Comparison of clinical body composition methods in people taking weight-inducing atypical antipsychotic medications.

The purpose of this study was to compare the accuracy of clinical methods to estimate body fat (%BF) in people who take weight-inducing atypical antipsychotic medications. Forty-seven people (35 males, 12 females) with previously diagnosed psychotic illness who had been taking atypical antipsychotic medications for more than 6 months took part in this study. Percentage body fat was estimated using bioelectrical impedance analysis (BIA) and anthropometry from previously published prediction equations and compared with that measured using the deuterium dilution technique which served as the criterion measure. Bland-Altman analyses were used to assess the agreement between measures. In the males, %BF determined using BIA with the Lukaski equation was the only clinical method with mean differences that were not significant from criterion values. While in the females, %BF determined from BMI was the only method that was significantly different from the criterion values. All of the methods of estimating %BF except Watson equations provided consistent estimates across the weight range. Therefore, this study suggests that in a group of people who predominantly had schizophrenia and were taking atypical antipsychotic medications, BIA using the equation of Lukaski was the best indicator of %BF, although on an individual basis the accuracy was poor. BMI underestimated %BF to a greater significant extent than BIA. The use of BIA rather than BMI may provide a better indicator of adiposity in people who take weight inducing antipsychotic medications.

Bioelectric impedance is a better indicator of obesity in men with schizophrenia than body mass index.

Body mass index (BMI) is commonly used as an indicator of obesity, although in both clinical and research settings the use of bioelectric impedance analysis (BIA) is commonplace. The purpose of this study was to examine the relationship between BMI, BIA and percentage body fat to determine whether either is a superior indicator of obesity in men with schizophrenia. The reference method of deuterium dilution was used to measure total body water and, subsequently, percentage body fat in 31 men with schizophrenia. Comparisons with the classification of body fat using BMI and BIA were made. The correlation between percentage body fat and BMI was 0.64 whereas the correlation between percentage body fat and BIA was 0.90. The sensitivity and specificity in distinguishing between obese and overweight participants was 0.55 and 0.80 for BMI and 0.86 and 0.75 for BIA. BIA proved to be a better indicator of obesity than BMI. BMI misclassified a large proportion of men with schizophrenia as overweight when they had excess adiposity of sufficient magnitude to be considered as obese. Because of the widespread use of BMI as an indicator of obesity among people with schizophrenia, the level of obesity among men with schizophrenia may be in excess of that previously indicated.

Energy expenditure and physical activity in clozapine use: implications for weight management.

OBJECTIVE: The management of atypical antipsychotic-induced weight gain is a significant challenge for people with mental illness. Fundamental research into energy metabolism in people taking atypical antipsychotic medication has been neglected. The current study of men with schizophrenia taking clozapine aimed to measure total energy expenditure (TEE) and energy expended on physical activity--activity energy expenditure (AEE) and to consider the clinical implications of the findings. METHOD: The well-established reference method of doubly labelled water (DLW) was used to measure TEE and AEE in men with schizophrenia who had been taking clozapine for more than 6 months. Resting energy expenditure was determined using indirect calorimetry. RESULTS: The TEE was 2511+/-606 kcal day-1 which was significantly different to World Health Organization recommendations (more than 20% lower). The Physical activity level (PAL) was 1.39+/-0.27 confirming the sedentary nature of people with schizophrenia who take clozapine. CONCLUSIONS: The findings support the need for weight management strategies for people with schizophrenia who take clozapine to focus on the enhancement of energy expenditure by increasing physical activity and reducing inactivity or sedentary behaviours, rather than relying primarily on strategies to reduce energy intake.

Resting energy expenditure is lower than predicted in people taking atypical antipsychotic medication.

Resting energy expenditure (REE) is lower than predicted in persons taking atypical antipsychotic medication, and weight management is a significant clinical challenge for some of them. However, to date there have been no published guidelines to assist clinicians in choosing appropriate prediction equations to estimate energy expenditure in persons taking atypical antipsychotic medications. The objectives of this study were to measure REE in a group of men taking the atypical antipsychotic clozapine and to determine whether REE can be accurately predicted for this population using previously published regression equations. REE was measured using indirect calorimetry via a ventilated hood on eight men who had completed at least 6 months of treatment with clozapine. Comparisons between measured REE and predicted REE using five different equations were undertaken. The commonly-used Harris-Benedict and Schofield equations systematically overestimated REE. Predictions of REE from other equations were too variable for clinical use. When estimating energy requirements as part of a weight-management program in men who have been taking clozapine for 6 months, predictions of REE from the equations of Harris-Benedict and Schofield should be reduced by 280 kcal/day.

Atypical antipsychotic weight gain: a major clinical challenge.

OBJECTIVE: The major aim of this paper is to review findings from weight management intervention studies to consider clozapine and/or olanzapine induced weight gain. A parallel aim is to summarize the challenges facing future research and provide an overview of best practice in the management of weight in mental health patients. METHOD: A systematic literature search was conducted using Medline, Cinahl and PsychINFO data bases and reference lists from relevant published articles. Five studies which reported weight control practices in patients taking atypical antipsychotic medications were located and reviewed. RESULTS: The studies reviewed provide some important descriptive clinical insights; however, common shortcomings include small subject numbers and methodological drawbacks such as lack of a control group. CONCLUSIONS: There is some evidence that weight gain associated with atypical antipsychotic medication can be ameliorated by lifestyle changes such as improved nutritional practices and increased physical activity. Lifestyle interventions for individuals with psychotic disorders may need to be adapted to be most effective; for example, using strategies to counter increased appetite and to enhance physical activity. Clinicians need to be vigilant and persistent in monitoring and intervening if weight gain occurs. A standardized screening tool and clinical pathway would help clinicians to target appropriate interventions for each person prescribed atypical antipsychotic medication.