MUNICH – When it comes to predicting mortality in diabetes patients, the foot may trump the heart.
Over a 5-year period, patients who had the most severe foot pathology were almost four times more likely to die than those who had a constellation of cardiovascular risk factors. The association with foot pathology stayed strong and, in a multivariate analysis, was the only factor that remained significantly associated with death in the cohort, Dragan Tesic, MD, said at the annual meeting of the European Association for the Study of Diabetes.
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“On average, our patients with severe foot pathology had a 5-year shortening of their lifespan,” said Dr. Tesic of the University of Novi Sad, Serbia. This finding was even more pronounced in younger patients: Those aged 55 years and younger with severe foot pathology died a median of 14 years earlier than their normal expected lifespan would have ended.
Dr. Tesic and his colleagues conducted a 5-year mortality analysis of 244 patients with diabetes, 12% of whom had type 1 disease. The analysis included cardiovascular risk factors (hypertension, triglycerides, cholesterol levels, fibrinogen, proteinuria, and smoking); diabetes duration; coronary artery and cerebrovascular disease; and peripheral artery disease.
Foot pathology was determined according the recently published clinical guidelines by the International Working Group on the Diabetic Foot (IWGDF) (Diab Met Res Rev. 2016. doi: 10.1002/dmrr.2694).
The document parses the diabetic foot into four severity categories:
• 0: No peripheral neuropathy.
• 1: Peripheral neuropathy.
• 2: Peripheral neuropathy with peripheral artery disease and/or a foot deformity.
• 3: Peripheral neuropathy and a history of a foot ulcer or a lower-extremity amputation.
At baseline, patients were a median of 68 years old, though they ranged in age from 36 to 83 years. The mean duration of diabetes was 17 years, and the mean HbA1c was 8.9%. About half had retinopathy; no one was on hemodialysis.
By 5 years, 53 patients (22%) had died. Their median age was 70 years – 5 years short of the Serbian national life expectancy. However, deaths were evenly distributed among the age groups, Dr. Tesic said: 30% of deceased patients were aged 40-64, 41% aged 65-74, and 28% aged 74 and older.
The causes of death were sudden cardiac death (38%), acute coronary syndrome (32%), stroke (11%), cancer (13%), and sepsis (6%).
There were no significant between-group differences in the type of diabetes; any lipid parameter; diabetic retinopathy; proteinuria; or cardiovascular or cerebrovascular disease. However, patients who died had significantly more severe foot pathology, with 71% scoring either a 2 or 3 on the IWGDF scale compared with 36% of those who were still alive. This level of foot pathology was seen in every age group of the deceased patients: 75% of those in the youngest, 54% of those in the middle group, and 73% of those in the oldest group.
Those who died had developed their foot lesions earlier (66 years vs. 69 years). They had poorer ankle reflexes, and worse results on the Neuropad, a visual indicator test for human diabetic neuropathy. Those who died were older (70 years vs. 66 years), had a longer diabetes duration (20 years vs. 17 years), and more hypertension (79% vs. 61%).
But in a multivariate analysis, only the IWGDF score remained a significant predictor of mortality (odds ratio, 3.78). All of the cardiovascular risk factors, as well as age, diabetes duration, and glucose measures, had no effect on survivalk in that analysis.
The study underscores the importance of preventing and treating diabetic neuropathy and foot complications, Dr. Tesic stressed.
“I like to say that I see an opportunity in every difficulty. The examination of the diabetic foot may be time-consuming, but without that we are not delivering adequate or appropriate care to our patients.”
He had no financial disclosures.