Data Science
Loop diuretics and heart failure outcomes
The challenge
Heart failure is increasingly prevalent amongst adults, particularly as they get older, and is one of the top reasons people end up in hospital or die. The condition is characterised by water and salt retention, also known as congestion, with non-specific symptoms and signs, and is usually diagnosed only when individuals are so sick that they need to be admitted to hospital. Loop diuretics are a key treatment for congestion and are strongly recommended by guidelines to improve symptoms in those with heart failure. The challenge was to determine how frequently loop diuretics were used in a community setting without a diagnosis of heart failure, and how their use related to patient outcomes.
The research
Pseudoanonymised electronic patient records were linked for adults with cardiovascular disease or dispensed a loop diuretic, served by the NHS Greater Glasgow & Clyde Health Board, and accessed through the West of Scotland’s Safe Haven. These records include information on demographics, primary care diagnoses, hospital admissions, community-based prescriptions, and death records. Patients were categorised based on heart failure and/or use of loop diuretic, or neither, and followed up for five years using descriptive statistics and time-to-event analyses. Of the 198,898 adults included, 16% were receiving loop diuretics. Of those, only 25% had a diagnostic record of heart failure. Patients receiving loop diuretics without a diagnosis of heart failure were older, and more likely to be women. Surprisingly, those receiving loop diuretics had higher hospitalisation and mortality rates than those with only a diagnosis of heart failure.
The impact
This study shows that many more patients, especially women, are prescribed loop diuretics than are diagnosed with heart failure. Mortality is more strongly associated with loop diuretics than with a diagnosis of heart failure. Either a diagnosis of heart failure is often missed, or loop diuretics are associated with conditions with a prognosis similar to heart failure, or loop diuretics increase mortality; all might be true. Patients prescribed a loop diuretic should be carefully reviewed and further investigated. Additionally, the use of a loop diuretic in the community provides a simple, objective marker of patients at an increased risk of hospitalisation and death.
Lead
Read the paper
The study, Loop diuretic therapy with or without heart failure: impact on prognosis, is published in European Heart Journal.
