In a recent publication, Nancy E. Morden, M.D., M.P.H, of Dartmouth Medical School, and researchers from the University of Michigan, Ann Arbor, provided evidence against the long held belief among health care providers of a correlation between high rates of cardiometabolic disease and schizophrenia.
Morden and her collaborators examined the rates of cardiometabolic disease and mortality in 65,362 patients in the Veteran Affairs (VA) health system over eight years, comparing patients with and without schizophrenia. Subsets of patients with schizophrenia were matched to those without serious mental illness (non–SMI) on a variety of conditions including age, time of health service access, race, marital status, psychiatric comorbidities, and tobacco exposure.
Because the researchers were concerned with the prevalence of premature death in each of these populations, they calculated the number of years of potential life lost (YPLLs) based on US life expectancy data, and compared group trends, like obesity, to trends in the US population.
The results showed that although schizophrenic patients experienced significantly higher rates of death due to all causes, mortality due to cardiometabolic diseases varied. In the early years of this study, the prevalence of obesity, diabetes and hypertension was greater among schizophrenic patients. The non–SMI population, however, suffered higher rates of mortality from dyslipidemia and coronary artery disease for all years in the study.
Overall, the researchers found a much smaller mortality gap between the schizophrenia and non–SMI groups than previously determined. They note, however, that for both of these populations mortality rates were significantly higher than those in the general US population. Furthermore, morbidity and mortality among the studied veterans did not significantly improve during the eight years studied, suggesting that additional efforts are needed to improve veteran healthcare.
The study had some limitations. Because the data was compiled from VA records, it could have contained inaccuracies or lack potentially confounding variables such as education, diet, physical activity, and environment. Despite these possibilities, however, the researchers assert that correcting for these variables would likely reduce the mortality gap further, rather than detract from their conclusions.
While rates of cardiometabolic disease continue to increase among veterans, there does not seem to be a significant difference in the disease rates between schizophrenic and non–SMI patients. Rather the pitfalls of the VA health system should be addressed to reduce the mortality rates in both groups, which have not improved appreciably during the years included in the study.