Prediction model for rapid estimated glomerular filtration rate decline in type 2 diabetes mellitus

Table 1 Comparison of baseline characteristics between rapid and non-rapid estimated glomerular filtration rate decline groups, n (%)

Characteristic	Total (n = 302)	Rapid decline group (n = 89)	Non-rapid decline group (n = 213)	Statistical value	P value
Demographics
Age (year), mean ± SD	58.7 ± 10.3	62.3 ± 9.8	57.1 ± 10.2	t = 3.912	< 0.001
Male	174 (57.6)	52 (58.4)	122 (57.3)	χ2 = 0.035	> 0.05
Diabetes duration (years), mean ± SD	9.2 ± 5.8	11.8 ± 6.2	8.1 ± 5.3	t = 4.783	< 0.001
Follow-up time (years), mean ± SD	2.5 ± 0.8	2.6 ± 0.7	2.5 ± 0.8	t = 0.952	> 0.05
Renal function parameters
Baseline eGFR (mL/minute/1.73 m2), mean ± SD	72.1 ± 19.6	58.4 ± 15.7	78.6 ± 18.3	t = 8.745	< 0.001
UACR (mg/g), median (P25, P75)	98.3 (28.5, 412.7)	368.5 (125.3, 892.6)	45.2 (18.7, 156.3)	Z = 7.821	< 0.001
Metabolic parameters
HbA1c (%), mean ± SD	7.8 ± 1.5	8.7 ± 1.6	7.4 ± 1.2	t = 6.892	< 0.001
Serum uric acid (μmol/L), mean ± SD	387.3 ± 81.5	428.6 ± 82.3	368.5 ± 75.4	t = 5.632	< 0.001
Hemoglobin (g/L), mean ± SD	127.4 ± 17.2	115.8 ± 16.4	132.5 ± 14.8	t = 8.124	< 0.001
Blood pressure
Systolic blood pressure (mmHg), mean ± SD	138.2 ± 17.4	145.8 ± 18.2	134.6 ± 15.7	t = 4.982	< 0.001
Medication use
RAAS inhibitor use	194 (64.2)	47 (52.8)	153 (71.8)	χ2 = 9.876	0.002
SGLT-2 inhibitor use	131 (43.4)	28 (31.5)	103 (48.4)	χ2 = 6.892	0.009

Continuous variables with normal distribution are presented as mean ± SD and compared using independent samples t-test. Skewed data are presented as median (P25, P75) and compared using Mann-Whitney U test. Categorical variables are presented as n (%) and compared using χ² test. eGFR: Estimated glomerular filtration rate; UACR: Urine albumin-to-creatinine ratio; HbA1c: Hemoglobin A1c; RAAS: Renin-angiotensin-aldosterone system; SGLT-2: Sodium-glucose cotransporter-2.

Table 2 Univariate analysis of risk factors for rapid estimated glomerular filtration rate decline, n (%)

Risk factors	Rapid decline (n = 89)	Non-rapid decline (n = 213)	χ2 value	P value
Age
≥ 60 years	58 (65.2)	96 (45.1)	15.32	< 0.001
< 60 years	31 (34.8)	117 (54.9)
Diabetes duration
≥ 10 years	54 (60.7)	82 (38.5)	18.76	< 0.001
< 10 years	35 (39.3)	131 (61.5)
HbA1c control
≥ 8.0%	52 (58.4)	56 (26.3)	32.45	< 0.001
< 8.0%	37 (41.6)	157 (73.7)
Baseline eGFR
< 60 mL/minute/1.73 m2	64 (71.9)	72 (33.8)	41.28	< 0.001
≥ 60 mL/minute/1.73 m2	25 (28.1)	141 (66.2)
UACR
≥ 300 mg/g	58 (65.2)	48 (22.5)	52.36	< 0.001
< 300 mg/g	31 (34.8)	165 (77.5)
Systolic blood pressure
≥ 140 mmHg	58 (65.2)	84 (39.4)	22.15	< 0.001
< 140 mmHg	31 (34.8)	129 (60.6)
Diastolic blood pressure
≥ 90 mmHg	38 (42.7)	62 (29.1)	8.47	0.004
< 90 mmHg	51 (57.3)	151 (70.9)
Hyperuricemia
Yes	56 (62.9)	68 (31.9)	26.83	< 0.001
No	33 (37.1)	145 (68.1)
Anemia
Yes	62 (69.7)	68 (31.9)	31.54	< 0.001
No	27 (30.3)	145 (68.1)
Hypoalbuminemia
Yes	34 (38.2)	48 (22.5)	12.65	< 0.001
No	55 (61.8)	165 (77.5)
History of hypertension
Yes	72 (80.9)	142 (66.7)	9.82	0.002
No	17 (19.1)	71 (33.3)
History of coronary heart disease
Yes	28 (31.5)	42 (19.7)	7.31	0.007
No	61 (68.5)	171 (80.3)
RAAS inhibitor use
Non-use	42 (47.2)	60 (28.2)	11.73	0.001
Use	47 (52.8)	153 (71.8)
SGLT-2 inhibitor use
Non-use	61 (68.5)	110 (51.6)	8.95	0.003
Use	28 (31.5)	103 (48.4)

Hyperuricemia: Serum uric acid ≥ 420 μmol/L (males) or ≥ 360 μmol/L (females); anemia: Hemoglobin < 130 g/L (males) or < 120 g/L (females). HbA1c: Hemoglobin A1c; eGFR: Estimated glomerular filtration rate; UACR: Urine albumin-to-creatinine ratio; RAAS: Renin-angiotensin-aldosterone system; SGLT-2: Sodium-glucose cotransporter-2.

Table 3 Comparison with established diabetic kidney disease risk prediction models

Performance metric	Our nomogram	KFRE-8	KFRE-4	KDIGO stratification
Discrimination
AUC (95%CI)	0.876 (0.836-0.916)	0.811 (0.769-0.853)	0.782 (0.738-0.826)	0.758 (0.713-0.803)
P value (vs nomogram)	-	0.018	0.002	< 0.001
Sensitivity (%)	81.5	73.0	68.5	61.8
Specificity (%)	79.8	76.1	74.6	78.4
Reclassification
NRI	-	0.312 (< 0.001)	0.428 (< 0.001)	-
IDI	-	0.089 (< 0.001)	0.156 (< 0.001)	-
Calibration
Hosmer-Lemeshow χ²	6.34	11.28	15.76	18.92
P value	0.61	0.19	0.046	0.015
Clinical utility
Net benefit (30% threshold)	0.31	0.18	0.14	0.09

CI: Confidence interval; KFRE: Kidney failure risk equation; KDIGO: Kidney Disease: Improving Global Outcomes; AUC: Area under the curve; NRI: Net reclassification improvement; IDI: Integrated discrimination improvement.