Association between a frailty index based on common laboratory tests and QTc prolongation in older adults: the Rugao Longevity and Ageing Study

Association between a frailty index based on common laboratory tests and QTc prolongation in older adults: the Rugao Longevity and Ageing Study Teng Ma,1–3,* Jian Cai,4,* Yin-Sheng Zhu,5 Xue-Feng Chu,5 Yong Wang,5 Guo-Ping Shi,5 Zheng-Dong Wang,5 Shun Yao,1–3 Xiao-Feng Wang,1–3 Xiao-Yan Jiang6–8 1Unit of Epidemiology, Ministry of Education Key Laboratory of Contemporary Anthropology, Fudan University, Shanghai, People's Republic of China; 2State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, Shanghai, People's Republic of China; 3National Clinical Research Center for Aging and Medicine (Huashan), Huashan Hospital, Fudan University, Shanghai, People's Republic of China; 4Department of Neurology, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, People's Republic of China; 5Rugao People's Hospital, Rugao, Jiangsu, People's Republic of China; 6Key Laboratory of Arrhythmias of the Ministry of Education of China, Tongji University School of Medicine, Shanghai, People's Republic of China; 7Department of Pathology and Pathophysiology, Tongji University School of Medicine, Shanghai, People's Republic of China; 8Institute of Medical Genetics, Tongji University, Shanghai, People's Republic of China *These authors contributed equally to this work Background: Risk factors for heart rate-corrected QT interval (QTc) proglongation should be explored to stratify high-risk individuals to aid the prevention of incident cardiovascular events and mortality. The diversity of risk factors for QTc prolongation suggests that use of the frailty index (FI), indicating general health deficits, may be an effective approach, especially in the elderly, to identify the risk of QTc prolongation. Methods: We used the data of 1,780 individuals aged 70–87 years from the Rugao Longevity and Ageing Study (RuLAS), a community-based longitudinal study. The FI was constructed using 20 routine laboratory tests, plus the body mass index and measures of systolic and diastolic blood pressures (FI-Lab). Results: The mean FI-Lab value was 0.24±0.09. The mean heart rate-corrected QT interval (QTc) was 407±38 ms. The prevalence of QTc prolongation was 5.2% in elderly community populations aged 70–87 years. A higher FI-Lab value was associated with a higher risk for QTc prolongation. Each 10% increase in the FI-Lab value increased the odds ratio (OR) by 33% (OR: 1.33; 95% CI: 1.07–1.64). Compared with the lowest quartile, the top quartile FI-Lab score was associated with a 2.50-fold QTc prolongation risk in elderly individuals (95% CI: 1.21–5.19). Conclusion: An FI based on routine laboratory data can identify older adults at increased risk for QTc prolongation. The FI approach may therefore be useful for the risk stratification of QTc prolongation. Keywords: QTc prolongation, frailty, frailty index, Chinese elderly