Chest
Volume 128, Issue 4, October 2005, Pages 2443-2447
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Clinical Investigations
Spirometry in the Primary Care Setting

https://doi.org/10.1378/chest.128.4.2443Get rights and content

Study objective

To determine if screening spirometry in the primary care setting influences the physician's diagnosis and management of obstructive lung disease.

Design

Diagnosis and management assessed before and after the intervention of screening spirometry.

Participants

A total of 1,034 patients who had ever smoked and were at least 35 years of age presenting to primary care practices for any reason.

Setting

Rural primary care practices.

Measurements and results

Physicians were asked prior to and following presentation of spirometry test results if they thought airflow obstruction was present and if they planned to change management based on the results. A new diagnosis of unsuspected airflow obstruction was made by the physician in 93 patients (9%), and a prior diagnosis of airflow obstruction was removed after spirometry in 115 patients (11%). After viewing the spirometry results, physicians reported that they would change patient management in 154 patients (15%). Most planned management changes occurred when airflow obstruction was newly diagnosed (57 of 93 patients, 61%) and when the diagnosis of airflow obstruction remained unchanged (80 of 195 patients, 41%). A 6-month chart review documented the addition of respiratory medications in 8% of patients.

Conclusion

Screening spirometry influences physicians' diagnosis of airflow obstruction and management plans especially in patients with moderate-to-severe obstruction.

Section snippets

Geographic Location

Primary care practices were recruited from rural Eastern Ontario, Canada. The practices had to be within a 2-h driving distance of The Ottawa Hospital, which allowed the hospital-based research assistants to drive to the practices each day to perform spirometry. The practices were chosen because they did not have spirometry on-site or within the community, in order to avoid contamination of results. Several rural communities were selected to assess variability between practices. The practices

Subjects

Eligible patients were all patients presenting to their primary care practitioners for any reason, who were at least 35 years of age, and who had smoked at least 20 packages of cigarettes in their lifetime. The patients were administered a brief questionnaire by the clinic receptionist that determined age, smoking history, and willingness to participate. Those patients who were eligible and agreed to participate were approached by the research assistant and signed informed consent. Patients who

Baseline Data Collection

Interviewer-administered questionnaires included questions about smoking, respiratory symptoms, and diagnosed respiratory illnesses taken from the American Thoracic Society questionnaire,4 which has been standardized and tested for reliability. Spirometry was performed in the practice building before the patients were seen by their physicians, by trained research assistants using a portable spirometer (MicroLab 3500; Micro Medical; Auburn, ME). Testing was done with the patients seated, and a

Statistical Analysis

The criterion for diagnosis of airflow obstruction was a prebronchodilator FEV1/FVC ratio < 0.7. Results were stratified by severity based on FEV1. The χ2 statistic was used to test associations between the FEV1/FVC ratio < 0.7 (yes/no), the physician's diagnosis of obstruction (yes/no), and the physician's plan to change management (yes/no). κ statistics were used to measure agreement between test results and physician's diagnosis.

Results

The study included eight rural communities with populations between 1,206 and 4,406. A total of 23 primary care physicians and 1,046 patients participated. Of the 1,046 patients, 1,034 had acceptable and reproducible spirometry results. One hundred eighty patients (17.4%) had airflow obstruction, defined as a prebronchodilator FEV1/FVC ratio < 0.7. There was no significant difference in prevalence of obstruction between the eight study sites (χ2 p = 0.17). The mean age of the study patients was

Discussion

Previous studies23 of screening spirometry in primary care practice have reported the incidence of newly diagnosed airflow obstruction to range from 8 to 20%. The variation in incidence of newly diagnosed airflow obstruction may in part be explained by the differences in the patient populations studied and by the study definitions used for airflow obstruction. In our study, the addition of spirometry resulted in a new physician diagnosis of unsuspected airflow obstruction in 9% of patients.

ACKNOWLEDGMENT

The authors thank the following physicians who participated in this study: A. Assemi, M. Buxton, G. Carvers, P. Coolican, M. Crabtree, C. Davis, R. Dawes, C. Deschenes, M. Dolan, W. Domanko, G. Houze, G. Jacques, H. Langill, J. Marston, G. Peters, H. Prins, E. Rivington, N. Soni, A. Thomas, and S. Wicklum. The authors thank Dr. Josiah Lowry for help with the study design. The authors would also like to thank the study research assistants: Gay Pratt, Dominique Bleskie, and Ena Gaudet.

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This project was supported by an unrestricted grant from Glaxo-Smith-Kline. Glaxo-Smith-Kline had no role in the design, implementation, analysis, or interpretation of the study results.

Reproduction of this article is prohibited without written permission from the American College of Chest Physicians (www.chestjournal.org/misc/reprints.shtml).

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