体质指数与老年心力衰竭患者血浆脑利钠肽水平的相关性研究

The effect of body mass index on B-type natriuretic peptide in elderly heart failure

目的:脑利钠肽(BNP)在诊断心力衰竭时有重要的价值,但BNP与体质指数呈负相关,探讨结合体质指数确定BNP的正常值范围,提高BNP在诊断老年心力衰竭患者中的实际临床应用价值。方法:病例选取2006-2009年在临床怀疑急性心力衰竭的676例老年患者(年龄≥65岁),盲法检测BNP水平,并获取上述患者的体质指数资料,心力衰竭的诊断由两名高年资的心内科医师汇总患者的临床资料独立做出诊断,对二者诊断不符合的患者剔除,临床医师在诊断心力衰竭时对患者的BNP检测结果不知情。结果:其中340例诊断为心力衰竭,心力衰竭患者在消瘦、正常体重、超重、肥胖患者中的BNP平均值分别为2400ng/L、1890ng/L、1720ng/L、1400ng/L,在无心力衰竭者分别为79ng/L、65ng/L、52ng/L、48ng/L。通过研究发现低体重及正常体重患者若以200ng/L为正常值标准,超重患者以150ng/L、肥胖患者以100ng/L时具有最佳诊断价值。结论:在临床实际工作中应用BNP诊断心力衰竭时应注意结合患者的体质指数,确定不同的正常值范围,使得BNP在实际工作中应用价值提高。

Objective：B-type natriuretic peptide （BNP） is valuable in diagnosing heart failure （HF）, but there is an inverse relation between BNP levels and body mass index （BMI）. So its utility in obese patients is still unknown. we evaluated differential cut-points for BNP according to BMI to determine whether alternative cut-points can improve its diagnosis value.Methods：676 suspect elderly HF patients were enrolled. BNP was measured on arrival, and BMI measurements were available for all of people. The clinical diagnosis of HF was adjudicated by 2 independent cardiologists who were blinded to BNP results.Results：There were 340 HF patients in this study. The mean BNP levels （pg/ml） in lean, normal, over weight and obese patients with HF were 2400, 1890, 1720 and 1400, while those of 79, 65, 52 and 48 were in the matched patinets without HF, respectively. The BNP cut-points to maintain 90% sensitivity for a HF diagnosis were 200 pg/ml for lean and normal subjects, 150 pg/ml for overweight subjects, and 100 pg/ml for obese patients.Conclusions：BMI influences the selection of cut-points for BNP in diagnosing HF. A low cut-point should be used in severely obese patients to preserve the sensitivity, and a high cut-point in lean patients should be used to increase its specificity.