Differences in spirometry interpretation algorithms: influence on decision making among primary-care physicians.

BACKGROUND: Spirometry is recommended for the diagnosis of asthma and chronic obstructive pulmonary disease (COPD) in international guidelines and may be useful for distinguishing asthma from COPD. Numerous spirometry interpretation algorithms (SIAs) are described in the literature, but no studies highlight how different SIAs may influence the interpretation of the same spirometric data. AIMS: We examined how two different SIAs may influence decision making among primary-care physicians. METHODS: Data for this initiative were gathered from 113 primary-care physicians attending accredited workshops in Canada between 2011 and 2013. Physicians were asked to interpret nine spirograms presented twice in random sequence using two different SIAs and touch pad technology for anonymous data recording. RESULTS: We observed differences in the interpretation of spirograms using two different SIAs. When the pre-bronchodilator FEV1/FVC (forced expiratory volume in one second/forced vital capacity) ratio was >0.70, algorithm 1 led to a 'normal' interpretation (78% of physicians), whereas algorithm 2 prompted a bronchodilator challenge revealing changes in FEV1 that were consistent with asthma, an interpretation selected by 94% of physicians. When the FEV1/FVC ratio was <0.70 after bronchodilator challenge but FEV1 increased >12% and 200 ml, 76% suspected asthma and 10% suspected COPD using algorithm 1, whereas 74% suspected asthma versus COPD using algorithm 2 across five separate cases. The absence of a post-bronchodilator FEV1/FVC decision node in algorithm 1 did not permit consideration of possible COPD. CONCLUSIONS: This study suggests that differences in SIAs may influence decision making and lead clinicians to interpret the same spirometry data differently.

Chronic cough. Three most common causes.

OBJECTIVE: To describe an approach to diagnosis and treatment of patients with chronic cough. QUALIITY OF EVIDENCE: MEDLINE was search for reports of studies comducted between 1970 and 2000 on chronic cough and its epidemiology, natural history, diagnois, and theraphy. Articles were further selected based on clinical relevance and design. Most articles reviewed were epidemiology cohort and case studies and reviews. MAIN MESSAGE: Chronic cough, a commom ailment amoung adults, is often a diagnostic challenge. Most cases of chronic cough are associated with postnasal drip syndrome (PNDS), asthma, gastroesphageal reflux disease (GERD), or some combination of these. Initial investigation should include chest radiography to ruke out more ominous causes of chronic cough. Examinations and trials of treatment can diagnose PNDS, asthma, and GERD. Combination treatments are often necessary for managing chronic cough. CONCLUSION: The most common causes of chronic cough are PNDS, asthma, GERD, or some combination of these. A systematic approach to diagnosis and treatment is effective for most cases of chronic. cough.