Potential Role and Expression Level of Urinary CXCL8 in Different Stages of Incipient Diabetic Nephropathy with Undiminished Creatinine Clearance: A Pilot Study

Figures & data

Figure 1 Flowchart of the enrollment and grouping of the patients.

Abbreviations: DN, diabetic nephropathy; eGFR, estimated glomerular filtration rate; UACR, urinary albumin-to-creatinine ratio.

Table 1 Demographic, Clinical and Laboratory Characteristics of Patients in Different Stages of Incipient DN

	Non-DN Group (n=22)	Hyperfiltration Group (n=21)	Microalbuminuria Group (n=16)	Overt DN Group (n=29)	P-Value
Age (years)	60.09±8.19	55.14±11.57	62.94±10.66	62.00±12.96	0.12
Gender, n (% of female)	9 (40.9)	6 (28.6)	7 (43.8)	18 (62.1)	0.119
BMI (kg/m^2)	25.55±2.42	25.79±4.11	24.82±2.58	26.44±3.71	0.49
Waist circumference (cm)	89.80±8.96	90.65±9.43	87.08±7.25	91.32±11.64	0.663
Smoking history, n (% of yes)	9 (42.9)	10 (47.6)	5 (31.2)	4 (13.8)	0.09
Diabetes course (years)	8.00 [3.00, 14.75]	5.00 [1.00, 10.00]	16.50 [5.00, 20.25]	11.00 [7.00, 20.00]	0.025
Family history of diabetes, n (% of yes)	10 (50.0)	10 (50.0)	7 (46.7)	13 (44.8)	0.98
History of stroke, n (% of yes)	5 (23.8)	3 (14.3)	3 (18.8)	7 (25.0)	0.803
Hypertension, n (% of yes)	9 (42.9)	12 (57.1)	10 (62.5)	18 (64.3)	0.472
Oral ACEI/ARB, n (% of yes)	6 (27.3)	4 (19.0)	1 (6.2)	9 (31.0)	0.258
HbA1c (%)	8.38±1.82	8.96±2.00	9.33±2.05	8.54±1.78	0.48
Serum creatinine (μmol/L)	65.22±10.52	53.55±7.88	64.29±8.56	75.25±17.13	<0.001
Cystatin C (mg/L)	1.05±0.14	0.94±0.18	1.10±0.24	1.22±0.26	0.001
CRP (mg/L)	2.05±2.12	3.17±3.93	3.95±5.98	4.10±3.79	0.652
LDL-c (mmol/L)	2.53±0.78	2.94±1.18	2.86±1.03	2.79±0.95	0.551
UACR (mg/g)	7.57±4.95	8.30±4.21	58.87±77.65	123.41±165.25	<0.001
eGFR (mL/min·1.73 m^2)	103.82±7.54	138.47±17.92	103.36±8.35	84.91±17.21	<0.001
uCXCL8 (pg/μmol Cr)	3.11±4.13	1.40±1.01	5.01±4.01	4.41±4.60	0.017

Notes: The non-DN group included patients with UACR <30 mg/g and 90≤ eGFR <120 mL/min·1.73 m²; the hyperfiltration group included patients with UACR <30 mg/g and eGFR ≥120 mL/min·1.73 m²; the microalbuminuria group included patients with 30≤ UACR <300 mg/g and 90≤ eGFR <120 mL/min·1.73 m²; and the overt DN group included patients with UACR ≥300 mg/g or 60≤ eGFR <90 mL/min·1.73 m².

Abbreviations: BMI, body mass index; ACEI/ARB, angiotensin-converting enzyme inhibitors or angiotensin receptor blockers; Hb_A1c, glycosylated hemoglobin A1c; CRP, C-reactive protein; LDL-c, low-density lipoprotein cholesterol; UACR, urinary albumin-to-creatinine ratio; eGFR, estimated glomerular filtration rate; uCXCL8, urinary CXCL8; Cr, creatinine.

Figure 2 Urinary CXCL8 expression in different stages of incipient diabetic nephropathy.

Note: *P<0.05 in the post-hoc analysis.

Abbreviations: DN, diabetic nephropathy; uCXCL8, urinary CXCL8.

Table 2 Correlations Between uCXCL8 and Other Clinical and Laboratory Parameters in DN

	r	P-Value
Age	0.219	0.040
Gender	0.193	0.071
Body mass index	−0.006	0.952
Waist circumference	0.059	0.615
Smoking history	−0.21	0.051
Diabetes course	0.213	0.046
Family history of diabetes	−0.04	0.716
History of stroke	−0.018	0.866
Hypertension	0.074	0.497
Oral ACEI/ARB	0.053	0.621
HbA1c	0.058	0.620
Serum creatinine	0.055	0.610
Cystatin C	0.337	0.004
C-reactive protein	0.113	0.478
LDL-c	0.047	0.665
UACR	0.233	0.031
eGFR	−0.292	0.006

Abbreviations: ACEI/ARB, angiotensin-converting enzyme inhibitors or angiotensin receptor blockers; Hb_A1c, glycosylated hemoglobin A1c; LDL-c, low-density lipoprotein cholesterol; UACR, urinary albumin-to-creatinine ratio; eGFR, estimated glomerular filtration rate.

Table 3 Crude and Adjusted Analyses of Relationships Between uCXCL8 and Classic DN in Regression Analysis

	Crude OR (95% CI)	Crude P-Value	Adjusted OR (95% CI)	Adjusted P-Value
uCXCL8	1.23 (1.03, 1.47)	0.023	1.17 (0.98, 1.4)	0.045
Age	1.03 (0.99, 1.08)	0.170	0.98 (0.93, 1.04)	0.513
Diabetes course	1.07 (1.01, 1.14)	0.026	1.06 (0.98, 1.14)	0.139
Cystatin C	88.02 (5.51, 1406.59)	0.002	41.73 (2.39, 728.11)	0.004

Abbreviations: uCXCL8, urinary CXCL8; OR, odds ratio; CI, confidence interval.