QT Interval Prolongation in Users of Selective Serotonin Reuptake Inhibitors in an Elderly Surgical Population

Abstract

To investigate the association between the use of a selective serotonin reuptake inhibitor (SSRI) and the occurrence of QT interval prolongation in an elderly surgical population. A cross-sectional study was conducted among patients (> 60 years) scheduled for outpatient preanesthesia evaluation in the period 2007 until 2012. The index group included elderly users of an SSRI. The reference group of nonusers of antidepressants was matched to the index group on sex and year of scheduled surgery (ratio, 1:1). The primary outcome was the occurrence of QT interval prolongation shown on electrocardiogram. The QT interval was corrected for heart rate (QTc interval). The secondary outcome was the duration of the QTc interval. The outcomes were adjusted for confounding by using regression techniques. The index and reference groups included 397 users of an SSRI and 397 nonusers, respectively. QTc interval prolongation occurred in 25 (6%) and 19 (5%) index and reference patients, respectively. After adjustment for confounding, users of an SSRI did not have a higher risk for QTc interval prolongation compared to nonusers: OR = 1.1 (95% CI, 0.5 to 2.0). The adjusted mean QTc interval length in users of an SSRI and nonusers was comparable (difference of 1.5 milliseconds [95% CI, -1.8 to 4.8]). Use of the most frequently used SSRIs citalopram and paroxetine was not associated with a higher risk of QTc interval prolongation nor with lengthening of the QTc interval duration. The use of an SSRI by elderly surgical patients was not associated with the occurrence of QT interval prolongation.