Physical disease in schizophrenia: a population-based analysis in Spain

BACKGROUND: Physical disease remains a challenge in patients with schizophrenia. Our objective was to determine the epidemiological characteristics and burden of physical disease in hospitalized patients with schizophrenia. METHODS: We analyzed the 2004 Spanish National Hospital Discharge Registry, identified records coded for schizophrenia (295.xx) and characterized the physical diseases using the ICD-9 system and the Charlson Index. We also calculated standardized mortality ratios (SMRs) versus the general population adjusted by age and calendar time. RESULTS: A total of 16, 776 cases (mean age: 43 years, 65% males) were considered for analysis. Overall, 61% of cases had at least one ICD-9 physical code and 32% had more than one ICD-9 code. The Charlson index indicated that 20% of cases had a physical disease of known clinical impact and prognostic significance. Physical disease appeared early in life (50% of cases were 15-31 years of age) and increased rapidly in incidence with age. Thus, for patients aged 53 years or more, 84% had at least one physical ICD-9 code. Apart from substance abuse and addiction, the most prevalent diseases were endocrine (16%), circulatory (15%), respiratory (15%), injury-poisoning (11%), and digestive (10%). There were gender-related differences in disease burden and type of disease. In-hospital mortality significantly correlated with age, the Charlson Index and several ICD-9 groups of physical disease. Physical disease was associated with an overall 3.6-fold increase in SMRs compared with the general population. CONCLUSIONS: This study provides the first nationally representative estimate of the prevalence and characteristics of physical disease in hospitalized patients with schizophrenia in Spain. Our results indicate that schizophrenia is associated with a substantial burden of physical comorbidities; that these comorbidities appear early in life; and that they have a substantial impact on mortality. This information raises concerns about the consequences and causes of physical disorders in patients with schizophrenia. Additionally, it will help to guide the design and implementation of preventive and therapeutic programs from the viewpoint of clinical care and in terms of health-care service planning.