Responsiveness of the SF-36 and a condition-specific measure of health for patients with varicose veins

Approaches to measuring patient perceptions of outcome for varicose veins were tested using a postal questionnaire incorporating a clinically derived specific measure of varicose veins severity and the SF-36 health survey. The questionnaire was administered to 373 patients with varicose veins, 287 of whom had been referred to hospital for their varicose veins and 86 who had just consulted a general practitioner for the condition. The response rate exceeded 75%. Test-retest reliability was assessed by mailing patients a similar questionnaire at two weeks. The validity of the two instruments was assessed by comparing patient scores to general practitioner ratings of symptom severity and complications associated with varicose veins. Standardized response means (mean change in scores divided by the standard deviation of the change in scores) were used to quantify and compare the responsiveness of the two measures. Levels of test-retest reliability, as assessed by the intraclass correlation coefficient, were acceptable and the instruments appear to have good levels of validity. Patients who were or were not admitted to hospital for surgery on their veins had significant improvements in perceived health status on both the specific measure and the SF-36. The specific measure was the most responsive to changes in health status for both patients who were admitted to hospital for surgery and those receiving alternative forms of management. These two approaches might be suitable as part of a package of outcome measures for use in clinical trials to assess the effectiveness of different interventions far varicose veins.