The Inaccuracy of Patient Recall for COPD Exacerbation Rate Estimation and Its Implications: Results from Central Adjudication

[What Is an Acute COPD Exacerbation? Results of a Survey among Primary Care Physicians in the German-Speaking Part of Switzerland]

What Is an Acute COPD Exacerbation? Results of a Survey among Primary Care Physicians in the German-Speaking Part of Switzerland Abstract. Acute exacerbations have a relevant impact on morbidity and mortality in patients with chronic obstructive pulmonary disease (COPD), which is why prophylactic and early treatment have become indispensable. However, COPD exacerbations are significantly under-diagnosed, possibly due to linguistic discrepancies between physician and patient. The aim of this study was to disclose how exacerbations are perceived by the GPs (general practitioners) and their patients and what linguistic conventions they use. This survey showed that GPs and their patients quite often have a divergent notion a common of COPD exacerbations.

Towards precision in defining COPD exacerbations

COPD is the most prevalent chronic respiratory disease worldwide and a major cause of disability and death. Acute exacerbations of COPD remain a key feature of the disease in many patients and research assessing interventions to prevent and treat them requires a robust definition with high sensitivity and specificity. To date, no such definition exists, and multiple different definitions are used in clinical studies depending on the research question. The strengths and weaknesses of current definitions are discussed in the context of evolving knowledge and different settings in which studies are undertaken. Whether identification and recording of exacerbations remains essentially clinical, or can be identified with a dependable biomarker, it should be sensitive and adaptable to context while retaining clarity and facilitating data collection. This is essential to progress a better understanding of the pathophysiology and phenotypic expression of exacerbations to reduce their impact and personal burden for patients.

COPD exacerbations carry high risk for long-term disability and death. As the search for a standardised measure continues, study investigators must ensure definitions are explicit and justified to better understand how to prevent and manage these episodes.https://bit.ly/2UNqScy

Recommendations for COPD management in Central and Eastern Europe

INTRODUCTION

The Global Initiative for Chronic Obstructive Lung Disease (GOLD) strategy report provides guidance on effective management of chronic obstructive pulmonary disease (COPD) according to local healthcare systems. However, COPD is a heterogenous disease and certain aspects, including prevalence, disease-time course and phenotype distribution, can differ between countries. Moreover, features of clinical practice and healthcare systems for COPD patients can vary widely, even in geographically close and economically similar countries.

AREAS COVERED

Based on an initial workshop of respiratory physicians from eleven countries across Central and Eastern Europe (CEE) in December 2018 and subsequent discussions, this article offers region-specific insights from clinical practice and healthcare systems in CEE. Taking GOLD 2020 recommendations into account, we suggest approaches to adapt these into national clinical guidelines for COPD management in CEE.

EXPERT OPINION

Several factors should be considered when optimizing management of COPD in CEE compared with other regions, including differences in smoking status, vaccination uptake, prevalence of tuberculosis and nontuberculous mycobacteria, and variations in healthcare systems. We provide guidance and algorithms for pharmacologic and non-pharmacologic management of COPD for the following scenarios: initial and follow-up treatment, treatment of patients with frequent exacerbations, and withdrawal of inhaled corticosteroids where appropriate.

Impact of PIF, Inhalation Technique and Medication Adherence on Health Status and Exacerbations in COPD: Protocol of a Real-World Observational Study (PIFotal COPD Study)

INTRODUCTION

Dry powder inhalers (DPIs), a commonly prescribed inhaler type for respiratory diseases, require patients to generate sufficient peak inspiratory flow (PIF) to ensure optimal drug delivery to the airways. Effectiveness of therapy also requires a good inhalation technique and adequate medication adherence. For patients with chronic obstructive pulmonary disease (COPD), recent studies conducted in tertiary care suggest that DPI users with suboptimal PIF have poorer COPD-related health status and increased exacerbation risk versus those with optimal PIF. The PIFotal study will investigate the impact of PIF, inhalation technique and medication adherence on patient-reported outcomes in patients with COPD in primary care using a DPI for their maintenance therapy.

