Introduction: The Peripheral Artery Disease questionnaire (PAQ) is a well-validated disease-specific health status measure in patients with peripheral arterial disease (PAD). We aimed to define a ‘clinically meaningful’ 12-month change in PAQ scores from a patients’ perspective.
Methods: A total of 1275 patients who consulted 16 PAD specialty clinics across the US, Netherlands, and Australia for new, or worsening, claudication symptoms, were enrolled in the PORTRAIT study. As a substudy, 532 patients completed the 20-item PAQ questionnaire at enrollment, 3, 6, and 12 months. During each follow-up assessment, patients also answered a standardized Global Assessment of Health (GAH) scale that asked whether, compared with their last interview, patients felt worse, the same, or better. We confirmed independence of responses to the GAH scale in the 3- through 12-month follow-ups with timing of the assessment (interaction for time*GAH response non significant) and primary PAD treatment for a patient received (interaction for PAD treatment [invasive vs. non-invasive]*GAH response non significant). We then built a repeated measures model to derive the predicted PAQ summary score change by GAH scale response group.
Results: Over the 3-12 months follow-up, 12-16% classified themselves as feeling ‘worse’, 55-51% as ‘the same’, and 32-32% reported feeling ‘better’, respectively. The ranges of predicted PAQ summary scores for the Global Assessment of Health scale response groups are presented in the Figure.
Conclusion: Thresholds for clinically meaningful changes in the PAQ suggest that patients who perceive a clinical change in their health status differ by ~7 points from those who have not changed. This interpretative framework will be instrumental in better understanding the meaningfulness of PAD treatment effects in clinical trials as seen from a patients’ perspective.