Article Text

A mixed methods study to compare models of spirometry delivery in primary care for patients at risk of COPD
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1. J A Walters,
2. E C Hansen,
3. D P Johns,
4. E L Blizzard,
5. E H Walters,
6. R Wood-Baker
1. 1
Menzies Research Institute, University of Tasmania, Australia
1. Dr J A Walters, Menzies Research Institute, PB 34, Clinical School, University of Tasmania, Hobart 7001, Australia; Julia.Walters{at}utas.edu.au

## Abstract

Background: To increase recognition of airflow obstruction in primary care, we compared two models of spirometry delivery in a target group at risk of chronic obstructive pulmonary disease (COPD).

Methods: A 6 month qualitative/quantitative cluster randomised study in eight practices compared opportunistic spirometry by “visiting trained nurses” (TN) with optimised “usual care” (UC) from general practitioners (GPs) for smokers and ex-smokers, aged over 35 years. Outcomes were: spirometry uptake and quality, new diagnoses of COPD and GPs’ experiences of spirometry.

Results: In the eligible target population, 531/904 (59%) patients underwent spirometry in the TN model and 87/1130 (8%) patients in the UC model (p<0.0001). ATS spirometry standards for acceptability and reproducibility were met by 76% and 44% of tests in the TN and UC models, respectively (p<0.0001). 125 (24%) patients tested with the TN model and 38 (44%) with the UC model reported a pre-existing respiratory diagnosis (p<0.0001). Three months after spirometry, when the ratio of forced expiratory volume in 1 s/forced vital capacity (FEV1/FVC) was <0.7 and no prior COPD diagnosis was reported, nine (8%) participants had a new doctor recorded COPD diagnosis in practices with the TN model and two (8%) participants in practices with the UC model. Mislabelling of participants with a diagnosis of COPD when FEV1/FVC was ⩾0.7 was present in both models prior to and after spirometry. GPs valued high quality spirometry and increased testing of patients at risk of COPD in the TN model. They identified limitations, including the need for better systematic follow-up of abnormal spirometry and support with interpretation, which may explain persisting underdiagnosis of COPD in practice records.

Conclusions: Although opportunistic testing by visiting trained nurses substantially increased and improved spirometry performance compared with usual care, translating increased detection of airflow obstruction into diagnosis of COPD requires further development of the model.

Trial registration number: Australian Clinical Trials Registry: registration No 12605000019606.

## Statistics from Altmetric.com

A high proportion of chronic obstructive pulmonary disease (COPD) in the community remains undiagnosed.1 2 Previously unrecognised airflow obstruction was found in 19% of current smokers over 35 years of age in general practice3 and although spirometry is essential for the diagnosis of COPD,4 5 performing spirometry in primary care is not without difficulties. These include lack of access to reliable equipment, lack of training, patient reluctance to travel and financial disincentives.68 There has been little operational research on how to overcome such practical difficulties. The aim of this study was to compare the effects of two practice based models of spirometry delivery, opportunistic spirometry by visiting trained nurses and “usual care” in practices provided with equipment, training and payment, on spirometry uptake and application in patients at risk of COPD and translation into new diagnoses of COPD recorded by general practitioners (GPs).

## METHODS

### Participants and study design

Practices were recruited through a newsletter distributed to all practices in Southern Tasmania (74 urban/suburban and 20 rural). Six urban and two rural general practices responded and were included and randomised. The study protocol was approved by the Southern Health and Medical Human Research Ethics Committee. Signed informed consent was obtained from GPs in participating practices and from patients at recruitment, which occurred between November 2004 and June 2005.

### Spirometry delivery models

Using a random numbers table, practices were randomised to models for delivery of spirometry to patients in the target group at risk of COPD defined by: age over 35 years and ever smoked regularly. In the trained nurse model (TN), nurses trained in spirometry testing visited each practice for two 3 h sessions per week to perform opportunistic testing. Practice staff invited any patient in the target group who attended during a spirometry session to undergo lung function testing. Spirometry was also advertised by posters or performed at the request of GPs. Printed spirometer output (without classification or interpretation) was faxed to GPs within 48 h.

