Division of Pulmonary and Critical Care Medicine, Rush University Medical Center, Chicago, IL.
Center for Pharmacoeconomic Research, University of Illinois at Chicago, Chicago, IL.
Chest. 2012 Jan;141(1):87-93. doi: 10.1378/chest.11-0024. Epub 2011 Jul 14.
Acute exacerbations of COPD (AE-COPD) are a leading cause of hospitalizations in the United States. To estimate the burden of disease (eg, prevalence and cost), identify opportunities to improve care quality (eg, performance measures), and conduct observational comparative effectiveness research studies, various algorithms based on the International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) codes have been used to identify patients with COPD. However, the validity of these algorithms remains unclear.
We compared the test characteristics (sensitivity, specificity, positive predictive value, and negative predictive value) of four different coding algorithms for identifying patients hospitalized for an exacerbation of COPD with chart review (reference standard) using a stratified probability sample of 200 hospitalizations at two urban academic medical centers. Sampling weights were used when calculating prevalence and test characteristics.
The prevalence of COPD exacerbations (based on the reference standard) was 7.9% of all hospitalizations. The sensitivity of all ICD-9-CM algorithms was very low and varied by algorithm (12%-25%), but the negative predictive value was similarly high across algorithms (93%-94%). The specificity was > 99% for all algorithms, but the positive predictive value varied by algorithm (81%-97%).
Algorithms based on ICD-9-CM codes will undercount hospitalizations for AE-COPD, and as many as one in five patients identified by these algorithms may be misidentified as having a COPD exacerbation. These findings suggest that relying on ICD-9-CM codes alone to identify patients hospitalized for AE-COPD may be problematic.
COPD（慢性阻塞性肺病）急性加重是美国住院的主要原因。为了评估疾病负担（如患病率和成本）、确定改善护理质量的机会（如绩效指标），并进行观察性比较有效性研究，已经使用了基于国际疾病分类，第九修订版，临床修正版（ICD-9-CM）代码的各种算法来识别 COPD 患者。然而，这些算法的有效性尚不清楚。
我们比较了四种不同编码算法（基于国际疾病分类，第九修订版，临床修正版（ICD-9-CM）代码）识别在两个城市学术医疗中心住院治疗的 COPD 加重患者的测试特征（敏感性、特异性、阳性预测值和阴性预测值），使用分层概率样本进行了 200 例住院患者的图表审查（参考标准）。在计算患病率和测试特征时使用了采样权重。
COPD 加重（基于参考标准）的患病率为所有住院患者的 7.9%。所有 ICD-9-CM 算法的敏感性都非常低，并且因算法而异（12%-25%），但所有算法的阴性预测值都相似（93%-94%）。所有算法的特异性均>99%，但阳性预测值因算法而异（81%-97%）。
基于 ICD-9-CM 代码的算法将低估 AE-COPD 的住院治疗，并且多达五分之一的患者可能被这些算法错误地识别为患有 COPD 加重。这些发现表明，仅依赖 ICD-9-CM 代码来识别因 AE-COPD 住院的患者可能存在问题。
