Retrospectively Registered Protocol, Statistical Analysis Plan, and Methodological Audit Trail for Oral Second-Generation H1-Antihistamine Regimens for Allergic Rhinitis: Systematic Review and Network Meta-Analysis of Effects and Estimability

This OSF Open-Ended Registration contains version 1.0 of a retrospectively reconstructed protocol, statistical analysis plan, exact search strategies, chronology of review conduct, amendment-and-deviation log, retrospective-registration statement, and SHA-256 manifest for the systematic review and network meta-analysis “Oral Second-Generation H1-Antihistamine Regimens for Allergic Rhinitis: Systematic Review and Network Meta-Analysis of Effects and Estimability”. The review was not prospectively registered. Search execution, study selection, quantitative extraction, evidence appraisal, the principal statistical analyses, implementation-independent computational replication, and figure production were completed between 1 and 28 July 2026. Manuscript drafting, final interpretive synthesis, and the supplementary appendix were completed after 28 July and before registration, except for insertion of the final repository identifiers. The registration provides a time-stamped methodological audit trail but not the bias protection of prospective registration. Associated analytic repository: Zenodo reserved DOI 10.5281/zenodo.21780525. The Zenodo record was an unpublished draft at the time of OSF registration and will be released after assignment of the OSF DOI.