Prevalence of frailty, multimorbidity, and polypharmacy and their association with health outcomes in hospitalized older adults: a prospective multicenter cohort study

BACKGROUND: The growing burden of frailty, multimorbidity, and polypharmacy among older adults presents major challenges to healthcare systems worldwide. These interrelated conditions are known to worsen clinical outcomes, yet data from the region are limited. This study aimed to examine the prevalence and clinical impact of frailty, complex multimorbidity, and polypharmacy among hospitalized older adults in Oman. METHODS: A prospective, multicenter cohort study was conducted in general internal medicine wards of two tertiary hospitals in Oman. Patients aged ≥ 65 years were consecutively enrolled and assessed for frailty using Clinical Frailty Scale (CFS), multimorbidity using the Charlson Comorbidity Index (CCI) and a definition of complex multimorbidity (≥ 3 chronic conditions), and polypharmacy (≥ 5 medications). Clinical outcomes included hospital length of stay (LOS), in-hospital mortality, HD/ICU admission, 30- and 90-day mortality, and 30- and 90-day readmission. Multivariable regression and Kaplan-Meier survival analyses were used. RESULTS: Among 369 patients, high frailty, complex multimorbidity, and polypharmacy were present in 139 (37.67%), 126 (34.15%), and 243 (65.85%) patients, respectively. Higher frailty was associated with longer LOS (6.49 vs. 4.88 days, p < 0.01) and increased in-hospital mortality (15.11% vs. 3.54%, p < 0.01). High frailty independently predicted 30-day mortality (adjusted odds ratio [aOR] 5.68, p < 0.01) and 90-day mortality (aOR 3.53, p < 0.01). Complex multimorbidity independently predicted 30-day readmission (aOR 1.92, p = 0.015), 30-day mortality (aOR 2.12, p = 0.026), and 90-day mortality (aOR 2.42, p < 0.01). Kaplan-Meier and adjusted Cox regression analyses showed lower 90-day survival and higher mortality risk among patients with high frailty (adjusted hazard ratio [aHR] 3.16, 95% CI 1.69-5.89, p < 0.001) and complex multimorbidity (aHR 1.85, 95% CI 1.15-2.98, p = 0.011). CONCLUSION: Frailty, complex multimorbidity, and polypharmacy were common among hospitalized older adults in Oman. High frailty and complex multimorbidity were the most consistent predictors of adverse outcomes, supporting early recognition, structured geriatric assessment pathways, and future targeted patient-centered interventions.