PHILADELPHIA—Diabetic patients on dialysis who have foot ulcers or who have undergone a foot amputation have a much higher mortality rate at two years than diabetic patients on dialysis without these pathologies, British investigators reported at the 72nd Scientific Sessions of the American Diabetes Association.

Agbor Ndip, MD, specialist registrar and senior clinical fellow at the Manchester Royal Infirmary, and colleagues examined the impact of foot ulcers and amputations on mortality in 192 diabetic patients undergoing dialysis a their institution.

Study participants underwent comprehensive foot examination at enrollment to assess for neuropathy, peripheral arterial disease, foot deformities, and foot ulcers/amputation.

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Overall, 102 patients, or 53.1%, had died after two years. Thirty-five (59.3%) of 59 patients who had a foot ulcer at baseline had died after two years compared with 55 (41.4%) of 133 patients who did not have a foot ulcer at baseline. Additionally, 26 (74.3%) of 35 patients who had a foot amputation at baseline were dead at two years versus 64 (40.8%) of 157 patients without amputation at baseline. The differences in two-year mortality rates between patients with and without foot pathology were statistically significant.

Foot disease was a strong predictor of mortality on multivariate analysis that controlled for the type and duration of diabetes, age, gender, and patient history of retinopathy, ischemic heart disease, congestive heart failure, cerebrovascular disease, amputation, foot ulcer, peripheral vascular disease, and neuropathy, an active foot ulcer, or poor baseline glycemic control.

Patients with an active foot ulcer at enrollment had a 119% increase in the risk of death whereas patients with a history of amputation had a 38%.

“These data highlight the disquietingly high mortality rates in dialysis-treated diabetic patients with foot ulcers or amputations and underscore the importance of integrating structured foot care and amputation prevention in dialysis units,” Dr. Ndip said. “On the positive side, dialysis patients frequently attend clinics [for dialysis] and are therefore amenable to preventive intervention.”

Dr. Ndip acknowledged that it is not yet clear why dialysis patients with foot ulcers or amputations have a higher mortality rate than dialysis patients without such complications. “It may be that they are suicidal after having an amputation, as one audience member suggested,” he said. “However, the suggestion that the findings may be explained by the higher rate of co-morbidities in dialysis patients is unfounded since our findings were maintained after we accounted for the classic risk factors for mortality.”
He said that future research will involve an examination of patients’ death certificates or coroners’ reports to determine the cause of mortality in the study population.

He noted that the study is the first of its kind to examine prospectively the effect of foot complications on mortality in dialysis patients, which allowed for good case ascertainment.

However, he added that only about 15% of patients had foot amputations at the time of enrollment, which may be a potential study limitation.