Correlation between bone mineral density and neutrophil/lymphocyte ratio in patients with rheumatoid arthritis / 中华风湿病学杂志

ABSTRACT

Objective:To investigate the relationship between neutrophil/lymphocyte ratio (NLR) and bone mineral density (BMD) in rheumatoid arthritis (RA), and to evaluate its diagnostic value in RA with osteoporosis.Methods:134 RA patients and 69 healthy subjects were screened and NLR levels were compared between the two groups. Bone mineral density of lumbar L1-4 and femoral neck was measured by dual energy X-ray absorption (DXA), and the patients were divided into normal bone mass group (44 cases), reduced bone mass group (47 cases) and osteoporosis group (43 cases). Height, weight, course of disease, mean platelet volume, erythrocyte sedimentation rate (ESR), C-reactionprotein (CRP), complement C3, complement C4, rheumatoid factor (RF), anti-cyclic citrullinated peptide (anti-CCP) antibody, bone mineral density and other related indicators were recorded. The differences of NLR, body mass index(BMI) gender, age and other indicators among the three groups were compared by One-way Analysis of Variance (ANOVA) and Kruskal-Wallis test, or χ2 test. Correlation analysis was conducted to detect the correlation between NLR, bone mass and each indicator, and ordered multi-classification Logistic regression analysis was used to evaluate the im-pact of each indicator on osteoporosis, and receiver operating characteristic curve (ROC) was used to predict the diagnostic value of NLR and combined related indicators on osteoporosis. Results:NLR of RA patients (3.1±1.7) was higher than that of healthy controls (1.7±0.5) ( F=21.27, P<0.001). In the osteoporosis group, the reduced bone mass group, and the normal bone mass group, age (66±8), (62±10), (50±13), disease course (15±10), (9±8, (7±7), BMI (20±4) kg/m 2, (22±3) kg/m 2, (24±3) kg/m 2, NLR (3.9±2.3, 2.7±1.2, 2.6±1.0), CRP (41±43) mg/L, (28±34) mg/L, (18±26) mg/L, ESR (46±30) mm/1 h, (36±26) mm/1 h, (26±20) mm/1 h were significantly different among the three groups ( χ2=32.92, P<0.001; H=17.41, P<0.001; F=12.04, P<0.001; H=11.62, P=0.030; H=13.78, P=0.001; F=7.18, P=0.001). Correlation analysis showed that NLR was correlated with CRP, ESR, anti-CCP antibody, femoral neck bone mineral density, DAS28 score and age. The correlation coefficients were 0.49 ( P<0.001), 0.39 ( P<0.001), 0.30( P<0.001), -0.18( P=0.042), 0.50( P<0.001), 0.17( P=0.046), respectively. Femoral neck was correlated with age, BMI, course of disease, CRP, ESR. The correlation coefficients were -0.46( P<0.001), 0.38 ( P<0.001),-0.39 ( P<0.001), -0.34 ( P<0.001), the correlation coefficients of L1-4 with age, BMI, CRP and ESR were -3.41( P<0.001), 0.39( P<0.001), -0.22( P=0.010), -2.42( P=0.005), respectively. There was no correlation between bone mineral density and DAS28 and anti-CCP antibody. Ordered multi-classification Logistic regression analysis showed that age, course of disease, NLR and ESR were risk factors for osteoporosis, and their OR values were 1.12 ( P<0.001), 1.05 ( P=0.025), 1.29 ( P=0.031), 1.02 ( P=0.039), 0.28 ( P=0.008), respectively. Body mass index ( OR=0.76, P<0.001) were protective factors. ROC curve showed that the AUC area of NLR was 0.68, the AUC area of NLR, BMI, age, sex and course of disease was 0.90, the cut-off value was 0.20, sensitivity was 0.95, and specificity was 0.73[95% CI(0.84, 0.95)]. Conclusion:In osteoporosis, NLR is related to bone mass and disease activity of patients with rheumatoid arthritis. Combined with other related indexes, NLR can be used as a predictive diagnostic index and has a guiding role in clinical practice.