Table 3. Incidence of Further 3-Step Progression of Retinopathy and PDR Between DCCT Closeout and EDIC Year 10 Stratified by the Level of Retinopathy at DCCT Closeout.
| Further 3-Step Progression |
PDRa |
|||||||
|---|---|---|---|---|---|---|---|---|
| Retinopathy Level at DCCT Closeout | No. at Riskb | No. With Event | Adjusted Hazard Reductionc(95% CI), % | P Valued | No. at Riske | No. With Event | Adjusted Hazard Reductionc (95% CI), % | P Valued |
| All levels | 1349 | 53 (43 to 61) | <.001 | 1314 | 56 (37 to 70) | <.001 | ||
| Intensive therapy | 681 | 187 | 666 | 45 | ||||
| Conventional therapy | 668 | 322 | 648 | 121 | ||||
| Stratum 1: no retinopathy | 47 (26 to 62) | <.001 | 72 (42 to 87) | .001 | ||||
| Intensive therapy | 194 | 71 | 194 | 1 | ||||
| Conventional therapy | 123 | 68 | 122 | 2 | ||||
| Stratum 2: microaneurysm only | 63 (47 to 74) | <.001 | ||||||
| Intensive therapy | 274 | 53 | 273 | 9 | ||||
| Conventional therapy | 219 | 87 | 219 | 20 | ||||
| Stratum 3: mild non-PDR | 58 (34 to 73) | <.001 | 58 (19 to 78) | .009 | ||||
| Intensive therapy | 148 | 31 | 148 | 15 | ||||
| Conventional therapy | 200 | 83 | 199 | 40 | ||||
| Stratum 4: moderate or severe non-PDR | 40 (9 to 60) | .02 | 39 (-3 to 64) | .06 | ||||
| Intensive therapy | 65 | 32 | 50 | 20 | ||||
| Conventional therapy | 126 | 84 | 104 | 59 | ||||
Abbreviations: CI, confidence interval; DCCT, Diabetes Control and Complications Trial; EDIC, Epidemiology of Diabetes Interventions and Complications; PDR, proliferative diabetic retinopathy.
For PDR, strata 1 and 2 were combined in stratified analysis and in adjustment for all-levels-combined analysis because of the low event rate in these 2 strata.
The sample size for all levels is the same as in Figure 2A (n = 1349), based on all EDIC evaluations in all subjects, including those at EDIC years 4 and 10 and those in a quarter of these subjects at other EDIC years, among those patients who were free of scatter photocoagulation during DCCT.
The Weibull model was performed for each stratum and for all levels combined after adjustment for primary/secondary cohort, glycated hemoglobin value at entry to the DCCT, and diabetes mellitus duration at DCCT baseline. Analysis of all levels combined was also adjusted for the level of retinopathy at the end of the DCCT. Hazard reduction is for intensive therapy as compared with conventional therapy.
P values were based on the Wald χ2 test from the Weibull model.
The sample size for all levels is the same as in Figure 3A (n = 1314), based on all EDIC evaluations in all subjects, including those at EDIC years 4 and 10 and those in a quarter of these subjects at other EDIC years, among those patients who were free of PDR during DCCT. Among the 1314, 5 patients who did not have retinopathy evaluation at DCCT closeout were excluded from the stratified analysis.