazine have been known for leading to weight gain (ref. 2). It is possible that psychiatrists were so concerned of the problem of extrapyramical side-effects and tardive dyskinesia of the old antipsychotics that metabolic syndrome did not receive the attention it deserved.
The current results from the CATIE study are certainly meaningful. A limitation, however, is that although the study was large and the inclusion criteria were relatively broad for a randomized, double-blind study, CATIE was not a population based study.
There is a dearth of such population based studies which assess the problem of obesity and metabolic syndrome. Only population based studies can provide a true estimate of the global impact of the problem.
References
1. Dixon L, Weiden P, Delahanty J, Goldberg R, Postrado L, Lucksted A and Lehman A. Prevalence and correlates of diabetes in national schizophrenia samples. Schizophrenia Bulletin 2000; 26 (4); 903-912
2. Allison DB, Mentore JL, Heo M, Chandler LP, Cappelleri JC, Infante MC and Weiden PJ. Antipsychotic-induced weight gain: a comprehensive research synthesis. American Journal of Psychiatry 1999; 156 (11); 1686-1696 (Free full text article)