Table 1. Characteristics of included studies, sorted alphabetically.
| Reference | Location | Time period | Patient source description | Data type | N (denominator) |
RA definition | Follow-up time (mean, years) |
Quality rating (range 0-5) |
|---|---|---|---|---|---|---|---|---|
| Bonafede 2012 | US | 2004-2008 | Commercial database (privately insured) | Admin | 26,911 | 2 RA-coded visits | 1 | 5 |
| de Thurah 2010 | Denmark | 1996-2006 | Nationwide register | Admin | 1,516 | 1 RA-coded visit | 2 | 5 |
| Della Rossa 2010 | Italy | 2006-2007 | Population-wide physician & patient survey | Clinical | 34 | ACR criteria | CS | 5 |
| DeWitt 2009 | US | 2006 | RA database (ARAMIS) | Clinical | 679 | RA or suspected RA | CS | 3 |
| Edwards 2005 | UK | 1987-2002 | Nationwide register | Admin | 34,364 | 2 RA-coded visits | 7 | 5 |
| Gonzalez-Alvaro 2008 | Spain | 2000-2004 | 34 clinics (EMECAR) | Clinical | 789 | ACR criteria | 4 | 5 |
| Goycochea-Robles 2007 | Mexi co | 2002-2003 | Multiple clinics; 58 physicians | Clinical | 1,096 | ACR criteria | CS | 4 |
| Grijalva 2008 | US | 2004 | State-wide low-income health insurance program | Admin | 5,600 | 2 RA-coded visits | 1 | 5 |
| Jamal 2011 | Canada | 2003-2006 | 15 rheumatologists | Clinical | 204 | RA or suspected RA | CS | 4 |
| Kahn 2007 | US | 1999-2003 | University clinic | Clinical | 568 | RA or suspected RA | 1 | 5 |
| Khanna 2007 | US | 2003 | State-wide low-income health insurance program | Admin | 1,157 | 1 RA-coded visit | CS | 5 |
| Kiely 2009 | UK | 2002-2007 | 19 centers (ERAN) | Clinical | 691 | RA or suspected RA | 0.5 | 5 |
| Lukas 2009 | France | 2002-2005 | Early RA database; 14 centers (ESPOIR) | Clinical | 775 | RA or suspected RA | 0.3 | 5 |
| Montag 2011 | Australia | 2007-2008 | 2 community clinics | Clinical | 1,059 | RA or suspected RA | CS | 4 |
| Rantalaiho 2010 | Finland | 2006-2007 | Nationwide register | Admin | 3,628 | 1 RA-coded visit | 0.3 | 5 |
| Schmajuk 2007 | US | 1996-2003 | State-wide low-income health insurance program | Admin | 5,864 | 3 RA-coded visits | 1 | 5 |
| Schmajuk 2011 | US | 2005-2008 | Nationwide Medicare managed care plans | Admin | 93,143 | 2 RA-coded visits | 1 | 5 |
| Soderlin 2010 | Sweden | 2005 | RA registry (Malmo) | Clinical | 1,049 | ACR criteria | CS | 4 |
| Sokka 2008(a) | US | 2000-2004 | University clinic | Clinical | 103 | RA or suspected RA | 5 | 5 |
| Sokka 2008(b)* | Finland | 2000-2004 | Hospital clinic | Clinical | 497 | RA or suspected RA | 2 | 5 |
| Solomon 2012 | US | 1996-2007 | National Ambulatory Care Medical Survey | Clinical | 859 | 1 RA-coded visit | CS | 5 |
| Sung 2012 | Korea | 2008-2010 | Nationwide register | Clinical | 4,721 | ACR criteria | CS | 5 |
| Teh 2008 | Malaysia | 2006-2007 | Hospital clinic | Clinical | 154 | ACR criteria | CS | 4 |
| Westhoff 2009 | Germany | 2008 | Population-wide survey | Clinical | 41 | ACR criteria | CS | 4 |
| Widdifield 2010 | Canada | 1997-2006 | Province-wide physician billing data | Admin | 24,942 | 2 RA-coded visits | 1 | 5 |
| Yamanaka 2007 | Japan | 2006 | National registry (IORRA) | Clinical | 4,933 | ACR criteria | 0.5 | 4 |
| Yelin 2005 | US | 1999-2002 | Northern California RA Panel | Clinical | 438 | ACR criteria | 1 | 4 |
| Ziegler 2010 | Germany | 2007 | Nationwide register | Clinical | 3,323 | ACR criteria | 1 | 5 |
Location: US: United States; UK:United Kingdom;
Data type: Admin: Administrative data; Survey: Population-based survey; Clinical: Patients evaluated by a physician as part of a RA registry;
Follow-up: CS: cross-sectional
Numbers in italics are approximated from study data
*
Sokka 2008 appears twice because 2 distinct cohorts were described