Ukpabi Ogba J, Onwubere Basden Jc
Federal Medical Centre, Umuahia, Nigeria.
University of Nigeria Teaching Hospital, Ituku Ozalla, Enugu, Nigeria.
Afr Health Sci. 2017 Dec;17(4):1092-1100. doi: 10.4314/ahs.v17i4.17.
Prolonged corrected QT (QTc) has been identified as a risk factor for malignant arrhythmias and sudden cardiac death. Caucasian studies have shown a definite relationship between QTc prolongation and Cardiac Autonomic Neuropathy (CAN) in diabetic subjects.
To determine the prevalence of prolonged QTc in Black diabetic individuals with CAN and to ascertain how prolonged QTc correlated with the severity of CAN among these patients.
A total of 176 adult diabetic subjects were studied, 87 males and 89 females. There was a control group of non-diabetic individuals. Cardiac autonomic function was assessed using five cardiovascular autonomic function tests. CAN was diagnosed if 2 or more of these tests were abnormal. Severity of CAN was determined according to the number of abnormal tests. QTc > 0.440 was regarded as prolonged.
Fifty-one out of the 176 diabetic subjects (29%) had CAN. The prevalence of prolonged QTc in diabetic subjects with CAN was 12%. QTc was prolonged in 1.6% and 0.6% of diabetic individuals without CAN and controls respectively. Although QTc correlated strongly with cardiac autonomic function neuropathy, there was no definite relationship between QTc prolongation and severity of CAN.
This study in a Black population is in agreement with the well-known relationship between QTc prolongation and CAN reported in Caucasian studies. In view of the wide variability of QTc in this study population, it is suggested that relative QTc increase may be a better indicator of CAN than a definite QTc prolongation of greater than 0.440.
校正QT间期（QTc）延长已被确定为恶性心律失常和心源性猝死的危险因素。高加索人群的研究表明，糖尿病患者的QTc延长与心脏自主神经病变（CAN）之间存在明确关联。
确定患有CAN的黑人糖尿病个体中QTc延长的患病率，并确定QTc延长与这些患者中CAN严重程度的相关性。
共研究了176名成年糖尿病患者，其中男性87名，女性89名。设有一个非糖尿病个体的对照组。使用五项心血管自主功能测试评估心脏自主功能。如果这些测试中有两项或更多项异常，则诊断为CAN。根据异常测试的数量确定CAN的严重程度。QTc>0.440被视为延长。
176名糖尿病患者中有51名（29%）患有CAN。患有CAN的糖尿病患者中QTc延长的患病率为12%。无CAN的糖尿病个体和对照组中QTc延长的比例分别为1.6%和0.6%。虽然QTc与心脏自主神经功能神经病变密切相关，但QTc延长与CAN严重程度之间没有明确关系。
这项针对黑人人群的研究与高加索人群研究中报道的QTc延长与CAN之间的已知关系一致。鉴于本研究人群中QTc的广泛变异性，建议相对QTc增加可能比明确的QTc延长大于0.440更能作为CAN的指标。
