Table 2—

Characteristics of studies that have assessed cognitive functioning in patients with type 1 diabetes, comparing different diabetic characteristics

First author (ref.)Type (grp 1/grp 2)n (grp 1/grp 2)% Males (grp 1/grp 2)Age (grp 1/grp 2)HbA1 (grp 1/grp 2)Duration (grp 1/grp 2)Calculated age at onset (grp 1/grp 2)Included complications and characteristicsExclusion criteria or absent characteristicsSubjects matched for
Hung et al. 1984 (33)Poor MC/good MC12/2067/6535.1/34.1513 ± 0.9/10 ± 0.820.2/22.815/14R,NNeND
Skenazy et al. 1984 (19)Vis imp/non-vis imp20/1970/5328 ± 6.1/32.1 ± 6ND/ND18.7 ± 5.9/15.3 ± 7.89/17H,N,R,NeNDND
Holmes 1986 (7)Poor MC/good MC8/19100/10020.9 ± 2.4/23.4 ± 5.412.4 ± 0.7/8.2 ± 1.67.8 ± 4.1/8.4 ± 5.713/15NDPE,SES
Holmes et al. 1988 (34)Poor MC/good MC6/10100/10022.2 ± 4.3/24 ± 5.310.1 ± 1/6.9 ± 0.87.5 ± 3.8/6.7 ± 4.415/14NDRND
Prescott et al. 1990 (35)Poor MC/good MC20/2050/5040.3 ± 11.6/39.8 ± 1013.1 ± 1.6/8.9 ± 115.2 ± 10.5/14 ± 10.325/26NDNDSES
Widom et al. 1990 (21)Poor MC/good MC9/844/5022 ± 3/27 ± 5.711.8 ± 1.2/8 ± 0.612 ± 6/7 ± 2.810/20R,NDN,NeND
Wredling et al. 1990 (4)Sev hy/no sev hy17/17ND/ND49 ± 18/48 ± 177.9 ± 1.6/8.8 ± 1.628 ± 18/29 ± 1321/19N,R,PNDE
Langan et al. 1991 (36)Sev hy/no sev hy24/2358/4837.9 ± 6.4/38.5 ± 5.310 ± 2.3/10.2 ± 1.810.7 ± 4/13 ± 427/25R,N,Ne,HCV,P,PDND
Sachon et al. 1992 (3)IHA/NHA30/2577/6041 ± 13/34 ± 107.4 ± 1.2/8.6 ± 1.918 ± 13/15 ± 1124/19N,Ne,RNDO,SES
Ryan et al. 1993 (27)Compl/no compl113/2949/5534.3 ± 5.4/30.7 ± 5.610.6 ± 1.7/10.7 ± 1.925.9 ± 5.6/20.5 ± 5.88/10N,Ne,RNDE,SES
Chabriat et al. 1994 (37)Sev hy/no sev hy15/6ND/ND47.6 ± 17/42.8 ± 197.2 ± 1.7/7.1 ± 0.819.6 ± 16/11.3 ± 728/32H,R,M,N,CVE
Gold et al. 1995 (38)IHA/NHA10/10ND/ND35 ± 7.7/37.4 ± 5.19.7 ± 1/10.3 ± 2.212.8 ± 4.4/17.9 ± 7.823/19HP,R,NND
Maran et al. 1995 (28)Poor MC/good MC10/860/7532 ± 4/36 ± 310.1 ± 0.2/7.7 ± 0.317 ± 3/16 ± 215/20NDNDND
DCCT 1996 (39)
    >5 episodesSev hy/no sev hy23/1,045ND/ND<50/<50ND/ND>6/>6NDR,Ne,N,PND
    1–5 episodesSev hy/no sev hy314/1,045ND/ND<50/<50ND/ND>6/>6NDR,Ne,N,PND
Reichard et al. 1996 (40)Poor MC/good MC48/43NDND/ND8.3 ± 1/7.2 ± 0.6ND/NDNDRND
Hershey et al. 1997 (29)Sev hy/no sev hy26/12ND/ND26.2 ± 6.6/22.8 ± 7.7ND/ND>5/>5<14R,NE
Kramer et al. 1998 (30)
    HypoglycemiaSev hy/no sev hy55/5335/5738 ± 14/34 ± 127 ± 1.6/6.9 ± 1.317.6 ± 11.6/10.8 ± 10.620/23H,N,RP,NeA
    MCHbA1c >6.5/HbA1c <6.5ND/NDND/NDND/NDND/NDND/ND>16H,N,RP,NeA
Snoek et al. 1998 (31)Sev hy/no sev hy9/936.9 ± 6.7/36.9 ± 6.77.4/7.413.4/13.424/27PA,S
Howorka et al. 2000 (41)Sev hy/no sev hy13/1446/3636.1 ± 10.2/36.1 ± 107.6 ± 1/7.3 ± 1.216.7 ± 7.4/15.6 ± 8.619/20RP,CV,N,CIA,S
Strachan et al. 2000 (42)IHA/NHA20/2065/6036.4 ± 14.7/34 ± 12.58.3 ± 1.3/10 ± 1.715.5 ± 7.6/13 ± 8.220/21NDPA,S
Ferguson et al. 2003 (8)R/no R25/4650/4031.5 ± 6/26.4 ± 4.68.9 ± 1.3/8.4 ± 1.221.6 ± 5.9/17 ± 4.610/9HyN,Ne,H,PND
  • Data are means ± SD, unless otherwise indicated. A, age; CI, cardiac insufficiency; Compl, diabetes complications; DL, dyslipidemia; E, education; Gluc, hypoglycemia prevented during testing; H, hypertension or hypertensive treatment; Hy, severe hypoglycemic episodes; IHA, impaired awareness of hypoglycemia; MC, metabolic control; N, neuropathy; ND, not specifically defined; Ne, nephropathy and/or microalbuminuria; NHA, normal awareness of hypoglycemia; O, occupation; P, psychiatric problems and/or use of psychoactive drugs and/or addiction to alcohol or other substances; R, retinopathy; S, sex; SES, socioeconomic status; Sev hy, episodes of severe hypoglycemia; Vis imp, visually impaired.