Effects of cinacalcet treatment on QT interval in hemodialysis patients

OBJECTIVE Cinacalcet is a calcimimetic drug that acts via calcium-sensing receptors (CaSRs) and increases the sensitivity of CaSRs on the parathyroid gland; thus, it lowers calcium and phosphorus levels as well as parathormone levels. Prolongation of the QT interval is recognized as a risk factor for the development of ventricular arrhythmias and sudden death. Patients with end-stage renal disease (ESRD) are sensitive for QT prolongation and torsade de pointes more than the normal population. In this study, we aimed to evaluate the effects of cinacalcet on the electrocardiogram (ECG), particularly changes in the QT interval, in patients with ESRD. METHODS Thirty-seven patients (21 males and 16 females) undergoing maintenance hemodialysis for at least 12 months were included in this retrospective study. Patients receiving cardioactive and antiarrhythmic drugs and those having a history of any cardiac or cerebrovascular events, active malignancy, and infections were excluded. Baseline ECG measurements of patients were performed over the newest ECG measurements that were obtained within 1 month before initiating the cinacalcet treatment, and the ECG measurements of patients after the cinacalcet treatment were performed according to the most recent ECG that was taken within the last 1 week in the clinic. We recorded the heart rate and QT values of patients before and after treatment and then calculated the corrected QT values (QTc). The Statistical Package for the Social Sciences (SPSS) ver. 21.0 was used for statistical analysis. RESULTS The mean age of patients was 52.24±14.49 years. Prolongation of QTc was statistically significant compared with the baseline QTc value (baseline: 396.62±42.04 msec; after treatment: 404.97±43.47 msec; p=0.031). We found a positive correlation between the prolongation of QTc and treatment dose of cinacalcet (p<0.005, r=0.560). CONCLUSION Clinicians should be very careful for life threatening cardiac side effects while increasing the dose of cinacalcet treatment in hemodialysis patients who have a borderline or prolonged QTc interval.