Patterns of physical activity and survival following cardiac resynchronization therapy implantation: the ALTITUDE activity study

Aims

Cardiac resynchronization therapy with implantable defibrillator backup (CRT-D) improves outcomes, but predictors and markers of response remain limited. Physical activity information collected by CRT devices may provide insights to CRT response and the relationship between activity changes and survival.

Methods and results

Patients entered into the LATITUDE remote monitoring system from 2008 to 2012 after receipt of a new CRT-D were eligible. Mean daily activity was calculated from LATITUDE uploads at baseline (first 3-10 days following implant) and 6 months (180-210 days). Pairwise differences for baseline-6-month activity were calculated, and survival according to quintiles of 6-month activity change was assessed. Cox regression was used to examine the adjusted association between survival and baseline-6-month activity change. A total of 26 509 patients were followed for a median of 2.3 years (mean age 70.2 ± 11.0 years, 70.7% male). Mean baseline activity was 66.2 ± 47.7 min/day, with mean paired increase at 6 months of 37.1 ± 48.2 min/day [95% CI (confidence interval), 36.5-37.6, P < 0.0001], though 15.5% of patients did not improve or worsened at 6 months. Survival at 3 years was significantly higher in the largest baseline-6-month activity change quintile vs. the lowest quintile (88.9% vs. 62.1%, log-rank P-value < 0.001). Adjusted for age and gender, higher 6-month activity change was associated with a lower risk of death (adjusted hazard ratios 0.65 per 30 min increase in activity, 95% CI, 0.63-0.67).

Conclusions

Change in physical activity between baseline and 6 months following CRT implantation is strongly associated with survival.

Risk Factors and Temporal Trends of Complications Associated With Transvenous Implantable Cardiac Defibrillator Leads

Background

The transvenous implantable cardioverter‐defibrillator (ICD) lead is the most common source of complications in a traditional ICD system. This investigation aims to determine the incidence, predictors, and costs associated with these complications using a large insurance database.

Methods and Results

Data from the OptumLabs™ Data Warehouse, which include diagnosis, physician and procedure codes, and claims from patient hospitalizations, were analyzed. Patients with a de novo ICD or cardiac resynchronization therapy defibrillator implanted from January 1, 2003, through June 30, 2015, were included; those who did not have continuous coverage beginning 1 year before implantation were excluded, resulting in 40 837 patients followed up over an average of 2.3±2.1 years. Patients were followed up until they had the procedure or their last active date in the database. Of 20 580 device procedures, 2165 (5.3%) and 771 (1.9%) had mechanical and infectious complications, respectively. The 5‐year rate of freedom from mechanical complication was 92.0% and 89.3% for ICDs and cardiac resynchronization therapy defibrillators, respectively. Infectious complications were more likely in patients with a history of atrial fibrillation, diabetes mellitus, and renal disease, and the risk increased with subsequent device procedures. Younger age, female sex, lack of comorbidities, and implantations between 2003 and 2008 were associated with more mechanical complications.

Conclusions

Incidence of mechanical and infectious complications of transvenous ICD leads over long‐term follow‐up is much higher in the real world than in clinical studies. In our study cohort, 1 of 4 transvenous ICD leads had mechanical complications when followed up to 10 years. The high rate of reintervention leads to additional complications.

Consumer segmentation and time interval between types of hospital admission: a clinical linkage database study

Background

Healthcare policies target unplanned hospital admissions and 30-day re-admission as key measures of efficiency, but do not focus on factors that influence trajectories of different types of admissions in the same patient over time.

Objectives

To investigate the influence of consumer segmentation and patient factors on the time intervals between different types of hospital admission.

Research design, subjects and measures

A cohort design was applied to an anonymised linkage database for adults aged 40 years and over (N = 58 857). Measures included Mosaic segmentation, multimorbidity defined on six chronic condition registers and hospital admissions over a 27-month time period.

Results

The shortest mean time intervals between two consecutive planned admissions were: 90 years and over (160 days (95% confidence interval (CI): 146-175)), Mosaic groups 'Twilight subsistence' (171 days (164-179)) or 'Welfare borderline' and 'Municipal dependency' (177 days (172-182)) compared to the reference Mosaic groups (186 days (180-193)), and multimorbidity count of four or more (137 days (130-145)). Mosaic group 'Twilight subsistence' (rate ratio (RR) 1.22 (95% CI: 1.08-1.36)) or 'Welfare borderline' and 'Municipal dependency' RR 1.20 (1.10-1.31) were significantly associated with higher rate to an unplanned admission following a planned event. However, associations between patient factors and unplanned admissions were diminished by adjustment for planned admissions.

