Prevalence and 3-year incidence of physical illnesses after schizophrenia diagnosis: Comparison with general population

Abstract

Aim: People with schizophrenia are at a greater risk of poor physical health than the general population. This study investigated the annual incidence of physical illnesses after a new schizophrenia diagnosis, which has rarely been investigated in the literature.

Methods: The authors collected data from Taiwan's National Health Insurance Research Database from January 1, 1996, to December 31, 2013, and enrolled 1910 patients with newly diagnosed schizophrenia cases aged 10-40 years and 7640 age- and sex-matched controls from the general population. They estimated the 1-year prevalence and annual incidence rate ratio (IRR) of specified physical diseases across 3 years in the schizophrenia group compared with the controls.

Results: Several physical illnesses were prevalent within 1 year of schizophrenia diagnosis. Regarding incident physical illnesses, patients had a moderate to strong risk of numerous physical illnesses (IRR > 3.0: ischemic heart disease, cerebrovascular disease, diabetes mellitus, and cancer; IRR 1.8-3.0: other forms of heart disease, vein and lymphatic diseases, pneumonia, chronic hepatic disease, and ulcer disease) within the first year after schizophrenia diagnosis. The IRRs of most physical illnesses declined over 3 years, except for that of cerebrovascular disease, which significantly increased (IRR > 3.0) over the 3 years after schizophrenia diagnosis. Cerebrovascular disease had a significant incidence risk (IRR > 3) persistently across the 3 years.

Conclusion: Various comorbid physical illnesses can occur in the early stages of schizophrenia. Clinicians should consider these vulnerabilities to physical illnesses during the evaluation of patients with newly diagnosed schizophrenia by attempting to prevent, screen for, and manage them.

Keywords: Incidence; Incidence rate ratio; Physical comorbidity; Schizophrenia; Trend.