Long-term prognosis of diabetic foot patients and their limbs: amputation and death over the course of a decade

Abstract

Objective: There is a dearth of long-term data regarding patient and limb survival in patients with diabetic foot ulcers (DFUs). The purpose of our study was therefore to prospectively investigate the limb and person survival of DFU patients during a follow-up period of more than 10 years.

Research design and methods: Two hundred forty-seven patients with DFUs and without previous major amputation consecutively presenting to a single diabetes center between June 1998 and December 1999 were included in this study and followed up until May 2011. Mean patient age was 68.8 ± 10.9 years, 58.7% were male, and 55.5% had peripheral arterial disease (PAD). Times to first major amputation and to death were analyzed with Kaplan-Meier curves and Cox multiple regression.

Results: A first major amputation occurred in 38 patients (15.4%) during follow-up. All but one of these patients had evidence of PAD at inclusion in the study, and 51.4% had severe PAD [ankle-brachial pressure index ≤0.4]). Age (hazard ratio [HR] per year, 1.05 [95% CI, 1.01-1.10]), being on dialysis (3.51 [1.02-12.07]), and PAD (35.34 [4.81-259.79]) were significant predictors for first major amputation. Cumulative mortalities at years 1, 3, 5, and 10 were 15.4, 33.1, 45.8, and 70.4%, respectively. Significant predictors for death were age (HR per year, 1.08 [95% CI, 1.06-1.10]), male sex ([1.18-2.32]), chronic renal insufficiency (1.83 [1.25-2.66]), dialysis (6.43 [3.14-13.16]), and PAD (1.44 [1.05-1.98]).

Conclusions: Although long-term limb salvage in this modern series of diabetic foot patients is favorable, long-term survival remains poor, especially among patients with PAD or renal insufficiency.

Figure 1

A: Relevance of the presence and severity of PAD for the cumulative probability of a first major limb amputation. To avoid complexity, PAD not classified because of medial arterial calcification is not shown (n = 8; only 1 event of first major limb amputation). The highest curve represents no PAD, the second curve represents mild PAD, the third curve represents moderate PAD, and the lowest curve represents severe PAD. B: Relevance of the presence or absence of PAD, advanced renal disease, or both combined for the cumulative probability of death. The highest curve represents no PAD and no renal disease, the second curve represents renal disease and no PAD, the third curve represents PAD and no renal disease, and the lowest curve represents PAD and renal disease.