Of 36 165 OPTIMIZE-HF hospitalizations for patients aged 65 and older, 29 301 (81%) were matched to Medicare fee-for-service claims records, representing 25 901 OPTIMIZE-HF patients. After exclusions and removal of additional nonunique patients, 25 245 distinct OPTIMIZE-HF patients remained. We identified another 929 161 Medicare beneficiaries with heart failure during this time period who were not enrolled in OPTIMIZE-HF. shows the differences in baseline characteristics between the groups. Mean age was 80 years in both groups. Less than half of all patients were men (44% in the OPTIMIZE-HF group, 43% in the non-OPTIMIZE-HF group) and both groups were predominantly white (86% in the OPTIMIZE-HF group, 85% in the non-OPTIMIZE-HF group). The geographic distribution of patients was slightly different between the cohorts. Although both groups were composed of national samples, fewer OPTIMIZE-HF patients resided in the southern and northeastern US Census regions than did non-OPTIMIZE-HF beneficiaries, reflecting the geographic distribution of OPTIMIZE-HF participating hospitals.6
Rates of comorbidity were qualitatively similar across groups. Due to large sample sizes, many differences were statistically significant, though these are unlikely to represent clinically meaningful differences between groups. Rates of chronic atherosclerosis, valvular and rheumatic heart disease, renal failure, and specified heart arrhythmias were at least 4 percentage points higher in OPTIMIZE-HF patients than in non-OPTIMIZE-HF patients. Chronic atherosclerosis, hypertension, and cardiac arrhythmia were the most commonly observed comorbid conditions in both cohorts, affecting at least half of all patients.
Baseline Characteristics of Index Heart Failure Cohorts
There were differences between the hospitals that participated in OPTIMIZE-HF and those that did not (). The average annual volume of heart failure discharges in participating hospitals was more than double the volume in nonparticipating hospitals, and participating hospitals were significantly more likely to offer advanced cardiovascular services.
shows unadjusted mortality rates and all-cause and cardiovascular readmission rates for each cohort. Across all years, rates of in-hospital and 30-day mortality for OPTIMIZE-HF and non-OPTIMIZE-HF patients were similar. At 1 year, unadjusted mortality was significantly higher among OPTIMIZE-HF patients (37.2% vs 35.7%; P < .001) (). In univariate analyses, the hazard of mortality at 1 year was slightly higher among OPTIMIZE-HF patients as compared with non-OPTIMIZE-HF patients (unadjusted hazard ratio [HR], 1.06; 95% confidence interval [CI], 1.02–1.09). At 30 days, both all-cause and cardiovascular readmission rates were similar for OPTIMIZE-HF and non-OPTIMIZE-HF patients. Within 30 days, approximately one fifth of all patients were readmitted to the hospital for any reason and 1 in 10 had a cardiovascular readmission. At 1 year, unadjusted all-cause readmissions were significantly lower among OPTIMIZE-HF patients (64.2% vs 65.8%; P = .04), but unadjusted cardiovascular readmissions were similar (39.4% for OPTIMIZE-HF patients vs 40.6% for non-OPTIMIZE-HF patients; P = .15) (). In univariate analyses, OPTIMIZE-HF patients were similar to non-OPTIMIZE-HF patients with regard to readmission (HR for all-cause readmission, 0.97; 95% CI, 0.93–1.00; HR for cardiovascular readmission, 0.97; 95% CI, 0.93–1.01).
Unadjusted Patient-Level Heart Failure Mortality and Readmission Rates
Clinical Outcomes of Patients Hospitalized at OPTIMIZE-HF Hospitals and Non-OPTIMIZE-HF Hospitals
Controlling for other variables, OPTIMIZE-HF patients were similar to non-OPTIMIZE-HF patients with regard to the hazard of mortality (adjusted hazard ratio [HR], 1.02; 95% confidence interval [CI], 0.98–1.06) (). The hazard of death increased by 25% with each 5-year increase in age (95% CI, 1.25–1.25), was 19% higher in men than in women (95% CI, 1.18–1.20), and was significantly lower for black patients compared with nonblack patients (HR, 0.85; 95% CI, 0.84–0.87). The hazard of death was also significantly lower in patients with a history of previous cardiac procedures. All comorbid conditions were independently associated with mortality. Conditions associated with an increased hazard of more than 50% included cardiorespiratory failure and shock, renal failure, protein-calorie malnutrition, metastatic cancer, and chronic liver disease.
Adjusted Predictors of Mortality and 1-Year Readmission
In multivariable analysis, patients in OPTIMIZE-HF were less likely than non-OPTIMIZE-HF patients to be readmitted to the hospital. We observed small but significant decreases in the hazards of all-cause (HR, 0.94; 95% CI, 0.92–0.97) and cardiovascular readmission (HR, 0.94; 95% CI, 0.91–0.98). Age and sex were less strongly associated with the hazard of all-cause readmission than with mortality (HR for age per 5 years, 1.03; 95% CI, 1.03-1.03; HR for male sex, 0.97; 95% CI, 0.97–0.98). Sex was not associated with cardiovascular readmission, although age was (HR, 1.01; 95% CI, 1.00–1.01). In contrast to the mortality model, the hazards of all-cause readmission (HR, 1.09; 95% CI, 1.08–1.10) and cardiovascular readmission (HR, 1.18; 95% CI, 1.16–1.19) were greater for black patients than for others. Most comorbid conditions were independently associated with readmission, but less strongly so than with mortality. An index length of stay greater than 7 days was associated with a 13% greater hazard of all-cause readmission (95% CI, 1.12–1.14) and a 3% greater hazard of cardiovascular readmission (95% CI, 1.02–1.04).
The characteristics and outcomes of Medicare patients hospitalized with heart failure during the registry period but not enrolled in OPTIMIZE-HF were also compared with those who were enrolled. Within OPTIMIZE-HF hospitals, 15 311 Medicare patients (38%) were discharged during the hospital’s registry enrollment period but not enrolled in the OPTIMIZE-HF registry. Patients not enrolled were qualitatively similar to enrolled patients (data not shown).Within OPTIMIZE-HF hospitals, the outcomes were similar between enrolled patients and non-enrolled patients. In-hospital mortality was slightly lower among enrolled patients (4.7% vs 5.7% in non-enrolled patients), but 30-day mortality was similar between the 2 groups (11.9% in enrolled patients vs 12.4% in non-enrolled patients). At 1 year, unadjusted mortality was slightly higher among enrolled patients (37.2% vs 35.3% in non-enrolled patients; P = .005). Readmission rates were similar in both groups at 30 days (all-cause readmission: 20.8% in enrolled patients vs 20.5% in non-enrolled patients; cardiovascular readmission: 10.5% in enrolled patients vs 10.1% in non-enrolled patients). At 1 year, readmission rates were slightly higher in enrolled patients (all-cause readmission: 64.2% in enrolled patients vs 62.6% in non-enrolled patients; P = .007; cardiovascular readmission: 39.4% in enrolled patients vs 36.1% in non-enrolled patients, P < .001).