Association between annual changes and visit-to-visit variability of serum uric acid and the kidney outcome in a general population

Figures & data

Table 1. Serum uric acid annual changes and variability in groups categorized by kidney outcomes.

	Non-rapid eGFR decline (N = 10,203)	Rapid eGFR decline (n = 535)	p Value	Non-CKD (N = 10,488)	CKD (N = 240)	p Value
Annual UA change (mg/dL/y)	−0.03 ± 0.37	0.19 ± 0.53	<.001	−0.02 ± 0.38	0.08 ± 0.55	.008
Mean UA (md/dL)	5.95 ± 1.37	6.55 ± 1.54	<.001	5.95 ± 1.36	7.19 ± 1.55	<.001
SD of UA (mg/dL)	0.89 ± 0.43	1.07 ± 0.62	<.001	0.90 ± 0.44	1.27 ± 0.68	<.001
CV of UA (%)	0.15 ± 0.07	0.16 ± 0.08	.002	0.15 ± 0.07	0.18 ± 0.08	<.001
VIM of UA	0.90 ± 0.39	0.99 ± 0.50	<.001	0.90 ± 0.39	1.10 ± 0.53	<.001
ARV of UA	1.08 ± 0.60	1.26 ± 0.79	<.001	1.08 ± 0.61	1.40 ± 0.80	<.001

Table 2. Baseline characteristics of each group categorized by serum uric acid SD quantiles.

SD of serum UA	Q1	Q2	Q3	Q4	p Value
N	2685	2684	2685	2684
Age (years)	47.43 ± 14.95	47.37 ± 14.67	48.65 ± 14.76	50.6 ± 14.82	<.001
Sex (male (%))	1193 (44.40)	1325 (49.37)	1488 (55.42)	1694 (66.11)	<.001
Albumin (g/L)	45.85 ± 2.42	45.80 ± 2.47	45.85 ± 2.44	45.77 ± 2.49	.552
Total protein (g/L)	75.75 ± 3.99	75.44 ± 3.91	75.4 ± 4.03	75.71 ± 4.05	.001
Hb (g/L)	138.38 ± 17.99	139.9 ± 18.11	140.92 ± 17.65	143.04 ± 17.29	<.001
FBG (mmol/L)	4.97 ± 1.16	4.93 ± 1.16	4.95 ± 1.22	5.09 ± 1.41	<.001
Cholesterol (mmol/L)	1.17 [0.81–1.76]	1.24 [0.85–1.81]	1.30[0.92–1.97]	1.51[1.03–2.28]	<.001
Triglycerides (mmol/L)	4.68 ± 1.13	4.72 ± 1.13	4.81 ± 1.13	4.97 ± 1.17	<.001
HDL-c (mmol/L)	1.34 ± 0.38	1.33 ± 0.37	1.33 ± 0.37	1.33 ± 0.36	.466
LDL-c (mmol/L)	1.98 ± 1.29	2.14 ± 1.25	2.15 ± 1.3	2.03 ± 1.41	<.001
UA (mg/dL)	5.35 ± 1.32	5.49 ± 1.38	5.71 ± 1.43	6.38 ± 1.81	<.001
Serum creatinine (μmol/L)	66.53 ± 13.94	68.05 ± 15.08	69.54 ± 15.15	71.01 ± 15.22	<.001
BUN (mmol/L)	5.22 ± 1.48	5.17 ± 1.39	5.24 ± 1.41	5.37 ± 1.39	<.001
eGFR (mL/min/1.73 m^2)	101.67 ± 14.14	101.24 ± 14.49	99.73 ± 14.33	97.96 ± 14.52	<.001
eGFR change (mL/min/1.73 m^2/year)	−0.63 ± 2.09	−0.70 ± 1.90	−0.72 ± 1.96	−0.93 ± 2.46	<.001
Serum UA change (mg/dL/year)	0.00 ± 0.17	−0.01 ± 0.26	−0.02 ± 0.35	−0.03 ± 0.61	.004
mean UA (md/dL)	5.43 ± 1.28	5.68 ± 1.24	6.01 ± 1.23	6.79 ± 1.37	<.001
SD of UA (mg/dL)	0.41 ± 0.14	0.73 ± 0.07	0.98 ± 0.08	1.49 ± 0.38	<.001
CV of UA (%)	0.08 ± 0.03	0.13 ± 0.03	0.17 ± 0.04	0.22 ± 0.06	<.001
VIM of UA	0.46 ± 0.18	0.78 ± 0.14	1.00 ± 0.17	1.37 ± 0.34	<.001
ARV of UA	0.52 ± 0.23	0.88 ± 0.24	1.17 ± 0.32	1.77 ± 0.68	<.001

Alb: albumin; BUN: blood urea nitrogen; Hb: hemoglobin; UA: uric acid; eGFR: estimated glomerular filtration rate; ARV: average real variability; CV: coefficient of variation; SD: standard deviation; VIM: variability independent of the mean.

