Table 1.
Characteristics of the included studies-Part I
| Study | Country | Design/study duration | Sample source | Definition criteria | |
|---|---|---|---|---|---|
| IBD | RA | ||||
| Aletaha-2019 [17] | USA | Retrospective Cohort/10 years | MarketScan Commercial Claims and Encounters database | ≥2 claims at least 30 days apart with ICD-9 codes (555.x, 556.x) | ≥2 claims at least 30 days apart with ICD-9 codes (714, 714.0, 714.8, 714.89, 714.9) |
| Bae-2017a [14] | Korea | Cross-sectional/NA | National Health Insurance Database | ≥5 health contacts due to UC/ CD as the principal diagnosis with ICD-9 codes (K50, K51) | ≥5 health contacts due to RA as the principal diagnosis with ICD-9 codes (M05, M06) |
| Burisch-2019 [16] | Denmark | Retrospective Cohort/10 years |
National Patient Registry |
≥2 diagnoses with ICD-8 codes (563.01, 563.19) or ICD-10 codes (K50, K51) | ≥1 diagnosis with ICD-10 codes (M05, M06.0, M06.8, M06.9) |
| Cohen-2008-1 [16] | USA | Cross-Sectional/ NA | IMS Health Integrated Administration Claims Database | ≥1 claim with ICD-9 codes (555.x, 556.x) | ≥1 claim with ICD-9 codes (714.x) |
| Cohen-2008-2 [13] | USA | Cross-Sectional/ NA | MarketScan Commercial Claims and Encounters Database | ≥1 claim with ICD-9 codes (555.x, 556.x) | ≥1 claim with ICD-9 codes (714.x) |
| Halling-2017a [12] | Denmark | Cross-Sectional/ NA |
National Patient Registry |
ICD-10 codes (K50, K51) | ICD-10 codes |
| Kappelman-2011 [11] | USA | Cross-Sectional/ NA | PharMetrics Patient-Centric Database | ≥3 health contacts with associated ICD-9 codes (555.x, 556.x), or ≥ 1 claim with associated medication history | ICD-9 codes |
| Park-2019 [15] | Korea | Retrospective cohort/4 years | National Health Insurance Database | ICD-10 codes (K50, K51) and registration codes (V130, V131) for the rare/intractable disease patient-support program | ICD-10 codes and registration codes for the rare/intractable disease patient-support program |
| Puolakka-2014 [19] | Finland | Case-control/4 years | National Registry of the Social Insurance Institution | ICD-10 codes (K50, K51) | ICD-10 codes (M05, M06) |
| Kronzer-2019 [18] | USA | Case-control/10 years | Single-center biobank | Questionnaire | ≥2 diagnoses at least 30 days apart with ICD-9 codes (714.0, 714.9) plus use of a disease modifying antirheumatic drug |
| Weng-2007 [10] | USA | Cross-sectional/NA | Northern California region of the Kaiser Permanente Medical Care Plan | ≥2 diagnoses with ICD-9 codes (555.x, 556.x) | ≥2 diagnoses with ICD-9 codes (714.0, 714.3x) |
| Yang-2018a [9] | Korea | Cross-Sectional/NA | National Health Insurance Database | ICD-10 codes (K50, K51) and registration codes (V130, V131) for the rare/intractable disease patient-support program | ICD-10 codes (M05, M06) |
CD Crohn Disease, IBD Inflammatory Bowel Diseases, NM Not Mentioned, ICD-8 International Classification of Disease 8th revision, ICD-9 International Classification of Disease 9th revision, ICD-10 International Classification of Disease 10th revision, NA Not Apply, RA Rheumatoid Arthritis, UC Ulcerative Colitis
aThese cross-sectional studies were not included in the statistical meta-analysis as the populations in these studies overlapped with those in the other cohort studies