From the Journals

Risk factors for foot ulcers differ for type 1 and type 2 diabetes



Danish researchers have linked multiple factors to higher risk of first-time diabetic foot ulcers (DFUs) in patients with type 1 and type 2 diabetes, although some of the factors – older age, smoking, history of cardiovascular disease, and longer duration of diabetes – seem to indicate increased risk only in type 1 disease, according to the new study findings.

The authors suggest that since clinical information gathered from patients during routine follow-up visits often includes mention of the risk factors for first-time DFU, it could form the basis of a risk stratification process for first-time DFU that can be integrated into the electronic record system and easily incorporated into routine care.

DFU is a significant complication for both type 1 and type 2 diabetes, but no previous research has stratified the risk factors for first-time DFUs by type of diabetes, emphasized the study authors, led by Sine Hangaard, MSc, of Steno Diabetes Center Copenhagen.

For the new study, the researchers tracked 5,588 patients with type 1 diabetes and 7,113 with type 2, all of whom were treated at a hospital clinic in Denmark between 2001 and 2015. The authors noted that the patients with type 2 disease who were treated at the center were clinically more complicated and had a longer disease duration than average type 2 patients, whereas the patients with type 1 diabetes did not differ from average type 1 patients.

Several factors boosted the risk of first-time DFU in both types of disease, including high or low levels of albumin excretion, advanced diabetic retinopathy, limited or nonexistent vibration sense, symptoms of neuropathy, and absence of foot pulses per univariable regression (all P less than .01). The researchers linked the neuropathy and absences of foot pulses to especially high spikes in risk.

Female gender was protective for type 1 and type 2 disease (hazard ratios, 0.7 and 0.5, respectively; P = .0000). Various body mass index levels seemed to have no impact on risk.

Three factors that posed a higher risk for first-time DFU in type 1 disease, but not type 2, were: smoking (HR, 1.4 vs. no smoking, P = .0220), age of 60-79 years (HR, 1.7 vs. age 40-59; P = .0000), cardiovascular disease (HR, 2.2 vs. no cardiovascular disease; P = .0000), and diabetes duration of between 5 and 20 years (HR, 2.2 vs. less than 5 years; P = .0027) or 20 years or more (HR, 5.2 vs. less than 5 years; P = .0000).

The authors noted that “25% of all patients with diabetes develop DFU during their lifetime, and DFUs precede 80% of all lower leg amputations in patients with diabetes.” In addition, DFU often occurs in feet already compromised by neuropathy or peripheral vascular disease, and is therefore associated with greater risk for infection, poorer outcomes, recurrent ulceration, amputation, and increased mortality. These risks underscore the need for the earliest-possible identification of first-time DFU and timely adoption of effective, preventative strategies, they wrote.

The study was not funded. Several of the authors reported that they own shares in Novo Nordisk.

SOURCE: Hangaard S et al. Diabetes Res Clin Pract. 2019 Apr 18;151:177-86.

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