Authors:

A Urbinati¹ , P Pellicori² , J Cuthbert³ , D Pan³ , S Kazmi³ , F Guerra¹ , A Capucci¹ , AL Clark³ , JG Cleland² , ¹Marche Polytechnic University of Ancona - Ancona - Italy , ²University of Glasgow - Glasgow - United Kingdom , ³Castle Hill Hospital - Hull - United Kingdom ,

Background: Blood electrolyte disorders are common in patients hospitalized for heart failure: serum chloride is usually measured but rarely considered. 

Methods and results: Between October 2012 and November 2016, patients hospitalized with worsening heart failure enrolled in the OPERA-HF, a single-centre, prospective, observational study had serum chloride measured at admission and discharge. 1145 patients (mean age 75±12 years, median NTproBNP 4999 (IQR: 2331-10971) ng/l, of whom 62% had HFrEF on echocardiography, were enrolled. Hypochloraemia (serum chloride < 96 mmol/l) was present in 161 patients (14%) at admission and in 390 patients (34%) at discharge. Compared to patients in the highest quintile (median chloride 107 mmol/l; range 105-117 mmol/l), those in the lowest quintile of serum chloride at admission (median 94 mmol/l, range 76-97 mmol/l) were more likely to die (hazard ratio [HR]: 1.88; 95% confidence interval [CI]: 1.43-2.47, p<0.001). Increasing chloride, but not sodium or potassium, levels at admission were independently associated with lower all-cause mortality (HR 0.94; 95% CI 0.89 to 0.99; p=0.035). Compared to those who had normal chloride levels at admission and discharge, those who developed hypochloraemia during admission (HR:1.58; 95% CI 1.29-1.93, p<0.001), or those who remained hypochloraemic (HR: 2.07; 95% CI 1.61-2.66, p<0.001 ) had a higher mortality. Patients in whom hypochloraemia was corrected during hospitalisation had the same survival as those who were never hypochloraemic (HR: 1.08; 95% CI 0.65-1.79, p=0.761).

Conclusion: Hypochloraemia is a common electrolyte disorder in patients admitted with worsening heart failure and is a powerful predictor of increasing mortality.