The significance of metabolic alkalosis on acute decompensated heart failure: the ALCALOTIC study.

Aims: To determine the prevalence and the impact on prognosis of metabolic alkalosis (MA) in patients admitted for acute heart failure (AHF).

Methods and results: The ALCALOTIC is a multicenter, observational cohort study that prospectively included patients admitted for AHF. Patients were classified into four groups according to their acid-base status on admission: acidosis, MA, respiratory alkalosis, and normal pH (reference group for comparison). Primary endpoint was all-cause in-hospital mortality, and secondary endpoints included 30/90-day all-cause mortality, all-cause readmission, and readmission for HF. Associations between endpoints and acid-base alterations were estimated in a multivariate Cox regression model including sex, age, comorbidities, and Barthel index and expressed as hazard ratio (HR) with 95% confidence interval (95% CI). Six hundred sixty-five patients were included (84 years and 57% women), and 40% had acid-base alterations on admission: 188 (28%) acidosis and 78 (12%) alkalosis. The prevalence (95% CI) of MA was 9% (6.8-11.2%). Patients with MA were more women; had fewer comorbidities, better renal function, and higher left ventricle ejection fraction values; and received more treatment with oral acetazolamide during hospitalization and at discharge. MA was not associated with a higher risk of in-hospital mortality and 30/90-day all-cause mortality or readmissions but was associated with a significant increase in readmissions for HF at 30 and 90 days (adjusted HR [95% CI] 3.294 [1.397-7.767], p = 0.006 and 2.314 [1.075-4.978], p = 0.032).

Conclusion: The prevalence of MA in patients admitted for AHF was 9%, and its presence was associated with more readmissions for HF but not with all-cause mortality.