Validation of the “Doorbell Test”: A Novel Functional Test of Frailty and Clinical Status After Acute Decompensated Heart Failure

Abstract

Acute decompensated heart failure (ADHF) carries a high event rate following discharge. The complex interplay between age, frailty and decongestion may lend itself to a functional test. In the doorbell test the patient simulates answering the doorbell. They are timed rising from a recumbent position, bending over twice and walking 10 metres, this time is added to the change in respiratory rate. We aimed to determine if the doorbell test was associated with post ADHF events (death or readmission). The test was performed at hospital discharge, with follow up at 30-days and 1-year. In 74 patients at 30-days there was a 14% event rate. At 1-year there were 40 (54%) events (9 deaths and 31 readmissions, 28 were cardiovascular of which 14 were [heart failure] HF). Amongst those who had an event at 30-days only doorbell test scores were different (58 [36,72] vs 32 [26,53] p < 0.05). One-year (1-year) events were associated with doorbell test scores (47 [29,62] vs 30 [26,42] p < 0.05), body weight (78 kg [68,94] vs 95 [76,105] (p < 0.05), creatinine (134 mmol/L [114, 173] vs 99 [82, 133] p < 0.01) and age (76 years [61,86] vs 67 [53, 73] p < 0.01). Heart failure readmissions were associated with doorbell test scores (56 [46,68] vs 30 [26,47] p < 0.001). Death was associated with body weight (74 kg [69,81] vs 88 [72,101] p < 0.05) and age (83 years [78,86] vs 69 [55,77] p < 0.01). After age stratification, the hazard ratio for heart failure readmission associated with a high doorbell test score was 11.08 (95%C.I. 2.01-61.17 p = 0.006), while the hazard ratio for 1-year cardiovascular readmission was 4.62 (95%C.I. 1.71-12.51 p = 0.003). There was no association with 1-year mortality. The doorbell test represents a novel test of multiple domains of the ADHF pre-discharge state and demonstrates an association with 30-day and 1-year rehospitalisation.