Conclusion

Specific consumer segmentation and patient factors were associated with shorter time intervals between different types of admissions. The findings support innovation in public health approaches to prevent by a focus on long-term trajectories of hospital admissions, which include planned activity.

The distribution of blood eosinophil levels in a Japanese COPD clinical trial database and in the rest of the world

Background

Blood eosinophil measurements may help to guide physicians on the use of inhaled corticosteroids (ICS) for patients with chronic obstructive pulmonary disease (COPD). Emerging data suggest that COPD patients with higher blood eosinophil counts may be at higher risk of exacerbations and more likely to benefit from combined ICS/long-acting beta₂-agonist (LABA) treatment than therapy with a LABA alone. This analysis describes the distribution of blood eosinophil count at baseline in Japanese COPD patients in comparison with non-Japanese COPD patients.

Methods

A post hoc analysis of eosinophil distribution by percentage and absolute cell count was performed across 12 Phase II–IV COPD clinical studies (seven Japanese studies [N=848 available absolute eosinophil counts] and five global studies [N=5,397 available eosinophil counts] that included 246 Japanese patients resident in Japan with available counts). Blood eosinophil distributions were assessed at baseline, before blinded treatment assignment.

Findings

Among Japanese patients, the median (interquartile range) absolute eosinophil count was 170 cells/mm³ (100–280 cells/mm³). Overall, 612/1,094 Japanese patients (56%) had an absolute eosinophil count ≥150 cells/mm³ and 902/1,304 Japanese patients (69%) had a percentage eosinophil ≥2%. Among non-Japanese patients, these values were 160 (100–250) cells/mm³, 2,842/5,151 patients (55%), and 2,937/5,155 patients (57%), respectively. The eosinophil distribution among Japanese patients was similar to that among non-Japanese patients. Within multi-country studies with similar inclusion criteria, the eosinophil count was numerically lower in Japanese compared with non-Japanese patients (median 120 vs 160 cells/mm³).

Interpretation

The eosinophil distribution in Japanese patients seems comparable to that of non-Japanese patients; although within multi-country studies, there was a slightly lower median eosinophil count for Japanese patients compared with non-Japanese patients. These findings suggest that blood eosinophil data from global studies are of relevance in Japan.

Cortical thickness and metabolite concentration in chronic stroke and the relationship with motor function

BACKGROUND

Hemiparesis is one of the most prevalent chronic disabilities after stroke. Biochemical and structural magnetic resonance imaging approaches may be employed to study the neural substrates underpinning upper-extremity (UE) recovery after chronic stroke.

OBJECTIVE

The purposes of this study were to 1) quantify anatomical and metabolic differences in the precentral gyrus, and 2) test the relationships between anatomical and metabolic differences, and hemiparetic arm function in individuals in the chronic stage of stroke recovery. Our hypotheses were: 1) the Stroke group would exhibit reduced precentral gyrus cortical thickness and lower concentrations of total N-acetylaspartate (tNAA) and glutamate+glutamine (Glx) in the ipsilesional motor cortex; and 2) that each of these measures would be associated with UE motor function after stroke.

METHODS

Seventeen individuals with chronic (>6 months) subcortical ischemic stroke and eleven neurologically healthy controls were recruited. Single voxel proton magnetic resonance spectroscopy (H1MRS) was performed to measure metabolite concentrations of tNAA and Glx in the precentral gyrus in both ipsilesional and contralesional hemispheres. Surface-based cortical morphometry was used to quantify precentral gyral thickness. Upper-extremity motor function was assessed using the Wolf Motor Function Test (WMFT).

RESULTS

Results demonstrated significantly lower ipsilesional tNAA and Glx concentrations and precentral gyrus thickness in the Stroke group. Ipsilesional tNAA and Glx concentration and precentral gyrus thickness was significantly lower in the ipsilesional hemisphere in the Stroke group. Parametric correlation analyses revealed a significant positive relationship between precentral gyrus thickness and tNAA concentration bilaterally. Multivariate regression analyses revealed that ipsilesional concentrations of tNAA and Glx predicted the largest amount of variance in WMFT scores. Cortical thickness measures alone did not predict a significant amount of variance in WMFT scores.

CONCLUSION

While stroke impairs both structure and biochemistry in the ipsilesional hemisphere our data suggest that tNAA has the strongest relationship with motor function.

