Table 3

Characteristics of cohort-controlled echocardiographic studies included in analysis

Author

Year

Patient selection

Ascertainment of drug exposure

Mean duration (days)

Blinding of outcome assessment

Gardin [10]

2000

Recruited by physicians known to be frequent prescribers – 25 centres. Controls from same centres

Medical records and interview – dexfenfluramine, or combination of fenfluramine-phentermine

252

Performed blind, tapes read blind at central laboratory

Hensrud [11]

1999

Patients from double-blind randomized controlled trial

In trial of fenfluramine-phentermine

284

Blinded reviewer

Jollis [12]

2000

Prescription registry data for 33 practices, controls from same centres

Prescription registry – fenfluramine-phentermine together

337

Blinded reviewer

Khan [13]

1998

Participated in drug study at medical centre, controls from media advert

Medical records and self-reports – dexfenfluramine, fenfluramine or phentermine.

615

67 unblinded; others performed blind

Shively [14]

1999

Recruited by prescribers at 26 centres; controls were obese patients at same centres with no drugs for 5 years

Medical records – dexfenfluramine

207

Blinded and told not to discuss medication history

Wee [15]

1998

46/76 patients with previous echo from two academic centres; patients acted as their own controls

Medical records – dexfenfluramine or fenfluramine

Median 160

Performed unblinded; reread in blinded manner by one of two readers

Weissman [16]

1998

1072/1212 patients from double-blind randomized controlled trial

In a trial of dexfenfluramine

71

Double blinding of trial maintained

Loke et al. BMC Clinical Pharmacology 2002 2:6   doi:10.1186/1472-6904-2-6