Outcome measures for COPD treatments: a critical evaluation

Automated Identification of Common Disease-Specific Outcomes for Comparative Effectiveness Research Using ClinicalTrials.gov: Algorithm Development and Validation Study

Background

Common disease-specific outcomes are vital for ensuring comparability of clinical trial data and enabling meta analyses and interstudy comparisons. Traditionally, the process of deciding which outcomes should be recommended as common for a particular disease relied on assembling and surveying panels of subject-matter experts. This is usually a time-consuming and laborious process.

Objective

The objectives of this work were to develop and evaluate a generalized pipeline that can automatically identify common outcomes specific to any given disease by finding, downloading, and analyzing data of previous clinical trials relevant to that disease.

Methods

An automated pipeline to interface with ClinicalTrials.gov’s application programming interface and download the relevant trials for the input condition was designed. The primary and secondary outcomes of those trials were parsed and grouped based on text similarity and ranked based on frequency. The quality and usefulness of the pipeline’s output were assessed by comparing the top outcomes identified by it for chronic obstructive pulmonary disease (COPD) to a list of 80 outcomes manually abstracted from the most frequently cited and comprehensive reviews delineating clinical outcomes for COPD.

Results

The common disease-specific outcome pipeline successfully downloaded and processed 3876 studies related to COPD. Manual verification indicated that the pipeline was downloading and processing the same number of trials as were obtained from the self-service ClinicalTrials.gov portal. Evaluating the automatically identified outcomes against the manually abstracted ones showed that the pipeline achieved a recall of 92% and precision of 79%. The precision number indicated that the pipeline was identifying many outcomes that were not covered in the literature reviews. Assessment of those outcomes indicated that they are relevant to COPD and could be considered in future research.

Conclusions

An automated evidence-based pipeline can identify common clinical trial outcomes of comparable breadth and quality as the outcomes identified in comprehensive literature reviews. Moreover, such an approach can highlight relevant outcomes for further consideration.

Chronic obstructive pulmonary disease classification, phenotypes and risk assessment

Chronic obstructive pulmonary disease (COPD) is a heterogeneous disease. Various classification systems and phenotypes have been proposed. This review highlights the current classifications of COPD, describes the major phenotypes and provides a blue print for risk assessment of COPD. It is likely that more phenotypes and endotypes of COPD will be described paving the way to personalized medicine for patients with COPD.

Pulmonary rehabilitation for chronic obstructive pulmonary disease

BACKGROUND

Widespread application of pulmonary rehabilitation (also known as respiratory rehabilitation) in chronic obstructive pulmonary disease (COPD) should be preceded by demonstrable improvements in function (health-related quality of life, functional and maximal exercise capacity) attributable to the programmes. This review updates the review reported in 2006.

OBJECTIVES

To compare the effects of pulmonary rehabilitation versus usual care on health-related quality of life and functional and maximal exercise capacity in persons with COPD.

SEARCH METHODS

We identified additional randomised controlled trials (RCTs) from the Cochrane Airways Group Specialised Register. Searches were current as of March 2014.

SELECTION CRITERIA

We selected RCTs of pulmonary rehabilitation in patients with COPD in which health-related quality of life (HRQoL) and/or functional (FEC) or maximal (MEC) exercise capacity were measured. We defined 'pulmonary rehabilitation' as exercise training for at least four weeks with or without education and/or psychological support. We defined 'usual care' as conventional care in which the control group was not given education or any form of additional intervention. We considered participants in the following situations to be in receipt of usual care: only verbal advice was given without additional education; and medication was altered or optimised to what was considered best practice at the start of the trial for all participants.

DATA COLLECTION AND ANALYSIS

We calculated mean differences (MDs) using a random-effects model. We requested missing data from the authors of the primary study. We used standard methods as recommended by The Cochrane Collaboration.

