Regional intensity of vascular care and lower extremity amputation rates.

OBJECTIVE: Because patient-level differences do not fully explain the variation in lower extremity amputation rates across the United States, we hypothesized that variation in intensity of vascular care may also affect regional rates of amputation and examined the relationship between the intensity of vascular care and the population-based rate of major lower extremity amputation (above-knee or below-knee) from vascular disease. METHODS: Intensity of vascular care was defined as the proportion of Medicare patients who underwent any vascular procedure in the year before amputation, calculated at the regional level (2003 to 2006), using the 306 hospital referral regions in the Dartmouth Atlas of Healthcare. The relationship between intensity of vascular care and major amputation rate, at the regional level, was examined between 2007 and 2009. RESULTS: Amputation rates varied widely by region, from one to 27 per 10,000 Medicare patients. Compared with regions in the lowest quintile of amputation rate, patients in the highest quintile were commonly African American (50% vs 13%) and diabetic (38% vs 31%). Intensity of vascular care also varied across regions: <35% of patients underwent revascularization in the lowest quintile of intensity, whereas nearly 60% underwent revascularization in the highest quintile. Overall, an inverse correlation was found between intensity of vascular care and the amputation rate, ranging from R = -0.36 for outpatient diagnostic and therapeutic procedures to R = -0.87 for inpatient surgical revascularizations. Analyses adjusting for patient characteristics and socioeconomic status found patients in high-intensity vascular care regions were significantly less likely to undergo amputation without an antecedent attempt at revascularization (odds ratio, 0.37; 95% confidence interval, 0.34-0.37; P < .001). CONCLUSIONS: The intensity of vascular care provided to patients at risk for amputation varies, and regions with the most intensive vascular care have the lowest amputation rate, although the observational nature of these associations do not impart causality. High-risk patients, especially African American diabetic patients residing in low-intensity vascular care regions, represent an important target for systematic efforts to reduce amputation risk.

Racial disparities in the use of revascularization before leg amputation in Medicare patients.

OBJECTIVE: Black patients with peripheral arterial disease undergo amputation at two to four times the rate of white patients. In order to determine whether differences in attempts at limb salvage might contribute to this disparity, we studied the limb care received prior to amputation by black patients compared with whites. METHODS: Using inpatient Medicare data for the years 2003 through 2006, we identified a retrospective sample of all beneficiaries who underwent major lower extremity amputation. "Limb salvage care" was defined as limb-related admissions and procedures that occurred during the 2 years prior to amputation. We used multiple logistic regression to compare rates of revascularization and other limb care received by black versus white amputees, adjusting for individual patient characteristics. We then controlled for hospital referral region in order to assess whether differences in care might be attributable to the geographic regions in which black and white patients received care. Finally, we examined the timing of revascularization relative to amputation for both races. RESULTS: Our sample included 24,600 black and 65,881 white amputees. Compared with whites, black amputees were more likely to be female and had lower socioeconomic status. Average age, rates of diabetes, and levels of comorbidity were similar between races. Black amputees were significantly less likely than whites to have undergone revascularization (23.6% vs 31.6%; P < .0001), any limb-related admission (39.6% vs 44.7%; P < .0001), toe amputation (12.9% vs 13.8%; P < .0005), or wound debridement (11.6% vs 14.2%; P < .0001) prior to amputation. After adjusting for differences in individual patient characteristics, black amputees remained significantly less likely than whites to undergo revascularization (odds ratios [OR], 0.72 [95% confidence interval, .68-.76]), limb-related admission (OR, 0.81 [0.78-0.84]), or wound debridement prior to amputation (OR, 0.80 [0.75-0.85]). Timing of revascularization relative to amputation was similar between races. Observed differences in care were shown to exist within hospital referral regions and were not accounted for by regional differences in where black and white patients received care. CONCLUSION: Black patients are much less likely than whites to undergo attempts at limb salvage prior to amputation. Further studies should explore whether this disparity might be attributable to race-related differences in severity of arterial disease, patient preferences, or physician decision making.

Variation in the use of lower extremity vascular procedures for critical limb ischemia.

BACKGROUND: Many believe that variation in vascular practice may affect limb salvage rates in patients with severe peripheral arterial disease. However, the extent of variation in procedural vascular care obtained by patients with critical limb ischemia (CLI) remains unknown. METHODS AND RESULTS: By using Medicare 2003 to 2006 data, we identified all patients with CLI who underwent major lower extremity amputation in the 306 hospital referral regions described in the Dartmouth Atlas of Healthcare. For each patient, we studied the use of lower extremity vascular procedures (open surgery or endovascular intervention) in the year before amputation. Our main outcome measure was the intensity of vascular care, defined as the proportion of patients in the hospital referral region undergoing a vascular procedure in the year before amputation. Overall, 20,464 patients with CLI underwent major lower extremity amputations during the study period, and collectively underwent 25,800 vascular procedures in the year before undergoing amputation. However, these procedures were not distributed evenly: 54% of patients had no vascular procedures performed in the year before amputation, 14% underwent 1 vascular procedure, and 32% underwent >1 vascular procedure. In the regions in the lowest quintile of vascular intensity, vascular procedures were performed in 32% of patients. Conversely, in the regions in the highest quintile of vascular intensity, revascularization was performed in 58% of patients in the year before amputation (P<0.0001). In analyses accounting for differences in age, sex, race, and comorbidities, patients in high-intensity regions were 2.4 times as likely to undergo revascularization in the year before amputation than patients in low-intensity regions (adjusted odds ratio, 2.4; 95% CI, 2.1-2.6; P<0.001). CONCLUSIONS: Significant variation exists in the intensity of vascular care provided to patients in the year before major amputation. In some regions, patients receive intensive care, whereas in other regions, far less vascular care is provided. Future work is needed to determine the association between intensity of vascular care and limb salvage.