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Abstract: PO1566

Obesity at Time of Diagnosis Is Associated with Proteinuria in Glomerular Disease

Session Information

Category: Glomerular Diseases

  • 1203 Glomerular Diseases: Clinical, Outcomes, and Trials

Authors

  • Zeitler, Evan, UNC Kidney Center, Chapel Hill, North Carolina, United States
  • Hu, Yichun, UNC Kidney Center, Chapel Hill, North Carolina, United States
  • Poulton, Caroline J., UNC Kidney Center, Chapel Hill, North Carolina, United States
  • Blazek, Lauren N., UNC Kidney Center, Chapel Hill, North Carolina, United States
  • Mottl, Amy K., UNC Kidney Center, Chapel Hill, North Carolina, United States
  • Flythe, Jennifer E., UNC Kidney Center, Chapel Hill, North Carolina, United States
  • Hogan, Susan L., UNC Kidney Center, Chapel Hill, North Carolina, United States
Background

Obesity is an established risk factor for chronic kidney disease (CKD). The relationship between obesity and glomerular disease outcomes is not well studied.

Methods

We evaluated a cohort of adult patients with biopsy-proven IgA nephropathy, focal segmental glomerulosclerosis (FSGS), ANCA-associated vasculitis (ANCA), or membranous nephropathy (MN) between January 2014 and June 2020, with follow up through April 2021. We categorized body mass index (BMI) at time of biopsy as <25 kg/m2, 25 kg/m2≥BMI<30 kg/m2 or ≥30 kg/m2. We used Fisher's exact and Kruskal-Wallis tests to compare baseline characteristics between groups and a proportional hazards model to evaluate factors associated with CKD progression to kidney replacement therapy (KRT). We used the sign rank test to compare Kaplan-Meier curves of KRT-free survival.

Results

The cohort included 153 patients: 77 (50%) male with median age 50 (IQR 38-65) years and median BMI 28 (IQR 24-34) kg/m2. Compared to patients with lower BMIs, patients with BMI >25 kg/m2 had higher median urine protein to creatinine ratios (uPCR) (p=0.02, Table 1). In univariate analyses, factors associated with progression to KRT were: blood pressure (p = 0.01), uPCR (p <0.01), and lower eGFR (p<0.001). BMI at biopsy was not associated with CKD progression, adjusted HRs (95% CIs): BMI 25≥BMI<30 kg/m2 - 1.09 (0.42-2.83); BMI ≥30 kg/m2- 1.54 (0.68-3.52). Logrank p-value for KM curves was 0.004, with paired uPCR values imparting the greatest distinction between curves (data not shown).

Conclusion

Among glomerular disease patients, BMI was associated with proteinuria, but not with progression to KRT.

Baseline Characteristics Across BMI Groups
Baseline characteristic: median [IQR] or n (%)All
(N = 153)
BMI < 25
(n = 43)
BMI 25-30
(n = 42)
BMI ≥ 30
(n = 68)
p
Age (years)50
(38, 65)
50
(30, 72)
54
(42, 62)
49
(40, 62)
0.95
Male77 (50)18 (42)27 (64)32 (47)0.10
Race (self-reported)
Black
White
Other
-
39(26)
88(58 )
24(15)
(N = 151)
-
6 (14 )
29 (69)
7 (16 )
-
10 (23)
25(59)
7(16)
(n = 41)
-
23(34)
34 (50)
10 (14)
(n = 67)
0.22
Primary disease
ANCA
FSGS
IgAN
Membranous
-
54(35)
36(23)
42(27)
21(13)
-
21 (48)
7 (16)
13 (30)
2 (4)
-
14 (33)
11 (26)
8 (19)
9 (21)
-
19 (27)
18 (26)
21 (30)
10 (14)
0.10
Systolic BP (mmHg)134
(120, 145)
(N = 152)
131
(118, 142)
130
(122, 145)
138
(127, 149)
(n = 67)
0.14
Diastolic BP (mmHg)76.00
(70, 84)
(N = 152)
74.00
(68, 82)
75.00
(70, 82)
78.00
(72, 88)
(n = 67)
0.35
eGFR (ml/min/1.73m2)43
(19, 83)
46
(20, 82)
56
(21, 87)
38
(18, 75)
0.35
uPCR (g/g Cr)2.33
(1.0, 5.6)
(N = 151)
1.50
(0.6, 3.4)
(n = 42)
2.90
(1.1, 5.7)
3.40
(1.3, 7.9)
(n = 67)
0.02
uPCR (g/g Cr)
< 2
>= 2
-
67 (44)
84 (56)
(N = 151)
-
27 (65)
15 (35)
(n = 42)
-
16 (38)
26 (62)
-
24(36)
43(64)
(n = 67)
0.01
KRT during follow up42 (27)11 (26)11 (26)20 (29)0.92
Death during follow up11 (7)4 (9)1 (2)6 (9)0.41

Funding

  • NIDDK Support