Amputation trends for patients with lower extremity ulcers due to diabetes and peripheral artery disease using statewide data

Objective: This study reports all-payer amputation rates using state-based administrative claims data for high-risk patients with lower extremity (LE) ulcers and concomitant peripheral artery disease (PAD), diabetes mellitus (DM), or combination PAD/DM. In addition, we characterize patient factors that affect amputation-free survival. We also attempted to create a measure of a patient's ability to manage chronic diseases or to access appropriate outpatient care for ulcer management by accounting for hospital and emergency department (ED) visits in the preceding 60 days to determine how this also affects amputation-free survival. Methods: Patients admitted to nonfederal hospitals, seen in an ED, or treated in an eligible ambulatory surgery center within California from 2005 through 2013 with an International Classification of Diseases, Ninth Revision, Clinical Modification diagnosis code for a disease-specific LE ulcer were identified in the California Office of Statewide Health Planning and Development database. All subsequent hospital, ED, and ambulatory surgery center visits and procedures are captured to identify whether a patient underwent major amputation. Yearly amputation rates were determined to analyze trends. Amputation-free survival for the PAD, DM, and PAD/DM groups was determined. Cox modeling was used to evaluate the effect of patient characteristics. Results: There were 219,547 patients identified with an incident LE ulcer throughout the state. Of these, 131,731 were DM associated, 36,193 were PAD associated, and 51,623 were associated with both PAD and DM. From 2005 to 2013, the number of patients with LE ulcers who required inpatient admission, presented to the ED, or had outpatient procedures was stable. However, there was a statistically significant increase in overall disease-associated amputation rates from 5.1 in 2005 to 13.5 in 2013 (P <.001). Patients with PAD/DM had the greatest increase in amputation rates from 10 per 100 patients with LE ulcers in 2005 to 28 per 100 patients in 2013 (P <.001). Despite that patients with PAD/DM were 8 years younger than patients with PAD only, they had similar amputation-free survival. Within all age groups, men had worse amputation-free survival than women did. Race did not predict amputation-free survival, but having multiple prior ED or hospital admissions was a significant predictor of worse amputation-free survival. Conclusions: Potentially preventable amputations associated with high-risk diseases are increasing among patients who require inpatient hospital admission, present to the ED, or require outpatient interventional treatment. This trend is most notable among patients with a combination of PAD and DM. Patients with repeated hospitalizations before admission for the LE ulcer had the highest risk of amputation.