The furosemide diagnostic test in suspected slow-onset heart failure: popular but not useful

Early, slow-onset heart failure is difficult to diagnose from just signs and symptoms. The physician needs ancillary diagnostic tests. The 'loop-diuretic test' or 'furosemide test', characterized as weight loss and alleviation of symptoms after a short course of a loop-diuretic, could be a candidate. The furosemide test is not formally mentioned in the guidelines and no evidence could be found in the literature. We asked general practitioners (GPs) about their actual use of the furosemide test and studied the diagnostic accuracy in patients with suspected heart failure.

General practitioners completed a questionnaire about their use of the furosemide test. We then performed a diagnostic accuracy study among a representative and consecutive sample of patients suspected of new, slow-onset heart failure by the GP and who were referred to the rapid access heart failure diagnostic facility of one hospital. All patients underwent a standardized diagnostic work-up including echocardiography. The reference standard for the diagnosis of heart failure was the decision of an expert panel. Forty of the 54 GPs had actually used the furosemide test in the past year and 70% considered the test to be useful. Forty seven patients underwent the furosemide test and 12 (25%) were diagnosed with heart failure. None of the effects of the test (weight loss, alleviation of symptoms) was significantly associated with heart failure.

We cannot support the use of the furosemide test as an ancillary diagnostic test in patients suspected of new, slow-onset heart failure.