METHODS AND ANALYSIS

This cross-sectional observational study will assess 1200 patients (aged ≥ 40 years, diagnosed with COPD and using a DPI for COPD maintenance therapy for ≥ 3 months) from the Netherlands, Spain, Portugal, Poland, Greece and Australia. Assessments will consist of (1) PIF measurements (usual patient inhalation manoeuvre, maximal PIF against resistance of own inhaler, and maximal PIF against low resistance); (2) Clinical COPD Questionnaire (CCQ), COPD Assessment Test and Test of Adherence to Inhalers scores; and (3) video recordings of patient inhalation technique. Dependent variables include health status (CCQ score), number of self-reported exacerbations in previous 12 months, and healthcare resource utilisation in previous 6 months. Independent variables include PIF values, inhalation technique errors, medication adherence, and demographic and clinical characteristics. In the primary analysis, the mean difference in CCQ score between patients (1) with optimal/suboptimal PIF, (2) exhibiting/not exhibiting inhalation technique errors, and (3) adhering/not adhering to medication will be examined in a multivariable linear mixed model.

ETHICS

The study protocol was approved by ethics committees/institutional review boards of all participating sites prior to enrolment; written informed consent was obtained from all study participants.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov: NCT04532853.

Real-life experience with high-frequency chest wall oscillation vest therapy in adults with non-cystic fibrosis bronchiectasis

Background:

High frequency chest wall oscillation (HFCWO) has long been used for airway clearance for patients with cystic fibrosis. Only limited research has evaluated this therapy in adult patients with non-cystic fibrosis bronchiectasis (NCFB).

Methods:

Data from 2596 patients from a registry of adult bronchiectasis patients using HFCWO therapy was used to evaluate hospitalization patterns before and after initiation of HFCWO therapy, as well as antibiotic use and self-reported metrics of quality of life. Self-reported outcomes were also reviewed by cross-checking with sampled patient charts and found to be consistent.

Results:

The number of patients who had at least one respiratory-related hospitalization decreased from 49.1% (192/391) in the year before to 24.0% (94/391) in the year after starting HFCWO therapy (p-value < 0.001). At the same time, the number of patients who required three or more hospitalizations dropped from 14.3% (56/391) to 5.6% (22/391). Patients currently taking oral antibiotics for respiratory conditions decreased from 57.7% upon initiation of therapy to 29.9% within 1 year (p < 0.001). Patients who subjectively rated their “overall respiratory health” as good to excellent increased from 13.6% upon initiation of therapy to 60.5% in 1 year (p < 0.001) and those who rated their “ability to clear your lungs” as good to excellent increased from 13.9% to 76.6% (p < 0.001).

Conclusion:

NCFB patients showed improved self-reported outcomes associated with the initiation of HFCWO therapy as measured by number of hospitalizations, antibiotic use, and the subjective experience of airway clearance. The improvement was observed early on after initiation of therapy and sustained for at least 1 year.

The reviews of this paper are available via the supplemental material section.

The Identification and Cost of Acute Chronic Obstructive Pulmonary Disease Exacerbations in a United States Population Healthcare Claims Database

Almost half of chronic obstructive pulmonary disease (COPD) exacerbations are estimated to be inaccurately reported by patients, inconsistently recorded in medical records, or not measured due to coding errors inherent to administrative claims. This retrospective observational study aimed to develop an algorithm capable of detecting acute COPD exacerbations (AECOPD) in healthcare claims and estimate costs associated with AECOPD over a 12-month period. Commercial and Medicare Advantage healthcare plan members (≥40 years old) with evidence of COPD were identified from US healthcare-claims database. To refine the algorithm detecting AECOPD in claims data, sensitivity and positive-predictive value calculations were performed to compare AECOPD identification in healthcare claims versus medical charts. Analyses were also performed to examine total exacerbation-related costs for events identified with the new claims algorithm plus events missed. The final algorithm had a sensitivity of 84.9%, with a positive-predictive value of 67.5%. Medical records were abstracted for 402 patients. In the overall sample of healthcare claims (n = 243,998), the algorithm detected ≥1 AECOPD event in 61.3% of patients. The mean cost per patient during an AECOPD episode, identified by the final algorithm, was USD 6,760 (n = 301), with an incremental average cost of USD 607 (n = 122) to 'unobserved' episodes (not reported in claims data) among the chart sample. After multivariate modeling, predicted yearly exacerbation costs translated to USD 1.12 billion per 100,000 patients (USD 12,000 per patient), with 35.76 million associated with unobserved exacerbations. While the final algorithm warrants further validation and study, these findings highlight unobserved AECOPD and their economic burden.

