McGill M, Molyneaux L, Spencer R, Heng L F, Yue D K
Diabetes Center, Royal Prince Alfred Hospital Camperdown, New South Wales, Australia.
Diabetes Care. 1999 Apr;22(4):598-602. doi: 10.2337/diacare.22.4.598.
The purpose of this study was to evaluate the effects of different testing sites and buckling strengths on the sensitivity and specificity of using the Semmes-Weinstein monofilament to detect patients with insensate foot. The impact on workload required to educate and follow up these high-risk individuals was estimated by modeling in our patient population with a documented status of neuropathy.
Using the 5.07/10-g monofilament, one observer tested 132 randomly selected subjects with diabetes at five sites on the right foot. The sensitivity and specificity of each site and combinations of sites in detecting vibration perception threshold > 40 was calculated. In addition, two monofilaments, one with a buckling force of 5 g and the other with a force of 15 g, were compared by testing 200 randomly selected patients. An estimate of the prevalence of insensate foot and workload was made by modeling the findings to the 5,270 patients with neuropathy status registered on our computerized database.
Specificity of the 5.07/10-g monofilament to detect insensate foot at each of the five sites is high, at approximately 90%, but there is considerably more variation and lower sensitivity, ranging from 44-71%. Data derived from the use of different combinations of sites showed that more stringent criteria are associated with lower sensitivity but higher specificity. If the foot is considered insensate when either of sites 3 and 4 (plantar aspect of the first and fifth metatarsal heads, respectively) cannot feel the monofilament, there is reasonable sensitivity and specificity (80-86%, respectively). By modeling on our diabetes center population, it can be demonstrated that the choice of different methodologies leads to different conclusions about the prevalence of severe neuropathy, ranging from 3.4 to 29.3%.
Using a combination of sites 3 and 4 for monofilament testing gives a reasonable compromise for time, sensitivity, and specificity. Minor changes in sensitivity and specificity can lead to major changes in the prevalence of neuropathy, with implications for workload.
本研究旨在评估不同测试部位和屈曲强度对使用Semmes-Weinstein单丝检测足部感觉减退患者的敏感性和特异性的影响。通过对我们有神经病变记录状态的患者群体进行建模，估计了对这些高危个体进行教育和随访所需工作量的影响。
一名观察者使用5.07/10克单丝在132名随机选择的糖尿病患者的右脚五个部位进行测试。计算每个部位以及部位组合在检测振动觉阈值>40时的敏感性和特异性。此外，通过对200名随机选择的患者进行测试，比较了两种单丝，一种屈曲力为5克，另一种为15克。通过将研究结果应用于我们计算机数据库中登记的5270名有神经病变状态的患者，对足部感觉减退的患病率和工作量进行了估计。
5.07/10克单丝在五个部位中每个部位检测足部感觉减退的特异性都很高，约为90%，但变化更大且敏感性较低，范围为44%-71%。来自不同部位组合使用的数据表明，更严格的标准与较低的敏感性但较高的特异性相关。如果当部位3和4（分别为第一和第五跖骨头的足底侧面）中的任何一个部位无法感觉到单丝时，就认为足部感觉减退，那么就有合理的敏感性和特异性（分别为80%-86%）。通过对我们糖尿病中心人群进行建模，可以证明不同方法的选择会导致关于严重神经病变患病率的不同结论，范围从3.4%到29.3%。
将部位3和4组合用于单丝测试在时间、敏感性和特异性方面给出了合理的折衷。敏感性和特异性的微小变化可能导致神经病变患病率的重大变化，这对工作量有影响。
