"GOLD or lower limit of normal definition? a comparison with expert-based diagnosis of chronic obstructive pulmonary disease in a prospective cohort-study"

Abstract

BackgroundThe Global initiative for chronic Obstructive Lung Disease (GOLD) defines COPD as a fixed post-bronchodilator ratio of forced expiratory volume in 1 second and forced vital capacity (FEV1/FVC) below 0.7. Age-dependent cut-off values below the lower fifth percentile (LLN) of this ratio derived from the general population have been proposed as an alternative. We wanted to assess the diagnostic accuracy and prognostic capability of the GOLD and LLN definition when compared to an expert-based diagnosis.MethodsIn a prospective cohort study, 405 patients aged ≥ 65 years with a general practitioner's diagnosis of COPD were recruited and followed up for 4.5 (median; quartiles 3.9; 5.1) years. Prevalence rates of COPD according to GOLD and three LLN definitions and diagnostic performance measurements were calculated. The reference standard was the diagnosis of COPD of an expert panel that used all available diagnostic information, including spirometry and bodyplethysmography.ResultsCompared to the expert panel diagnosis, 'GOLD-COPD' misclassified 69 (28%) patients, and the three LLNs misclassified 114 (46%), 96 (39%), and 98 (40%) patients, respectively. The GOLD classification led to more false positives, the LLNs to more false negative diagnoses. The main predictors beyond the FEV1/FVC ratio for an expert diagnosis of COPD were the FEV1 % predicted, and the residual volume/total lung capacity ratio (RV/TLC). Adding FEV1 and RV/TLC to GOLD or LLN improved the diagnostic accuracy, resulting in a significant reduction of up to 50% of the number of misdiagnoses. The expert diagnosis of COPD better predicts exacerbations, hospitalizations and mortality than GOLD or LLN.ConclusionsGOLD criteria over-diagnose COPD, while LLN definitions under-diagnose COPD in elderly patients as compared to an expert panel diagnosis. Incorporating FEV1 and RV/TLC into the GOLD-COPD or LLN-based definition brings both definitions closer to expert panel diagnosis of COPD, and to daily clinical practice.

The Association of Weight With the Detection of Airflow Obstruction and Inhaled Treatment Among Patients With a Clinical Diagnosis of COPD

“…We also used both the LLN and the GOLD defi nitions of AFO, achieving similar results for both despite the limitations of each method. 18 Regardless of the AFO criteria used, we found that as BMI increased, so did the likelihood of COPD misdiagnosis.…”

“…These findings have important implications because obese patients are at greater risk of diabetes, hypertension, coronary heart disease, and mortality compared with normal weight patients. [17][18][19] Among obese patients misdiagnosed with COPD, missing the chance to diagnose and treat other conditions associated with dyspnea, particularly cardiovascular disease, may put them at even greater risk of poor health outcomes.…”

Airflow limitation by the Global Lungs Initiative equations in a cohort of very old adults

“…Although GP-reported COPD diagnosis is not the gold standard, it is the real-life situation. In another study, even when using diagnosis by a panel of lung disease experts, 17% of cases were missed by the fixed and 28% by the LLN cut-off, while airflow limitation by the fixed cut-off had higher agreement with the expert panel's diagnosis [23].…”

The View of the Turkish Thoracic Society on the Report of the GOLD 2017 Global Strategy for the Diagnosis, Management, and Prevention of COPD

“…It is simple and independent of reference values and has been used in numerous clinical trials. This criterion may lead an over-and underestimation of airflow obstruction depending on age compared with the lower limit of normal (LLN) values [22,23]. In concordance with GOLD, the TTS has encouraged clinicians to perform spirometry.…”