Methods for safety and endpoint ascertainment: identification of adverse events through scrutiny of negatively adjudicated events

Background

The primary goal of phase 2 and 3 clinical trials is to evaluate the safety and effectiveness of therapeutic interventions, and efficient and reproducible ascertainment of important clinical events, either as clinical outcome events (COEs) or adverse events (AEs), is critical. Clinical outcomes require consistency and clinical judgment, so these events are often adjudicated centrally by clinical events classification (CEC) physician reviewers using standardized definitions. In contrast, AEs are reported by sites to the trial coordinating center based on common reporting criteria set by regulatory authorities and trial sponsors. These different requirements have led to the development of separate tracks for COE and AE review.

Main body

Potential COEs that fail to meet standardized definitions for CEC adjudication – i.e. negatively adjudicated events (NAE) – may meet criteria for AEs. Trial oversight practices require the sponsor to process AEs regardless of how the AEs are submitted; therefore, review of NAEs may be necessary to ensure that important AEs do not go unreported. The Duke Clinical Research Institute (DCRI) developed and implemented a process for scrutinizing NAEs to detect potential missed serious AEs. Initial experience with this process across two trials suggests that approximately 0.2% of NAEs are serious unexpected AEs that were not otherwise reported and another 1.5% are serious expected AEs.

Conclusions

Given their infrequent concealment of serious AEs in two large trials assessing cardiovascular outcomes, routine scrutiny of NAEs to identify AEs is not recommended at this time, though it may be useful in some trials and should be carefully considered by the trial team. Closer integration of data across safety surveillance and endpoint adjudication systems may enable scrutiny of NAEs when indicated while limiting complexity associated with this process.

Diffusion tensor imaging of white matter integrity in relation to smoking index and exacerbations in severe chronic obstructive pulmonary disease

Background

Diffusion tensor imaging (DTI) is a non-invasive MR modality that provides an evaluation of brain tissue microstructure and architecture in vivo. We aimed to assess the diagnostic value of DTI parameters in evaluating cerebral white matter integrity in patients of severe chronic obstructive pulmonary disease (COPD) and correlate these parameters with smoking index (SI) and the number of exacerbations in the last year.

This prospective study included 30 COPD male past smoker patients and 15 age- and sex-matched nonsmoker controls. Staging of COPD, SI and number of exacerbations in the last year were obtained. Routine brain MRI and DTI were done in all subjects. The selected white matter tracts’ fractional anisotropy (FA), and mean diffusivity (MD) were calculated in the region of interest in axial slices.

Results

The mean FA and MD values of all selected white matter tracts showed a high significant difference (p < 0.001) between patients and control group. The correlation between FA, SI and exacerbation frequency was not significant in the majority of white matter tracts (p > 0.05). The correlation between MD, SI and exacerbation frequency was significant for the majority of tracts (p < 0.05).

Conclusion

DTI metrics are valuable non-invasive tools in evaluating the white matter abnormalities in COPD patients. Smoking index and frequency of exacerbations have possible relation to extra-pulmonary cerebral manifestations of COPD.

Exploring the potential benefits of digital health technology for the management of COPD: a qualitative study of patient perceptions

Engaging chronic obstructive pulmonary disease (COPD) patients to actively participate in self-management has proven difficult. Digital health technology (DHT) promises to facilitate a patient-centred care model for the management of COPD by empowering patients to self-manage effectively. However, digital health studies in COPD have yet to demonstrate significant patient outcomes, suggesting that this research has still to adequately address the needs of patients in the intervention development process. The current study explored COPD patients' perceptions of the potential benefits of DHT in the self-management and treatment of their disease. A sample of convenience was chosen and participants (n=30) were recruited from two Dublin university hospitals and each underwent a qualitative semi-structured interview. Thematic analysis of the data was completed using NVivo 12 software. Six themes were identified: symptom management, anxiety management, interaction with physician, care management, personalising care and preventative intervention. In our findings, patients reported a willingness to take a more active role in self-management using DHT. They perceived DHT potentially enhancing their self-management by improving self-efficacy and engagement and by supporting healthcare professionals to practise preventative care provision. The findings can be used to inform patient-centred COPD digital interventions for researchers and clinicians who wish to develop study aims that align with the needs and preferences of patients.

