The association of long-term glycaemic variability versus sustained chronic hyperglycaemia with heart rate-corrected QT interval in patients with type 2 diabetes

PLoS One. 2017 Aug 28;12(8):e0183055. doi: 10.1371/journal.pone.0183055. eCollection 2017.

Abstract

Objectives: Prolonged heart rate-corrected QT(QTc) interval is related to ventricular arrhythmia and cardiovascular mortality, with considerably high prevalence of type 2 diabetes. Additionally, long-term glycaemic variability could be a significant risk factor for diabetic complications in addition to chronic hyperglycaemia. We compared the associations of long-term glycaemic variability versus sustained chronic hyperglycaemia with the QTc interval among type 2 diabetes patients.

Methods: In this cross-sectional study, 2904 type 2 diabetes patients were recruited who had undergone at least four fasting plasma glucose (FPG) and 2-hour postprandial plasma glucose (PPG) measurements (at least once for every 3 months, respectively) during the preceding year. Long-term glycaemic variabilities of FPG and 2-hour PPG were assessed by their standard deviations (SD-FPG and SD-PPG, respectively), and chronic fasting and postprandial hyperglycaemia were assessed by their means (M-FPG and M-PPG, respectively). HbA1c was also determined upon enrolment to assess current overall glycaemic control. QTc interval was estimated from resting 12-lead electrocardiograms, and more than 440 ms was considered abnormally prolonged.

Results: Patients with prolonged QTc interval (≥440 ms) had greater M-FPG, M-PPG, SD-PPG and HbA1c than those with normal QTc interval but comparable SD-FPG. QTc interval was correlated with M-FPG, M-PPG, SD-PPG and HbA1c (r = 0.133, 0.153, 0.245 and 0.207, respectively, p = 0.000) but not with SD-FPG (r = 0.024, p = 0.189). After adjusting for metabolic risk factors via multiple linear regression analysis, SD-PPG, M-PPG and HbA1c (t = 12.16, 2.69 and 10.16, respectively, p = 0.000) were the major independent contributors to the increased QTc interval. The proportion of prolonged QTc interval increased significantly from 10.9% to 14.2% to 26.6% for the first (T1) to second (T2) to third (T3) tertiles of SD-PPG. After adjusting via multiple logistic regression analysis, the odd ratios of prolonged QTc interval of the T2 and T3 versus the T1 of SD-PPG were 1.15 (95% CI, 0.82-1.60) and 2.62 (1.92-3.57), respectively.

Conclusions: Increased long-term variability of PPG is a strong independent risk factor for prolonged QTc interval in type 2 diabetes patients, in addition to long-term postprandial hyperglycaemia and current HbA1c.

MeSH terms

  • Adult
  • Aged
  • Blood Glucose / metabolism*
  • Cross-Sectional Studies
  • Diabetes Mellitus, Type 2 / blood*
  • Diabetes Mellitus, Type 2 / physiopathology
  • Electrocardiography
  • Female
  • Heart Conduction System / physiopathology*
  • Heart Rate / physiology*
  • Humans
  • Hyperglycemia / blood*
  • Hyperglycemia / physiopathology
  • Middle Aged
  • Postprandial Period
  • Risk Factors

Substances

  • Blood Glucose

Grants and funding

The study was funded by the Scientific Research Program of Nantong (MS22015065), http://www.ntkj.gov.cn/; the Scientific Research Program of Health and Planning Commission of Jiangsu (H201553), http://www.jswst.gov.cn/jsswshjhsywyh/index.html;and the Scientific and Educational Program for Health Care Prosperity of Jiangsu (Young Medical Talents Project: QNRC2016408), http://www.jswst.gov.cn/jsswshjhsywyh/index.html. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.