Epidemiology and comorbidity of severe mental illnesses in the community: findings from a computerized mental health registry in a large Israeli health organization

Maccabi Healthcare Services, a large health maintenance organization (HMO) operating in Israel, has recently constructed a
computerized registry of patients with severe mental illnesses (SMI). In the present study, we aimed to use this registry
to investigate the epidemiology of schizophrenia and bipolar affective disorder among adults, and to assess their comorbidity
and mortality compared to the general population.

In this historical cohort study, we investigated the age- and sex-specific prevalence and incidence rates of HMO members diagnosed
with schizophrenia or bipolar affective disorder between 2003 and 2009. We compared their medical comorbidity and mortality
to the general HMO population.

A total of 8,848 and 5,732 patients were diagnosed with bipolar (crude prevalence rate of 5 per 1,000) and schizophrenia (3
per 1,000), respectively. The annual incidence rates were 4.2 and 2.4 per 1,000 for schizophrenia and bipolar disorder, respectively.
On average, schizophrenic men were diagnosed 4–5 years earlier than schizophrenic women. Compared to the general population,
schizophrenia and bipolar disorder patients had a 12- and 9-year shorter life expectancy, respectively. They were also more
likely to be diagnosed with diabetes mellitus (odds ratio of 1.9 and 1.6, respectively).

The current study demonstrates the potential use of automated medical databases to characterize the epidemiology of SMI in
the community. The increased comorbidity and mortality among these patients has important implication for health authorities
for prevention and delivery of health-care services.