分析血清骨保护素(osteoprotegerin, OPG)与慢性阻塞性肺疾病(chronic obstructive pulmonary, COPD)患者骨丢失和骨质疏松诊断的关系。

收集2021年1月至2024年3月我院收治的95例疾病稳定的COPD患者，根据双能X射线吸收法(Dual-energy X-ray absorption method, DEXA)分为骨密度(bone density, BMD)正常组35例、BMD减少组37例和骨质疏松组23例，酶联免疫吸附测定法(enzyme-linked immunosorbent assay, ELISA)测定血清OPG的水平。

BMD正常组体质量指数(body mass index, BMI)、用力肺活量(forced vital capacity, FVC)高于BMD减少和骨质疏松患者(P<0.05)。骨质疏松患者糖化血红蛋白(glycosylated hemoglobin, HbA1c)低于BMD正常和BMD减少组，第1秒用力呼气量(one second forced expiratory volume, FEV₁)低于BMD正常组(P<0.05)。随着BMD的降低，腰椎BMD、T评分以及髋部BMD、T评分逐渐降低(P<0.001)；血清OPG水平逐渐升高(F＝23.257，P<0.001)。GOLD分级1~2级患者血清OPG水平(178.90±71.33)pg/ml低于GOLD分级3~4级患者(234.12±81.06)pg/ml(P<0.05)。Spearman相关性显示血清OPG水平与FEV₁(Rho＝－0.205，P＝0.046)、FEV₁/FVC(Rho＝－0.236，P＝0.022)、FEV_{25_75}(Rho＝－0.226，P＝0.028)呈微弱负相关性。将上述BMI、HbA1c、FVC、FEV₁、OPG作为自变量纳入多元线性回归方程，结果显示BMI、HbA1c、血清OPG与腰椎T值相关(P<0.05)；而BMI、血清OPG还与髋部T值相关(P<0.05)。BMD正常组为对照，血清OPG诊断BMD减少的AUC为0.737(95%CI：0.617~0.857)，截断值为187.01 pg/ml；以BMD正常和BMD减少患者为对照，血清OPG诊断骨质疏松的AUC为0.825(95%CI：0.741~0.909)，截断值为206.39 pg/ml；以BMD减少组为对照，血清OPG诊断BMD减少的AUC为0.683(95%CI：0.550~0.815)，截断值为187.01 pg/ml(P<0.05)。

高血清OPG水平与COPD患者骨质疏松风险有关，因此OPG可能是这种COPD相关共病的生物标志物。

To explore the relationship between serum osteoprotegerin (OPG) and the diagnosis of bone loss and osteoporosis in patients with chronic obstructive pulmonary disease (COPD).

From January 2021 to March 2024, ninety-five COPD patients with stable disease were recruited from Our hospital, and were divided into the normal bone mineral density (BMD) group (n=35), the reduced BMD group (n=37), and the osteoporosis group (n=23) according to the dual-energy X-ray absorptiometry (DEXA), and enzyme-linked immunosorbent assay (ELISA) was used to determine the serum OPG levels.

Body mass index (BMI) and forceful lung capacity (FVC) were higher in the BMD normal group than in the BMD reduced and osteoporotic patients (P<0.05). Glycosylated hemoglobin (HbA1c) was lower in osteoporotic patients than in the BMD normal and reduced BMD groups, in addition to lower force expiratory volume in 1 second (FEV₁) than in the BMD normal group (P<0.05). As BMD decreased, lumbar spine BMD and T scores as well as hip BMD and T scores gradually decreased (P<0.001); while serum OPG levels gradually increased (F=23.257, P<0.001). Serum OPG levels were significantly lower in patients with Global Initiative for Chronic Obstructive Lung Disease (GOLD) classification 1-2 than in patients with GOLD classification 3-4 (t=-3.332, P=0.001). Spearman′s correlation showed a weak negative correlation between serum OPG levels and FEV₁(Rho=-0.205, P=0.046), FEV₁/FVC (Rho=-0.236, P=0.022), and FEV_{25_75} (Rho=-0.226, P=0.028). The above BMI, HbA1c, FVC, FEV₁, and OPG were included as independent variables in the multiple linear regression equation, and the results showed that BMI, HbA1c, and serum OPG were independently correlated with lumbar spine T-scores (P<0.05); whereas, BMI and serum OPG were also independently correlated with hip T-scores (P<0.05). The BMD normal group was used as a control, and serum OPG diagnosed decreased BMD with an AUC was 0.737(95%CI: 0.617~0.857), and the cutoff value was 187.01 pg/ml; with the patients with normal BMD and reduced BMD as the control, the AUC of serum OPG for diagnosing osteoporosis was 0.825 (95%CI: 0.741~0.909), and the cutoff value was 206.39 pg/ml; with the reduced BMD group as a control, the AUC of serum OPG for diagnosis of BMD reduction was 0.683 (95%CI: 0.550~0.815), and the cutoff value was 187.01 pg/ml; all P<0.05.

High serum OPG levels are associated with the risk of osteoporosis in COPD patients, therefore OPG may be a biomarker for this COPD related comorbidity.