We compared the accuracy of cutaneous pressure perception-threshold measurements with that of other sensory-threshold measurements for detecting diabetic foot ulcer patients. Three hundred fourteen non-insulin-dependent diabetic patients were studied, of whom 91 had either a current foot ulcer or a history of foot ulceration. Foot ulcer patients had much higher pressure perception thresholds at the hallux than those without foot ulcers (mean +/- SE 4.63 +/- 0.05 vs. 3.54 +/- 0.04 U, P less than 0.001). The magnitude of association was higher than that for vibration thresholds and markedly greater than those for cool and warm thresholds. Pressure thresholds were highly accurate for identifying foot ulcer patients. At a threshold level of 4.21 U, the sensitivity was 0.84, with a specificity of 0.96. At similar sensitivities for vibration and thermal thresholds, specificities were lower. Foot ulceration and cutaneous pressure perception threshold are strongly associated. Pressure-threshold measurements are extremely accurate and perform at least as well as other quantitative sensory tests in identifying foot ulcer patients. Assessment of the foot pressure threshold may have promise as a simple and inexpensive method for detecting diabetic patients at risk for foot ulcers.

These data suggest that although sensory function tends to be normal at diagnosis in NIDDM patients, there appears to be a diminution in sensory function as the disease progresses. An interaction between metabolic factors and height may influence sensory function early in the course of NIDDM.

Sensory function was prospectively examined in 201 Type 2 diabetic patients over a 2-year period. Quantitative sensory testing for vibration, cool, warm, and pressure perception at the hallux was performed at baseline, 1-month, 1-year, and 2-year visits. There were statistically significant increments of thresholds for all sensory modalities from the baseline visit to the 1-year visit (p < 0.001) and from the 1-year visit to the 2-year visit (p < 0.001). Thirty percent of 77 subjects considered to be at low risk for foot ulceration at baseline progressed to a higher risk category at the 2-year visit. There were no significant differences in mean glycosylated haemoglobin, height, sex distribution, age, or diabetes duration when patients who had a faster progression of insensitivity were compared with patients who had a slower progression. There was a high degree of autocorrelation between baseline and 2-year visits for all sensory modalities (r = 0.83 to r = 0.88, p < 0.001 for all). Also, changes in sensory thresholds from the baseline to 2-year visits for one modality tended to correlate with other modalities (r = 0.36 to r = 0.70, p < 0.001 for all). These data indicate that an appreciable proportion of Type 2 diabetic patients are at risk for a marked rate of decline of sensory function, and suggest a need for at least yearly quantitative sensory testing.

Plasma lipid measurements were obtained at the time that 545 subjects were screened for diabetes mellitus. Both the women and men diagnosed with diabetes had significantly higher triglyceride levels (p < 0.05) and lower high-density-lipoprotein cholesterol (HDL-cholesterol) levels (p < 0.05) than those with normal glucose tolerance. Low-density-lipoprotein cholesterol (LDL-cholesterol) levels were only higher in the diabetic women (p < 0.001). Differences in lipid values were diminished somewhat with allowances for the waist-hip ratio. HDL-cholesterol values were inversely related to fasting insulin levels in the normoglycaemic men and women (p < 0.01), but not in the diabetic individuals. Triglyceride levels were strongly positively related to insulin values in the normoglycaemic men and women (p < 0.001 for both), while associations tended to be smaller in the diabetic subjects. In 13 of the diabetic individuals who were not medicated for diabetes over a period of 17.5 +/- 4.6 months, changes in HDL-cholesterol levels were positively related (p = 0.80, < 0.001) and changes in triglyceride levels inversely related (r = -0.70, p < 0.01) to changes in insulin values. These data indicate that at diagnosis Type 2 diabetic patients have an atherogenic lipid pattern that may be related in part to differences in adipose distribution. In addition, the data suggest that HDL-cholesterol is positively related and triglyceride inversely related to insulin action.