Department of Critical Care Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.
Department of Medicine, Weill Cornell Medical College, New York, NY, USA.
BMC Pulm Med. 2017 Dec 15;17(1):204. doi: 10.1186/s12890-017-0532-1.
Acute respiratory distress syndrome (ARDS) is potentially underrecognized by clinicians. Early recognition and subsequent optimal treatment of patients with ARDS may be facilitated by usage of biomarkers. Surfactant protein D (SP-D), a marker of alveolar epithelial injury, has been proposed as a potentially useful biomarker for diagnosis of ARDS in a few studies. We tried to validate the performance of plasma SP-D levels for diagnosis of ARDS.
We conducted a retrospective analysis using data from three (two in USA and one in Korea) prospective biobank cohorts involving 407 critically ill patients admitted to medical intensive care unit (ICU). A propensity score matched analysis (patients with versus without ARDS, matched 1:1) was carried out using significant variables from multiple logistic regression. The diagnostic accuracy of plasma SP-D as a diagnostic marker of ARDS was assessed by receiver operating characteristic curve analysis.
Out of the 407 subjects included in this study, 39 (10%) patients fulfilled ARDS criteria. Patients with ARDS had higher SP-D levels in plasma (p < 0.01) and higher hospital-mortality (p < 0.001) than those without ARDS. Thirty eight subjects with ARDS (cases) were successfully matched for propensity for ARDS with 38 subjects without ARDS (controls). Plasma levels of SP-D were higher in cases with ARDS compared to their matched controls without ARDS [median 20.8 ng/mL (interquartile range, 12.7-38.4) versus 7.9 (4.1-17.0); p = 0.001]. The area under the receiver operating characteristic curve for SP-D for the diagnosis of ARDS was 0.71 (95% confidence intervals, 0.60-0.83). A cut-off point of 12.7 ng/mL for SP-D yielded sensitivity of 74% and specificity of 63%.
High levels of SP-D within 48 h after ICU admission might serve as a diagnostic marker for ARDS in patients hospitalized in medical ICU. Further prospective trials are required to validate the diagnostic role of SP-D in ARDS, and if its usefulness is greater in direct than in indirect ARDS, as well as across different strata of severity of ARDS.
急性呼吸窘迫综合征（ARDS）可能未被临床医生充分识别。通过使用生物标志物，可能会促进对 ARDS 患者的早期识别和随后的最佳治疗。表面活性蛋白 D（SP-D）是肺泡上皮损伤的标志物，在一些研究中被提出作为诊断 ARDS 的潜在有用生物标志物。我们试图验证血浆 SP-D 水平对 ARDS 的诊断性能。
我们使用来自三个（两个在美国，一个在韩国）前瞻性生物库队列的 407 名重症监护病房（ICU）入住的危重病患者的数据进行了回顾性分析。使用多元逻辑回归的显著变量进行倾向评分匹配分析（有与无 ARDS 的患者，1:1 匹配）。通过接收者操作特征曲线分析评估血浆 SP-D 作为 ARDS 诊断标志物的诊断准确性。
在这项研究中纳入的 407 名受试者中，39 名（10%）患者符合 ARDS 标准。ARDS 患者的血浆 SP-D 水平较高（p<0.01），且住院死亡率较高（p<0.001）。38 名 ARDS 患者（病例）成功地与 38 名无 ARDS 患者（对照）匹配了 ARDS 的倾向。与无 ARDS 的匹配对照相比，有 ARDS 的病例的血浆 SP-D 水平更高[中位数 20.8ng/mL（四分位距，12.7-38.4）与 7.9（4.1-17.0）；p=0.001]。用于 ARDS 诊断的 SP-D 的受试者工作特征曲线下面积为 0.71（95%置信区间，0.60-0.83）。SP-D 的截断值为 12.7ng/mL 时，灵敏度为 74%，特异性为 63%。
ICU 入住后 48 小时内 SP-D 水平升高可能是 ICU 住院患者 ARDS 的诊断标志物。需要进一步的前瞻性试验来验证 SP-D 在 ARDS 中的诊断作用，如果其在直接 ARDS 中的作用大于间接 ARDS，以及在 ARDS 严重程度的不同分层中作用更大，则需要进一步验证。
