Establishing Thresholds for Minimal Clinically Important Differences for the Peripheral Artery Disease Questionnaire

Area of Science:

• Vascular Medicine
• Health Outcomes Research
• Patient-Reported Outcomes

Background:

• Minimum Clinically Important Differences (MCID) are crucial for interpreting patient-reported outcomes (PROs).
• No established MCID from patients' perspectives exists for peripheral artery disease (PAD)-specific health status tools.
• The Peripheral Artery Questionnaire (PAQ) is a widely used instrument for assessing PAD health status.

Purpose of the Study:

• To prospectively establish the MCID for the PAQ from patients' perspectives.
• To determine the magnitude of change in PAQ scores that patients perceive as important.

Main Methods:

• Prospective study of patients with new or worsened claudication from the PORTRAIT registry.
• Collected PAQ and Global Assessment of Functioning (GAF) scale data at baseline and 3- and 6-month follow-ups.
• Calculated mean PAQ score changes based on GAF categories and used multivariable linear regression for adjusted MCID estimates.

Main Results:

• MCIDs for PAQ summary scale improvement and worsening were 8.7 and -11.0, respectively.
• After multivariable adjustment, MCIDs were 8.9 for improvement and -11.2 for worsening.
• No significant interaction was found between treatment type (invasive vs. noninvasive) and GAF response.

Conclusions:

• A 10-point change in the PAQ summary score represents an MCID for patients experiencing new or worsened claudication.
• This MCID estimate requires external validation but can guide the interpretation of PAQ scores in clinical trials and routine care.
• The findings contribute to a better understanding of patient-centered outcomes in peripheral artery disease management.