Thyroid Health Outcomes Registry for Surgery

Comprehensive Analysis of Quality and Outcomes in Thyroid Surgery Using Real-World Clinical Data

THORS is a single-center ambidirectional observational cohort study conducted at Moscow Multidisciplinary Clinical Center "Kommunarka". The study combines retrospective analysis of routinely collected clinical data from patients who underwent thyroid surgery beginning in January 2023 with ongoing prospective accrual of new eligible patients and longitudinal updating of follow-up information. No diagnostic or therapeutic intervention is assigned by the research protocol; all treatment decisions are made as part of routine clinical care. The program evaluates the structure and outcomes of thyroid surgery, postoperative complications, histopathology, repeat and completion procedures, long-term oncologic and functional outcomes, health-care resource use, and the quality and reproducibility of real-world data. Applicable outcomes from the international Core Outcome Set for surgical treatment of differentiated thyroid carcinoma (COS-DTC) are incorporated where they can be reliably measured. The first frozen historical analytical baseline includes 968 unique patients and 1,017 thyroid operations performed from 06 January 2023 through 13 February 2026. The cohort remains open to ongoing enrollment and follow-up

THORS is an umbrella real-world-data research program designed as an open, single-center, ambidirectional observational cohort. The historical component uses secondary data generated during routine care, including operative records, hospitalizations, pathology and immunohistochemistry reports, inpatient and outpatient clinical documentation, repeat admissions, follow-up encounters, and available resource/cost information. After registration, new eligible patients continue to enter the cohort prospectively as part of ordinary clinical practice, and clinically available follow-up information is added longitudinally. The research protocol does not assign the type or extent of thyroid surgery, lymph-node dissection, diagnostic testing, or adjuvant treatment.

The program uses linked patient-, hospitalization-, operation-, pathology-, complication-, and follow-up-level data structures. Raw source values, technically normalized data, automated screening signals, author clinical classification, independent expert classification, and adjudicated values are retained as separate layers whenever applicable. Each substantive substudy has a prespecified scientific question, eligibility criteria, outcome definitions, data freeze, and statistical analysis plan. Missingness, source provenance, discordance between data sources, classification error, and repeated observations within patients are explicitly evaluated.

Clinical objectives include description of surgical practice and pathology; clinically verified postoperative complications; functional outcomes; repeat, completion, and recurrence-related surgery; long-term oncologic outcomes; comparisons of clinically relevant surgical strategies when adequate confounding control is possible; and health-care resource use. Methodological objectives include reproducibility of cohort construction and phenotyping, multi-source detection and expert adjudication of outcomes, data-quality assessment, and the feasibility of measuring the 13 COS-DTC outcomes in routine data.

The historical cohort predates registration. Analyses already completed or initiated on historical data are treated as retrospective baseline analyses and are not represented as prospectively registered. Future substudies are date-stamped through protocol/SAP versions and frozen analytical datasets. The complete prespecified THORS research portfolio is listed in Appendix A of this registration dossier, including methodological, clinical, prognostic, comparative, economic, specialized, long-term, and transferability studies. Prospective questionnaires, research-only biospecimen collection, or additional study-specific procedures require the relevant ethics approval and, when they materially change the registered protocol, an amendment or a separate registration record.

Inclusion Criteria:

• Patient undergoes or previously underwent an operation involving the thyroid gland at the study institution during the study period.
• The operation was performed for a benign or malignant thyroid disease, including primary, completion, or repeat thyroid surgery.
• Source data permit linkage of the patient, hospitalization, operation, and index date.
• For a specific substudy, the participant/episode meets the additional prespecified requirements for the relevant exposure and outcome.

Exclusion Criteria:

- Procedure predominantly involving the parathyroid glands without a confirmed relationship to thyroid disease.

• Procedure or record without a confirmed relationship to thyroid disease.
• Technical duplicate record.
• Episode for which the essential temporal sequence or index date cannot be established for the relevant analysis.
• Record lacking the minimum data required to determine the primary outcome of the specific substudy.