title: Development of an algorithm for identifying rheumatoid arthritis in the Korean National Health Insurance claims database.
abstract: This study aimed to develop an identification algorithm for validating the International Classification of Diseases-Tenth diagnostic codes for rheumatoid arthritis (RA) in the Korean National Health Insurance (NHI) claims database. An individual copayment beneficiaries program for rare and intractable diseases, including seropositive RA (M05), began in South Korea in July 2009. Patients registered in this system pay only 10 % of their total medical costs, but registration requires an official report from a doctor documenting that the patient fulfills the 1987 ACR criteria. We regarded patients registered in this system as gold standard RA and examined the validity of several algorithms to define RA diagnosis using diagnostic codes and prescription data. We constructed nine algorithms using two highly specific prescriptions (positive predictive value >90 % and specificity >90 %) and one prescription with high sensitivity (>80 %) and accuracy (>75 %). A total of 59,823 RA patients were included in this validation study. Among them, 50,082 (83.7 %) were registered in the individual copayment beneficiaries program and considered true RA. We tested nine algorithms that incorporated two specific regimens [biologics and leflunomide alone, methotrexate plus leflunomide, or more than 3 disease-modifying anti-rheumatic drugs (DMARDs)] and one sensitive drug (any non-steroidal anti-inflammatory drug (NSAID), any DMARD, or any NSAID plus any DMARD). The algorithm that included biologics, more than 3 DMARDs, and any DMARD yielded the highest accuracy (91.4 %). Patients with RA diagnostic codes with prescription of biologics or any DMARD can be considered as accurate cases of RA in Korean NHI claims database.
authors.affiliation: Department of Rheumatology, Hanyang University Hospital for Rheumatic Diseases, Seoul, 133-792, South Korea.
authors.forename: Soo-Kyung
authors.initials: SK
authors.lastname: Cho
authors.forename: Yoon-Kyoung
authors.initials: YK
authors.lastname: Sung
authors.forename: Chan-Bum
authors.initials: CB
authors.lastname: Choi
authors.forename: Jeong-Mi
authors.initials: JM
authors.lastname: Kwon
authors.forename: Eui-Kyung
authors.initials: EK
authors.lastname: Lee
authors.forename: Sang-Cheol
authors.initials: SC
authors.lastname: Bae
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000627:therapeutic use; D018501:Antirheumatic Agents / Q000627:therapeutic use; D001172:Arthritis, Rheumatoid / Q000175:diagnosis* / Q000188:drug therapy / Q000453:epidemiology*; D001688:Biological Products / Q000627:therapeutic use; D059019:Clinical Coding / Q000145:classification; D016208:Databases, Factual / Q000706:statistics & numerical data*; D004359:Drug Therapy, Combination; D005260:Female; D006801:Humans; D007344:Insurance Claim Reporting / Q000706:statistics & numerical data*; D007555:Isoxazoles / Q000627:therapeutic use; D000077339:Leflunomide; D008297:Male; D008727:Methotrexate / Q000627:therapeutic use; D008875:Middle Aged; D009313:National Health Programs / Q000706:statistics & numerical data*; D015203:Reproducibility of Results; D056910:Republic of Korea / Q000453:epidemiology; D055815:Young Adult
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D018501:Antirheumatic Agents; D001688:Biological Products; D007555:Isoxazoles; D000077339:Leflunomide; D008727:Methotrexate
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