#### GP experience

Fifteen GPs (52%) from practices with the TN model and 13 GPs (68%) from practices with the UC spirometry model participated in six in-depth focus groups. Of the major themes that emerged (table 3), some were important for GPs from practices with either spirometry model, such as the need for appropriate spirometry reimbursement and the necessity of achieving high quality results. Only in practices with the UC model did GPs emphasise their own difficulties in performing spirometry and the paramount importance of having a practice nurse to perform spirometry testing. GPs in practices with the TN model thought GP initiated spirometry would be unlikely in the absence of a prior diagnosis and felt that opportunistic spirometry had major advantages for convenience and acceptability to patients. This was particularly relevant for smokers who might be reluctant to raise concerns about respiratory symptoms with GPs, because they felt guilty about self-induced lung damage. Organised follow-up, specifically focussed on spirometry, was thought essential in both models of spirometry, but a recall system after opportunistic testing would increase an already heavy GP workload and increase costs for patients in Australian primary care.

Table 3 Summary of themes on spirometry from focus group discussions with general practitioners in practices receiving the visiting trained nurse (TN) model or usual care (UC) model of spirometry delivery

All GPs claimed to use spirometry to diagnose COPD but rarely in isolation, often placing greater emphasis on other clinical patient information. They questioned the value of the label, both in terms of patient understanding and promoting change in patient behaviour. A label was felt by some GPs to lack intrinsic value in the absence of a cure. When considering the scenario of a patient with spirometry typical of moderate COPD, various terms used as labels included “reduced lung function”, “obstructive” and “respiratory problem”, and COPD was rarely specifically named. GPs varied in their knowledge of spirometric indices, but most expressed uncertainty and agreed they needed assistance with interpretation. Options suggested were: developing expertise within a practice, computerised support or outside expert interpretation. Flow–volume curves were valued by GPs themselves in assessing the presence of obstruction and in demonstrating this to patients. Only GPs in practices with the TN model valued spirometry for monitoring lung function objectively and compared this positively to routine management of other chronic diseases such as diabetes and hypertension.

The most likely consequences of spirometry elicited from GPs in both spirometry models were being prompted to identify and record patients’ smoking status and initiate discussion on cessation. Spirometry, even when normal, was used to personalise and reinforce advice on quitting.

## DISCUSSION

This study was unique in using qualitative assessment to explore and validate quantitative findings16 17 of the impact of two models of delivery of spirometry in general practice.18 We found that opportunistic trained nurse performed spirometry led to a substantially higher proportion of the population at risk of developing COPD having spirometry performed compared with usual care by GPs equipped and trained in spirometry. Spirometry performed in both models resulted in an increase in GP diagnosis of COPD. However, in practices with the visiting TN model, substantial underdiagnosis remained after a period that allowed for follow-up and further investigations in patients with spirometric evidence of airflow obstruction.

Direct invitations for spirometry by a nurse were highly acceptable to patients and GPs, although we had a higher non-participation rate compared with other similar studies,3 19 mainly caused by time constraints and illness in this opportunistic testing model within the GP clinic. However, the study design aimed to reflect busy “real world” general practice, both without pre-selection or exclusions in the target group and in utilisation and interpretation of spirometry by GPs.

The high proportion of visiting nurse performed spirometry satisfying ATS standards for acceptability and repeatability11 was similar to that reported in studies using trained staff in general practice3 20 or in the community21 and greater than achieved in practices with the UC model where the quality was variable and reflected the lack of GP expertise self-identified in our qualitative data. There was a consensus that the nature of GPs’ work was not compatible with performing spirometry to consistently high standards, but this could be achieved with adequate training and experience by practice nurses. A low rate of good quality testing in practice was found previously7 although a recent study found higher rates achieved in some practices with intensive 2 day spirometry training.22

Use of spirometry without post-bronchodilator measurement in order to limit refusals23 may overestimate the prevalence of airflow obstruction in each model. However, more mild obstruction was identified by opportunistic testing compared with testing in the UC model or as reported in an open access spirometry service for GPs in the UK.21 Spirometry use for a diagnosis of COPD is low with models that rely on GP initiation or referral.24 25 Our qualitative data indicated that initiation of testing may not occur in the absence of previously identified disease with known underreporting by patients of symptoms.26

