Interventions for promoting physical activity in people with cystic fibrosis
Abstract
This is a protocol for a Cochrane Review (Intervention). The objectives are as follows:
To evaluate the effectiveness of interventions or strategies which promote participation in physical activity in daily life in individuals with CF.
Background
Description of the condition
Cystic fibrosis (CF) is a complex, progressive, life‐limiting disease predominantly affecting children and young adults. It is the most common inherited, life‐shortening illness of childhood with a carrier rate of 1 in 25, and an incidence of 1 in 2500 live births (Massie 2005). It is a multi‐system disease that is characterised by chronic suppurative lung disease, including bronchiectasis, progressing to respiratory failure (Koch 1993). Mortality due to CF has improved considerably over the past decades with children born this century expected to live into their fourth and fifth decades, and beyond (CF Foundation 2009).
Physical activity is an encompassing term relating to any bodily movement that results in an increase in energy expenditure above baseline resting energy expenditure (Casparen 1985). Physical activity includes structured exercise and sport activities, as well as activities involved in play, work, transportation, chores and recreational pursuits (WHO 2010). Habitual physical activity (HPA) implies the performance of physical activity within the context of regular daily life (Clanchy 2011).
Participation in physical activity on a regular basis has important health benefits particularly in reducing the risk of non‐communicable diseases such as obesity and heart disease (WHO 2010). In healthy adults at least 150 minutes of physical activity each week (moderate‐vigorous intensity) is required to improve cardiorespiratory fitness, bone health and reduce the risk of non‐communicable diseases and depression (WHO 2010). Consequently, strategies designed to improve the uptake of physical activity are of great importance. In an earlier review targeting healthy individuals, Foster found professional advice with continued support could encourage short‐term improvement in physical activity participation, with more research required to identify the best long‐term strategies (Foster 2005).
In individuals with CF there are no established targets for participation in physical activity, nor have ideal strategies to promote physical activity been identified. Although supervised group‐exercise programs are regularly used to improve physical activity levels in other chronic lung diseases (Cote 2005), the unique nature of CF prevents the use of this strategy. Due to the significant risks associated with cross‐infection, patients must be segregated and isolated from their peers (Kerem 2005) and are not permitted to exercise together in pulmonary rehabilitation programs. Consequently physical activity interventions are usually limited to advice and support provided at an individual’s clinic visit. Whether alternative interventions, for example coaching or motivational interviewing, have a more positive influence on the uptake and continuation of physical activity in the CF population is unclear.
Description of the intervention
Physiological, behavioural, psychological and environmental variables impact on the performance of physical activity (Pate 1995). Strategies which address these variables and: provide education regarding health benefits (Pate 1995); provide physical skills practice (Andersen 1998); overcome perceived barriers fostering enjoyment of activity and providing motivation (Pate 1995), are strategies which are likely to be successful in promoting ongoing adherence to physical activity participation.
Healthcare professionals generally regard participation in physical activity as beneficial for people with CF (Bradley 2008). Undertaking regular physical activity may diminish dyspnoea and improve exercise tolerance, as well as exert a positive influence on bone mineral accretion, blood glucose regulation and clearance of pulmonary secretions (Bradley 2008; Dwyer 2011). Despite being regularly prescribed, adherence to exercise programs is poor. In the adult CF population, adherence to prescribed exercise programs has been reported at around 50% (Shepherd 1990; White 2007). Furthermore, participation in exercise decreases with increasing perception of illness severity, with patients ascribing decreased importance and increased burden of exercise compared to other therapies when disease severity increases (Myers 2009). Identifying strategies which promote the uptake and continued participation in physical activity could have long‐term health benefits for people with CF. Whether the same strategies to promote activity participation are effective in both adults and children may be elucidated in this review.
How the intervention might work
A prior Cochrane review has focused on interventions to promote physical activity in previously sedentary adults, however, the review excluded those who had pre‐existing medical conditions (Foster 2005). Consequently, it is unknown whether interventions identified in the review which target behaviour adaptation or involve strategies for delivering physical activity programmes, have application to individuals with CF.
If strategies that promote physical activity participation are successful in improving uptake and ongoing participation in physical activity for individuals with CF, then health improvements such as improved blood glucose control, bone mineral accretion (Bradley 2008) and enhanced clearance of pulmonary secretions could be expected (Bradley 2008; Dwyer 2011). Such improvements may be reflected as increases in exercise capacity, respiratory function and quality of life, all of which are associated with improved prognostic outcomes in CF (Hebestreit 2006; Troosters 2009; Schneiderman‐Walker 2005).
