Ewing试验及心率变异性对初诊2型糖尿病患者心血管自主神经病变诊断的比较

目的了解初诊2型糖尿病患者的心血管自主神经病变（CAN）患病情况及其特点，比较Ewing试验及心率变异性（HRV）两种常用评价方法对诊断CAN的差异。方法以2009年5月至2010年12月广东省4家医院（中山大学附属第三医院、汕头大学医学院第一附属医院、广东省人民医院、南方医科大学珠江医院）内分泌科收治的90例初诊2型糖尿病患者为糖尿病组，其中男58例，女32例，平均年龄（47±1）岁。以同期40名健康体检者为对照组，其中男21名，女19名，平均年龄为（45±2）岁。所有受试者均接受Ewing试验和24h动态心电图检查并分析HRV指标以诊断CAN，对比两种方法的结果差异。计量资料间比较采用t检验或单因素方差分析，等级资料采用秩和检验。结果（1）Ewing试验显示糖尿病组CAN阳性率[22．2％（20／90）]高于对照组[7．5％（3／40），X2=4．12，P〈0．05]；糖尿病组Ewing试验总评分（92．5分）高于对照组（7．0分，Z=-3．72，P〈0．01），Ewing试验各指标（Valsalva指数、深呼吸心率差、立卧位心率变化及血压差）评分均较对照组升高，差异均有统计学意义（z值分别为-2．99、-2．23、-1．99、-2．36，均P〈0．05）。（2）HRV分析显示糖尿病组CAN阳性率[34．4％（31／90）]高于对照组[12．5％（5／40），X2=6．66，P〈0．05]；糖尿病组HRV中反映副交感神经功能的指标[全部正常窦性心搏问期（N—N）的标准差、连续5min正常R—R间期均值的标准差及低频功率]均降低，与对照组相比差异均有统计学意义（t值分别为2．06、2．24、6．48，均P〈0．05），而代表交感神经功能的指标（全程相邻N．N间期之差的均方根值、相邻R—R间期差异≥50ms的百分数、高频功率）差异均无统计学意义（t值分别为0．27、0．15、1．40，均P〉0．05）。结论Ewing试验和HRV检测均显示初诊2型糖尿病患者中CAN阳性率较高，且以副交感神经损害为主；HRV检测较Ewing试验的CAN阳性率高。

Comparison of Ewing test and heart rate variability for cardiovascular autonomic neuropathy in patients with newly diagnosed type 2 diabetes mellitus

Objective To assess the positive rate and characteristics of cardiovascular autonomic neuropathy （CAN） in patients with newly diagnosed type 2 diabetes and to compare Ewing test with heart rate variability （HRV） for identifying CAN. Methods Ninety newly diagnosed type 2 diabetic patients （diabetic group） and 40 healthy subjects （control group） were enrolled from Department of Endocrinology and Metabolism of 4 hospitals in Guangdong Province （the Third Affiliated Hospital of Sun Yat-sen University, the First Affiliated Hospital of Shantou University Medical College, Guangdong General Hospital, Zhujiang Hospital of Southern Medical University）. The diabetic group included 58 males and 32 females, with an average age （47 ± 1 ） years. The control group included 21 males and 19 females, with an average age （45 ±2） years. Standard Ewing test and Holter （HRV analysis） were used to evaluate CAN, and comparison of these two diagnostic methods was committed. Difference of measurement data was compared with t test or one-way ANOVA and rank sum test was used for ranked data. Results （ 1 ） The results of Ewing test showed that the positive rate of CAN in newly diagnosed type 2 diabetic patients （22. 2% （20/90）） was higher than that in the controls （7. 5% （3/40）, X2 =4. 12,P 〈0. 05）. The Ewing scores in the diabetic patients （ 92. 5 ） were significantly higher than those in the controls （ 7.0, Z = -3.72,P 〈 0. 01 ）. The indexes of Ewing test （ including valsalva ratio, heart-rate variation during deep breathing, heart rate and blood pressure response on standing） in the diabetic patients（92. 5） were higher than those in the controls （Z value was - 2. 99, - 2. 23, - 1.99 and - 2. 36, respectively, all P 〈 0. 05 ）. （2） HRV analysis showed that the positive rate of CAN in newly diagnosed type 2 diabetic patients （34.4% （31/90） ）, was higher than that in the controls （ 12. 5 % （ 5/40 ）, X2 = 6. 66, P 〈 0. 05 ）. HRV indices related to parasympathetic function （ including standard deviation of all normal-to-normal （N-N） intervals （ SDNN）, standard deviation of the averages of N-N intervals in all 5 rain segments （SDANN） and power in the low frequency range （LF） in the diabetic patients significantly decreased compared with those in the controls （ t value was 2. 06, 2. 24 and 6. 48, respectively, all P 〈 0. 05 ）, but there was no significant difference in those related to the sympathetic function such as root mean square of successive differences in R-R interval （RMSSD） , percentage of R-R intervals differing more than 50 ms from the preceding one （PNN50） and power in the high frequency range （HF） （ t value was 0. 27, 0. 15 and 1.40, respectively, all P 〉 0. 05 ）. Conclusions Both Ewing tests and HRV showed a higher positive rate of CAN in the newly diagnosed type 2 diabetic patients than that in the control group, and parasympathetic function was mainly damaged. More CAN patients were detected by HRV than by Ewing test.