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 >2000ml 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 975ml, 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.