Correlation between serum 25 (OH)D values and disease activity of the treatment na?ve systemic lupus erythematosus patients / 中华风湿病学杂志

ABSTRACT

Objective To explore the prevalence of vitamin D deficiency in the new onset and treatment-naive systemic lupus erythematosus (SLE) patients and study the correlation between serum 25(OH)D values and disease activity of SLE. Methods A retrospective case series analysis was done in 117 new-onset and treatment-na?ve SLE hospitalized patients during May 2016 and May 2017 in the Department of Rheumatology of the First Affiliated Hospital of Xi'an Jiaotong University and 39 age and gender matched healthy controls. Cinical and demographic details were collected. Disease activity of SLE was evaluated according to the systemic lupus erythematosus disease activity index (SLEDAI) score. The t-test, Mann-Whitney U test, Chi-square test, Spearman rank correlation coefficient test and multivariate linear regres sion were performed. Results Among the 117 SLE patients, 102 were female (87.2％) with the mean age of (36 ± 15) years. The median duration before diagnosis was 5(1, 12) months and the mean SLEDAI score was (12 ±7). The mean level of 25(OH)D was significantly lower in SLE patients [(10.1±6.0) ng/ml] than in healthy controls [(17 ±8) ng/ml, t=-5.273, P<0.01 ], and the prevalence of vitamin D deficiency was higher in SLE patients (109/117, 93.2％) than in healthy controls (28/39, 71.8％, x2=12.486, P<0.01). With 10 ng/ml as the cut-off point of serum 25 (OH)D, patients were divided into two groups. The percentages of haematological damage (84.3％ vs 66.0％, x2=5.321, P=0.021), lupus nephritis (32.9％ vs 14.9％, x2=4.759, P=0.029) and serositis (28.6％ vs 8.5％, x2=6.940, P=0.008), SLEDAI score [(13±8) vs (9±5), t=3.503, P=0.001)] and 24-hour urinary protein [(0.57±1.05) vs (0.21±0.46), t=2.437, P=0.017] were significantly higher in the 25 (OH)D<10 ng/ml group, but complement C3 [(0.5±0.3) g/L vs (0.7±0.3) g/L t=-2.441, P=0.016] and hemoglobin [(93±19) g/L vs (104 ±19) g/L, t=-3.052, P=0.003) were significantly lower in this group. The differences were statistically significant. SLEDAI score (r=-0.433, P=0.000), 24-hour urinary protein (r=-0.434, P=0.000)was significantly inversely correlated and complement C3 (r=0.296, P=0.001), hemoglobin (r=0.323, P=0.000) was significantly positively correlated with serum 25(OH)D level. There was an independent inverse correlation between SLEDAI score and serum 25(OH)D levels (β=-0.376, P=0.000). Conclusion The prevalence of vitamin D deficiency in the new-onset and treatment-naive systemic lupus erythematosus patients is significantly higher than that in healthy controls. There is an independent inverse correlation between serum 25 (OH)D values and disease activity of SLE.