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Table 2 Meta-analyses Selected for Review

From: Assessing observational studies of medical treatments

Brief Title Year Medical Condition Treatment 1 v Treatment 2 Failure Outcome No. of studies (RCT, OS) Reasons for excluding OSs previously compared to RCTs [13]
Anticoagulants 1977 Myocardial Infarction Control v Anticoagulants Mortality Ioannidis: (6, 12) Kunz: (6, 12) Three used alternately assigned controls [23-25].
Quinidine 1992 Atrial fibrillation Control v Quinidine Relapse into atrial fibrillation Ioannidis: (6, 5) Kunz: (6, 6) One did not have 3-month follow-up [53].
Trial of Labor 1995 Breech delivery No trial v Trial of Labor 5 minute Apgar Ioannidis: (2, 6) None excluded.
Colposuspension 1 1996 Incontinence Anterior colporrhaphy v Colposuspension No cure of incontinence Ioannidis: (4, 11) Five were in a foreign language [54-58].
Colposuspension 2 1996 Incontinence Needle suspension v Colposuspension No cure of incontinence Ioannidis: (3, 9) One used failed surgery instead of incontinence as an outcome [59]. One was a controlled trial [26]. Three were in a foreign language [55, 56, 60].
Transcutaneous Electrical Nerve Stimulation (TENS) 1996 Post-operative pain Control v TENS No pain relief Ioannidis: (2, 4) Kunz: (17, 19) None excluded.
Early Discharge 1997 Childbirth Conventional v Early Maternal Morbidity Ioannidis: (1, 3) Added one study from original meta-analysis [36].
Hip screw 1999 Hip fracture Fixed nail plates v Sliding hip screw Total complications Ioannidis: (1, 6) One "OS" was an RCT [27].
Local Anesthesia 1996 Carotid Endarterectomy General v Local Anesthesia Stroke or death Ioannidis: (3, 14) One from a non-peer reviewed abstract [61], 1 from unpublished data [62], one in a foreign language [63].
Hysterosalpingo-graphy (HSG) 1999 Infertility Water v Oil in Hysterosalpingography No Pregnancy Ioannidis: (5, 6) None excluded.
  1. RCT = Randomized Controlled Trial
  2. OS = Observational Study