Achieving ASDAS Inactive Disease Status in Axial Spondyloarthritis in Clinical Trials: A Systematic Review and Meta-analysis

Objective Axial Spondyloarthritis Disease Activity Score (ASDAS) is a composite score that measures disease activity in axial spondyloarthritis (axSpA) and is based on patient-reported outcomes and objective measures of inflammation. An ASDAS score of < 1.3 indicates inactive disease (ASDAS-ID) in axSpA clinical trials and is considered equivalent to clinical remission. We hypothesized that achieving ASDAS< 1.3 represents a stringent target that may be difficult to attain in randomized clinical trials. We aimed to evaluate the proportion of patients achieving inactive disease compared to low disease activity i.e, ASDAS<2.1 (ASDAS-LDA) with axSpA in clinical trials. Methods A comprehensive literature search was conducted in MEDLINE, Embase, the Cochrane Database of Systematic Reviews, the Cochrane Central Register of Controlled Trials, and the EU Clinical Trials Register to identify eligible studies published from inception through August 2025. Clinical trials reporting ASDAS inactive disease or low disease activity were included. Eligible studies enrolled patients with radiographic or non-radiographic axial spondyloarthritis treated with biologic therapies, including Tumor Necrosis Factor inhibitors (TNF-i), Interleukin-17 inhibitors (IL-17i), or targeted synthetic disease-modifying antirheumatic drugs (tsDMARDs) such as Janus Kinase inhibitors (JAK-i). Risk of bias was assessed using the Cochrane Risk of Bias tool, and two independent reviewers screened all records, with disagreements resolved by a senior author. A meta-analysis was performed, and data were synthesized using forest plots to calculate pooled odds ratios with 95% confidence intervals(CI). Study heterogeneity was assessed using the I² statistic. Results A total of 41 unique studies were included; 19 randomized clinical trials (RCTs) were identified with 6171 patients included in the meta-analysis. Additionally, twenty-two open-label extension (OLE) studies were included. Several OLE publications originated from the same parent RCT and therefore did not represent independent studies. The pooled proportion of patients achieving inactive disease status in the treatment group was 0.24 (95% CI: 0.18-0.31) at 12–24 weeks, 0.22 (95% CI: 0.17-0.28) during weeks 48–52 in open-label extension phases, and 0.35 (95% CI: 0.25-0.43) during weeks 96–156. The odds of achieving inactive disease were 0.30 (95% CI: 0.17-0.51) compared to low disease activity in the treatment group. Conclusion This study demonstrates that attainment of ASDAS inactive disease in axSpA clinical trials is consistently low, reflecting the stringency of this remission threshold within trial designs. These findings underscore the importance of interpreting ASDAS-ID alongside ASDAS-LDA, which may represent a more attainable and clinically meaningful disease state when remission is not achieved.