Study on correlation between serum uric acid level and brachial ankle pulse wave velocity in patients with systemic lupus erythematosus

Objective To investigate the relationship between serum uric acid (UA) level and brachial-ankle pulse wave velocity (baPWV) in patients with systemic lupus erythematosus (SLE) and lupus nephritis (LN). Methods A total of 110 hospitalized, out-patient and healthy examinees from January 2017 to September 2017 were selected from Kailuan General Hospital.They were divided into three groups: (1)Fifty-five healthy controls were examined at the same time, and those who had no history of hypertension, myocardial infarction and stroke were excluded by physical examination.(2)Thirty-four SLE patients without LN were diagnosed according to the SLE classification standard revised by the American Society of Rheumatology (ACR) in 1997, excluding those with lupus nephritis.(3)21 SLE patients with LN were diagnosed according to the SLE classification standard revised by the American Society of Rheumatology (ACR) in 1997.Pearson correlation coefficient and multivariate linear regression model were used to analyze the related factors affecting baPWV. Results The level of baPWV and the proportion of baPWV (≥1400 cm/s) in SLE without LN group and SLE with LN group were higher than those in healthy control group (all P<0.05). In SLE without LN group, baPWV was positively correlated with age, systolic blood pressure(SBP)and total cholesterol(CHOL)(r=0.623, 0.528, 0.402, P<0.01 or P<0.05), and negatively correlated with blood uric acid(UA) (r=-0.371, P<0.05), but the correlation was not significant.The correlation between UA and baPWV disappeared after after correction of age, SBP, diastolic blood pressure (DBP) by partial correlation analysis.In SLE with LN group, baPWV was positively correlated with SBP, DBP and serum creatinine(Cr) (r=0.815, 0.725, 0.464, P<0.01 or P<0.05). Multivariate stepwise regression analysis showed that SBP was independently correlated with baPWV in SLE group (t=2.54, P=0.026); UA in SLE group without LN was independently negatively correlated with baPWV(t=-2.96, P=0.042); UA(t=4.24, P=0.013) and SBP(t=7.70, P=0.002) were independently positively correlated with baPWV in SLE group with LN.Logistic regression analysis showed that SLE was a risk factor for baPWV (≥1 400 cm/s), and the OR (95% CI) was 4.31 (1.56-11.88), P=0.005, and there was statistical significance after adjusting for age, SBP, DBP, body mass index (BMI). However, UA was not a risk factor for baPWV (≥ 1 400 cm/s) (P values were 0.163 and 0.519, respectively). Conclusion The degree of arteriosclerosis in SLE patients is higher than that in normal subjects, and the level of UA in SLE patients may be related to baPWV. Key words: Systemic lupus erythematosus; Lupus nephritis; Blood uric acid; Brachial-ankle pulse wave velocity