Classifying the severity of COPD: are the new severity scales better than the old?

BACKGROUND: Forced expiratory volume in 1 second cut-off points establish the severity of chronic obstructive pulmonary disease (COPD). OBJECTIVES: To compare how the American Thoracic Society (ATS), the British Thoracic Society (BTS), the Global Initiative for COPD (GOLD) and the ATS-European Respiratory Society (ATS-ERS) guidelines for rating COPD severity predict several significant outcomes. DESIGN: Five-year prospective cohort study. Spirometry was performed and health-related quality of life (HRQoL) assessed using the Short Form 36 Health Survey and the Saint George's Respiratory Questionnaire. Hospital admissions resulting from COPD exacerbation and mortality during a 5-year follow-up period were recorded. RESULTS: In all guidelines, the number of admissions was directly associated with COPD severity. The sensitivity and specificity for 5-year respiratory mortality were respectively 0.21 and 0.97 for the GOLD/ATS-ERS, 0.51 and 0.79 for the BTS, and 0.37 and 0.89 for the ATS guidelines. A similar pattern was seen for all-cause mortality. For HRQoL, statistically significant differences between guidelines were seen only for the BTS and ATS scales. CONCLUSIONS: These guidelines did not consistently stratify patients with regard to 5-year mortality and HRQoL. Although the BTS system was slightly superior, none of the guidelines were closely related to these outcomes. Other instruments are needed for a better determination of the severity of COPD.

[Comparison between the 1993 and 2002 Guidelines of the Spanish Society of Pulmonology and Thoracic Surgery (SEPAR) for identifying respiratory events in polysomnography tests]. / Comparación entre las normativas de la SEPAR de 1993 y 2002 en la lectura de los eventos respiratorios de las mismas polisomnografías.

OBJECTIVE: To compare the results of applying both the 1993 and 2002 guidelines of the Spanish Society of Pulmonology and Thoracic Surgery (SEPAR) to identify respiratory events during nighttime polysomnography tests. PATIENTS AND METHODS: One hundred twenty consecutive patients with medium to high suspicion of sleep apnea-hypopnea syndrome (SAHS) were included in the study. The 1993 guidelines recommended the use of a thermistor and the evaluation of only apneas and hypopneas. The 2002 guidelines, on the other hand, recommended the use of a thermistor, nasal pressure cannula, and thoracoabdominal bands so that respiratory effort related to arousals could be studied along with apneas and hypopneas. In our study we did not use an esophageal pressure catheter. We calculated the apnea index, hypopnea index, and apnea-hypopnea index (AHI) and determined the number of patients who would be diagnosed with SAHS (AH I > or =10) and the number for whom initiation of continuous positive airway pressure treatment would be recommended (AHI > or =30) according to the 2 sets of guidelines. RESULTS: Polysomnographic tests were valid for 118 of the 120 patients (80% men). The mean (SD) age was 51 (11.6) years and the mean body mass index 31.2 (4.3). Using the 1993 guidelines, the AHI was less than 10 in 25 patients, between 20 and 29 in 38, and 30 or more in 50. In the group overall, mean apnea and hypopnea indices and AHI were all significantly higher with the 2002 guidelines than with the 1993 criteria. With the 1993 criteria, the mean AHI was 33.16 and with 2002 criteria, 45.02 (P<.05). Sixty-four percent of the studies considered normal according to the 1993 SEPAR guidelines were considered apneic according to the 2002 guidelines. Of the patients considered not to need continuous positive airway pressure according to the 1993 SEPAR guidelines, 47.61% did need therapy according to the 2002 guidelines. CONCLUSIONS: There are significant differences in AHI, and in both apnea and hypopnea indices depending on whether the 1993 or the 2002 SEPAR guidelines are applied.