Table 2

Risk predictions for the different risk groups as determined by the Icelandic and Gloucester models and referable diabetic retinopathy (RDR) events observed in the Diabetes Watch programme cohort during the study period

ModelRisk groupNumber in risk groupNumber of eventsRate of progression to RDR (per 1000 PYs)Exposure time (PYs)
Icelandic (score quintile)118835.6537
218835.2581
318858.3601
418869.4636
51872340.0576
Gloucester model using 2 DR gradings only (risk groups)A819207.72585
D581380.0162
E20232.861
F400.011
G20344.468
H700.021
I11288.223
Gloucester model using 2 DR gradings and systemic variables and diabetes duration (score quintile)118823.4582
218847.3546
318858.8570
41881016.0626
51871931.3606
Gloucester model using 1 DR grading and systemic variables (score quintile)118823.6557
218847.1562
318846.9577
418869.3649
51872441.1584
  • For completeness, group B=R1 in the first screening in one eye and R0 in both eyes in the second screening; group C=R1 in the first screening in both eyes and R0 in both eyes in the second screening.

  • Risk groups A=no DR in both eyes in first and second screenings; D=no DR in first screening, background DR in second screening in one eye; E=background DR in one eye in first and second screenings; F=background DR in both eyes in first screening, background DR in one eye only in second screening; G=R0 in both eyes in first screening; R1 in both eyes in second screening; H=background DR in one eye in first screening, background DR in both eyes in second screening; I=background DR in both eyes in first and second screenings.

  • PY, patient-year.