Sg study highlights clinical, economic burden of diabetic foot ulcers

A retrospective study from Singapore has shown that amputations for diabetic foot ulcers render a substantial healthcare and economic burden to patients.

“[T]here was significant clinical and economic burden of diabetic foot ulcers, with a high wound per patient ratio and escalating healthcare costs corresponding to more proximal amputation levels,” the researchers said.

The study population comprised 1,729 patients (mean age 63.4 years, 64.4 percent male, 61.4 percent Chinese) who were treated either as inpatients or outpatients for diabetic foot ulcers at a tertiary hospital in Singapore between 2013 and 2017. Baseline median HbA_1c was 9.9 percent. The most common comorbidities were dyslipidaemia (93.6 percent), hypertension (88.7 percent), and peripheral arterial disease (PAD; 74.8 percent). About 14 percent of patients had peripheral neuropathy. Patients had an average follow-up of 2.9 years.

Each patient had a mean 6.1 wounds over the 5-year study, primarily affecting the toes (39.2 percent) or foot plantar surface (34.4 percent), with an average 2.12 diabetic foot ulcers per year. [Int Wound J 2020;doi:10.1111/iwj.13540]

Patients had a mean one emergency department visit, 8.1 specialist outpatient clinic visits, and 0.58 hospitalizations per patient-year. The readmission rate at 30 days was 12.7 percent.

About 53 percent of patients underwent minor (distal to the ankle) amputations, including 36.4 percent who underwent toe amputations and 16.9 percent transmetatarsal amputations, while 6.5 percent underwent major (proximal to the ankle) amputations. The mean duration of hospitalization was 16.6 days overall, specifically 13.3, 20.5, and 59.6 days for ulcer-only, minor, and major amputations, respectively.

Direct healthcare costs to the patients included physician fees, inpatient hospitalization, procedures, supportive dressings, and adjuvant therapy. The mean cost for patients with amputations due to ulcers only was SGD 4,776 per patient-year. The mean cost for minor and major amputations was higher at SGD 14,845 and SGD 42,730 per patient-year, respectively.

The probability of survival among patients who underwent major amputation was 97.4 and 91.0 percent at 1 and 5 years, respectively, while minor amputation-free survival was lower at 80.9 and 56.9 percent, respectively. Overall survival was 93.8 and 62.1 percent at 1 and 5 years, respectively.

Several factors were tied to an increased likelihood of all-cause mortality including older age (hazard ratio [HR], 1.07; p<0.001), major amputation (HR, 1.80; p<0.001), PAD (HR, 1.37; p=0.015), ischaemic heart disease (IHD; HR, 10.77; p<0.001), previous stroke (HR, 1.22; p=0.041), and end-stage renal failure (ESRF; HR, 1.37; p=0.002).

Risk factors for major amputation were age (HR, 1.04; p=0.002), IHD (HR, 12.27; p=0.033), PAD (HR, 27.95; p<0.001), and ESRF (HR, 1.92; p=0.002). Risk factors for minor amputations were male sex (HR, 1.35) and PAD (HR, 7.39; p<0.001 for both).

“Similar to global data, there is a high clinical and economic burden of diabetic foot ulcers within Southeast Asia and the tropics,” said the researchers. “Hence, active measures to prevent diabetic foot ulcers will help to decrease the economic burden of diabetic foot disease,” they said.

“Primary prevention via [control of diabetes] should be a focus for population health interventions,” they continued, noting that patients with PAD, who had a higher risk of mortality and amputations, “should be the subset of patients for early and aggressive limb salvage interventions.”