Each year 1 million Americans are diagnosed with heart failure, a serious condition that causes shortness of breath, weakness, and excess fluid. Diuretics are the main therapy for fluid removal but there has long been concern about potential damage to kidneys with their aggressive use. In a new study, Yale researchers and their co-authors show that this approach may increase serum creatinine levels—a measure of kidney function—but it does not appear to cause kidney injury and may even lead to better outcomes.

Tariq Ahmad and the Jeffery Testani research group used data from a publicly available clinical trial of heart failure to determine whether increases in creatinine indicated kidney injury. They found that a “bump” in creatinine caused by aggressive diuretic use was not associated with any evidence of kidney damage.

The finding runs counter to long-standing perceptions about the clinical implications of creatinine increases with diuretic use in heart failure. It also raises important questions about how both clinicians and investigators should respond to worsening kidney function in patients with heart failure, said the researchers. The study was published in Circulation.