Objectives Many studies have investigated multimorbidity, whose prevalence varies according to settings and data sources. However, few studies on this topic have been conducted in Italy, a country with universal healthcare and one of the most aged populations in the world. The aim of this study was to estimate the prevalence of multimorbidity in a Northern Italian region, to investigate its distribution by age, gender and citizenship and to analyse the correlations of diseases. Design Cross-sectional study based on administrative data. Setting Emilia-Romagna, an Italian region with-1/44.4 million inhabitants, of which almost one-fourth are aged ≥65 years. Participants All adults residing in Emilia-Romagna on 31 December 2012. Hospitalisations, drug prescriptions and contacts with community mental health services from 2003 to 2012 were traced to identify the presence of 17 physical and 9 mental health disorders. Primary and secondary outcome measures Descriptive analysis of differences in the prevalence of multimorbidity in relation to age, gender and citizenship. The correlations of diseases were analysed using exploratory factor analysis. Results The study population included 622 026 men and 751 011women, with a mean age of 66.4 years. Patients with multimorbidity were 33.5% in 75 years and >60% among patients aged ≥90 years; among patients aged ≥65 years, the proportion of multimorbidity was 39.9%. After standardisation by age and gender, multimorbidity was significantly more frequent among Italian citizens than among immigrants. Factor analysis identified 5 multimorbidity patterns: (1) psychiatric disorders, (2) cardiovascular, renal, pulmonary and cerebrovascular diseases, (3) neurological diseases, (4) liver diseases, AIDS/HIV and substance abuse and (5) tumours. Conclusions Multimorbidity was highly prevalent in Emilia-Romagna and strongly associated with age. This finding highlights the need for healthcare providers to adopt individualised care plans and ensure continuity of care. © 2016 Published by the BMJ Publishing Group Limited.

Primary care Public health Epidemiology

personality disorder patient care immigrant depression chronic lung disease HIV Infections anxiety disorder Human immunodeficiency virus infection schizophrenia congestive heart failure malignant neoplasm Dementia heart infarction neoplasm Cardiovascular Diseases Neoplasms human epidemiology Peptic Ulcer middle aged psychosis Paralysis neurologic disease ethnic group diabetes mellitus Ethnic Groups Aged hypertension substance abuse morbidity Multimorbidity Liver Diseases liver disease Nervous System Diseases drug dependence multiple chronic conditions dysthymia bipolar disorder Mental Disorders Cross-Sectional Studies mental disease Young Adult Humans migrant cross-sectional study cardiovascular disease Adolescent male intellectual impairment Emigrants and Immigrants female Aged, 80 and over very elderly cost of illness rheumatic disease peripheral vascular disease solid tumor prevalence Article Kidney Diseases major clinical study adult age outcome assessment kidney disease Italy citizenship acquired immune deficiency syndrome cerebrovascular disease somatoform disorder