PURPOSE: To date there are no reports which describe how closely the decision logic of various spirometry interpretation algorithms (SIA) conform to guideline defined spirometric diagnosis of asthma and chronic obstructive lung disease (COPD); the current study addresses this issue.
METHODS: Medline/Embase were used (search words, spirometry, interpretation, algorithms, asthma and COPD diagnosis, guidelines) to identify SIA related material since 1990, including the following commonly cited resources; 1) www.goldcopd.org, and 2) ATS/ERS Task Force: Standardization of Spirometry, www.thoracic.org/section/publication/statements. Many other international resources were identified.
RESULTS: We observed considerable variability among SIA as outlined below:1) many could not be used as stand alone documents.2) some SIA lacked a logic string leading to a post-bronchodilator (PD) forced expiratory volume in one second (FEV1)/forced vital capacity (FVC) ratio; an omission which hinders COPD diagnosis.3) some SIA used PD changes in FEV1 to distinguish between asthma and COPD; a strategy which could lead to disease misclassification.4) some SIA did not suggest bronchodilator challenge if the FEV1/FVC was> 0.70; a strategy which could result in under-diagnosis of asthma.5) some SIA recommend tests which cannot be obtained in a timely manner; a strategy which could result in unnecessary delay in treatment.6) We developed a new SIA designed to address many of the limitations outlined above and which conforms to current guidelines on asthma and COPD diagnosis.
CONCLUSION: The variation in SIA identified could have important clinical implications, including disease misclassification. The new SIA offers some important advances compared to existing SIA, including logic strings that facilitate differentiation of asthma from COPD.
CLINICAL IMPLICATIONS: Our results suggest that there is a need for standardization of SIA. Given the spirometric overlap between asthma and COPD there is a need to develop SIA that minimize the risk of disease misclassification and that can be used as stand alone documents, particularly among primary care providers. While the new SIA provides important new information, further studies are needed to understand how different SIA influence spirometric diagnosis and clinical decision making.
DISCLOSURE: Anthony D Urzo, No Financial Disclosure Information; No Product/Research Disclosure Information