This study estimates the annual prevalence of schizophrenia in the U.S. based on administrative claims data analyses and a comprehensive literature review.
The 2002 annual prevalence rate of schizophrenia in the U.S. was estimated separately for privately insured, government insured (Medicare, Medicaid), and uninsured populations. The 2002 annual prevalence for privately insured individuals was calculated based on a de-identi?ed administrative claims database of approximately 3.0 million privately insured bene?ciaries covering the period from 1999 to 2003. The 2002 prevalence of Medicaid enrollees was calculated from Medi-Cal claims covering the period from 2000–2002. The 2002 schizophrenia prevalence in Medicare population was calculated as a weighted average of the prevalence rates of Medicaid/Medicare dual eligibles and private insurance program enrollees over 65. Published statistics were used to estimate the prevalence of schizophrenia in the uninsured population and to weight prevalence rates in different populations to estimate the 2002 annual schizophrenia prevalence in the general U.S. population.
The annual prevalence rate of schizophrenia in the U.S. in 2002 was estimated at 0.5%. The Medicaid population was identi?ed as having the highest schizophrenia prevalence rate in the U.S. (1.7% for non Medicare dual eligible enrollees), whereas annual schizophrenia prevalence rates in Medicare and privately insured population were 0.7% and 0.1%, respectively. The disease was also more prevalent in the uninsured population (1.1%). Prevalence rates for women were highest in an older age group (56–65 years), whereas men’s prevalence rates peaked somewhat earlier (46–55 years).
The results suggest that schizophrenia may be more prevalent in the U.S. general population than previously estimated in some epidemiology survey studies, especially given the fact that claims database analyses usually provide lower bounds of prevalence estimates. Schizophrenia is most prevalent in the low income and uninsured populations than in the privately insured or Medicare populations.