Longitudinal change of FEV1 and inspiratory capacity: clinical implication and relevance to exacerbation risk in patients with COPD

Background and objective

FEV₁ is the gold standard for assessment of COPD. We compared efficacy of FEV₁, inspiratory capacity (IC), and IC to total lung capacity (TLC) ratio in the evaluation of COPD and their association with exacerbation.

Methods

We analyzed the association of dyspnea severity, quality of life status, and lung function with lung function measurements and exacerbation risk in 982 patients enrolled in the Korea COPD Subgroup Registry and Subtype Research study. Exacerbation and longitudinal lung function change were evaluated in 3 years’ follow-up.

Results

The FEV₁, IC, and IC to TLC ratio showed comparable negative correlations with dyspnea severity and quality of life status, and positive correlation with exercise capacity. In patients with >2 events/year, annual rate of change in FEV₁ and IC tended to decline more rapidly in those with FEV₁ <50% than in those with FEV₁ >50% (−14.46±19.40 mL/year vs 12.29±9.24 mL/year, P=0.213; −4.75±17.28 mL/year vs −78.05±34.16 mL/year, P=0.056 for FEV₁ and IC, respectively), without significance.

Conclusion

Longitudinal changes in IC and FEV₁ were not significantly associated with exacerbation risk.

Characterization of cardiovascular clinical events and impact of event adjudication on the treatment effect of darapladib versus placebo in patients with stable coronary heart disease: Insights from the STABILITY trial

BACKGROUND

Clinical Endpoint Classification (CEC) in clinical trials allows FOR standardized, systematic, blinded, and unbiased adjudication of investigator-reported events. We quantified the agreement rates in the STABILITY trial on 15,828 patients with stable coronary heart disease.

METHODS

Investigators were instructed to report all potential events. Each reported event was reviewed independently by 2 reviewers according to prespecified processes and prespecified end point definitions. Concordance between reported and adjudicated cardiovascular (CV) events was evaluated, as well as event classification influence on final study results.

RESULTS

In total, CEC reviewed 7,096 events: 1,064 deaths (696 CV deaths), 958 myocardial infarctions (MI), 433 strokes, 182 transient ischemic attacks, 2,052 coronary revascularizations, 1,407 hospitalizations for unstable angina, and 967 hospitalizations for heart failure. In total, 71.8% events were confirmed by CEC. Concordance was high (>80%) for cause of death and nonfatal MI and lower for hospitalization for unstable angina (25%) and heart failure (50%). For the primary outcome (composite of CV death, MI, and stroke), investigators reported 2,086 events with 82.5% confirmed by CEC. The STABILITY trial treatment effect of darapladib versus placebo on the primary outcome was consistent using investigator-reported events (hazard ratio 0.96 [95% CI 0.87-1.06]) or adjudicated events (hazard ratio 0.94 [95% CI 0.85-1.03]).

CONCLUSIONS

The primary outcome results of the STABILITY trial were consistent whether using investigator-reported or CEC-adjudicated events. The proportion of investigator-reported events confirmed by CEC varied by type of event. These results should help improve event identification in clinical trials to optimize ascertainment and adjudication.

Chronic Obstructive Pulmonary Disease Exacerbations: A Need for Action

Chronic obstructive pulmonary disease (COPD) is a leading cause of morbidity and mortality, with exacerbations contributing strongly to the overall severity and burden of disease at the individual level. Many patients with COPD are managed predominantly in the primary care setting; therefore, primary care physicians (PCPs) must be aware of and understand the causes, effects, and management of COPD exacerbations. This review offers practical information about how exacerbations are defined in the treatment setting, pathogenic and environmental causes, options for exacerbation treatment and prevention, and suggestions for improving care in the clinic. Exacerbations have a strong negative effect on patients and are associated with an increased risk of further exacerbations and decreases in lung function. Thus, it is important that exacerbations not requiring hospitalization be identified and confidently managed in the clinical setting. Understanding treatment options for acute exacerbations and maintenance treatment to prevent future exacerbations may help PCPs better understand what they can do to support their patients. This review aims to provide useful guidance for PCPs to identify exacerbations and adjust their practice for optimal management of exacerbations in patients with COPD. It also aims to encourage PCPs that they have an important task in integrating effective COPD management into the primary care setting.

