Association Between Disturbed Serum Phosphorus Levels and QT Interval Prolongation

Abstract

INTRODUCTIONQT interval prolongation is a risk factor for fatal arrhythmias and other cardiovascular complications. QT interval prolongation in hemodialysis (HD) patients is not well understood. Hypocalcemia is a suspected, but poorly verified etiology in these patients, and the association between serum phosphorus levels and QT interval prolongation is unknown. We sought to determine the prevalence of QT interval prolongation in HD patients and to verify the association between pre-dialysis serum Ca and P levels and QT interval prolongation. METHODSA cross-sectional study was conducted on adult maintenance HD patients enrolled in the Japanese Society for Dialysis Therapy and Renal Data Registry 2019. After assessing patient characteristics, linear regression analysis was performed with pre-dialysis serum Ca and P levels as exposures and a rate-corrected QT (QTc) interval as the outcome. RESULTSA total of 204,530 patients were analyzed with a mean QTc of 451.2 msec (SD = 36.9 msec). On multivariable analysis, estimated change in QTc (coefficients, [95% confidence interval {CI}])] per 1 mg/dL increase in serum Ca and P was -2.02 [-3.00, -1.04] and 5.50 [3.92,7.09], respectively. In the restricted cubic spline curve, estimated change in QTc increased with lower values of serum Ca. The correlation between serum P and QTc showed a U-shaped curve. CONCLUSIONDecreased serum Ca levels and decreased and increased serum P levels may be associated with QT interval prolongation in maintenance HD patients.