Table 1—

Description of included RCTs

CharacteristicsPatient-important outcomesSurrogate outcomesPhysiological and other laboratory measures
n4238119
Year of publication2002 (1998–2003)2002 (1995–2003)2002 (1987–2003)
Journal of publication*
    General medical26 (62)20 (53)21 (18)
    Diabetes16 (38)6 (16)47 (39)
    Metabolism and nutrition0 (0)12 (32)51 (43)
Region of work
    North America12 (29)11 (29)37 (31)
    Europe19 (45)17 (45)52 (44)
    Asia0 (0)4 (11)10 (8)
    Other11 (26)6 (16)20 (17)
Number of centers
    Single center24 (57)24 (63)90 (76)
    Few centers (<10)3 (7)6 (16)20 (17)
    Many centers (>10)15 (36)8 (21)9 (8)
Type of patients
    Type 2 diabetes15 (36)19 (50)82 (69)
    Type 1 diabetes8 (19)5 (13)20 (17)
    Type 1 or 2 diabetes9 (21)4 (11)3 (2.5)
    At risk of diabetes4 (10)3 (8)3 (2.5)
    Other6 (14)7 (18)11 (9)
Exclusion of women3 (7)1 (3)13 (11)
Exclusion of elderly (were elderly could be eligible)20/31 (64)14/22 (64)33/44 (75)
Exclusion of ethnic group2 (5)1 (3)2 (2)
Type of interventions
    Drug30 (71)29 (76)94 (79)
        vs. placebo141562
        vs. active drug131230
        vs. usual care or no intervention322
    Nutrition0 (0)2 (5)17 (14)
    Education, counseling, or psychological interventions8 (19)4 (10)4 (3)
    Other interventions4 (10)3 (8)4 (3)
Funding
    For-profit sources only25 (60)18 (47)53 (45)
    For-profit and not-for-profit sources9 (21)7 (18)29 (24)
    Not-for-profit sources only8 (19)13 (34)37 (31)
  • Data are median (range) or n (%).

  • *

    * General medical journals: New England Journal of Medicine (n = 10), Lancet (n = 11), JAMA (n = 10), BMJ (n = 8), Annals of Internal Medicine (n = 10), and Archives of Internal Medicine (n = 10). Diabetes journals: Diabetes Care (n = 19), Diabetes (n = 17), Diabetic Medicine (n = 18), Diabetologia (n = 19), and Diabetes/Metabolism Research and Reviews (n = 10). Metabolism and nutrition journals: Journal of Clinical Endocrinology and Metabolism (n = 18), Metabolism:clinical and experimental (n = 11), American Journal of Clinical Nutrition (n = 10), European Journal of Clinical Nutrition (n = 8), and Journal of the American College of Nutrition (n = 10).