Adaptation of the Charlson Comorbidity Index for Register-Based Research in Sweden.

Comorbidity indices are often used to measure comorbidities in register-based research. We aimed to adapt the Charlson comorbidity index (CCI) to a Swedish setting. Four versions of the CCI were compared and evaluated by disease-specific experts. We created a cohesive coding system for CCI to 1) harmonize the content between different international classification of disease codes (ICD-7,8,9,10), 2) delete incorrect codes, 3) enhance the distinction between mild, moderate or severe disease (and between diabetes with and without end-organ damage), 4) minimize duplication of codes, and 5) briefly explain the meaning of individual codes in writing. This work may provide an integrated and efficient coding algorithm for CCI to be used in medical register-based research in Sweden.

Informations de copyright

© 2021 Ludvigsson et al.

Déclaration de conflit d'intérêts

Ludvigsson coordinates an unrelated study on behalf of the Swedish Inflammatory Bowel Disease Quality Register that has received funding from the Janssen Corporation. Askling is the principal investigator for Abbvie, BMS, Eli Lilly, Merck, Pfizer, Roche, Samsung Bioepis, and Sanofi mainly pertaining to a national safety surveillance of rheumatology drugs. The other authors report no conflicts of interest in this work.