Information for researchers and clinicians

RCT to compare the cost-effectiveness of two alternative case-finding approaches for identifying undiagnosed COPD.

There is significant under-diagnosis of COPD in the UK and elsewhere and many GP groups have actively started to seek undiagnosed cases. However, the most effective and cost-effective approach is not known as published studies are small and/or without comparison groups.

We plan to recruit 28 practices and randomly assign patients aged 40-79 years who are current or ex-smokers, to either an “active case-finding arm” or an “opportunistic only” arm. We will also compare with a further 28 practices undertaking “routine care”. Patients in the “opportunistic only” arm will receive a questionnaire about simple respiratory symptoms when they attend surgery routinely. Patients in the “active” arm will not only be flagged for these questions in surgery, but will also be actively sent a questionnaire by post.

Any patients who report any of the relevant respiratory symptoms will be invited for spirometry, and we estimate that approximately 16% of these will subsequently be diagnosed with COPD. We will compare which method is the most effective and cost-effective in identifying new patients, and also undertake sensitivity analysis and modelling to project future benefits of different approaches. We also plan a series of qualitative interviews to explore patients’ views.

Primary care cohort and prognostic index

The prognosis of COPD is not well understood, with limited treatment options, especially in people with mild/moderate disease. Prognostic indices have been largely developed in patients with more severe disease although recent indices have been proposed in primary care. These need external validation and potentially modification/improvement in large primary care populations representative of the full range of COPD severity, including undiagnosed disease, if they are to find application in clinical practice.

We plan to recruit a cohort of ~2000 new and existing COPD patients from ~70 practices in the West Midlands to establish a platform for testing novel interventions and to evaluate the validity of existing prognostic indices (and also assess the potential for improvements). These patients will be recruited from the practices involved in the case-finding trial above. They will be followed up for the duration of the programme in the first instance, with 6-monthly follow-up for 3 years. Patients will have a range of physiological and questionnaire-based measures at baseline and subsequent follow-up (eg spirometry, BMI, age, sex, ethnicity, medical history, smoking history, dyspnoea, QoL, exercise capacity, muscle strength, medications, respiratory symptoms, physical activity levels and occupation).

The primary endpoint is hospitalisation, with secondary endpoints including respiratory hospitalisations, GP consultations, exacerbations and mortality.

Data from other countries suggest that people with COPD have a poorer employment history than people without COPD, but there are no data quantifying this in the UK, and no studies to examine presenteeism (poor performance at work). Presenteeism is also important as it is associated with future ill health and absenteeism. There are no studies of workplace based interventions to improve work performance in people with COPD who may benefit.

Questions

A. Among COPD patients of working age, which factors are associated with employment, absenteeism and presenteeism?
B. Among COPD patients in employment, how does disease progression (lung function decline, exacerbations) over time affect occupational performance (work absenteeism and presenteeism)?
C. Among those with poor work performance what is the feasibility and benefits of offering formal occupational health (OH) assessment and subsequent recommendations aimed at improving work-based indices?

Design

Cross-sectional (A) and longitudinal data (B) from the cohort participants will be used to address the first two questions. A feasibility study of formal OH assessment will be undertaken in those with poor work performance

Setting

Practices in the West Midlands involved in the Birmingham COPD Cohort study

Cross-sectional analyses

Participants
Those of working age (40-65 years: n~760) in the COPD cohort are eligible for cross-sectional analysis, and a subset (those in paid employment at baseline n~200) for the longitudinal analyses.

Exposures
These will be collected at baseline within the cohort study using validated measures, including:

•Demographic information (age, sex, socioeconomic status)
•Disease severity (lung function, smoking history, comorbidities),
•Occupation.

During follow up of patients in work, information on exacerbations, change in treatment and symptoms, and change in lung function from baseline to follow up will also be collected.

Outcomes
The following data will be obtained by self-report at baseline:

1. Employment status
2. Absenteeism: self-reported absenteeism over the last 12 months
3. Presenteeism

The absenteeism and presenteeism questionnaires will be re-administered 6-monthly to the subset of the cohort in employment at baseline, in addition to the other measures recorded in the whole cohort. There is some evidence that presenteeism scores can change over time, in response to interventions and this project will provide further information on its use in this context.

Analysis

Cross-sectional:
The relationship between COPD severity, sociodemographic factors, other health status measures, occupation and the outcomes of interest (employment status, presenteeism score and absenteeism) at baseline will be described. Multivariable analyses will be used to examine the relationship between disease severity and outcomes, adjusting for the other factors if relevant.

Longitudinal:
Experience of disease severity (e.g. frequency of exacerbations, need for medications) in relation to patterns of absenteeism/presenteeism will be assessed. A labour market analysis model will also be used to explore which are the main determinants of working and whether they may be modifiable.

Feasibility of a formal occupational health assessment

Design
Non-controlled feasibility intervention study

Participants
Participants with COPD in current employment will be eligible.

Intervention: occupational health assessment
Subjects invited for an occupational health assessment will be offered a review by an occupational health practitioner for formal assessment of their work in the context of the workplace. This will result in a formal individualised report outlining any hazards in the workplace and recommendation for workplace or work improvement modifications to control and minimise risk. The report will be fed back to the patient and if they wish it, sent to their employer.

Outcomes and analysis
Participants will be followed up for 6 months following intervention. The main outcomes will be feasibility (number of assessments completed, range of recommendations) and acceptability (satisfaction questionnaire and interviews). Structured questionnaires will be administered to all participants a month after the assessment to ask about their experience and satisfaction with the process and outcome of assessment. Questions will also address potential barriers to implementation of recommendations.

In addition, up to 20 participants will be interviewed (to theme saturation) about the relevance of the assessment for them. These will be carried out ~3 months later to allow participants to reflect on benefit from the initial assessment and the consequences.

Secondary outcomes will include any change in outcome measures (work productivity, HRQL) at 6-month follow-up.