Long-term prognosis for diabetic patients with foot ulcers

Abstract

Objective: To evaluate the recurrence of foot ulcers as well as the cumulative amputation and mortality rates in diabetic patients with previous foot ulcers.

Design: A prospective study of consecutively presenting diabetic patients admitted to the Department of Internal Medicine because of foot ulcer with a median follow-up of 4 years.

Setting: A multidisciplinary foot-care team.

Population: Five-hundred-and-fifty-eight consecutive diabetic patients with foot ulcers treated between 1 July 1983 and 31 December 1990 were followed to final outcome. Out of these patients, 468 healed either primarily (n = 345) or after minor or major amputations (n = 123) and 90 died before healing had occurred. Those 468 patients who healed were included in this prospective study from the time of healing.

Main outcome measures: Patients were followed according to a standardized protocol with registration of foot lesions, amputation, morbidity and mortality. Clinical examination was performed twice yearly.

Results: After 1, 3 and 5 years of observation 34%, 61% and 70% of the patients, respectively, had developed a new foot ulcer. The recurrence rate of foot lesions was slightly higher among patients who previously had had an amputation (P < 0.05, P < 0.01 and non-significant, respectively). Among patients with previous primary healing the cumulative amputation rates were 3%, 10% and 12% after 1, 3 and 5 years of follow-up compared with 13%, 35% and 48% among those who previously healed after amputation, irrespective of previous amputation level (P < 0.001 at all time-points). All amputations except three were initiated by a foot ulcer deteriorating to deep infection or progressive gangrene. The long-term survival ratio was lower among patients healed after previous amputation (80%, 59%, 27%) compared with patients with previously primary healing (92%, 73%, 58%) after 1, 3 and 5 years of observation, respectively (P < 0.001, P < 0.01 and P < 0.001 respectively). The mortality rate was twice as high among primarily healed and four times as high among patients with amputation compared to an age- and sex-matched Swedish population.

Conclusion: These findings stress the need for life-long surveillance of the diabetic foot at risk and the necessity of preventive foot care among diabetic patients with previous foot lesions, and particularly among those who had had a previous amputation.