Recruitment of patients with Chronic Obstructive Pulmonary Disease (COPD) from the Clinical Practice Research Datalink (CPRD) for research

Databases of electronic health records (EHR) are not only a valuable source of data for health research but have also recently been used as a medium through which potential study participants can be screened, located and approached to take part in research. The aim was to assess whether it is feasible and practical to screen, locate and approach patients to take part in research through the Clinical Practice Research Datalink (CPRD). This is a cohort study in primary care. The CPRD anonymised EHR database was searched to screen patients with Chronic Obstructive Pulmonary Disease (COPD) to take part in a research study. The potential participants were contacted via their General Practitioner (GP) who confirmed their eligibility. Eighty two practices across Greater London were invited to the study. Twenty-six (31.7%) practices consented to participate resulting in a pre-screened list of 988 patients. Of these, 632 (63.7%) were confirmed as eligible following the GP review. Two hundred twenty seven (36%) response forms were received by the study team; 79 (34.8%) responded ‘yes’ (i.e., they wanted to be contacted by the research assistant for more information and to talk about enrolling in the study), and 148 (65.2%) declined participation. This study has shown that it is possible to use EHR databases such as CPRD to screen, locate and recruit participants for research. This method provides access to a cohort of patients while minimising input needed by GPs and allows researchers to examine healthcare usage and disease burden in more detail and in real-life settings.

Screening anonymized electronic health records could prove a valuable, time-saving method for identifying patient cohorts for research projects. Jennifer Quint at Imperial College, London, and co-workers used primary care databases provided by doctors’ surgeries in London to find suitable patients for a study monitoring daily chronic obstructive pulmonary disease (COPD) symptoms. Using carefully-designed algorithms, the researchers identified 988 COPD patients who met eligibility criteria and lived within defined localities. Quint’s team then asked the patients’ doctors to review and approve the list for their own practice, thus limiting the doctors’ workload for selecting patients. The researchers approached 632 patients to invite them to participate in the research; 66 were enrolled. This provided an adequate number for the study, though the team highlight a need to improve strategies that encourage patients to take part in research.

Effects of the "Living well with COPD" intervention in primary care: a comparative study

The pivotal objective of chronic obstructive pulmonary disease (COPD) self-management programmes is behaviour change to avoid moderate and severe exacerbations and improve health related quality of life.In a prospectively planned, controlled study, COPD patients who participated in the "Living well with COPD" (LWWCOPD) self-management intervention were compared with usual care patients from the primary care COPD Cohort ICE COLD ERIC, who did not receive self-management intervention (NCT00706602) The primary outcome was behaviour change and disease-specific health related quality of life after 1 year. Secondary end-points included exacerbation rates. We calculated mixed linear, zero-inflated negative binomial and logistic regression models and used propensity scores to counteract confounding.467 patients, 71 from the LWWCOPD and 396 from the usual care cohort, were included. The differences between intervention and control were 0.54 (95% CI 0.13-0.94) on the Chronic Respiratory Questionnaire domain "mastery", 0.55 (95% CI 0.11-0.99) on "fatigue", 0.54 (0.14-0.93) on "emotional function" and 0.64 (95% CI 0.14-1.14) on "dyspnoea". The intervention considerably reduced the risk of moderate and severe exacerbations (incidence rate ratio 0.36, 95% CI 0.25-0.52).Self-management coaching in primary care improves health-related quality of life and lowers exacerbation rates and health care use.

Frequency of COPD in health care workers who smoke

Objective:

COPD is one of the major causes of morbidity and mortality worldwide. Health care providers should counsel their smoking patients with COPD to quit smoking as the first treatment step. However, in countries with high prevalences of smoking, health care workers may also be smokers. The aim of this study was to determine the frequency and severity of COPD in health care workers who smoke.

Methods:

This was a cross-sectional study. All health care workers who smoke, from nine health care centers in Serbia, were invited to participate in the study and perform spirometry. The diagnosis of COPD was based on a post-bronchodilator FEV₁/FVC ratio of < 0.70. All patients completed the COPD Assessment Test and the Fagerström Test for Nicotine Dependence.

Results:

The study involved 305 subjects, and 47 (15.4%) were male. The mean age of the participants was 49.0 ± 6.5 years. Spirometry revealed obstructive ventilatory defect in 33 subjects (10.8%); restrictive ventilatory defect, in 5 (1.6%); and small airway disease, in 96 (31.5%). A diagnosis of COPD was made in 29 patients (9.5%), 25 (86.2%) of whom were newly diagnosed. On the basis of the Global Initiative for COPD guidelines, most COPD patients belonged to groups A or B (n = 14; 48.2%, for both); 1 belonged to group D (3.6%); and none, to group C. Very high nicotine dependence was more common in those with COPD than in those without it (20.7% vs. 5.4%, p = 0.01).