Why it is important to do this review
Previous reviews in CF have focused on exercise participation and measures of exercise or aerobic capacity (Bradley 2008). This review will allow clinicians to identify appropriate intervention strategies for encouraging uptake and long‐term participation in physical activity. This review will also allow identification of new areas of future research for promoting physical activity participation in people with CF. Novel strategies may be required to enhance participation in physical activity whilst maintaining strict infection control procedures.
Objectives
To evaluate the effectiveness of interventions or strategies which promote participation in physical activity in daily life in individuals with CF.
Methods
Criteria for considering studies for this review
Types of studies
Randomised and quasi‐randomised controlled trials.
Types of participants
People with CF aged over five years, with any degree of disease severity. Diagnosis of CF confirmed by clinical criteria and sweat testing or genotype analysis.
Types of interventions
We will include all strategies designed to promote increased participation in daily physical activity for individuals with CF. This may include interventions in both the inpatient and outpatient setting. Where the study intervention is commenced in the inpatient setting the study must include follow‐up in the discharge period in order to evaluate the effects of the intervention on physical activity in daily life.
Any intervention aimed to increase participation in physical activity as its primary goal will be reviewed. These interventions may include but are not limited to:
• one‐off one‐to‐one counselling or advice;
• self‐directed or unsupervised participation in a prescribed physical activity programme;
• supervised physical activity session in the home;
• supervised physical activity session in a facility;
• on‐going face‐to‐face counselling or advice;
• telephone support;
• written material;
• Internet‐based or tele‐health advice and motivation;
• monitoring device for motivation, e.g. pedometer
Specific comparisons to be examined are:
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one or more interventions to promote physical activity versus no intervention;
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one or more interventions to promote physical activity versus a placebo intervention (e.g. attention control).
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one intervention to promote physical activity compared to another intervention to promote physical activity.
Studies where the primary focus is not activity promotion, but rather the assessment of physiological outcomes as a response to a physical exercise intervention will not be included in the review.
Types of outcome measures
Primary outcomes
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Participation in physical activity (change from baseline where possible, measured either subjectively e.g. by an activity diary, or objectively using a monitoring device e.g. a pedometer)
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intensity of physical activity (measured or estimated and reported in metabolic equivalents (METs), or patient rated in terms of perceived exertion score)
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time spent in physical activity (measured in minutes per week, sessions per week, etc)
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energy expenditure (in calories or joules)
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step count (using a monitoring device such as a pedometer)
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Health‐related quality of life measured by generic or disease specific assessments, or both
Secondary outcomes
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Exercise capacity (either maximal or submaximal where measured directly or by a standard field test)
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Pulmonary function tests (change in per cent predicted or absolute measures from baseline, or rate of decline)
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forced expiratory volume in one second (FEV1)
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forced vital capacity (FVC)
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forced expiratory flows between 25% and 75% of expired volume (FEF25‐75)
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Adverse outcomes (e.g. musculoskeletal injuries)
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Body composition in terms of body mass index (BMI) and lean body mass
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Bone mineral density (defined on dual energy X‐ray absorptiometry (DXA) scans)
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Adherence to the intervention programme
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Compliance with other CF treatments, e.g. airway clearance techniques and nebulised medication; any measure of compliance such as pill counts, self‐report diaries, electronic monitoring
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Cost evaluation
Search methods for identification of studies
Electronic searches
We will identify relevant studies from the Group's Cystic Fibrosis Trials Register.
The Cystic Fibrosis Trials Register is compiled from electronic searches of the Cochrane Central Register of Controlled Trials (Clinical Trials) (updated each new issue of The Cochrane Library), quarterly searches of MEDLINE, a search of EMBASE to 1995 and the prospective handsearching of two journals ‐ Pediatric Pulmonology and the Journal of Cystic Fibrosis. Unpublished work is identified by searching the abstract books of three major cystic fibrosis conferences: the International Cystic Fibrosis Conference; the European Cystic Fibrosis Conference and the North American Cystic Fibrosis Conference. For full details of all searching activities for the register, please see the relevant sections of the Cochrane Cystic Fibrosis and Genetic Disorders Group Module.
In addition, we will search search CINAHL (Ebscohost), PsycINFO (OvidSP) and the Physiotherapy Evidence Database (PEDro) for all years available (Appendix 1). We will identify potentially relevant, completed but unpublished studies, by searching clinical trials registers (WHO ‐ International Clinical Trials Register (incorporating clinicaltrials.gov); European Clinical Trials Register; and, Current Controlled Trials (incorporating the UK clinical trials register).
