Why Patient-Reported Outcomes Matter in MAC Treatment

This episode, "Why Patient-Reported Outcomes Matter in MAC Treatment," features Dr. Losier making the case for patient-reported outcomes in MAC trials.

Dr. Losier calls patient-reported outcome research one of the most important methodological advances presented at this year's ATS meeting, since MAC and NTM pulmonary disease trials have traditionally focused heavily on culture conversion. Culture conversion remains an essential endpoint, she says, but it does not capture what patients actually experience during treatment. Patients live with chronic cough, fatigue, dyspnea, sputum production, and impaired exercise capacity, and many also experience substantial treatment toxicity even after their cultures turn negative. The quality-of-life bronchiectasis respiratory domain questionnaire, or QOL-B, helps capture respiratory symptoms and their impact on daily function as a treatment outcome in its own right.

Investigators used this previously validated questionnaire, serially administering it to patients with MAC enrolled in clinical studies, including ENCORE. They evaluated its relationship with culture conversion, lung function, and global health assessments, and estimated a minimally clinically important difference using both anchor-based and distribution-based approaches. The instrument performed well, showing good internal consistency, test-retest reliability, and responsiveness to treatment-related change. Patients who achieved culture conversion had significantly greater improvement in QOL-B scores than those who did not. The minimally clinically important difference was approximately 8 to 10 points, and chronic cough, fatigue, dyspnea, and exercise tolerance were the symptoms with the greatest impact.

Dr. Losier's key takeaway is that treatment success should be viewed as multidimensional. Durable culture conversion remains fundamental, but a patient who converts their sputum while remaining profoundly symptomatic, or burdened by treatment toxicity, still needs that experience captured. In clinical trials, pairing QOL-B with microbiologic endpoints clarifies whether a treatment offers meaningful benefit. In practice, serial patient-reported outcomes could help identify patients who are improving, flag those needing additional intervention, and surface cases where treatment burden may outweigh its benefit.

Our final episode, "Where MAC and NTM Research Is Headed Next," closes the series with a look at where MAC and NTM research is headed next.