Quality of ambulatory care for diabetes and lower-extremity amputation.

Lower extremity amputation (LEA) is a serious complication of diabetes. We sought to determine whether quality of ambulatory care affects risk of LEA. We conducted a claims-based case-control study of 409 Medicare beneficiaries younger than age 75 with diabetes and LEA between January 1, 2003, and December 31, 2005. They were matched with controls with diabetes without LEA, on age, gender, number of diabetes outpatient visits, and (for those with hospital admissions between January 1, 2000, and December 31, 2002) number of comorbid conditions, diabetes complications, and peripheral vascular disease. Quality-of-care measures for cases and controls covered the period April 1, 1999, through March 31, 2001. LEA patients were less likely to have had lipid screening than controls (odds ratio = 0.73; 95% confidence interval = 0.53-0.99), and controls were more likely to use physicians with high performance in lipid screening (chi(2) = 6.631, P = .012) and hemoglobin A1c testing (chi(2) = 6.079, P = .014).