Conclusions:

In this sample of health care workers, the frequency of COPD was comparable with that in the general population. The presence of COPD in health care workers who smoke was associated with higher nicotine dependence.

Variability in objective and subjective measures affects baseline values in studies of patients with COPD

Rationale

Understanding the reliability and repeatability of clinical measurements used in the diagnosis, treatment and monitoring of disease progression is of critical importance across all disciplines of clinical practice and in clinical trials to assess therapeutic efficacy and safety.

Objectives

Our goal is to understand normal variability for assessing true changes in health status and to more accurately utilize this data to differentiate disease characteristics and outcomes.

Methods

Our study is the first study designed entirely to establish the repeatability of a large number of instruments utilized for the clinical assessment of COPD in the same subjects over the same period. We utilized SPIROMICS participants (n = 98) that returned to their clinical center within 6 weeks of their baseline visit to repeat complete baseline assessments. Demographics, spirometry, questionnaires, complete blood cell counts (CBC), medical history, and emphysema status by computerized tomography (CT) imaging were obtained.

Results

Pulmonary function tests (PFTs) were highly repeatable (ICC’s >0.9) but the 6 minute walk (6MW) was less so (ICC = 0.79). Among questionnaires, the Saint George’s Respiratory Questionnaire (SGRQ) was most repeatable. Self-reported clinical features, such as exacerbation history, and features of chronic bronchitis, often produced kappa values <0.6. Reported age at starting smoking and average number of cigarettes smoked were modestly repeatable (kappa = 0.76 and 0.79). Complete blood counts (CBC) variables produced intraclass correlation coefficients (ICC) values between 0.6 and 0.8.

Conclusions

PFTs were highly repeatable, while subjective measures and subject recall were more variable. Analyses using features with poor repeatability could lead to misclassification and outcome errors. Hence, care should be taken when interpreting change in clinical features based on measures with low repeatability. Efforts to improve repeatability of key clinical features such as exacerbation history and chronic bronchitis are warranted.

White matter lesions characterise brain involvement in moderate to severe chronic obstructive pulmonary disease, but cerebral atrophy does not

Background

Brain pathology is relatively unexplored in chronic obstructive pulmonary disease (COPD). This study is a comprehensive investigation of grey matter (GM) and white matter (WM) changes and how these relate to disease severity and cognitive function.

Methods

T1-weighted and fluid-attenuated inversion recovery images were acquired for 31 stable COPD patients (FEV₁ 52.1% pred., PaO₂ 10.1 kPa) and 24 age, gender-matched controls. T1-weighted images were segmented into GM, WM and cerebrospinal fluid (CSF) tissue classes using a semi-automated procedure optimised for use with this cohort. This procedure allows, cohort-specific anatomical features to be captured, white matter lesions (WMLs) to be identified and includes a tissue repair step to correct for misclassification caused by WMLs. Tissue volumes and cortical thickness were calculated from the resulting segmentations. Additionally, a fully-automated pipeline was used to calculate localised cortical surface and gyrification. WM and GM tissue volumes, the tissue volume ratio (indicator of atrophy), average cortical thickness, and the number, size, and volume of white matter lesions (WMLs) were analysed across the whole-brain and regionally – for each anatomical lobe and the deep-GM. The hippocampus was investigated as a region-of-interest. Localised (voxel-wise and vertex-wise) variations in cortical gyrification, GM density and cortical thickness, were also investigated. Statistical models controlling for age and gender were used to test for between-group differences and within-group correlations. Robust statistical approaches ensured the family-wise error rate was controlled in regional and local analyses.

Results

There were no significant differences in global, regional, or local measures of GM between patients and controls, however, patients had an increased volume (p = 0.02) and size (p = 0.04) of WMLs. In patients, greater normalised hippocampal volume positively correlated with exacerbation frequency (p = 0.04), and greater WML volume was associated with worse episodic memory (p = 0.05). A negative relationship between WML and FEV₁ % pred. approached significance (p = 0.06).

