Outcome on diabetic foot complications in relation to clinical examination and quantitative sensory testing: a case-control study.

A total of 405 diabetic patients who first attended St Thomas' Diabetes Clinic between 1982 and 1985 had a detailed standardized computerized first visit record, including a structured foot examination and toe vibration perception thresholds (VPT, Biothesiometer), were reviewed in 1995. None of the patients had a history of foot ulceration at first visit. Twenty-five patients (6.2%) developed foot ulcers (n = 11, 2.7%) or had an amputation (n = 14, 3.5%) over a mean 12-year period. Twenty of these patients were then individually matched with 3 non-ulcer patients. Statistically significant odds ratios (OR) were found for a baseline abnormal age-adjusted toe VPT (OR 4.38, CI 1.11-17.26; p = 0.01); abnormal clinical examination (at least 1 abnormality out of: ankle jerks, tuning fork or cotton wool sensation; OR 2.3, CI 1.00-5.20; p < 0.01); and HbA1 (OR 1.30, CI 1.01-1.66; P < 0.02) in patients who subsequently developed lower extremity complications. The sensitivity of VPT (70%) was better than that for clinical testing (55 %) in predicting long-term complications, although all tests showed similar specificity (70-72%). The risk of events also doubled for every 10 years of diabetes (OR 2.10, CI 1.11-4.30; p = 0.02). We conclude that age-corrected VPT measurements, which are objective and simple to perform, are better predictors of future foot complications than semi-quantitative tests in diabetes clinics. We encourage their use in the campaign to reduce the morbidity of diabetic peripheral neuropathy.