In this study, we propose a novel DPN severity classification based on coefficient of variance of R-R interval on ECG (CVRR) and nerve conduction study (NCS).
The subjects consisted of 182 patients (mean age 58.9 years-old; duration of diabetes 10.2 years, HbA1c 9.72% and BMI 26.0) with type 2 diabetes admitted to our hospital from 2015 to 2017. Based on NCS and CVRR during rest, the subjects were classified into six categories as follows; 1) N0C0: sural nerve sensory action potential (SP)>5μV and tibial nerve compound motor action potential (CP)>5mV + CVRR>2%, 2) N1C0: SP<5 and CP>5 + CVRR>2, 3) N2C0: SP<5 and CP<5 + CVRR>2, 4) N0C1: SP>5 and CP>5 + CCRR<2, 5) N1C1: SP<5 and CP>5 + CVRR<2 and 6) N2C1: SP<5 and CP<5 + CR<2. We examined the relationship between each category with urinary albumin excretion rate (logarithmic transformation: LogACR), eGFR, presence/absence of nephropathy (ACR>300mg/gCre and/or eGFR<30) or retinopathy, and PWV as an index of arteriosclerosis. For statistical analysis, one-way analysis of variance (ANOVA), multiple comparison (Tukey), covariance analysis and logistic regression analysis were used.
The one-way analysis revealed significant differences between each category in terms of age, the duration of diabetes, LogACR, eGFR and PWV. LogACR and PWV were significantly higher in the N2C1 than in the N0C0 (p<0.05). Even after correction with age, duration and gender, a significant difference (p=0.008) between groups was observed in LogACR and a trend in PWV (p=0.068). In the logistic regression analysis corrected by age, duration and gender, the odds ratio (OR) for retinopathy was 5.36 in N0C1, 11.10 in N1C0, 8.23 in N1C1 and 11.78 in N2C1 compared with N0C0 (p<0.01). The OR for nephropathy in N0C1 was 6.56, 7.91 in N1C1, 15.54 in N2C0 and 23.55 in N2C1 (p<0.05).
Severity classification of DPN based on NCS and CVRR during rest was well co-related to other diabetic complications, suggesting the usefulness of this novel classification to evaluate the severity of DPN.
H. Shimoda: None. H. Kamiya: Other Relationship; Self; MSD K.K., Ono Pharmaceutical Co., Ltd., Sanofi K.K., AstraZeneca, Astellas Pharma KK, Eli Lilly and Company, Novartis Pharma K.K., Dainippon Sumitomo Pharma Co., Ltd, Boehringer Ingelheim Pharmaceuticals, Inc., Takeda Pharmaceutical Co., Ltd, Ono Pharmaceutical Co., Ltd.. A. Watarai: None. T. Himeno: None. Y. Shibata: None. M. Motegi: None. M. Kato: None. Y. Yamada: None. E. Miura-Yura: None. M. Kondo: None. S. Tsunekawa: None. Y. Kato: Speaker's Bureau; Self; Merck Sharp & Dohme Corp., Sanofi, Takeda Pharmaceutical Company, Eli Lilly Japan. J. Nakamura: Other Relationship; Self; Astellas Pharma US, Inc., AstraZeneca, Ono Pharmaceutical Co., Ltd., MSD K.K., Kyowa Hakko Kirin Co., Ltd., Kowa Pharmaceuticals America, Inc., Sanofi K.K., Taisho Pharmaceutical Co., Ltd., Takeda Development Center Asia, Pte. Ltd., Mitsubishi Tanabe Pharma Corporation, Eli Lilly and Company, Novartis Pharma K.K., Pfizer Inc..