Correlations between FEV1 and patient-reported outcomes: A pooled analysis of 23 clinical trials in patients with chronic obstructive pulmonary disease

BACKGROUND

In clinical trials of inhaled bronchodilators, chronic obstructive pulmonary disease (COPD) guidelines recommend that patient-reported outcomes (PROs) are assessed alongside lung function. How these endpoints are related is unclear.

METHODS

Pooled longitudinal data from 23 randomised controlled COPD studies were analyzed (N = 23,213). Treatments included long-acting β₂ agonists, long-acting muscarinic antagonists (LABAs or LAMAs) and the LABA/LAMA combination QVA149. Outcome measures were Transition Dyspnoea Index (TDI) and St. George's Respiratory Questionnaire (SGRQ) scores, COPD exacerbation frequency and rescue medication use. Relationships between changes in trough forced expiratory volume in one second (ΔFEV₁) and outcomes following treatment were assessed using correlations of data summaries and model-based analysis: generalized linear mixed-effect regression modelling to determine if ΔFEV₁ could predict patient outcomes with different treatments.

RESULTS

Mean age was 64 years, 73% were male, and most had moderate (45%) or severe (52%) disease. Statistically significant correlations were observed between ΔFEV₁ and each outcome measure (exacerbations Rs = 0.05; rescue medication, SGRQ, TDI, r = 0.11-0.16; all p < .001). Patients with greater improvements in trough FEV₁ had on average better SGRQ and TDI scores, fewer exacerbations, and used less rescue medication. For SGRQ and TDI scores, minimal clinically important differences were observed over the range of pooled ΔFEV₁ values. Model-based predictions confirmed the treatment effect was partly explained by changes in FEV₁ from baseline with improvements in PROs observed across all treatments when trough FEV₁ improved. Across all endpoints active treatments were better than placebo (p < .0001), and LABA/LAMA treatment resulted in numerically better treatment outcomes than either monocomponent.

CONCLUSIONS

These data suggest that FEV₁ improvements post-bronchodilation correlate with PRO improvements. Further improvements in patient outcomes may be expected by maximizing lung function improvements.

TRIAL REGISTRATION

Registration details for the 23 randomised controlled studies used in this pooled analysis are supplied in Additional File 4.

Addition of Blood Pressure and Weight Transmissions to Standard Remote Monitoring of Implantable Defibrillators and its Association with Mortality and Rehospitalization

BACKGROUND

Among patients with implantable defibrillators (ICD), use of remote patient monitoring (RPM) is associated with lower risk of death and rehospitalization. Standard ICD RPM can be supplemented with weight and blood pressure data. It is not known whether standard RPM plus routine weight and blood pressure transmission (RPM+) is associated with better outcomes.

METHODS AND RESULTS

RPM+ patients (n=4106) were compared with patients who only transmitted standard ICD RPM data (n=14 183). Logistic regression models identified patient, physician, and hospital characteristics associated with RPM+ utilization. Mortality and rehospitalization were examined using landmark analyses at 180 days after ICD implant in Medicare fee-for-service patients. In these analyses, we examined the independent association between RPM+ utilization and times to events up to 3 years after device implantation with Cox regression models. We further examined whether the association between RPM+ and outcomes varied by frequency or type of transmissions. Determinants of RPM+ utilization included impaired ejection fraction, cardiac resynchronization therapy, and institutional practice. The risk of mortality of RPM+ patients was similar to standard ICD RPM patients (hazard ratio, 1.06; 95% confidence interval, 0.94-1.19; P=0.34). RPM+ patients also had similar risks of all-cause hospitalization (subdistribution hazard ratio, 1.03; 95% confidence interval, 0.94-1.14; P=0.52), cardiovascular hospitalization (subdistribution hazard ratio, 0.92; 95% confidence interval, 0.83-1.02; P=0.15), or heart failure hospitalizations (subdistribution hazard ratio, 0.90; 95% confidence interval, 0.78-1.05; P=0.18). RPM+ transmission frequency was not associated with outcomes.

CONCLUSIONS

In patients using standard ICD RPM, the added transmission of weight and blood pressure data was not associated with improved outcomes.

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.

Rescue medication use as a patient-reported outcome in COPD: a systematic review and regression analysis

Background

Reducing rescue medication use is a guideline-defined goal of asthma treatment, however, little is known about the validity of rescue medicine use as a marker of symptoms in chronic obstructive pulmonary disease (COPD). To improve patient outcomes, greater insight is needed into the relationship between rescue medication use and alternative COPD outcomes.

