Fig 1.
Description of study participants.
A total of 2,197 adult DM patients who visited ophthalmologic clinic at Kangnam Sacred Heart Hospital was screened. Among them, 17 patients were type 1 DM, 49 did not received retinal exam, 8 was diagnosed as hypertensive retinopathy, 6 already was blind, 6 had artificial eyes, and 1 had retinal vein occlusion. Another 400 patients were not available for serial renal function data over 1 year and 118 subjects were already in the advanced stage of chronic kidney disease (stage 4 and 5). Therefore, after excluding 605 patients, a total of 1,592 subjects were included in the final analysis for renal outcome.
Table 1.
Baseline characteristics of the subjects classified by diabetic retinopathy.
Fig 2.
Annual renal function decline rate according to initial diabetic retinopathy status.
To exclude the effect of baseline renal function upon future renal function decline rate, we performed subgroup analysis according to baseline CKD stages based on eGFR. In CKD stage 1 (n = 517), patients with NPDR and PDR at baseline showed faster decline of renal function compared to those without DR (-3.2±6.44 and -4.16±5.43 vs. -0.83±3.48 mL/min/1.73m2/year, p<0.001). The patients with NPDR and PDR with baseline CKD stages 2 (n = 797), 3a (n = 188), and 3b (n = 90) showed decline in renal function during follow up (-1.91±5.71, -0.53±4.25 and -2.3±3.34 mL/min/1.73m2 per year for NPDR and -3.97±6.08, -2.58±5.71 and -2.89±9.19 mL/min/1.73m2 per year for PDR) while those without DR showed preserved renal function during follow-up (0.47±3.22, 1.24±3.91 and 0.5±4.34 mL/min/1.73m2 per year, p<0.001). eGFR, estimated glomerular filtration rate; CKD, chronic kidney disease; DR, diabetic retinopathy; NPDR, non-proliferative diabetic retinopathy; PDR, proliferative diabetic retinopathy.
Fig 3.
Proportion of the subjects with CKD progression according to initial diabetic retinopathy status.
CKD progression was defined by one or more of the following: 1) decline in GFR category (≥90 [G1], 60–89 [G2], 45–59 [G3a], 30–44 [G3b], 15–29 [G4], <15 [G5] mL/min/1.73m2) accompanied by a 25% or greater drop in eGFR from baseline, 2) sustained decline in eGFR of more than 5 mL/min/1.73m2/year. The proportion of the subjects with CKD progression increased as DR severity increased (9.5 vs. 29.9 vs. 49.5%, p<0.001). GFR, glomerular filtration rate; DR, diabetic retinopathy; NPDR, non-proliferative diabetic retinopathy; PDR, proliferative diabetic retinopathy.
Table 2.
Risk factors associated with CKD progression.
Fig 4.
Proportion of the subjects with albuminuria progression according to initial diabetic retinopathy status.
Albuminuria progression was defined by one or more step progression in albuminuria (normo-albuminuria (UACR < 30mg/g) to micro-albuminuria (30mg/g ≤ UACR < 300 mg/g) or macro-albuminuria (UACR ≥ 300 mg/g), micro-albuminuria to macro-albuminuria) during follow-up. The proportion of the subjects with albuminuria progression increased as DR severity increased (14.4% vs. 27.1% vs. 43.5%, p<0.001). DR, diabetic retinopathy; NPDR, non-proliferative diabetic retinopathy; PDR, proliferative diabetic retinopathy.
Table 3.
Risk factors associated with albuminuria progression.
Table 4.
Binary logistic regression analysis for CKD progression.
Table 5.
Multiple logistic regression analysis for prediction of CKD progression.