Conclusions

There was no evidence of cerebral atrophy within this cohort of stable COPD patients, with moderate airflow obstruction. However, there were indications of WM damage consistent with an ischaemic pathology. It cannot be concluded whether this represents a specific COPD, or smoking-related, effect.

Electronic supplementary material

The online version of this article (doi:10.1186/s12890-017-0435-1) contains supplementary material, which is available to authorized users.

Prediction of long-term clinical outcomes using simple functional exercise performance tests in patients with COPD: a 5-year prospective cohort study

The 1-min sit-to-stand (1-min STS) test and handgrip strength test have been proposed as simple tests of functional exercise performance in chronic obstructive pulmonary disease (COPD) patients. We assessed the long-term (5-year) predictive performance of the 1-min sit-to-stand and handgrip strength tests for mortality, health-related quality of life (HRQoL) and exacerbations in COPD patients. In 409 primary care patients, we found the 1-min STS test to be strongly associated with long-term morality (hazard ratio per 3 more repetitions: 0.81, 95% CI 0.65 to 0.86) and moderately associated with long-term HRQoL. Neither test was associated with exacerbations. Our results suggest that the 1-min STS test may be useful for assessing the health status and long-term prognosis of COPD patients. This study was registered at http://www.clinicaltrials.gov/ (NCT00706602, 25 June 2008).

Bias away from the null due to miscounted outcomes? A case study on the TORCH trial

Count outcomes occur in virtually all disciplines, such as medicine, epidemiology or biology, but they often contain error. Recently, it has been shown that self-reported numbers of exacerbations of Chronic Obstructive Pulmonary Disease patients can be considerably miscounted. Motivated by this result, we reanalysed data from the Towards a Revolution in Chronic Obstructive Pulmonary Disease Health trial, a large randomized controlled trial with the self-reported number of exacerbations of Chronic Obstructive Pulmonary Disease patients as outcome. To adjust for miscounting error in the response of Poisson and (zero-inflated) negative binomial models, we introduce novel, general methodology. The key idea is to formulate a zero-inflated negative binomial model to capture the error mechanism. This parametric approach automatically circumvents drawbacks of previously suggested methodology that treats miscounted outcomes in the misclassification framework. Prior information for the response error model parameters was elicited from validation data of an external study and adaptively weighted to account for potential prior-data conflict. The results of the Bayesian hierarchical modelling approach indicated that the treatment effect has been overestimated in the original study. However, closer inspection revealed that this unexpected result was an artefact of an unaccounted time dependency of the treatment effect.

Biomarkers Predictive of Exacerbations in the SPIROMICS and COPDGene Cohorts

RATIONALE

Chronic obstructive pulmonary disease exacerbations are associated with disease progression, higher healthcare cost, and increased mortality. Published predictors of future exacerbations include previous exacerbation, airflow obstruction, poor overall health, home oxygen use, and gastroesophageal reflux.

OBJECTIVES

To determine the value of adding blood biomarkers to clinical variables to predict exacerbations.

METHODS

Subjects from the SPIROMICS (Subpopulations and Intermediate Outcomes Measures in COPD Study) (n = 1,544) and COPDGene (Genetic Epidemiology of COPD) (n = 602) cohorts had 90 plasma or serum candidate proteins measured on study entry using Myriad-RBM multiplex panels. We defined total exacerbations as subject-reported worsening in respiratory health requiring therapy with corticosteroids and/or antibiotics, and severe exacerbations as those leading to hospitalizations or emergency room visits. We assessed retrospective exacerbations during the 12 months before enrollment and then documented prospective exacerbations in each cohort. Exacerbations were modeled for biomarker associations with negative binomial regression including clinical covariates (age, sex, percent predicted FEV1, self-reported gastroesophageal reflux, St. George's Respiratory Questionnaire score, smoking status). We used the Stouffer-Liptak test to combine P values for metaanalysis.

MEASUREMENTS AND MAIN RESULTS

Between the two cohorts, 3,471 total exacerbations (1,044 severe) were reported. We identified biomarkers within each cohort that were significantly associated with a history of exacerbation and with a future exacerbation, but there was minimal replication between the cohorts. Although established clinical features were predictive of exacerbations, of the blood biomarkers only decorin and α2-macroglobulin increased predictive value for future severe exacerbations.

CONCLUSIONS

Blood biomarkers were significantly associated with the occurrence of exacerbations but were not robust between cohorts and added little to the predictive value of clinical covariates for exacerbations.