This study investigated the utility of different spirometry models to increase the diagnosis of COPD in actual primary care practice. The high level of missed opportunities for new diagnosis in patients with airflow obstruction and mislabelling of COPD found in practice record review are consistent with findings in other studies in primary care.7 13 27 Methods suggested by GPs to improve interpretation seem feasible and deserve further investigation.28 In addition to failure to interpret spirometry correctly, qualitative data analysis identified other factors contributing to non-diagnosis, including non-consultation by patients, time limitations and GPs’ preference for reactively addressing the patient’s own agenda during a consultation rather than being proactive. These factors have also been found to be deterrents to GPs initiating discussions with smokers.29

Cost effectiveness of spirometry for case finding in COPD will vary if a symptom screening tool is used30 but depends on subsequent reduced costs through better management and reduced progression of the disease resulting from successful smoking cessation.31 While we found GPs valued opportunistic testing primarily to improve identification of smoking status and initiate discussion on cessation, there is still no definitive conclusion on a positive impact of spirometry on smoking cessation.32

Consideration of the value of spirometry in primary care and choice of the most effective model for delivery requires a full cost–benefit analysis. Although data on costs have been generally lacking for other models they are included here to facilitate comparison.13 21 A cost–benefit analysis using data on opportunistic testing in patients at risk of COPD3 carried out for the National Institute of Clinical Excellence33 found spirometry was relatively cost effective in case finding (assuming optimum interpretation) compared with current practice in primary care. Incomplete follow-up of airflow obstruction detected on spirometry caused a large increase in cost per case in our study.

Our analysis assumes participating practices were a random sample of those in Southern Tasmania but although they contained a representative range, we cannot discount selection bias and the findings may not be generalisable to all primary care practice. UC model practices had involvement in medical training and willingness to participate in research. They may be more knowledgeable about guidelines and perform more spirometry than others.34

We conclude that it is possible to increase spirometry for case finding in primary care using a model of testing by visiting trained nurses. However, to translate increased detection of airflow obstruction into increased COPD diagnosis requires measures to overcome issues identified by qualitative analysis and, at the very least, provide GPs with assistance in interpretation of spirometry.18

## Acknowledgments

The authors thank Professor P Mudge for comment on study design, and the doctors and staff in participating practices for their cooperation. The authors thank research nurses S Davoren and E Hammer for performing spirometry and calibration checks, Dr J Gartlan and Dr R Boland who assisted with extraction of data from practice records.

## Appendix 1

### Spirometry Training Course: for general practitioners and practice nurses

Instructors: respiratory specialist physician, pulmonary physiologist, GP.

Course content

• Spirometry performance (40 min)

• Demonstration of simple spirometry spirogram and complex spirometry flow volume loop

• Potential complications of spirometry

• Contraindications to spirometry:

• Requirements for achieving consistently high quality spirometry

• Test performance instructions

• Acceptance criteria (need to obtain at least 3 technically acceptable blows)

• Reproducibility criteria

• Common causes of poor quality spirometry

• How to get quality spirometry

• Trouble shooting: patient related (with examples of curves)

• Interpretation: types of ventilatory defects

• Use of predicted values

• Demonstration using EasyOne spirometer and software (20 min)

• Practice spirometry with EasyOne (30 min)

• Spirometry: application in COPD (30 min)

• Diagnosis of COPD, differentiation from asthma

• Interpretation of airflow obstruction and classification of severity

• COPDX guidelines—indications for spirometry

• Review of clinical case examples.

## Appendix 2

### Acceptability assessment

1. Spirometry test did not meet EasyOne spirometer criteria for an unacceptable test:

1. back extrapolated volume greater than 150 ml or 5% whichever is greater;

2. time until peak flow greater than 120 ms;

3. expiration time less than 2 s or volume accumulation has not dropped below 100 ml per 0.5 s.

2. exhalation time (forced expiratory time) less than 6 s.

### Quality grading definitions used in EasyOne spirometer:

1. at least three acceptable tests AND the difference between the best two FEV and FVC values is equal to or less than 150 ml;

2. at least three acceptable tests AND the difference between the best two FEV and FVC values is equal to or less than 200 ml;

3. at least two acceptable tests AND the difference between the best two FEV and FVC values is equal to or less than 250 ml;

4. at least two acceptable trials but the results are not reproducible or only one acceptable trial;

5. no acceptable test available.

## Footnotes

• Funding: JAW was the recipient of a 2006 GlaxoSmithKline Australia postgraduate support grant.

• Competing interests: None.

• Ethical approval: The study protocol was approved by the Southern Health and Medical Human Research Ethics Committee.

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