Evaluation of the Construct Validity of a Risk Assessment Instrument for Venous Leg Ulcer Recurrence

The purpose of this study was to evaluate the construct validity of an instrument designed to predict the risk of recurrence of venous leg ulcers.

Methodological study to determine the validity of an existing instrument.

A convenience sample of 37 adults with a venous leg ulcer were recruited from the Southern District Health Board serving residents of the southern half of the South Island of New Zealand. Participants had a history of a venous leg ulcer within 4 weeks of healing; they were followed for 12 months to determine venous leg ulcer recurrence.

An 8-item instrument that was previously developed was evaluated. The instrument queries history of deep vein thrombosis and previous ulcers, duration of previous ulcer, body mass index, living alone, leg elevation, moving around on feet, and compression to measure the risk of recurrence. The construct validity of the VLU recurrence risk instrument was evaluated using the area under the receiver operating characteristic curve and the Hosmer-Lemeshow statistic.

The area under the curve was acceptable at 0.824 (95% CI, 0.695-0.952, P < .001) for the total risk assessment score; results were similar when the AUC was measured at 3- and 6-month follow-up visits.

The validation of a risk assessment tool for recurrence of venous leg ulcers in differing populations provides support for the tool's use in guiding individualized interventions more globally to address any modifiable risk factors, increase concordance, and thus reduce recurrence rates.