Prevalence of Hypochloremia in Patients With Heart Failure: A Systematic Review and Meta-Analysis.

There is no universal definition of low serum chloride, and included studies used 4 different cutoffs, so prevalence estimates are not directly comparable. The pooled estimate came from studies that disagreed very strongly (I2 96.6%), with individual estimates ranging from 7.4% to 31.5%. Publication bias was detected (Egger p=0.02), grey literature was not searched, and trim-and-fill changed the estimate to 15.2%, so the true prevalence may be different. The discharge finding rests on only 3 studies, so the rise from 12.5% to 27.0% is not well characterised. Most included studies were retrospective, and more than half were from the United States and Japan, limiting generalisability. This review reports prevalence only; it does not test whether monitoring or correcting low chloride improves heart failure outcomes.

Do not read the 14.0% pooled prevalence or 27.0% discharge prevalence as proof that correcting low serum chloride improves heart failure outcomes. This review pooled observational prevalence studies, and the paper states that whether correcting hypochloremia improves prognosis still needs randomised trials.