Core outcome domains for Mycobacterium avium complex pulmonary disease: a MACCOR study.

Background: Mycobacterium avium complex pulmonary disease (MAC-PD) is a chronic inflammatory disease with systemic manifestations affecting multiple aspects of patients' lives. Current microbiological outcome measures are often difficult to obtain and insufficient to reflect the impact of disease and treatment. We developed an international consensus-based set of core outcome domains (COD) for MAC-PD clinical trials using a modified Delphi consensus methodology. Methods: We invited relevant stakeholders in MAC-PD including people living with MAC-PD, their family members and friends, clinicians, researchers and research funding organisations to participate in an electronically administered Delphi consensus process. Participants rated preliminary domain importance, without regard to availability, feasibility or validity of potential measurement instruments. We used descriptive analyses to evaluate participant demographics and domain ratings, with predetermined criteria for COD inclusion. Results: A total of 306 participants representing 17 countries participated in round 1, 197 (64.4%) in round 2 and 173 (56.5%) in round 3. Over half of participants were people living with MAC-PD (57.2%), with 31.1% reporting their primary role as clinician, 9.2% as researcher. Symptoms, microbiology, treatment side-effects, chest imaging, physical function, treatment burden, and vitality/energy domains met criteria for COD inclusion in round 1. Disease recurrence and biomarkers met COD inclusion criteria in round 2 and round 3, respectively. Conclusion: Participants evaluated 11 outcome domains and suggested two additional domains for consideration, reaching COD consensus inclusion criteria for nine domains. Identification and dissemination of these CODs will help guide research priorities for measurement instruments and facilitate composite measure of disease activity development for MAC-PD.