New Haven, Conn. -- The rate of diabetes among persons taking certain newer anti-psychotic medications is higher than that found in the general population, Yale researchers report in a study in the American Journal of Psychiatry.
The study followed patients with schizophrenia and no history of diabetes who used four of six new atypical medications or conventional anti-psychotic medications. The atypical medications Ñ- clozapine, risperidone, olanzapine, quetiapine Ñ- are considered to cause fewer severe side effects. Two atypical medications were not included because they had just been approved at the time the study began.
Of the 56,849 patients in the sample, 7.3 percent of patients were diagnosed with diabetes mellitus during the one- to two-year follow up period, corresponding to an annual incidence rate of 4.4 percent. The rate was higher for patients taking clozapine and olanzapine.
"The rate is five to 10 times higher than the estimated rate of 6.3 cases per 1,000 in the general U.S. population," said Douglas Leslie, first author of the paper and assistant professor of psychiatry and epidemiology and public health.
Leslie and co-author Robert Rosenheck, M.D., professor of psychiatry and epidemiology and public health, said it is not known what causes the diabetes, but one possibility is weight gain associated with taking the medications. Other factors might be the mental illness itself, poorer overall physical health, unhealthy lifestyles, or less access to health care services, he said.
The study also found that only 0.2 percent of the patients were hospitalized for ketoacidosis -- which is an accumulation of ketone bodies associated with uncontrolled diabetes and is potentially life threatening.
Since they began their research, the U.S. Food and Drug Administration ordered all manufacturers of these drugs to include a warning on related medication labels about diabetes as a possible side effect.
Citation: American Journal of Psychiatry, Vol. 161: pp 1709-1711 (September, 2004)
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