Inpatient Mortality Risk Scores and Postdischarge Events in Hospitalized Heart Failure Patients: A Community-Based Study

Abstract

Background: The Acute Decompensated Heart Failure National Registry (ADHERE) and Get With The Guidelines (GWTG) registries have developed simple heart failure (HF) in-hospital mortality risk scores. We hypothesized that HF scores predictive of in-hospital mortality would perform as well for early postdischarge mortality risk stratification.

Methods and results: In this single-center, community-based, retrospective study of all consecutive primary HF hospitalizations (6203 hospitalizations in 3745 patients) from 2000 to 2013, the ADHERE and GWTG risk scores were calculated from admission data. There were 176 (3.0%) and 399 (6.7%), 869 (14.7%), and 1272 (21.5%) deaths in-hospital and at 30, 90, and 180 days postdischarge, respectively. The GWTG but not ADHERE risk score was well calibrated for in-hospital mortality. Both the ADHERE (C statistic 0.66 and 0.67, 0.64, and 0.64) and GWTG (C statistic 0.74 and 0.73, 0.71, and 0.70) HF risk scores were similarly predictive of in-hospital and 30-, 90-, and 180-day postdischarge mortality. The ADHERE risk score identified 10% and the GWTG risk score identified 20% of hospitalizations where 180-day postdischarge mortality was 50%, a prognostic bench mark for hospice referral. In contrast, hospitalizations characterized as lowest risk by the ADHERE (57% of hospitalizations; 180-day mortality 16.2%) or GWTG score (20% of hospitalizations; 180-day mortality 8.0%) had substantially lower mortality (odds ratios high versus low risk of 5-8 [ADHERE] and 11-18 [GWTG] across time points; P<0.0001 for all).

Conclusions: The simple ADHERE and GWTG scores stratify hospitalized HF patients for both inpatient and early postdischarge mortality risk, allowing comprehensive risk assessment on admission.

Keywords: heart failure; hospital readmission follow-up studies; hospitalization; human; risk assessment.

Figure 1. Distribution of Community Heart Failure Patients Across ADHERE CART Risk Groups

According to the ADHERE CART risk algorithm, community patients were divided into five risk groups (Low, Intermediate 3, Intermediate 2, Intermediate 1 and High) at each hospitalization using their admission blood urea nitrogen (BUN), systolic blood pressure (SBP), and serum creatinine. The distribution of ADHERE registry and community patients across the ADHERE CART Risk Groups is shown.

Figure 2. Distribution of Community Heart Failure Patients Across GWTG Heart Failure Risk Score Groups

The Get With the Guidelines (GWTG) score ranges from 0–100 and is calculated from the admission blood urea nitrogen (BUN), systolic blood pressure (SBP), age, sodium, heart rate (HR), race and presence of chronic obstructive pulmonary disease (COPD) as shown. The GWTG derivation study stratified patients according to deciles of score ranges. The distribution of community patients across the GWTG registry score deciles is shown.

Figure 3. In-hospital Mortality in Community and Derivation Cohort Patients by ADHERE CART and GWTG Risk Groups

Observed in-hospital mortality rates in the community population are shown compared to the respective predicted in-hospital mortality as reported for the ADHERE or GWTG scores.

Figure 4. In-hospital and Post-discharge Mortality in Community Patients by ADHERE CART risk group and GWTG Score Quintile

In-hospital, 30, 90 and 180 day mortality in the community sample according to the ADHERE CART risk groups or Get with the Guidelines (GWTG) score quintiles are shown. Patients at risk and numeric data are provided in Table 3.