Risk prediction of cardiovascular death based on the QTc interval: evaluating age and gender differences in a large primary care population

Abstract

AimsUsing a large, contemporary primary care population we aimed to provide absolute long-term risks of cardiovascular death (CVD) based on the QTc interval and to test whether the QTc interval is of value in risk prediction of CVD on an individual level.Methods and resultsDigital electrocardiograms from 173 529 primary care patients aged 50–90 years were collected during 2001–11. The Framingham formula was used for heart rate-correction of the QT interval. Data on medication, comorbidity, and outcomes were retrieved from administrative registries. During a median follow-up period of 6.1 years, 6647 persons died from cardiovascular causes. Long-term risks of CVD were estimated for subgroups defined by age, gender, cardiovascular disease, and QTc interval categories. In general, we observed an increased risk of CVD for both very short and long QTc intervals. Prolongation of the QTc interval resulted in the worst prognosis for men whereas in women, a very short QTc interval was equivalent in risk to a borderline prolonged QTc interval. The effect of the QTc interval on the absolute risk of CVD was most pronounced in the elderly and in those with cardiovascular disease whereas the effect was negligible for middle-aged women without cardiovascular disease. The most important improvement in prediction accuracy was noted for women aged 70–90 years. In this subgroup, a total of 9.5% were reclassified (7.2% more accurately vs. 2.3% more inaccurately) within clinically relevant 5-year risk groups when the QTc interval was added to a conventional risk model for CVD.ConclusionImportant differences were observed across subgroups when the absolute long-term risk of CVD was estimated based on QTc interval duration. The accuracy of the personalized CVD prognosis can be improved when the QTc interval is introduced to a conventional risk model for CVD.

Which QT Correction Formulae to Use for QT Monitoring?

“…The risk assessment for QT prolongation of in‐hospital patients is based on their medication profile, demographic risk factors, electrolyte disturbances, and monitoring of the corrected QT (QTc) interval . Large population studies have shown a relation between QTc and all‐cause mortality, cardiac mortality, and sudden cardiac death …”

Thyroid Function and Sudden Cardiac Death

“…28 This hyperdynamic state, which causes many of the symptoms in hyperthyroid patients, could be one of the mechanisms explaining the relation between thyroid hormone and SCD. Furthermore, thyroid hormones have been shown to lead to QT-interval prolongation, 29,30 which, in turn, is related to cardiovascular disease, in general, 31 and SCD, in particular. 18 Another pathway could be through various cardiovascular risk factors related to thyroid dysfunction, and thus leading to ischemic heart disease, in turn, a large contributor in SCD.…”

Impact of abiraterone acetate with and without prior docetaxel chemotherapy on the survival of patients with metastatic castration-resistant prostate cancer: a population-based study

“…Comorbidities identified included cardiovascular events and chronic diseases such as diabetes, hypertension and dyslipidemia, which are known to be associated with increased risk of cardiovascular disease and associated mortality. [8][9][10][11][12][13] Cardiovascular events were defined as follows: coronary heart disease: ICD-9 codes 410-414, ICD-10 codes 122-125, a medical procedure (coronary artery bypass grafting, angiography or angioplasty) or use of oral nitrate therapy; cerebrovascular disease: ICD-9 codes 430-438 or medical procedures; chronic heart failure: ICD-9 code 398.91, 402 or 428, or a prescription of furosemide with digoxin, angiotensin-converting-enzyme inhibitors, spironolactone or β-blockers; and diagnosis of arrhythmia: ICD-9 codes 426-427, a medical procedure using a pacemaker and the use of drugs for cardiac arrhythmias (amiodarone, digoxin, quinidine, disopyramide, flecainamide, mexiletine, procainamide, propafenone or sotalol).…”