Vascular Quality of Life Questionnaire-6 Before and After Supervised Exercise Therapy in Patients with Intermittent Claudication

Abstract

The Vascular Quality of Life Questionnaire-6 (VascuQoL-6) is a short, disease specific instrument used to determine health related quality of life (HRQoL) in patients with peripheral arterial disease. This study aimed to assess the minimally important difference (MID) and substantial clinical benefit (SCB) of the VascuQoL-6 in Dutch patients with intermittent claudication (IC) receiving supervised exercise therapy (SET). Consecutive patients with IC who were recruited from a single centre between January 2016 and December 2016 completed the VascuQoL-6 before initiation and after three months of SET. They subsequently answered an anchor question rating their current health status as much improved, improved, unchanged, deteriorated, or much deteriorated, compared with baseline. The MID for improvement and deterioration and SCB were calculated using anchor based and distribution based methods. A total of 124 patients with IC (58% male, mean age 68 years) completed the study protocol. Baseline VascuQoL-6 scores increased from 16.3 ± 4.4 to 18.7 ± 3.8 after three months of SET (p < .001). MID values ranged from+2.0 to+3.8 points regarding HRQoL improvement and from+0.2 to -2.2 points regarding HRQoL deterioration. The SCB ranged from+3.7 to+5.0 points. Depending on the MID approach, 32% - 41% of patients achieved a clinically meaningful improvement in HRQoL. Approximately one in three patients with IC reported a clinically meaningful improvement in HRQoL after three months of SET. The range of MID and SCB values provides caregivers with an idea of how much change in VascuQoL-6 scores is considered relevant or substantial by their patients. Applying cutoff points for MID and SCB may optimise the interpretation of trial results and may help to set a benchmark for success of SET.