PRISMA Flow chart outlining the study selection process.

<p>PRISMA Flow chart outlining the study selection process.</p

Type of diseases examined in the included studies (top 20).

<p>Type of diseases examined in the included studies (top 20).</p

Associations between spirometry-based COPD and potential risk factors and severity measures.

<p>COPD is defined on pre-and post-measurements and on LLN-definition and GOLD-definition.</p

Spirometry, questionnaire and electronic medical record based COPD in a population survey: Comparing prevalence, level of agreement and associations with potential risk factors

<div><p>Background</p><p>COPD-diagnosis is confirmed by post-bronchodilator (BD) spirometry. However, epidemiological studies often rely on pre-BD spirometry, self-reports, or medical records. This population-based study aims to determine COPD-prevalence based on four different operational definitions and their level of agreement, and to compare associations between COPD-definitions and risk factors.</p><p>Methods</p><p>COPD-prevalence in 1,793 adults from the general Dutch population (aged 18–70 years) was assessed based on self-reported data, Electronic Medical Records (EMR), and post-BD spirometry: using the FEV1/FVC below the lower limit of normal (LLN) and GOLD fixed cut-off (FEV1/FVC <0.70). Using spirometry as a reference, sensitivity was calculated for self-reported and EMR-based COPD. Associations between COPD and known risk factors were assessed with logistic regression. Data were collected as part of the cross-sectional VGO study (Livestock Farming and Neighboring Residents’ Health Study).</p><p>Results</p><p>The highest prevalence was found based on spirometry (GOLD: 10.9%, LLN: 5.9%), followed by self-report (4.6%) and EMR (2.9%). Self-reported or EMR-based COPD identified less than 30% of all COPD-cases based on spirometry. The direction of association between known risk factors and COPD was similar across the four definitions, however, magnitude and significance varied. Especially indicators of allergy were more strongly associated with self-reported COPD compared to the other definitions.</p><p>Conclusions</p><p>COPD-prevalence varied depending on the used definition. A substantial number of subjects with spirometry-based COPD cannot be identified with questionnaires or medical records which can cause underestimation of COPD-prevalence. The influence of the different COPD-definitions on associations with known risk factors was limited.</p></div

Flow chart of the data collection.

<p>Analyses are conducted on subjects with a pre-and post-bronchodilator (BD) measurement with a sufficient quality, with Electronic Medical Records (EMR) of good quality and with non-missing self-reported COPD.</p

Associations between spirometry-based COPD and potential risk factors and severity measures.

<p>COPD is defined on pre-and post-measurements and on LLN-definition and GOLD-definition.</p

Comparison of characteristics of subjects who agreed and disagreed to be contacted for a follow-up study, and subjects who participated and did not participate to the medical examination.

<p>Comparison of characteristics of subjects who agreed and disagreed to be contacted for a follow-up study, and subjects who participated and did not participate to the medical examination.</p

Prevalence and lung function characteristics for four different definitions of COPD, based on three sources: self-reported data, GP Electronic Medical Records, and spirometry.

<p>Prevalence and lung function characteristics for four different definitions of COPD, based on three sources: self-reported data, GP Electronic Medical Records, and spirometry.</p

Comparison of COPD prevalence based on four different definitions, presented in n cases and in % of total identified cases.

<p>Legend Fig 2: In total 243 COPD cases were ascertained by at least one definition. In total, 1793 subjects who had a pre- and post-BD lung function measurement with a sufficient quality (C or better), Electronic Medical Records (EMR) of good quality, and without missing data on self-reported COPD (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0171494#pone.0171494.g001" target="_blank">Fig 1</a>) were included. Self-report = self-reported data based on the ECRHSIII screening questionnaire, EMR = Electronic Medical Records, spirometry LLN = post-bronchodilator measurement of FEV1/FVC lower than FEV1/FVC-lower limits of normal, spirometry GOLD = post-bronchodilator measurement of FEV1/FVC < 0.70.</p

Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of COPD based on self-reported data and based on Electronic Medical Records compared with COPD based on spirometry–LLN and GOLD-definition.

<p>Agreement between the three different data sources was determined with Cohen’s Kappa.</p