Associations of chronic disease and multimorbidity with healthcare utilization, mortality and adverse events in Estonia.

Chronic disease affected 60.3% of adults and multimorbidity 42.0%, increasing steeply with age.

Healthcare utilization increased approximately linearly with each additional chronic disease, with 0.025 more inpatient visits, 0.034 emergency visits, 1.49 outpatient visits, and 4.04 prescriptions per person-year.

Multimorbidity was also associated with higher risk of healthcare-associated adverse events, with up to sevenfold higher hazards for several complications, particularly related to procedural/surgical and prosthesis-related complications, including infections.