biostudies-literatureLee SNational Cancer CenterNational Research Foundation (Korea)National Cancer Center (Korea)National Research Foundation66https://www.ebi.ac.uk/biostudies/studies/S-EPMC8035736biostudies-literatureUnknown21(1)<h4>Background</h4>Cancer patients' prognoses are complicated by comorbidities. Prognostic prediction models with inappropriate comorbidity adjustments yield biased survival estimates. However, an appropriate claims-based comorbidity risk assessment method remains unclear. This study aimed to compare methods used to capture comorbidities from claims data and predict non-cancer mortality risks among cancer patients.<h4>Methods</h4>Data were obtained from the National Health Insurance Service-National Sample Cohort database in Korea; 2979 cancer patients diagnosed in 2006 were considered. Claims-based Charlson Comorbidity Index was evaluated according to the various assessment methods: different periods in washout window, lookback, and claim types. The prevalence of comorbidities and associaBMC medical research methodologyImpact of comorbidity assessment methods to predict non-cancer mortality risk in cancer patients: a retrospective observational study using the National Health Insurance Service claims-based data in Korea.PMC8035736NCC-2110450-1NRF-2020R1A2C1A010115841710300-3Lee SCho HChang YJfalseImpact of comorbidity assessment methods to predict non-cancer mortality risk in cancer patients: a retrospective observational study using the National Health Insurance Service claims-based data in Korea.<h4>Background</h4>Cancer patients' prognoses are complicated by comorbidities. Prognostic prediction models with inappropriate comorbidity adjustments yield biased survival estimates. However, an appropriate claims-based comorbidity risk assessment method remains unclear. This study aimed to compare methods used to capture comorbidities from claims data and predict non-cancer mortality risks among cancer patients.<h4>Methods</h4>Data were obtained from the National Health Insurance Service-National Sample Cohort database in Korea; 2979 cancer patients diagnosed in 2006 were considered. Claims-based Charlson Comorbidity Index was evaluated according to the various assessment methods: different periods in washout window, lookback, and claim types. The prevalence of comorbidities and associa2021-01-01T00:00:00Z2021 Apr2025-04-05T16:17:44.876Z2022-02-09T15:46:31.006ZS-EPMC80357363383666610.1186/s12874-021-01257-2