Table 1.

Details of systematic literature review methodology

Databases	Electronic databases: MEDLINE, MEDLINE In-Process, and Embase Conference databases: ACR/ARHP Annual Meeting and EULAR Annual European Congress of Rheumatology archives
Time frame	Full-text articles: database start to July 12, 2018 Conference abstracts: January 1, 2013, to July 12, 2018
Inclusion criteria	Population: adult patients with axSpA Outcomes  Clinical: comorbidities, mortality, and disability and functional status (e.g., BASDAI, BASFI, BASMI)  Economic: direct/indirect costs, resource use data, type of cost data and value, and type of resource use and value  Humanistic: HRQOL and utility values and qualitative measures Study design: original research studies, including observational studies; claims database studies; surveys; and any study reporting cost, resource use, and HRQOL data
Exclusion criteria	Animal/in vitro studies and studies with children or patients with peripheral spondyloarthritis Non-English-language articles Interventional studies, including RCTs, nRCTs, or single-arm trials HTAs, reviews, editorials, case reports, and case series
Critical appraisal tools	Downs and Black Quality Index for assessing risk of bias [48]
Data extraction	Total number of patients analyzed, number of patients with outcome, mean, SD, SE, median, range, 95% CI, and P values, as applicable

ACR American College of Rheumatology, ARHP Association of Rheumatology Health Professionals, axSpA axial spondyloarthritis, BASDAI Bath Ankylosing Spondylitis Disease Activity Index, BASFI Bath Ankylosing Spondylitis Functional Index, BASMI Bath Ankylosing Spondylitis Metrology Index, EULAR European League Against Rheumatism, HRQOL health-related quality of life, HTA health technology assessment, nRCT nonrandomized controlled trial, RCT randomized controlled trial