The Association Between Red Blood Cell Distribution Width and the Severity of Diabetic Chronic Kidney Disease

Figures & data

Table 1 Groups of Diabetic CKD

Stage	Kidney Damage	eGFR
Stage 1 (G1)	Yes	≥90
Stage 2 (G2)	Yes	60–89
Stage 3–4 (G3a, G3b, G4)	Yes or no	15–59

Notes: Kidney damage mainly refers to albuminuria (urinary albumin/creatinine ratio ≥ 30mg/g), but also includes hematuria, other abnormal urine sediments, imaging or pathological abnormalities, etc.

Abbreviations: diabetic CKD, diabetic chronic kidney disease; eGFR, estimated glomerular filtration rate.

Table 2 Comparison Among the Three Groups in Demographic Data

Variables	Total (n = 396)	Stage 1 (n = 163)	Stage 2 (n = 138)	Stage 3–4 (n = 95)	Statistics	P
Age, years, Mean ± SD	61.17 ± 13.11	55.07 ± 13.23	64.59 ± 11.14	66.66 ± 11.29	F = 36.102	<0.001
Gender, n (%) (male)	190 (47.98)	66 (40.49)	75 (54.35)	49 (51.58)	χ^2= 6.398	0.041
BMI, kg/m^2, Mean ± SD	24.49 ± 3.71	24.88 ± 4.09	23.98±3.37	24.55 ± 3.44	F = 2.242	0.108
Duration of diabetes, month M (Q1, Q3)	96.00(36.00, 120.00)	60.00(6.00, 120.00)	120.00(60.00, 168.00)	120.00(60.00, 120.00)	χ^2= 39.470	<0.001
Drinking history, n (%) (yes)	10 (2.53)	6 (3.68)	4 (2.90)	0 (0.00)	–	0.159
Smoking history, n (%) (yes)	36 (9.09)	20 (12.27)	13 (9.42)	3 (3.16)	χ^2= 6.058	0.048
Systolic blood pressure, mmHg, Mean ± SD	145.33 ± 21.13	142.14 ± 19.30	147.21 ± 20.60	148.07 ± 24.18	F = 3.241	0.040
Diastolic blood pressure, mmHg, Mean ± SD	84.04 ± 11.17	85.34 ± 11.42	82.78 ± 10.46	83.66 ± 11.62	F = 2.047	0.130

Abbreviations: – refers to Fisher; Mean ± SD, mean ± standard deviation.

Table 3 Comparison Among the Three Groups in Laboratory Measurements

Variables	Total (n = 396)	Stage 1 (n = 163)	Stage 2 (n = 138)	Stage 3–4 (n = 95)	Statistics	P
Laboratory indicators
RDW, %, Mean±SD	13.39 ± 1.27	13.04 ± 1.34	13.52 ± 1.08	13.78 ± 1.25	F = 12.156	<0.001
FBG, mmol/L, M (Q1, Q3)	9.85 (7.18,12.85)	10.65 (7.84,13.78)	10.17 (6.86,12.87)	8.23 (5.93,10.76)	χ^2= 19.012	<0.001
HbAlc, %, Mean ± SD	9.61 ± 2.32	10.10 ± 2.30	9.62 ± 2.21	8.75 ± 2.30	F = 10.606	<0.001
TC, mmol/L, Mean ± SD	4.91 ± 1.41	4.90 ± 1.47	4.91 ± 1.32	4.94 ± 1.47	F = 0.024	0.976
TG, mmol/L, M (Q1, Q3)	1.64 (1.17,2.41)	1.68 (1.20,2.76)	1.61 (1.17,2.32)	1.61 (1.08,2.37)	χ^2= 1.588	0.452
UA, umol/L, Mean ± SD	335.33 ± 108.60	289.09 ± 85.60	335.27 ± 95.69	414.76 ± 116.20	F = 50.193	<0.001
CRP, mg/L, M (Q1, Q3)	3.26 (1.39,8.16)	2.93 (1.19,6.83)	3.46 (1.50,9.74)	3.90 (1.48,10.71)	χ^2= 3.822	0.148
History of drug use
RAAS inhibitor, n (%) (yes)	130 (32.83)	42 (25.77)	49 (35.51)	39 (41.05)	χ^2= 7.049	0.029
Insulin, n (%) (yes)	307 (77.53)	126 (77.30)	101 (73.19)	80 (84.21)	χ^2= 3.931	0.140
Statins, n (%) (yes)	198 (50.00)	82 (50.31)	72 (52.17)	44 (46.32)	χ^2= 0.783	0.676
Antiplatelet drugs, n (%) (yes)	147 (37.12)	53 (32.52)	53 (38.41)	41 (43.16)	χ^2= 3.062	0.216
Antihypertensive drugs, n (%) (yes)	160 (40.40)	49 (30.06)	62 (44.93)	49 (51.58)	χ^2= 13.341	0.001

Abbreviations: - refers to Fisher; Mean ± SD, mean ± standard deviation; RDW, red cell distribution width; FBG, fasting blood glucose; HbAlc, glycosylated hemoglobin; TC, total cholesterol; TG, triglycerides; UA, blood uric acid; CRP, C-reactive protein; RAAS, renin-angiotensin-aldosterone-system.

Figure 1 Violin plot of RDW for three groups. ***P<0.001.

Figure 2 Correlation coefficient heat map. *P < 0.1, **P < 0.05, ***P < 0.001 (CKD represents the severity of kidney disease).

Abbreviations: RDW, red blood cell distribution width; UA, blood uric acid; GLU, glucose; HbAlc, glycosylated hemoglobin; TC, total cholesterol; TG, triglycerides; CRP, C-reactive protein; diabetic CKD, diabetic chronic kidney disease.

Figure 3 Scatter plot matrix of laboratory measurements.

Figure 4 Multivariate ordinal logistic regression.

Abbreviations: RDW, red blood cell distribution width; UA, blood uric acid; SBP, systolic pressure; GLU, glucose; HbAlc, glycosylated hemoglobin; CRP, C-reactive protein; RAAS, renin–angiotensin–aldosterone system; OR, odds ratio; CI, confidence interval.

Figure 5 Multivariate ordinal logistic regression for subgroups (duration of diabetes).

Abbreviations: RDW, red blood cell distribution width; UA, blood uric acid; SBP, systolic pressure; GLU, glucose; HbAlc, glycosylated hemoglobin; CRP, C-reactive protein; RAAS, renin–angiotensin–aldosterone system; OR, odds ratio; CI, confidence interval.

Figure 6 Multivariate ordinal logistic regression for subgroups (HbA1c).

Abbreviations: RDW, red blood cell distribution width; UA, blood uric acid; SBP, systolic pressure; GLU, glucose; HbAlc, glycosylated hemoglobin; CRP, C-reactive protein; RAAS, renin–angiotensin–aldosterone system; OR, odds ratio; CI, confidence interval.