Methods

A systematic search of electronic databases (Embase®, MEDLINE® and Cochrane CENTRAL) was conducted from database start to 26 May, 2015. Studies of bronchodilator therapy with a duration of ≥24 weeks were included if they reported either mean change from baseline (CFB) in rescue medication use in puffs/day or % rescue-free days (%RFD), and at least one other COPD endpoint. Correlation and meta-regression analyses were undertaken to test the association between rescue medication use and other COPD outcomes using weighted means (weights proportional to the sample size of the treatment group) and unweighted means (equal weight for each treatment group). Each association was assessed at 6 months and study end.

Results

Forty-six studies involving 46,531 patients provided mean data from 145 treatment groups for evaluation. Changes in both measures of rescue medication use were correlated with changes in trough forced expiratory volume in one second ([FEV₁]; Pearson correlation coefficients |r| ≥ 0.63; p < 0.0001) and with St George’s Respiratory Questionnaire (SGRQ) score (|r| ≥ 0.70; p < 0.0001) at study end. Change in rescue medication use in puffs/day during the study correlated with annualized rates of moderate/severe exacerbations at 6 months and study end (both r = 0.66; p ≤ 0.0028). CFB in puffs/day was not well correlated with Transition Dyspnoea Index (TDI), but %RFD did correlate with TDI score at 6 months and study end (both r = 0.69; p < 0.0001). The values for CFB in puffs/day corresponding to the proposed minimal clinically important differences for trough FEV₁ and SGRQ score were -1.3 and -0.6 puffs/day, respectively. A -1.0 puffs/day CFB in rescue use corresponded to a change of 0.26 events/patient-year in moderate/severe exacerbations.

Conclusion

This analysis provides clear evidence of associations at a patient group level between rescue medication use and other clinically important COPD outcomes.

Electronic supplementary material

The online version of this article (doi:10.1186/s12931-017-0566-1) contains supplementary material, which is available to authorized users.

Evaluation of the psychometric properties of the St George's Respiratory Questionnaire in patients with severe asthma

PURPOSE

Limited data exist on the quantitative validity of the St George's Respiratory Questionnaire (SGRQ) in asthma populations. This study evaluated the psychometric properties of the SGRQ in patients with severe asthma.

METHODS

This was a post-hoc analysis of pooled data from MENSA (N = 576; NCT01691508) and SIRIUS (N = 135; NCT01691521), two randomized, placebo controlled trials of mepolizumab in patients with severe asthma. Patients completed the SGRQ at Baseline and Exit (MENSA Week 32; SIRIUS Week 24). Distributional characteristics, internal consistency reliability, test-retest reliability, convergent and discriminant validity, known-groups validity and responsiveness were assessed.

RESULTS

Internal consistency reliability was acceptable for the total and domain scores at Baseline and Exit (Cronbach's α was 0.92 and 0.94 at Baseline and Exit, respectively, for the total score). Test-retest reliability was demonstrated (intraclass correlation coefficients >0.7) for total score and the Activity and Impacts domains. Convergent and discriminant validity were demonstrated with measures associated or not associated with respiratory-related health status. Known groups validity based on baseline FEV₁% predicted, Asthma Control Questionnaire (ACQ)-5 score, exacerbations and eosinophil counts was demonstrated for the SGRQ total and domain scores. Responses to therapy based on clinician-rated response, patient-rated response, ACQ-5 change score and exacerbations generally correlated with improvements in SGRQ scores.

CONCLUSIONS

This analysis demonstrated that the SGRQ has acceptable psychometric properties in patients with severe asthma, exceeding the thresholds for adequate reliability, validity and responsiveness. The SGRQ appears to be a good instrument for identifying response to therapy in patients with severe asthma.

Socioeconomic Status as a Determinant of Health Status Treatment Response in COPD Trials

Background: Randomized controlled trials (RCTs) often recruit patients from low and high socioeconomic status (SES) countries, but little is known about the effect of SES on clinical outcomes, particularly patient-centered measures of symptomatic benefit. Methods: Combined individual chronic obstructive pulmonary disease (COPD) patient data from the placebo and long-acting bronchodilator arms of 17 RCTs (from the COPD Biomarkers Qualification Consortium database) were analyzed. Health status was measured using the St George's Respiratory Questionnaire (SGRQ) (minimum clinically important difference [MCID]: 4 units). Trials were grouped into short-term (≤12 months) and medium-term (>12 months to 48 months). A participant's country of residence was categorized into Low/Medium or High SES using World Health Organization criteria. Results: Data from 19765 individuals (6109 Low/Medium SES) were available. Patients in Low/Medium SES countries had more severe disease at baseline. Improvement in SGRQ score with placebo was ≈2 units greater in Low/Medium than in High SES countries; at its greatest, the improvement from baseline exceeded the MCID in Low/Medium countries. This difference was maintained for at least 1 year. Improvement with bronchodilator was also greater in Low/Medium versus High SES countries; overall there was no evidence that the treatment effect versus placebo was different between countries of different SES status. Conclusions: Participants in Low/Medium SES countries experienced significantly larger treatment effects, irrespective of treatment group (placebo and bronchodilator). Despite this, COPD patients in Low/Medium SES countries experienced a health status gain from long-acting bronchodilator treatment that is similar to that seen in High SES countries.

