RESUMO
AIMS/INTRODUCTION: To explore the relationship between heart rate-corrected QT (QTc) interval and diabetic peripheral neuropathy (DPN), and whether QTc interval has diagnostic utility for DPN beyond nerve conduction velocity. MATERIALS AND METHODS: A total of 965 patients with diabetes, including 473 patients with DPN and 492 patients without DPN, underwent standard 12-lead electrocardiography and detailed assessments of peripheral neuropathy. RESULTS: Patients with DPN had longer QTc intervals than those without. Among participants, from the first to fourth quartile of QTc interval, the proportion of patients with DPN appreciably increased and the nerve conduction velocity obviously decreased (P for trend <0.001). The univariate and multivariate analyses showed that prolonged QTc interval was closely associated with increased risk of DPN (univariable odds ratio 1.112, 95% confidence interval 1.097-1.127, P < 0.001; multivariable odds ratio 1.118, 95% confidence interval 1.099-1.137, P < 0.001). Receiver operating characteristic analysis for the diagnosis of DPN showed a greater area under the curve for QTc interval of 0.894 than the median nerve motor conduction velocity of 0.691, median nerve sensory conduction velocity of 0.664 and peroneal nerve motor conduction velocity of 0.692. The optimal cut-off point of QTc interval for DPN was 428.5 ms with sensitivity of 0.715 and specificity of 0.920 (P < 0.001). The combination of QTc interval and nerve conduction testing increased the area under the curve for the diagnosis of DPN (from 0.736 to 0.916; P < 0.001). CONCLUSIONS: QTc interval with 428.5 ms has more reliable diagnostic utility for DPN than nerve conduction velocity, and prolonged QTc interval is closely associated with an increased risk of DPN.