Searching other resources
We will review the reference list of all included studies for any additional trials suitable for inclusion. If required, first authors of included trials will be contacted via email for further study details, or for information regarding other relevant published or unpublished work.
Data collection and analysis
Selection of studies
Two authors (NC and AH) will independently assess the titles and abstracts of trials identified by the search process. The same two authors will then assess full‐text copies of potentially relevant trials for inclusion based upon the defined criteria. Each author will compile a list of studies that they believe meet the inclusion criteria. They will compare the lists and resolve any disagreements by discussion and consensus with arbitration by the third author (JA) if required.
Data extraction and management
Two authors (NC and AH) will independently extract data using specially developed, standardised data extraction forms. One author (NC) will enter data into the Cochrane software Review Manager (RevMan 2011) and a second author (AH) will check it. We will resolve disagreements by discussion between review authors or, if necessary, arbitration by a third author (JA).
We will include data at all relevant time points and report follow‐up data in groups comprising data reported at:
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less than or equal to one month (short‐term);
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from one to six months; and
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greater than six months.
Assessment of risk of bias in included studies
Two authors (NC and AH) will independently rate the risk of bias of the reviewed studies using a standardised grading system described in the Cochrane Handbook of Systematic Reviews of Interventions (Higgins 2011). We will assess the following domains as either ‘high’, ‘low’ or ‘unclear’ risk of bias:
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random sequence generation;
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allocation concealment;
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blinding (of participants, personnel and outcome assessors);
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incomplete outcome data sets;
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selective outcome reporting;
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other sources of bias.
We will resolve any disagreements between authors via consensus, or by arbitration from a third author (JA) if necessary.
Measures of treatment effect
Where possible, we will express the treatment effect for continuous outcomes in their original metrics using mean differences (MD) and 95% confidence intervals (CI). Where trials measure continuous outcomes using different scales, we will express the treatment effect as a standardised mean difference (SMD) with 95% CI. If there is more than one trial with a specific intervention, we will perform a meta‐analysis using the Cochrane statistical package RevMan (RevMan 2011).
We will report results for dichotomous data as risk ratios (RR) with 95% CIs.
Unit of analysis issues
If required, we will use the generic inverse variance method for analysis of cluster randomised trials. We will not include cross‐over trials in the review.
Dealing with missing data
Where available, we will extract data from intention‐to‐treat analyses. If the original researchers did not perform intention‐to‐treat analyses and sufficient raw data are available, we will complete intention‐to‐treat analyses before entering data into RevMan with the aim of limiting bias (RevMan 2011).
We will attempt to obtain essential missing data by contacting the original authors whenever possible.
Assessment of heterogeneity
The authors will assess clinical heterogeneity and only conduct meta‐analysis where they agree that the trials are sufficiently clinically homogenous in terms of study population, interventions and outcomes. We will describe any heterogeneity between the included studies using the standard chi‐squared test. We will assess the impact of any heterogeneity on the meta‐analysis using the I2 statistic (Higgins 2011): I2 = [Q‐df/Q] x 100% Where Q is the chi‐squared statistic and df is its degrees of freedom (Higgins 2011). This describes the percentage of the variability in effect estimates that is due to heterogeneity rather than sampling error (chance).The following guide will be used to interpret the I2 values:
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0% to 40%: might not be important;
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30% to 60%: may represent moderate heterogeneity;
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50% to 90%: may represent substantial heterogeneity;
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75% to 100%: considerable heterogeneity.
Assessment of reporting biases
We will attempt to reduce reporting bias through the following measures:
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we will perform comprehensive searches to identify randomised controlled trials;
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we will attempt to seek out and include relevant unpublished studies;
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where possible, we will use funnel plots to assess for small study effects if there are at least 10 studies included in the meta‐analysis (Higgins 2011).
If we obtain an asymmetrical funnel plot, we will explore alternative causes in addition to publication bias.
Data synthesis
We will use a fixed‐effect model to conduct the meta‐analysis, unless there is substantial heterogeneity (i.e. over 50%) (Higgins 2011), in which case we will use a random‐effects model. For outcomes where we find insufficient data, or where there is a high degree of heterogeneity, we will not perform a meta‐analysis and instead will present a narrative synthesis.
Subgroup analysis and investigation of heterogeneity
If there are sufficient data available, we will undertake the following subgroup analyses:
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children versus adults;
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supervised versus unsupervised interventions.
Meta‐analyses of sub‐groups will follow the same methodological principles as the primary analysis.
Sensitivity analysis
We will perform a sensitivity analysis by including only studies with an overall low risk of bias. If all trials are found to have a high risk of bias, a sensitivity analysis will be performed after exclusion of trials that did not conceal allocation.
