Matching 3 Observational Studies With the French National Healthcare Database (SNDS) to Assess the Long-Term Management of Rheumatoid Arthritis (RA) Patients Treated With Tocilizumab

OBJECTIVES: Since ToCiliZumab (TCZ) market introduction in France in 2010 for patients suffering from Rheumatoid Arthritis (RA), three real-world studies were conducted in France (NCT01185522: 2010-2011, NCT01392001: 2011-2013, NCT01474291: 2012-2013). As patients were followed maximum 12 months, the objective to link these studies with the national claim database (SNDS) was to generate long-term evidence on the management of RA in patients initiating TCZ.

METHODS: Index date was defined as TCZ first dispensation and follow-up period was up to ten years after index date (max 2019).

As no unique direct identifier was available in the data sources, a deterministic and iterative approach was employed to establish a link using several variables: dates of medical visits/hospitalizations, year of birth, gender, and national hospitals identifier (called FINESS).

The ethics approval process for access to SNDS database was obtained in July 2022 and data extraction was performed in November 2023.

RESULTS: A total of 1,494 patients were analyzed in previous observational studies and 1,602 patients were extracted from the SNDS database.

First step of the algorithm identified 1,455 (97.4%) matching patients

169 patients had to be excluded due to either identification/technical constraints from the SNDS or > 90 days gap between TCZ initiation from the observational studies and TCZ first dispensation date from the SNDS.

From the 1,286 patients matched, median age was 56.0 (Q1:48.0-Q3:66.0) years. Most patients were females (79.9%), 1,176 (91.4%) were aged < 75 years and 110 (8.6%) were aged ≥ 75 years. Median follow-up duration was 8.0 years (7.0-9.5).

CONCLUSIONS: This method of record linkage with pseudonymized data used in this study led to match 1,286 (86.1%) patients between the observational studies and the claim database (86.1%). This linkage allowed increasing patient follow-up by 8 years in median.