Aims: The osmolarity of human serum is restricted to a tightly regulated range, and any deviation has clinical implications. Our aim in this study was to establish whether differences in serum osmolarity in heart failure (HF) patients are related with a worse outcome.
Methods: We evaluated the prognostic value of serum osmolarity in patients with HF from the Spanish National Registry on Heart Failure (RICA), a multicenter, prospective registry that enrolls patients admitted for decompensated HF and follows them for 1year. Patients were divided into quartiles according to osmolarity levels. Primary endpoint was the combination of all-cause mortality and hospital readmissions for HF.
Results: A total of 2568 patients (47.46% men) were included. Patients with higher osmolarity were older, presented more comorbidities (especially diabetes mellitus and chronic kidney disease), and consequently had higher levels of glucose, urea, creatinine and potassium. During the 1-year follow-up, mortality among the quartiles was 18% (Q1), 18% (Q2), 23% (Q3) and 28% (Q4), p<0.001. After adjusting for baseline characteristics, high serum osmolarity was significantly associated with all-cause mortality (RR 1.02, 95% CI 1.01-1.03, p<0.001). We also found a significant increase in the combined endpoint of mortality and readmission among quartiles with higher osmolarity (p<0.001). Diabetes, eGFR, Barthel index, systolic blood pressure, body mass index, hemoglobin, NYHA class and beta-blocking agents were also independently associated with the primary endpoint.
Conclusions: In patients admitted for decompensated HF, high serum osmolarity predicts a worse outcome, and is associated with a higher comorbidity burden, supporting its use as a candidate prognostic target in HF.
Keywords: Congestive heart failure; Hyponatremia; Osmolarity.
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