Hospital readmission and mortality: associations to a hospital frailty risk score in a national sample of US older adults with pre-existing coronary heart disease, an observational study.

Background Coronary heart disease (CHD) is the most common form of heart disease and a leading cause of death in cardiovascular disease (CVD). Although frailty has been studied in CVD, a condition encompassing heart disease and stroke, frailty in hospitalized elders with CHD is under researched. The study aimed to examine how a Hospital Frailty Risk Score (HFRS) influenced readmission and in-hospital mortality rates in older patients with CHD.Methods Adults > 65 years with pre-existing CHD identified by ICD-10-CM codes from the 2016 Nationwide Readmissions Database (NRD) were included in the study. Frailty risk was determined using a validated Hospital Frailty Risk Score (HFRS) based on ICD-10-CM codes. Readmission was defined as a) any subsequent inpatient readmission and b) 30-day readmission after an index event. In-hospital mortality was measured as death during index event, any readmission death, and death during a 30-day readmission.Results Frailty risk was identified in 92.4% of the 1.09 million eligible adults with CHD. Readmission and in-hospital mortality rates were higher in frail patients. Compared to the non-frail, patients with low, intermediate, and high frailty risk showed 27% vs 28%, 47% vs 49%, and 42% vs 49% greater risk for readmission and 30-day readmission, respectively. Patients with intermediate and high frailty risk were 2.31 and 3.44 times more likely to die during the index events, 2.15 and 2.44 times more likely to die during readmission, and 2.26 and 2.68 times more likely to die during 30-day readmission.Conclusion Readmission and mortality rates increased proportionally to the level of frailty risk in older adults with CHD. CHD, frailty, and older age together profoundly impact patients’ health outcomes in negative ways and places patients at a higher risk of mortality and readmission rate than non-frail patients. Further research should investigate interventions to improve frailty risk in CHD.