MAIN RESULTS

Along with the 31 RCTs included in the previous version (2006), we included 34 additional RCTs in this update, resulting in a total of 65 RCTs involving 3822 participants for inclusion in the meta-analysis.We noted no significant demographic differences at baseline between members of the intervention group and those who received usual care. For the pulmonary rehabilitation group, the mean forced expiratory volume at one second (FEV1) was 39.2% predicted, and for the usual care group 36.4%; mean age was 62.4 years and 62.5 years, respectively. The gender mix in both groups was around two males for each female. A total of 41 of the pulmonary rehabilitation programmes were hospital based (inpatient or outpatient), 23 were community based (at community centres or in individual homes) and one study had both a hospital component and a community component. Most programmes were of 12 weeks' or eight weeks' duration with an overall range of four weeks to 52 weeks.The nature of the intervention made it impossible for investigators to blind participants or those delivering the programme. In addition, it was unclear from most early studies whether allocation concealment was undertaken; along with the high attrition rates reported by several studies, this impacted the overall risk of bias.We found statistically significant improvement for all included outcomes. In four important domains of quality of life (QoL) (Chronic Respiratory Questionnaire (CRQ) scores for dyspnoea, fatigue, emotional function and mastery), the effect was larger than the minimal clinically important difference (MCID) of 0.5 units (dyspnoea: MD 0.79, 95% confidence interval (CI) 0.56 to 1.03; N = 1283; studies = 19; moderate-quality evidence; fatigue: MD 0.68, 95% CI 0.45 to 0.92; N = 1291; studies = 19; low-quality evidence; emotional function: MD 0.56, 95% CI 0.34 to 0.78; N = 1291; studies = 19; mastery: MD 0.71, 95% CI 0.47 to 0.95; N = 1212; studies = 19; low-quality evidence). Statistically significant improvements were noted in all domains of the St. George's Respiratory Questionnaire (SGRQ), and improvement in total score was better than 4 units (MD -6.89, 95% CI -9.26 to -4.52; N = 1146; studies = 19; low-quality evidence). Sensitivity analysis using the trials at lower risk of bias yielded a similar estimate of the treatment effect (MD -5.15, 95% CI -7.95 to -2.36; N = 572; studies = 7).Both functional exercise and maximal exercise showed statistically significant improvement. Researchers reported an increase in maximal exercise capacity (mean Wmax (W)) in participants allocated to pulmonary rehabilitation compared with usual care (MD 6.77, 95% CI 1.89 to 11.65; N = 779; studies = 16). The common effect size exceeded the MCID (4 watts) proposed by Puhan 2011(b). In relation to functional exercise capacity, the six-minute walk distance mean treatment effect was greater than the threshold of clinical significance (MD 43.93, 95% CI 32.64 to 55.21; participants = 1879; studies = 38).The subgroup analysis, which compared hospital-based programmes versus community-based programmes, provided evidence of a significant difference in treatment effect between subgroups for all domains of the CRQ, with higher mean values, on average, in the hospital-based pulmonary rehabilitation group than in the community-based group. The SGRQ did not reveal this difference. Subgroup analysis performed to look at the complexity of the pulmonary rehabilitation programme provided no evidence of a significant difference in treatment effect between subgroups that received exercise only and those that received exercise combined with more complex interventions. However, both subgroup analyses could be confounded and should be interpreted with caution.

AUTHORS' CONCLUSIONS

Pulmonary rehabilitation relieves dyspnoea and fatigue, improves emotional function and enhances the sense of control that individuals have over their condition. These improvements are moderately large and clinically significant. Rehabilitation serves as an important component of the management of COPD and is beneficial in improving health-related quality of life and exercise capacity. It is our opinion that additional RCTs comparing pulmonary rehabilitation and conventional care in COPD are not warranted. Future research studies should focus on identifying which components of pulmonary rehabilitation are essential, its ideal length and location, the degree of supervision and intensity of training required and how long treatment effects persist. This endeavour is important in the light of the new subgroup analysis, which showed a difference in treatment effect on the CRQ between hospital-based and community-based programmes but no difference between exercise only and more complex pulmonary rehabilitation programmes.

Utility of the CAT in the therapy assessment of COPD exacerbations in China

BACKGROUND

Chronic obstructive pulmonary disease (COPD) exacerbations are accompanied with increased systemic inflammation, which accelerate the pulmonary function injury and impair the quality of life. Prompt and effective treatments for COPD exacerbations slow down the disease progression, but an objective instrument to assess the efficacy of the treatments following COPD exacerbations is lacking nowadays. The COPD Assessment Test (CAT) is an 8-item questionnaire designed to assess and quantify health status and symptom burden in COPD patients. We hypothesize that the change in CAT score is related to the treatment response following COPD exacerbations.

METHODS

78 inpatients with clinician-diagnosed acute exacerbation of COPD (AECOPD) completed the CAT, St George's Respiratory Questionnaire (SGRQ) and modified Medical Research Council (mMRC) Dyspnea Scale both at exacerbation and the 7th day of therapy, and a subgroup of 39 patients performed the pulmonary function test. Concentrations of serum C-reactive protein (CRP) and plasma fibrinogen were assayed at the same time. Correlations between the CAT and other measurements were examined.

RESULTS

After 7 days' therapy, the CAT and SGRQ scores, mMRC grades, as well as the concentrations of CRP and fibrinogen all decreased significantly (P < 0.001). Meanwhile, the FEV1% predicted had a significant improvement (P < 0.001). The CAT scores were significantly correlated with concurrent concentrations of CRP and fibrinogen, SGRQ scores, FEV1% predicted and mMRC grades (P < 0.05). The change in CAT score was positively correlated with the change of CRP (r = 0.286, P < 0.05), SGRQ score (r = 0.725, P < 0.001) and mMRC grades (r = 0.593, P < 0.001), but not with fibrinogen (r = 0.137, P > 0.05) or FEV1% predicted (r = -0.101, P > 0.05). No relationship was found between the changes of SGRQ score and CRP and fibrinogen (P>0.05).

CONCLUSIONS

The CAT is associate with the changes of systemic inflammation following COPD exacerbations. Moreover, the CAT is responsive to the treatments, similar to other measures such as SGRQ, mMRC dyspnea scale and pulmonary function. Therefore, the CAT is a potentially useful instrument to assess the efficacy of treatments following COPD exacerbations.

