The aim of this study was to examine the reproducibility of the new indicator test for sudomotor function (Neuropad) in type 2 diabetic patients. The study included 142 type 2 diabetic patients (70 men) with a mean age of 67.3 +/- 7.6 years and a mean diabetes duration of 14.2 +/- 6.3 years. Sudomotor function was assessed by means of colour change in the indicator test. Each patient was examined twice. Moreover, inter-observer variability was assessed in 60 patients (35 patients with sudomotor dysfunction, 25 patients without sudomotor dysfunction). In the right foot, a highly significant (r = 0.91, p = 0.001) correlation was observed between time until complete colour change of the test on the first (910.7 +/- 431.6 seconds) and second examination (935.8 +/- 440.1 seconds). In the left foot, a highly significant (r = 0.89, p = 0.001) correlation was observed between time until complete colour change of the test on the first (911.6 +/- 430.3 seconds) and second examination (940.5 +/- 441.2 seconds). Reproducibility was excellent both in patients with sudomotor dysfunction (p = 0.001) and in those without sudomotor dysfunction (p = 0.001). Agreement in diagnosis of sudomotor dysfunction between the two examinations was 98 %. Inter-observer reproducibility was excellent (p = 0.001), both in patients with sudomotor dysfunction and in those without sudomotor dysfunction. Intra- and interobserver Coefficient of Variance ranged between 4.1 % and 5.1 %.
Conclusions: These results indicate that reproducibility of the new indicator test for sudomotor function is excellent in type 2 diabetic patients with or without sudomotor impairment.