Table 1.
Characteristics of studies
| Source, country |
Study design |
Data source for patient identification |
Years of observ ation |
Number of RA cases in comparator groups |
Age per inclusion criteria; mean age, years |
Female sex |
Length of follow- up |
Effect estimate | Newcastle -Ottawa scale |
|---|---|---|---|---|---|---|---|---|---|
| De Jong et al. (16); Netherlands | case- control | Netherlands Information Network of General Practice (LINH) database | 2001- 2006 | 508 cases of RA (81 exposed to statins) and 2369 controls (204 exposed to statins) | ≥ 40; 63.4 (cases); 62.8 (controls) | 67.5% of cases and 65.8% of controls | Not specifie d | OR 1.71; 95% CI 1.16-2.53 | S**** C** E** |
| Tascilar et al. (14); UK | nested case- control | UK Clinical Practice research datalink (CPRD) | 1997- 2009 | 1357 cases of RA (1032 exposed to statins) and 13570 controls (11,118 exposed to statins) among 528,654 new statin users | ≥ 40; 63.7 (cases); 63.8 (controls) | 60.3% of cases and controls | Mean 39.2+/− SD 30.3 months | HR 0.77; 95% CI 0.63-0.95 for highest vs low statin intensity quintile | S**** C** E** |
| Jick et al. (17); UK | nested case- control | General practice research database (GPRD) | 1992- 2001 | 313 cases of RA (41 exposed to statins) and 1252 controls (194 exposed to statins) | 40-89; mean age not specified, shown distribution by age group | 60.7% of cases and controls | Not specifie d | OR 0.59; 95% CI 0.37-0.96 | S**** C** E* |
| Smeeth et al.(20); UK | cohort, retrosp ective | The Health Improvement Network (THIN) database | 1995- 2006 | 2,532 incident RA cases overall out of 729,529 individuals; 227 cases of RA in exposed to statins, 2,305 in unexposed | 40-80; mean age not specified, shown distribution by age group | 50.2% in unexpos ed, 49.3% in exposed | Median 4.3 years | HR 0.93; 95% CI 0.73-1.18 | S** C** O* |
| Hippisley- Cox et al. (19); UK | cohort, prospe ctive | Q research database | 2002- 2008 | 5,730 RA cases among 225,922 new statin users | 30-84; 57.2 (new users); 44.4 (non- users) | 46.4% in new users, 51.1% in | Not specifie d | HR for simvastatin. Men: 0.96; 95% CI 0.84-1.09; | S*** C** O** |
| non- users | women: 1.12; 95% CI 0.96- 1.32 | ||||||||
| de Jong et al. (15); UK | matched cohort, prospe ctive | CPRD | 1995- 2009 | 837 RA cases among 511,620 current statin users | ≥ 40; 63.0 (statin users); 62.8 (non- users) | 47.9% in statin users and non-users | Mean 3 +/− SD 2.5 years | HR 1.06; 95% CI 0.93-1.22 | S**** C** O** |
| Chodick et al. (13); Israel | cohort, retrosp ective | Maccabi Health Services (MHS) | 1998- 2007 | 2,578 RA cases among 211,627 new statin users | ≥ 18; 57.17 years | 50.9% | Mean 4.97 years | HR for highly persistent vs non-persistent patients: 0.58; 95% CI 0.52- 0.65 | S**** C** O*** |
| Schmidt et al. (18); US | cohort, retrosp ective | San Antonio area military healthcare system, Tricare Prime/Tricare Plus | 2003- 2010 | 104 RA cases among 6,956 statin users and 122 RA cases among matched 6,956 statin non-users driven from the population of 13,640 statin users and 32,848 nonusers | 30-85; 57 in users and non-users | 41.7% in users, 56.2% in non- users | Not specifie d | Unadjusted OR for RA cases (calculated from the data in the manuscript) 0.85; 95% CI 0.65-1.11 | S**** C** O** |
Newcastle-Ottawa scale: S= selection; C=comparability; E=exposure; O=outcome