Health-related quality of life as a potential predictor in chronic obstructive lung disease patients

Chronic obstructive pulmonary disease is used as an umbrella term for chronic bronchitis and emphysema and is the fourth most common cause of death in North America. Current therapies are based on reducing risk factors as there is no known cure for this disease and hence an important focus of clinical medicine has been the prevention of further decline in physical function and the enhancement of health-related quality of life. The objective of the study is to assess the relationship between the patients' reported health-related quality of life and the severity of disease as measured by clinical indicators. A prospective, nonrandomized, observational study was conducted. The population consisted of subjects presenting to the University of Maryland Medical Center and the Baltimore Veterans Administration outpatient clinic, enrolled according to a convenience, staggered sampling. The Airways obstruction Questionnaire-20, the Medical Outcomes Study short form-12 and the Health Utilities Index instruments were used, and descriptive, as well as multivariate analyses were performed using multivariate linear regression models. The chronic obstructive pulmonary disease cohort was predominantly Caucasian (64%) and male (68%). The disease-specific instrument (Airways obstruction Questionnaire-20) had weak associations with the utility scores as well as a mental component and mild association with a physical component. Results showed a mild association between the disease severity, which is based on the forced expiratory volume in 1 s value, and the health-related quality of life scores. Over a 3-month period, no change was seen in the patient-reported health-related quality of life and the change in health-related quality-of-life scores was not associated with disease severity.

Investigating activity in hospitalized patients with chronic obstructive pulmonary disease: a pilot study

OBJECTIVE

This study examined therapeutic mobility activity, and investigated whether serum levels of inflammatory biomarkers interleukin (IL)-6 and IL-10 varied between periods of rest and activity.

METHODS

This observational, exploratory study took place in a medical intensive care unit and in stepdown units at an urban, academic medical center managed by intensivists. Our sample included 17 adults with exacerbations of chronic obstructive pulmonary disease (COPD).

RESULTS

Our results indicate that activity can occur for about 20 minutes, early during a hospitalization, among critically ill adults with COPD exacerbations, and activity can progress safely over 2 days in an intensive-care or stepdown setting. Physical activity was low in intensity, as measured by actigraphy.

CONCLUSION

Although no significant differences were evident between serum inflammatory biomarkers at rest vs after activity in this small sample, trend-related data indicate that low-intensity activity has the potential to alter the inflammatory profile of hospitalized COPD adults.

Outcome measures in chronic obstructive pulmonary disease (COPD): strengths and limitations

Current methods for assessing clinical outcomes in COPD mainly rely on physiological tests combined with the use of questionnaires. The present review considers commonly used outcome measures such as lung function, health status, exercise capacity and physical activity, dyspnoea, exacerbations, the multi-dimensional BODE score, and mortality. Based on current published data, we provide a concise overview of the principles, strengths and weaknesses, and discuss open questions related to each methodology. Reviewed is the current set of markers for measuring clinically relevant outcomes with particular emphasis on their limitations and opportunities that should be recognized when assessing and interpreting their use in clinical trials of COPD.

The Relationship Between Exercise Tolerance and Other Outcomes in COPD

Exercise training has been shown to be a clinically effective therapeutic intervention for COPD patients resulting in a myriad of beneficial effects. These include improvements in exercise tolerance, health-related quality of life and activity levels. Activity levels can be assessed using health-related quality of life instruments or instruments designed especially for this purpose. Previous studies show that the relationships between activities of daily living, assessed using generic health-related quality of life instruments, and exercise vary considerably with correlations ranging from 0.18-0.72. The relationships between activities of daily living, assessed using disease specific health-related quality of life instruments, and exercise also vary considerably with correlations ranging from 0.14-0.59. The relationships between activities of daily living, assessed using activities of daily living instruments, and exercise are less variable and generally stronger with correlations ranging from 0.34-0.83. Relationships between generic health-related quality of life instruments and exercise vary considerably (0.19-0.65) as do relationships between disease specific health-related quality of life instruments and exercise (0.18-0.61). The correlations between changes in activities of daily living and changes in exercise following pulmonary rehabilitation are generally weak (0.13-0.28). The correlations between changes in health-related quality of life and changes in exercise following pulmonary rehabilitation are also generally weak. The fact that these outcomes are not tightly associated is due, in part, to the variability in responses to the instruments used and the fact that the various instruments were often designed to assess different constructs.

Update on the pharmacologic therapy for chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease is a treatable disease characterized by progressive airflow limitation. Prevention of disease progression; improvement of symptoms, exercise tolerance, and health status; and decrease in exacerbations and mortality are the goals of management. Inhaled short-acting bronchodilators are recommended for symptoms in mild disease, whereas inhaled long-acting bronchodilators are recommended for maintenance therapy of daily symptoms. When symptoms are not controlled using one bronchodilator, combining bronchodilators may be more effective. Combining a long-acting beta-agonist with an inhaled corticosteroid is more effective than either agent alone. Several novel therapies are in different stages of development.