Association of serum chloride concentration with the risk of major adverse cardiovascular events in patients undergoing peritoneal dialysis: the Fukuoka peritoneal dialysis registry (F-PDR).

BACKGROUND: Cardiovascular disease is the leading cause of death among patients undergoing peritoneal dialysis (PD). Serum chloride might provide prognostic information independent of serum sodium; however, its association with cardiovascular events in patients undergoing PD remains unclear. The aim of this study was to assess the association between serum chloride concentration and major adverse cardiovascular events (MACE) in patients undergoing PD. METHODS: We conducted a multicenter cohort study using data from the Fukuoka Peritoneal Dialysis Registry. A total of 1,043 PD patients were included after excluding those with a PD duration of <90 days. The primary outcome was MACE (cardiovascular death, nonfatal myocardial infarction, or nonfatal stroke). Serum chloride was analyzed in tertiles and per 1 mmol/L decrease. Associations were evaluated by multivariable-adjusted Cox proportional hazards models, further adjusting for serum sodium. RESULTS: Over a median follow-up of 681 days, 135 patients experienced MACE. Hypochloremia (< 96 mmol/L) was present in 32.5% of the patients. In multivariable-adjusted models, patients in the lowest serum chloride tertile showed a significantly higher risk of MACE compared with those in the highest tertile (hazard ratio [HR], 2.38; 95% confidence interval [CI], 1.28-4.42). Each 1 mmol/L decrease in serum chloride was also associated with increased risk of MACE (HR, 1.08; 95% CI, 1.01-1.16). CONCLUSIONS: Lower serum chloride concentration was independently associated with a higher risk of MACE in PD patients, even after adjusting for serum sodium. Serum chloride might provide information on cardiovascular risk, which was not fully reflected by serum sodium.