CHICAGO – Leg and foot amputations for elderly U.S. patients with peripheral artery disease dropped by more than half during the period 2000-2008 for unknown reasons, based on a review of Medicare data.
During the 9-year period studied, the rate of lower-extremity amputations among U.S. Medicare beneficiaries fell from 9,650/100,000 beneficiaries with peripheral artery disease (PAD) to 4,274/100,000, Dr. W. Schuyler Jones and his associates reported in a poster at the meeting.
Their analysis of the 2000-2008 Medicare data also showed significant regional variations in lower-extremity amputation rates in PAD patients, with the highest rate in New England and the lowest rate in the East North Central region (Illinois, Indiana, Michigan, Ohio, and Wisconsin). Again, no clear explanation exists for this pattern, said Dr. Jones, an interventional cardiologist at Duke University in Durham, N.C., and his associates.
Their analysis of data from the Centers for Medicare & Medicaid Services included 3,354,264 diagnosed with PAD during 2000-2008, of whom 249,310 (7%) underwent amputation of a foot or leg, either below or above the knee. The average age of all PAD patients was 77 years old among both those who underwent amputations and those who did not have this surgery. The analysis identified four factors that were significant, independent predictors of having an amputation: male sex, African American race, and the presence of renal disease or diabetes.
During the 9-year period, the annual incidence of patients newly diagnosed with PAD remained relatively steady, with 398,000 diagnosed in 2000 and 397,000 diagnosed in 2008. The rates showed some year-to-year fluctuation, ranging from a low of 304,000 in 2003 to a high of 517,000 in 2006.
In contrast, the annual incidence of lower-extremity amputations showed a clear downward trajectory, with a sharp drop starting in 2005. During 2000-2004, the annual amputation rate hovered at about 10,000 cases/100,000 patients with PAD, but then fell to 7,455/100,000 in 2005, and fell further to 4,261/100,000 in 2006. During the subsequent 2 years the rate remained at about the same low level first reached in 2006. Roughly similar patterns existed for the subgroups of patients who underwent above-the-knee amputations, below-the-knee amputations, or foot amputations.
The authors of the report performed an analysis of amputation rates by U.S. Census geographic regions for the entire period of 2000-2008 that they adjusted by regional differences in patients’ age, sex, race, comorbidities, and year of amputation. They set the amputation rate in the South Atlantic region as their reference level, and found four regions with significantly higher rates of amputations: New England ran 16% higher, the West South Central region (Arkansas, Louisiana, Oklahoma, and Texas) ran 12% higher, Mid Atlantic (Connecticut, New Jersey, New York, and Pennsylvania) was 8% higher, and the Pacific region (Alaska, California, Hawaii, Oregon, and Washington) was 3% above the reference level. Three other U.S. regions had amputations rates below the reference level, headed by the East North Central which ran 11% below the South Atlantic region, followed by the Mountain region at 10% lower, and the West North Central region (Iowa, Kansas, Minnesota, Missouri, Nebraska, North Dakota, and South Dakota) which was 5% below the reference level.
Dr. Jones said that he had no disclosures.