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Table 3 Outcome Differences Between RCTs and OSs

From: Assessing observational studies of medical treatments

Brief Title (outcome) Number of Studies Average Failure Rate (Number of Patients)
   Control** Treatment
Anticoagulants (MI) [13, 14, 64]    
   RCT 6 17% (1748) 14% (2106)
   OS 9 31% (3615) 16% (2598)
Quinidine (Afib) [13, 14, 28] 3 months    
   RCT 6 54% (390) 36% (413)
   OS 5 61%* (200) 53% (342)
Trial of labor (Breech) [13, 65]    
   RCT 2 2% (128) 3% (182)
   OS 6 5% (1043) 4% (1552)
Colposuspension 1 (Incontinence) [13, 66]    
   RCT 2 33% (134) 12% (139)
   OS 6 37% (508) 26% (374)
Colposuspension 2 (Incontinence) [13, 66]    
   RCT 2 31% (132) 12% (139)
   OS 4 32% (190) 23% (349)
TENS (Pain) [13, 14, 67]    
   RCT 2 18% (34) 3% (34)
   OS 4 76% (172) 56% (136)
Early Discharge (Childbirth) [13, 68]    
   RCT 1 8% (38) 5% (93)
   OS 4 21% (379) 19% (402)
Hip Screw (Hip Fx) [13, 69]    
   RCT 1 50% (26) 12% (33)
   OS 5 35% (290) 8% (560)
Local Anesthesia (CEA) [11, 13, 70]    
   RCT 3 5% (79) 5% (75)
   OS 11 5%* (1509) 2% (1713)
HSG (Infertility) [11, 13, 71]    
   RCT 5 81% (527) 69% (302)
   OS 6 74% (734) 58% (1072)
  1. RCT = Randomized Controlled Trial; OS = Observational Study
  2. MI = Myocardial Infarction
  3. Afib = Atrial fibrillation
  4. TENS = Transcutaneous electrical nerve stimulation
  5. Hip Fx = Hip Fracture
  6. CEA = Carotid Endarterectomy
  7. HSG = Hysterosalpingography
  8. ** The treatment group is listed in the row title. As seen in Table 1, the control (i.e. comparison) groups are the negative of the listed treatment except for the following: Control group for colposuspension 1 is colporrhaphy, colposuspension 2 is needle suspension, hip fracture is fixed nail plates, CEA is general anesthesia, infertility is water soluble medium.
  9. Significance testing was only done to test heterogeneity among the failure rates for the observational studies
  10. * P < .05 for test of heterogeneity of failure rates combined to create the average
  11. † P < .001 for test of heterogeneity of failure rates combined to create the average