Loop Diuretic Use is Associated With Adverse Clinical Outcomes in Acute Myocardial Infarction Patients With Low Volume Status.

To investigate the difference in the prognostic impact of loop diuretics in patients with acute myocardial infarction (AMI) based on plasma volume status, a total of 3,364 survivors of AMI who were registered in the large database of the Osaka Acute Coronary Insufficiency Study (OACIS) were studied. Plasma volume status was assessed by the estimated plasma volume status (ePVS) that was calculated based on a weight- and hematocrit-based formula at discharge. The endpoint was a composite endpoint of all-cause death and rehospitalization due to heart failure for 5 years. During a median follow-up period of 1.9 years, 90 and 223 patients had events in the groups with low ePVS (<median value of 4.07%) and high ePVS (≥4.07%), respectively. Multivariable Cox regression analysis showed that loop diuretics use was independently associated with an increased risk of the composite endpoint in the low ePVS group (hazard ratio [HR], 2.572; 95% confidence interval [CI], 1.386-4.771; p = 0.002), but not in the high ePVS group (HR, 1.028; 95% CI, 0.698-1.512; p = 0.890). These results were unchanged even in the propensity-score matched cohorts. There was no heterogeneity in the increased risk of the primary endpoints between various patient characteristics and loop diuretic use in the matched cohorts. In conclusion, prescription of loop diuretics at discharge was associated with increased risk of poor long-term prognosis in patients with AMI without PV expansion, but not with PV expansion. Therefore, careful observation is needed when loop diuretics are prescribed for AMI patients without PV expansion.