according to a national registry analysis.
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The incidence of any amputation trended downward from 2011 to 2019, Sara Hallström, MD, reported at the annual scientific sessions of the American Diabetes Association.
Levels of hemoglobin A1c have also trended downward over time in Sweden among those with type 1 diabetes, while renal function has remained stable among patients who did not undergo amputations, Dr. Hallström said in a virtual presentation.
“Observing stable renal function and decreasing levels of [hemoglobin] A1c, along with decreasing incidence of amputation, indicates a shift in the prognosis of persons with type 1 diabetes,” she said.
Drilling down on amputation risk in type 1 diabetes
Lower-extremity amputation is a major source of disability and distress in people with diabetes, and also poses a significant financial burden for the health care system, according to Dr. Hallström of Sahlgrenska University Hospital and the University of Gothenburg (Sweden).
“Limb loss due to amputation is not seldom a final outcome of diabetic foot ulcers,” she said in the presentation.
Most studies of amputation incidence and risk factors have grouped patients with different types of diabetes, though a few recent studies have singled out type 1 diabetes.
Among these is a 2019 study indicating a 40-fold higher risk of amputation among individuals with type 1 diabetes, compared with the general population, based on analysis of Swedish National Diabetes Register data from 1998 to 2013.
Trends over time
In the present study, Dr. Hallström and coinvestigators queried that same Swedish registry and identified 46,008 individuals with type 1 diabetes from 1998 to 2019. The mean age was 32.5 years and 55% were male. Overall, 1,519 of these individuals (3.3%) underwent amputation.
The incidence of any amputation fluctuated from 1998 to 2011, followed by a “decreasing trend over time” from 2011 to 2019, Dr. Hallström said.
The incidence of amputation per 1,000 patient-years was 2.84 in the earliest time period of 1998-2001, decreasing to 1.64 in 2017-2019.
Levels of A1c decreased over time, starting at 2012, both in participants with and without amputations, Dr. Hallström said. Renal function over that period remained stable in persons without amputation, and showed a decreasing trend in persons with amputation.
Compared with individuals with no amputations, those undergoing amputation were older (50 years vs. 32 years), had a longer duration of diabetes (34.9 years vs. 16.5 years), and had higher mean A1c, Dr. Hellström said. The amputee group also included a higher proportion of smokers, at 19.4% versus 14.0%, data show.
Risk factors for amputation included renal dysfunction, hyperglycemia, older age, smoking, hypertension, and cardiovascular comorbidities, according to the researcher.
U.S. amputations on the rise overall
While authors say results of this study point to a potentially improved prognosis for individuals with type 1 diabetes in Sweden, Robert A. Gabbay, MD, PhD, chief scientific and medical officer of the ADA, said amputation rates remains “concerning” based on U.S. data focused largely on type 2 diabetes.
Dr. Robert A. Gabbay
“The amputation rate is unfortunately rising,” he said. “Sadly, this continues to be an issue.”
Significant health disparities persist, he added, with Black Americans having two- to threefold higher rates of amputations.
To help reduce amputation rates, clinicians should be asking patient about claudication and using simple screening techniques such as inspecting patient’s feet. “The big deal here is preventing ulcer formation, because once the ulcer forms, it often doesn’t heal, and it’s a downward spiral,” he said.
In addition, recent research suggests seeking a second opinion may help: “Many of those amputations could be avoided, in part because people aren’t aware of some of the treatments that can open up the arteries and reestablish blood flow,” he added.
Dr. Hallström reported no conflicts of interest. One coauthor on the study provided disclosures related to Abbott, AstraZeneca, Boehringer Ingelheim, Lilly Diabetes, and Novo Nordisk.