Validation of inpatient international classification of disease ninth revision codes as predictors of venous leg ulcers

Venous leg ulcers (VLU) comprise about 70% of lower leg wounds and cost more than 14 billion USD per year. Patients with VLU are often admitted to the hospital; however, epidemiological study of this important patient subset is challenged by lack of validated database search protocol. Five International Classification of Diseases (ICD) 9 codes were identified for their relationship with VLUs (454.0, 454.2, 459.11, 707.9, and 707.10). The ICD9 code was considered to successfully predict a VLU if the wound was located in the gaiter area and had either relevant clinical findings, a positive venous study, and/or a diagnosis of VLU written in the physician note. The code 454.0, when combined with length of admission and subjects’ age, yielded high specificity (100%) and positive predictive value (100%), sacrificing sensitivity (34.4%). This formula represents a viable search criterion to identify VLU patients in large-scale datasets to examine patients’ outcomes, costs, and comorbidities.