Evaluating the Evidence for ASIA Syndrome: A Systematic Review of Clinical and Methodological Findings
Guillermo Alejandro Ramírez Luna, Álvaro Arbeláez Cortés, David Julián Del Castillo GilIntroduction:
Given the ongoing debate surrounding the validity of Autoimmune/ Inflammatory Syndrome Induced by Adjuvants (ASIA), this study aimed to evaluate the clinical evidence related to this syndrome, with particular emphasis on its major diagnostic criteria and methodological quality.
Methods:
A systematic review was conducted in accordance with PRISMA 2020 guidelines. Extracted data included demographic characteristics, exposure types, fibromyalgia-related symptoms, latency, histopathological findings, and autoantibody profiles. The risk of bias was assessed using validated tools appropriate to the study design.
Results:
Between 1983 and 2024, 51 studies were identified: 27 case series, 18 case reports, 4 cohort studies, 1 case-control study, and 1 cross-sectional study. Silicone was the most frequent exposure. Only 61% of case reports fulfilled ASIA criteria, while 59% of case series described fibromyalgia-compatible features. Complete improvement after removal was reported in 67% of case reports and 33% of case series. Comparative studies yielded inconsistent findings, and substantial outcome heterogeneity precluded meta-analysis.
Discussion:
The predominance of descriptive studies, heterogeneity in exposures, clinical manifestations, and study populations, as well as methodological limitations, restrict causal interpretation. Although symptomatic improvement following prosthesis removal was commonly reported, responses were variable and frequently incomplete. This uncertainty does not preclude the possibility that specific materials may trigger immune-mediated responses in susceptible individuals. Potential circularity may arise if clinically derived criteria identify cases that are subsequently used as evidence for the syndrome.
Conclusion:
Current evidence is insufficient to establish that manifestations grouped under ASIA constitute a distinct clinical entity with a common causal mechanism. Robust analytical, population-based studies with clearly defined exposures and appropriate comparison groups are warranted.