Serious Mental Illness and Risk for Hospitalizations and Rehospitalizations for Ambulatory Care-sensitive Conditions in Denmark: A Nationwide Population-based Cohort Study.

ABSTRACT

BACKGROUND: Hospitalizations for ambulatory care-sensitive conditions (ACSCs) and early rehospitalizations increase health care costs. OBJECTIVES: To determine if individuals with serious mental illnesses (SMIs) (eg, schizophrenia or bipolar disorder) are at increased risk for hospitalizations for ACSCs, and rehospitalization for the same or another ACSC, within 30 days. RESEARCH DESIGN: Population-based cohort study. PARTICIPANTS: A total of 5.9 million Danish persons aged 18 years and older between January 1, 1999 and December 31, 2013. MEASURES: The Danish Psychiatric Central Register provided information on SMI diagnoses and the Danish National Patient Register on hospitalizations for ACSCs and 30-day rehospitalizations. RESULTS: SMI was associated with increased risk for having any ACSC-related hospitalization after adjusting for demographics, socioeconomic factors, comorbidities, and prior primary care utilization [incidence rate ratio (IRR) 1.41; 95% confidence interval (95% CI), 1.37-1.45]. Among individual ACSCs, SMI was associated with increased risk for hospitalizations for angina (IRR 1.14, 95% CI, 1.04-1.25), chronic obstructive pulmonary disease/asthma exacerbation (IRR 1.87; 95% CI, 1.74-2.00), congestive heart failure exacerbation (IRR 1.25; 95% CI, 1.16-1.35), and diabetes (IRR 1.43; 95% CI, 1.31-1.57), appendiceal perforation (IRR 1.49; 95% CI, 1.30-1.71), pneumonia (IRR 1.72; 95% CI, 1.66-1.79), and urinary tract infection (IRR 1.70; 95% CI, 1.62-1.78). SMI was also associated with increased risk for rehospitalization within 30 days for the same (IRR 1.28; 95% CI, 1.18-1.40) or for another ACSC (IRR 1.62; 95% CI, 1.49-1.76). CONCLUSION: Persons with SMI are at increased risk for hospitalizations for ACSCs, and after discharge, are at increased risk for rehospitalizations for ACSCs within 30 days.