Validation of a Case Definition for Foot Complications Among Hospitalized Patients With Diabetes

Lower extremity ulcers (LEU) and amputations (LEA) as well as other foot complications are a serious preventable problem among patients with diabetes. To establish a hospital-based surveillance system for foot complications and to initiate quality improvement efforts to prevent future complications, we used a case definition developed by Harrington et al. (1). The authors developed this definition as part of a cost analysis study of foot complications among Medicare beneficiaries. The case definition utilizes ICD-9-CM diagnosis codes and Current Procedural Terminology, version 4 (CPT-4), procedural codes to identify patients with diabetes having a LEU, LEA, or other foot complications. First, patients with diabetes were identified based on hospitalization diagnoses. Then, the subgroup of patients with ICD-9-CM diagnoses of CPT-4 procedure codes for possible foot complications were identified. The ICD-9-CM diagnoses included LEU; carbuncle or furuncle of the foot; cellulitus of abscess of the toe or foot; gangrene; infectious myositis; unspecified myalgia or myositis; osteomyelitis; amputation or resection of the foot, ankle, leg, or knee and above; and late amputation stump complication. The CPT-4 procedures included …