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Lower limb amputations decreased, use of revascularization increased during past 15 years
The rate of lower limb amputations among Medicare beneficiaries decreased by 45% from 1996 to 2011, whereas the use of peripheral endovascular interventions and preventive care measures increased significantly, according to a new report.
“Although severe lower-extremity peripheral arterial disease affects more than 12 million people in the United States, secular trends in the risk of amputation remain unexplored in recent years,” researchers wrote.
Using CMS claims data from 1996 to 2011, researchers evaluated the number of lower limb amputations and revascularization procedures. They also analyzed rates of smoking and self-reported diabetes among adults older than 65 years via the Behavioral Risk Factor Surveillance System (1996-1999) and surveys of Medicare beneficiaries (2000-2011) and the rate at which preventive measures to limit amputations were used during the study period.
The rate of lower limb amputations was significantly decreased, from 196 per 100,000 patients in 1996 to 119 per 100,000 patients in 2011 (RR = 0.6; 95% CI, 0.59-0.61). The researchers primarily attributed this reduction to a significant decline in above-knee amputations (91 procedures per 100,000 patients vs. 47 per 100,000 patients; RR = 0.52, 95% CI, 0.51-0.52) and below-knee amputations (82 per 100,000 patients vs. 50 per 100,000 patients; RR = 0.61; 95% CI, 0.6-0.62).
However, they wrote, amputation remained common among black patients with diabetes and other high-risk subgroups despite the overall decrease observed.
Peripheral endovascular interventions grew increasingly more common during the study period. Use of diagnostic lower-extremity arteriography increased from 451 procedures per 100,000 patients to 1,124 per 100,000 patients from 1996 to 2011 (RR = 1.65; 95% CI, 1.56-1.73) and therapeutic endovascular interventions increased from 138 procedures per 100,000 patients to 584 per 100,000 patients (RR = 4.23; 95% CI, 4.17-4.28). Use of surgical bypass declined from 201 procedures per 100,000 patients in 1996 to 83 per 100,000 patients in 2011 (RR = 0.39; 95% CI, 0.38-0.41).
The prevalence of diabetes rose over time, from 16 cases per 100 patients to 26 per 100 patients (RR = 1.53; 95% CI, 1.23-1.91).
Measures intended to prevent amputation increased from 1996 and 2011, including routine foot examinations (40 per 100 patients to 68 per 100 patients; RR = 1.7; 95% CI, 1.13-2.57) and routine blood glucose tests (41 per 100 patients to 72 per 100 patients; RR = 1.76; 95% CI, 1.03-3.02).
“Our observational findings cannot imply causation, and we recognize that our study presents no direct causative experimental evidence to explain the decrease in amputation risk,” the researchers wrote. “However, it is evident that the increasing use of vascular and preventive care, especially among patients with diabetes, has been temporarily associated with lower rates of major amputation. While many debate whether open surgery, endovascular interventions or hybrid strategies are most effective in limiting amputation, the importance of preventive measures has likely been underestimated.”
Disclosure: The researchers report no relevant financial disclosures.