Prevalence of schizophrenia spectrum disorders in the Lazio region, Italy: use of an algorithm based on health administrative databases.

Abstract

Background: Mental healthcare provision is undergoing substantial reconfiguration in many regions of the world. Such changes require a broad, evidence-based approach incorporating epidemiological data and information on local needs. The objective of this study was to estimate the prevalence of schizophrenia spectrum disorders (SSD) in the Lazio region and its geographical distribution using regional administrative healthcare databases.

Methods: Cases of SSD (15-64 years old) were identified using an algorithm based on data from the hospital discharge registry (ICD IX CM: 295, 297, 298 [excl. 298.0], 299) and the ticket exemption database [code 044], between 2006 and 2019. We calculated crude, age- and gender-specific prevalence estimates on December 31, 2019. We also calculated age- and gender-adjusted prevalence to compare prevalence in different regional areas.

Results: We identified 18,371 cases. The overall prevalence was 5.03 per 1000 population (95% CI 4.96-5.10). Age-adjusted prevalence estimates were 4.18 (95% CI 4.09-4.27) per 1000 for women and 5.92 (95% CI 5.81-6.04) per 1000 for men. The prevalence was higher among older age groups, in both genders. There were differences in prevalence within the region, ranging from 4.25/1000 in the province of Viterbo to 5.42/1000 in Rome and 6.02/1000 in the province of Frosinone. When we analysed the subcategories of SSD, the three most frequent conditions were schizophrenia, schizoaffective disorder, and psychosis NOS. In general, the prevalence was higher in men for all the conditions but delusional disorders and brief psychosis.

Conclusions: Our results show that the overall prevalence of SSD among adults in the Lazio region is similar to those published in previous reviews, but an uneven regional distribution was observed. While possible underestimation must be considered, administrative databases represent a valuable source of information for epidemiological surveillance and healthcare planning.