Association Between Disturbed Serum Phosphorus Levels and QT Interval Prolongation

Sho Sasaki; Kiichiro Fujisaki; Masato Nishimura; Toshiaki Nakano; Masanori Abe; Norio Hanafusa; Nobuhiko Joki

doi:10.1016/j.ekir.2024.03.007

Association Between Disturbed Serum Phosphorus Levels and QT Interval Prolongation

Kidney Int Rep. 2024 Mar 13;9(6):1792-1801. doi: 10.1016/j.ekir.2024.03.007. eCollection 2024 Jun.

Authors

Sho Sasaki^{1

2}, Kiichiro Fujisaki³, Masato Nishimura⁴, Toshiaki Nakano⁵, Masanori Abe⁶, Norio Hanafusa⁷, Nobuhiko Joki⁸

Affiliations

¹ Department of Healthcare Epidemiology, School of Public Health in the Graduate School of Medicine, Kyoto University, Kyoto City, Kyoto, Japan.
² Center for Innovative Research for Communities and Clinical Excellence (CiRC2LE), Fukushima Medical University, Fukushima, Japan.
³ Department of Nephrology, Iizuka Hospital, Fukuoka, Japan.
⁴ Toujinkai Satellite Clinic, Kyoto, Japan.
⁵ Department of Medical and Clinical Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
⁶ Division of Nephrology, Hypertension and Endocrinology, Department of Medicine, Nihon University School of Medicine, Tokyo, Japan.
⁷ Department of Blood Purification, Tokyo Women`s Medical University, Tokyo, Japan.
⁸ Division of Nephrology, Toho University Ohashi Medical Center, Tokyo, Japan.

Abstract

Introduction: QT interval prolongation is a risk factor for fatal arrhythmias and other cardiovascular complications. QT interval prolongation in patients on hemodialysis (HD) 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 patients on HD and to verify the association between predialysis serum calcium (Ca) and phosphate (P) levels and QT interval prolongation.

Methods: A cross-sectional study was conducted on adult patients on maintenance HD who were enrolled in the Japanese Society for Dialysis Therapy and Renal Data Registry 2019. After assessing patient characteristics, linear regression analysis was performed with predialysis serum Ca and P levels as exposures and a rate-corrected QT (QTc) interval as the outcome.

Results: A total of 204,530 patients were analyzed with a mean QTc of 451.2 (standard deviation, 36.9) ms. After multivariable analysis, estimated change in QTc (coefficients; 95% confidence interval) per 1 mg/dl increase in serum Ca and P was -2.02 (-3.00 to -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.

Conclusion: Decreased serum Ca levels and decreased and increased serum P levels may be associated with QT interval prolongation in patients on maintenance HD.

Keywords: QT interval prolongation; calcium; hemodialysis; phosphate.