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

BACKGROUND

Multimorbidity is widespread, influencing disease progression and patient outcomes. Understanding the impact on the use of healthcare resources and healthcare associated harm is crucial for population-level interventions to reduce disease burden and improve quality of life.

METHODS

This retrospective study used administrative and clinical registry data from a 30% sample of the adult Estonian population. Multimorbidity was defined as ≥2 chronic diseases. Prevalence of chronic disease and multimorbidity was estimated among adults on January 1, 2024 (n = 324,942). Healthcare utilization included inpatient, outpatient, emergency visits, and prescription counts. Survival was assessed over five years following entry into multimorbidity strata (0-1, 2-4, 5-9, ≥10 conditions) in 2012-2024. We estimated 5-year risk of healthcare-associated harm diagnoses comparing patients with and without multimorbidity.

RESULTS

Chronic disease affected 60.3% of adults and multimorbidity 42.0%, increasing steeply with age. Multimorbidity was strongly associated with mortality, with adjusted hazard ratios of 1.61 (95% CI 1.57-1.66) for 2-4 conditions, 2.43 (2.36-2.51) for 5-9, and 3.35 (3.22-3.48) for ≥10 conditions compared with ≤1 condition. 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.

CONCLUSION

Multimorbidity is prevalent in the Estonian population, increases mortality and healthcare use, and may increase healthcare-associated harm.