Distance as a risk factor for amputation in patients with diabetes: a case-control study.

We studied the association between amputation and distance of patients' residences to a diabetes care centre. We performed a case-control study matching each case (amputation) with 5 controls (no amputation) by age and sex. We compared the distance of residence to the diabetes centre, duration and type of diabetes, haemoglobin-A1c levels and foot examination findings for cases and controls. We analysed the association between distance and the strongest predictors of amputation. Sixty-six cases of amputation and 313 controls were identified. Distance of residence was 12.1km greater for cases (p = 0.028). In multivariate analysis, only diabetes duration (OR/year 1.07, 1.03 to 1.11) and neuropathy (OR 10.73, 4.55 to 25.74) were significantly associated with amputation. Patients with neuropathy resided 97 km further than those without neuropathy (p = 0.01). Patients requiring amputation reside at greater distances from the diabetes centre, possibly due to higher rates of neuropathy.