TABLE 2

Adjusted risk reduction (95% CI) with intensive versus conventional treatment in the combined primary and secondary cohorts of the DCCT; the likelihood ratio χ2 test statistic values, P values, and R2 values for the group effect; and the percentage of the group χ2 value explained by the log of the current mean A1C

Risk reduction (%) (95% CI)χ2 testPR2% Explained by A1C
Retinopathy*
    Single three-step progression57 (48–65)78.3<0.00015.395.8
    Sustained three-step progression73 (65–80)96.7<0.00016.696.2
    SNPDR64 (42–77)21.0<0.00011.499.9
    Any laser61 (34–77)13.60.00030.999.5
    CSME29 (−5 to 52)3.00.0840.299.9
Nephropathy
    Microalbuminuria40 (23–53)16.2<0.00011.199.2
    Albuminuria59 (28–77)10.00.00160.796.7
Neuropathy at 5 years§68 (50–80)27.8<0.00013.991.8
  • * From a relative risk (hazards) estimate in a PH model stratified by the ETDRS level of retinopathy at baseline and adjusted for the pre-DCCT glycemic exposure represented by the preexisting duration of diabetes separately for the primary and secondary cohorts and the level of log(A1C) on eligibility screening.

  • From a PH model adjusted for primary vs. secondary cohort on entry, the log(AER) on entry, and the pre-DCCT glycemic exposure. Microalbuminuria is AER >40 mg/24 h, albuminuria AER >300 mg/24 h.

  • Subjects with microalbuminuria on entry deleted from analysis.

  • § From an OR in a logistic regression of odds, adjusted for primary vs. secondary cohort and the pre-DCCT glycemic exposure represented by the preexisting duration of diabetes separately for the primary and secondary cohorts, and the level of log(A1C) on eligibility screening. CSME, clinically significant macular edema; SNPDR, severe nonproliferative diabetic retinopathy.