Metabolic Syndrome and Metabolic Abnormalities in Schizophrenia and Related Disorders

Individuals with schizophrenia have high levels of medical comorbidity and cardiovascular risk factors. The presence of 3 or more specific factors is indicative of metabolic syndrome, which is a significant influence upon future morbidity and mortality. We aimed to clarify the prevalence and predictors of metabolic syndrome (MetS) in adults with schizophrenia and related disorders, accounting for subgroup differences. A PRISMA systematic search, appraisal, and meta-analysis were conducted of 126 analyses in 77 publications (n = 25 692). The overall rate of MetS was 32.5% (95% CI = 30.1%–35.0%), and there were only minor differences according to the different definitions of MetS, treatment setting (inpatient vs outpatient), by country of origin and no appreciable difference between males and females. Older age had a modest influence on the rate of MetS (adjusted R 2 = .20; P < .0001), but the strongest influence was of illness duration (adjusted R 2 = .35; P < .0001). At a study level, waist size was most useful in predicting high rate of MetS with a sensitivity of 79.4% and a specificity of 78.8%. Sensitivity and specificity of high blood pressure, high triglycerides, high glucose and low high-density lipoprotein, and age (>38 y) are shown in supplementary appendix 2 online. Regarding prescribed antipsychotic medication, highest rates were seen in those prescribed clozapine (51.9%) and lowest rates of MetS in those who were unmedicated (20.2%). Present findings strongly support the notion that patients with schizophrenia should be considered a high-risk group. Patients with schizophrenia should receive regular monitoring and adequate treatment of cardio-metabolic risk factors.

To the authors’ knowledge, the present large-scale meta-analysis is the first to demonstrate that almost 1 in 3 of unselected patients with schizophrenia suffer from MetS. We found 126 valid analyses in 77 publications within the period 2003 to July 2011 (see figure 1). This indicates that the cardio-metabolic risk in patients with schizophrenia is clearly becoming recognized as a key consideration in the long-term health of these patients. Examining individual cardio-metabolic risk abnormalities, 1 in 2 patients with schizophrenia are overweight, 1 in 5 appear to have significant hyperglycaemia, and at least 2 in 5 have lipid abnormalities when systematically tested .

Although with limitations, our findings demonstrate that patients with schizophrenia are a high-risk group for MetS. They should therefore be routinely screened for MetS risk factors at key stages.[54,55] This can be achieved by establishing a risk profile based on consideration of medical factors (eg, obesity, dyslipidaemia, hypertension, hyperglycaemia, and established diabetes) but also behavioral factors (eg, poor diet, smoking, and physical inactivity). This risk profile can then be used as a basis for ongoing monitoring, treatment selection, and management.

Our meta-analysis clearly demonstrates that MetS risk factors are highly prevalent in patients with schizophrenia. Psychiatrists need to be aware of the potential metabolic side effects of antipsychotic medication and to include them in the risk/benefit assessment when choosing a specific antipsychotic. The treating psychiatrists should also be responsible for the implementation of the necessary screening assessments and referral for treatment. Multidisciplinary assessment of medical and behavioral conditions is needed. Psychiatric treatment facilities should offer and promote healthy lifestyle intervention early in the course of disease aiming to prevent serious metabolic adverse effects. Future research should focus on evaluating interventions that target MetS and examine if cardio-metabolic outcomes are moderated by clinical characteristics and genetic factors.

Alex J. Mitchell, Davy Vancampfort, Kim Sweers, Ruud van Winkel, Weiping Yu, Marc De Hert

Schizophr Bull. 2013;39(2):306-318.

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