RECORD-HF (H&ERCTF): A retrospective cohort study of heart failure-related outcomes in patients who are prescribed a loop diuretic but who do not have a diagnosis of heart failure

Project Description

Loop diuretics are one of the most commonly prescribed medications in primary care yet there are few indications for loop diuretics other than the treatment of venous congestion in patients with heart failure (HF). A pilot study at a single General Practice in East Yorkshire found that of 94 patients who were taking loop diuretic without a diagnostic code for HF in their electronic record, 13% had incident HF, and 25% died or were hospitalised with HF during 2 years’ follow up. We hypothesise that a large proportion of patients who are prescribed a loop diuretic but who do not have a diagnosis of HF at baseline have unrecognised HF as the cause of their symptoms. Thus, our objective is to describe HF-related events (presentations to primary care with symptoms of HF, hospitalisation with HF, new HF diagnoses, and mortality - our primary outcomes) in a population of patients who are prescribed loop diuretic in primary care without a diagnosis of HF. Our project will use data from the Clinical Practice Research Datalink (CPRD) to investigate the link between loop diuretic prescriptions and HF-related events in patients without a HF diagnosis using time-to-event analysis (uni- and multivariable Cox regression) in two separate retrospective cohort comparisons. Firstly, a comparison between patients prescribed loop diuretic without diagnosis of HF (study population) and patients with known HF; and secondly, between the study population and patients with risk factors for HF (ischaemic heart disease or diabetes and hypertension) but not taking a loop diuretic.