Department of Clinical Epidemiology, Aarhus University Hospital, Aarhus, Denmark.
Clin Epidemiol. 2013 Aug 12;5:295-8. doi: 10.2147/CLEP.S44408. eCollection 2013.
Infant respiratory distress syndrome (IRDS) is the most common respiratory disease in preterm infants, and is associated with considerable morbidity and mortality. Valid data on IRDS are important in clinical epidemiological research.
The objective of this study was to estimate the positive predictive value (PPV) of the IRDS diagnosis registered in the population-based Danish National Patient Registry according to the International Classification of Diseases, 8th and 10th revisions.
Between January 1, 1977 and December 31, 2008, we randomly selected three patients per year, 96 in total, who were registered with an IRDS diagnosis in the Danish National Patient Registry and living in the northern part of Denmark. Data on the infants included information on the presence of predefined clinical symptoms. We defined IRDS as the presence of at least two of four clinical symptoms (tachypnea, retractions or nasal flaring, grunting, and central cyanosis), which had to be present for more than 30 minutes. Using medical record review as the reference standard, we computed the positive predictive value of the registered IRDS diagnosis including 95% confidence intervals (CIs).
We located the medical record for 90 of the 96 patients (94%), and found an overall PPV of the IRDS diagnosis of 81% (95% CI 72%-88%). This did not vary substantially between primary and secondary diagnoses. The PPV was higher, at 89% (95% CI 80%-95%), for preterm infants born before 37 weeks of gestation.
The PPV of the IRDS diagnosis in the Danish National Patient Registry is reasonable when compared with symptoms described in the corresponding medical records. The Danish National Patient Registry is a useful data source for studies of IRDS, particularly if restricted to preterm infants. Nonetheless, the potential impact of misclassification of the IRDS diagnosis must be considered.
婴儿呼吸窘迫综合征（IRDS）是早产儿最常见的呼吸系统疾病，与相当高的发病率和死亡率相关。IRDS 的有效数据对于临床流行病学研究非常重要。
本研究旨在评估基于人群的丹麦国家患者注册中心中，根据国际疾病分类第 8 版和第 10 版，IRDS 诊断的阳性预测值（PPV）。
1977 年 1 月 1 日至 2008 年 12 月 31 日，我们随机选择了每年每例患者 3 例，共 96 例，他们在丹麦国家患者注册中心登记患有 IRDS 且居住在丹麦北部。关于婴儿的数据包括了存在预先定义的临床症状的信息。我们将 IRDS 定义为存在至少四个临床症状中的两个（呼吸急促、肋间隙凹陷或鼻翼扇动、呻吟和中央性发绀），并且持续时间超过 30 分钟。使用病历回顾作为参考标准，我们计算了包括 95%置信区间（CI）在内的登记 IRDS 诊断的阳性预测值。
我们找到了 96 例患者中的 90 例（94%）的病历，总体上 IRDS 诊断的阳性预测值为 81%（95%CI 72%-88%）。初级和次级诊断之间没有明显差异。对于胎龄小于 37 周的早产儿，IRDS 诊断的阳性预测值更高，为 89%（95%CI 80%-95%）。
与相应病历中描述的症状相比，丹麦国家患者注册中心中 IRDS 诊断的阳性预测值是合理的。丹麦国家患者注册中心是研究 IRDS 的有用数据来源，特别是在仅限于早产儿的情况下。然而，必须考虑到 IRDS 诊断的错误分类的潜在影响。
