Development of Acute Decompensated Heart Failure Among Hospital Inpatients: Incidence, Causes and Outcomes

Background

We aimed to investigate the incidence, precipitants, and outcomes of acute decompensated heart failure (ADHF) that develops during the inpatient stay.

Methods

We undertook a case-control study in the medical, oncology, surgical, and orthopaedic wards of a tertiary referral hospital (February–May, 2016). Patients aged ≥18 years who developed ADHF during their inpatient stay were enrolled as cases. One control patient was matched to each case by age, gender, presenting complaint/surgery performed and co-morbidities. Multivariate regression was employed to determine variables associated with ADHF.

Results

The incidence of ADHF was 1.0% of patients. Eighty cases were well-matched to 80 controls (p > 0.05). ADHF precipitants comprised infection (30%), inappropriate intravenous (IV) fluid and medication management (23.8% and 8.8%, respectively), tachyarrhythmia (12.5%), ischaemic heart disease (8.8%), renal failure (1.3%), and other/unclear causes (15%). Three variables were associated with ADHF: not having English as the preferred language (OR 3.5, 95%CI 1.2–9.8), a history of ischaemic heart disease (OR 3.3, 95%CI 1.2–9.1), and the administration of >2000 ml of IV fluid on the day before the ADHF (OR 8.3, 95%CI 1.5–48.0). The day before the ADHF, cases were administered significantly more IV fluids than controls (median 2,757.5 versus 975 ml, p = 0.001). Medication errors mostly related to failure to restart regular diuretics. Cases had significantly greater length of stay (median 15 versus 6 days, p < 0.001) and mortality (12.5% versus 1.3%, p = 0.01).

Conclusions

New onset ADHF is common and a substantial proportion of cases are iatrogenic. Cases experience significantly increased length of hospital stay, morbidity, and mortality.

Introduction

Acute decompensated heart failure (ADHF) is a syndrome of dyspnoea associated with the rapid accumulation of fluid within the pulmonary interstitial and alveolar spaces as a consequence of acutely raised cardiac filling pressures [1]. Patients often require multi-drug treatment regimens and may experience decreasing function, long hospital and intensive care admissions, and high rates of rehospitalisation and mortality [2]. Its increasing global incidence has resultant individual and health care costs and leads to lost productivity [3], [4], [5], [6].

While ADHF is a common reason for presentation to hospital, it can also develop during the inpatient stay where it is associated with higher mortality [7], [8]. The precipitants of ADHF include myocardial ischaemia, infection, arrhythmias, and inappropriate medication, fluid or salt administration [9]. Hospital inpatients are subject to all of these factors, some of which are iatrogenic and potentially preventable. Intravenous (IV) fluid administration is one iatrogenic precipitant specific to the hospital setting.

Few studies have investigated the causes of ADHF when it develops in the inpatient setting. This is despite associated poorer outcomes and increases in both length of stay and mortality [7], [10], [11], [12], [13], [14]. We aimed to investigate the incidence, precipitants, and outcomes of ADHF that develops during the inpatient stay. We hypothesised that iatrogenic causes, including inappropriate IV fluid and medication management, comprise a substantial proportion of overall causes. The findings will identify inpatients at risk of ADHF and inform improvements in clinical practice that aim to mitigate this risk and improve patient care.