Values for categorical variables are given as counts (%); values for continuous variables, as the mean ± standard deviation or median [interquartile range]. p Values represent differences across quartiles.

Table 3. Incidence rate of eGFR rapid decline or CKD with respect to quartiles of UA variability.

			eGFR rapid decline			CKD
	Quantiles		Events	Incidence rate	p Value	Events	Incidence rate	p Value
Annual UA change	Q1 (N = 2590)	−0.48 ± 0.30	95	3.50%	<.001	56	2.10%	<.001
	Q2 (N = 2620)	−0.11 ± 0.06	64	2.40%		45	1.70%
	Q3 (N = 2580)	0.09 ± 0.06	107	4.00%		45	1.70%
	Q4 (N = 2413)	0.44 ± 0.22	269	10.00%		94	3.50%
SD of UA	Q1 (N = 2571)	5.43 ± 1.28	114	4.20%	<.001	26	1.00%	<.001
	Q2 (N = 2579)	5.68 ± 1.24	105	3.90%		38	1.40%
	Q3 (N = 2565)	6.01 ± 1.23	120	4.50%		65	2.40%
	Q4 (N = 2488)	6.79 ± 1.37	196	7.30%		111	4.10%
CV of UA	Q1 (N = 2546)	0.07 ± 0.02	139	5.20%	.001	47	1.80%	<.001
	Q2 (N = 2571)	0.13 ± 0.01	113	4.20%		53	2.00%
	Q3 (N = 2570)	0.17 ± 0.01	115	4.30%		49	1.80%
	Q4 (N = 2516)	0.24 ± 0.05	168	6.30%		91	3.40%
VIM of UA	Q1 (N = 2551)	0.44 ± 0.15	139	5.20%	<.001	39	1.50%	<.001
	Q2 (N = 2584)	0.76 ± 0.07	113	4.20%		50	1.90%
	Q3 (N = 2560)	1.00 ± 0.07	115	4.30%		53	2.00%
	Q4 (N = 2508)	1.42 ± 0.30	168	6.30%		98	3.70%
ARV of UA	Q1 (N = 2570)	0.45 ± 0.15	115	4.30%	<.001	37	1.40%	<.001
	Q2 (N = 2571)	0.83 ± 0.09	114	4.20%		38	1.40%
	Q3 (N = 2563)	1.16 ± 0.11	121	4.50%		64	2.40%
	Q4 (N = 2499)	1.90 ± 0.57	185	6.90%		101	3.80%

Table 4. ORs for study outcomes associated with 1 − SD increase in level of UA variability.

	UA change	p Value	SD	p Value	CV	p Value	VIM	p Value	ARV	p Value
1 − SD change	0.38		0.45		0.07		0.40		0.61
eGFR rapid change
Crude, OR [95%CI]	1.80 [1.64, 1.97]	<.001	1.38 [1.28, 1.48]	<.001	1.17 [1.07, 1.27]	<.001	1.24 [1.14, 1.34]	<.001	1.28 [1.19, 1.38]	<.001
Model, OR [95%CI]
1	1.60 [1.46, 1.76]	<.001	1.19 [1.10, 1.29]	<.001	1.17 [1.08, 1.27]	<.001	1.18 [1.09, 1.27]	<.001	1.12 [1.04, 1.21]	.004
2	1.69 [1.53, 1.86]	<.001	1.17 [1.08, 1.27]	<.001	1.16 [1.06, 1.25]	.001	1.16 [1.07, 1.25]	<.001	1.10 [1.02, 1.19]	.014
CKD
Crude, OR [95%CI]	1.30 [1.14, 1.48]	<.001	1.72 [1.58, 1.88]	<.001	1.37 [1.22, 1.53]	<.001	1.50 [1.35, 1.66]	<.001	1.44 [1.31, 1.57]	<.001
Model, OR [95%CI]
1	1.08 [0.95, 1.21]	.231	1.29 [1.16, 1.44]	<.001	1.33 [1.19, 1.50]	<.001	1.31 [1.18, 1.47]	<.001	1.12 [1.01, 1.25]	.031
2	1.28 [1.12, 1.47]	<.001	1.34 [1.20, 1.49]	<.001	1.37 [1.21, 1.54]	<.001	1.35 [1.20, 1.51]	<.001	1.15 [1.03, 1.28]	.014

UA: uric acid; CI: confidence interval.

Model 1 further adjusted for sex, age, and mean UA; model 2 further adjusted for BUN, FBG, hemoglobin, total protein, albumin, triglyceride, cholesterol, HDL-c, and LDL-c.

Data availability statement

The datasets used and/or analyzed during the current study are available from the correspondence author on reasonable request.