Eur Heart J Qual Care Clin Outcomes. 2022 Feb 15:qcac007. doi: 10.1093/ehjqcco/qcac007. Online ahead of print.
AIMS: Urinary sodium concentration (UNa) is a simple test advocated to assess diuretics efficacy and predict outcomes in acute heart failure (AHF). We performed a systematic review and meta-analysis to examine the association of UNa with outcomes of AHF.
METHODS AND RESULTS: We searched Embase and Medline for eligible studies that reported the association between UNa and outcomes of urinary output, weight loss, worsening renal function, length of hospital stay, re-hospitalisation, worsening heart failure and all-cause mortality in AHF. Nineteen observational studies out of 1592 screened records were included. For meta-analyses of outcomes, we grouped patients into high vs low UNa, with most studies defining high UNa as >48-65 mmol/L. In the high UNa group, pooled data showed a higher urinary output (mean difference 502ml, 95%CI 323-681, p<0.01), greater weight loss (mean difference 1.6kg, 95%CI 0.3-2.9, p = 0.01), and a shorter length of stay (mean difference -1.4 days, 95%CI -2.8 to -0.1, p = 0.03). There was no significant difference in worsening kidney function (OR 0.54, 95%CI 0.25-1.16, p = 0.1). Due to the small number of studies, we did not report pooled estimates for re-hospitalisation and worsening heart failure. High UNa was associated with lower odds of 30-day (OR 0.27; 95%CI 0.14-0.49, p<0.01), 90-day (OR 0.39,95% CI 0.25-0.59, p<0.01) and 12-month (OR 0.35; 95%CI 0.20-0.61, p<0.01) mortality.
CONCLUSION: High UNa after diuretic administration is associated with higher urinary output, greater weight loss, shorter length of stay, and lower odds of death. UNa is a promising marker of diuretic efficacy in AHF which should be confirmed in randomised trials.