The Association of Resting Heart Rate with the Presence of Diabetes in Korean Adults: The 2010-2013 Korea National Health and Nutrition Examination Survey

BACKGROUND Previous epidemiologic studies have shown that elevated resting heart rate (HR) is associated with higher cardiovascular disease (CVD) morbidity and mortality. Although the relationship between elevated HR and CVD is well established, the association between resting HR and diabetes has been relatively understudied, particularly in non-Western populations. OBJECTIVES We confirmed the association between the presence of type 2 diabetes and resting HR in the Korean adult population using data from the 2010-2013 Korea National Health and Nutrition Examination Survey (KNHANES). METHODS Among 25,712 adults (≥ 19 years of age) who participated in the 2010-2013 KNHANES, a total of 22,512 subjects completed laboratory examinations and were included in this analysis. The fasting plasma glucose (FPG) level was categorized into the following five groups: normal fasting glucose (NFG) 1 (<90 mg/dL), NFG 2 (90-99 mg/dL), impaired fasting glucose (IFG) 1 (100-110 mg/dL), IFG 2 (111-125 mg/dL), and diabetes (≥ 126 mg/dL). RESULTS The unadjusted weighted resting HRs were 69.6, 69.4, 69.8, 70.1, and 72.0 beats per minute (bpm) in the NFG 1, NFG 2, IFG 1, IFG 2, and diabetes groups, respectively (P<0.001). We assessed the adjusted weighted resting HR according to the FPG level after adjusting for age, sex, smoking history, high risk alcohol drinking, daily energy intake, waist circumference, serum total cholesterol level, serum triglyceride (TG) level, serum white blood cell (WBC) count, serum hemoglobin (Hb), and the presence of hypertension. The adjusted weighted resting HR significantly increased across the FPG groups (P<0.001). The weighted prevalence rates of diabetes were 6.8% (6.2-7.5%), 7.6% (6.7-8.5%), 8.0% (7.0-9.1%), and 11.8% (10.8-12.7%) in subjects with HR ≤ 64, 65-69, 70-75, and ≥ 76 bpm, respectively (P<0.001), after adjusting for the confounding factors mentioned above. Using resting HR ≤ 64 bpm as the control, resting HR ≥ 76 bpm was correlated with the presence of diabetes (adjusted OR 1.83, 95% CI 1.55-2.16, P<0.001). Each 10 bpm increment of HR increased the risk of the presence of diabetes by 35% (P<0.001). This association of high resting HR with the presence of diabetes was not influenced by the status of blood pressure (BP) medication. CONCLUSION We demonstrated that higher HR was associated with diabetes in a representative sample of Korean adults. These positive associations were independent of age, sex, current smoking, high risk alcohol drinking, daily energy intake, waist circumference, and the presence of hypertension and other potential confounders. This study suggests that individuals with higher resting HR are at risk of diabetes and that HR might provide an easy and simple surrogate marker for the risk of diabetes.