St George's Respiratory Questionnaire Score Predicts Outcomes in Patients with COPD: Analysis of Individual Patient Data in the COPD Biomarkers Qualification Consortium Database

Background: We aimed to estimate the usefulness of a disease specific health status measure, the St George's Respiratory Questionnaire (SGRQ), to predict outcomes in patients with chronic obstructive pulmonary disease (COPD). Methods: Individual patient-data of 12043 patients from long-term randomized clinical trials (2-4 years' duration) in the COPD Biomarkers Qualification Consortium database were analyzed. The adverse COPD outcomes were: exacerbations of COPD, hospital admissions due to exacerbation and all-cause mortality. Cox proportional hazards regression was used to calculate adjusted hazard ratios (HR) and 95% confidence intervals (CIs) for quartiles of SGRQ scores at baseline and time to first event, and time from first to second event, where appropriate. Results: The risk of adverse COPD outcomes increased with each increasing quartile of SGRQ score for all time to first event analyses. When comparing the lowest versus the highest quartile, the event risk (HRs [95% CIs]) increased by 40% for exacerbations (1.40 [1.29, 1.51]); 2-fold for hospital admissions (2.01 [1.78, 2.28]) and more than 2-fold for all-cause mortality (2.30 [1.91, 2.78]). For second event analyses in a subset of eligible patients, these trends persisted albeit with reduced risk estimates for exacerbations. Conclusions: Among patients with COPD, health status measured by a SGRQ score predicted exacerbations of COPD, hospital admissions due to exacerbations and their recurrence and death after adjustment. These data support the rationale for a health status measure use as a drug development tool and suggest that a health status measure may also have a role in risk assessment for COPD patients in routine medical care.

Baseline Severity as Predictor of Change in St George's Respiratory Questionnaire Scores in Trials of Long-acting Bronchodilators with COPD Patients

Background: In trials oflong-acting bronchodilators, health status is an important trial outcome, however the influence of baseline severity on response measured by St George's Respiratory Questionnaire (SGRQ) is not known. We have compared SGRQ changes between patients with chronic obstructive pulmonary disease (COPD) of mild-moderate severity or dyspnea (Global initiative for chronic Obstructive Lung disease [GOLD] grades 1 and 2; modified Medical Research Council [mMRC] grades 1 and 2) to those with severe-very severe severity or dyspnea (GOLD grades 3 and 4; mMRC grades 3 and 4). Methods: Combined individual patient data from the COPD Biomarkers Qualification Consortium database (trials of long-acting bronchodilators) were used comprising of patients from short-term (≤1-year duration; n=10802) and medium-term (2-4 years' duration; n=8963) studies. A repeated measures analysis of variance (ANOVA) was used to determine the effects of baseline severity (GOLD/mMRC) on SGRQ response to treatment. All treatment arms were combined. Results: In short-term studies, milder patients showed a greater response than those with more severe disease in terms of GOLD grade (partial Eta² = 0.03, p < 0.0001) and mMRC grade (partial Eta² = 0.05, p < 0.0001). Similar results were seen in the medium-term studies (partial Eta² = 0.02, p < 0.0001; mMRC: partial Eta² = 0.05, p < 0.0001,). Conclusions: Patients with less severe airflow limitation and less severe dyspnea showed larger improvements in SGRQ score than more severely obstructed or dyspneic patients. Although these severity influences are small (2%-5% of the variance in SGRQ score), they do suggest that pre-specified separate analyses are warranted to test for differences in response, based on baseline severity.

The COPD Biomarkers Qualification Consortium Database: Baseline Characteristics of the St George's Respiratory Questionnaire Dataset

The COPD Biomarkers Qualification Consortium (CBQC) is a public-private partnership formed in 2010 with a goal of qualifying biomarkers and clinical assessment tools for use in clinical or nonclinical decision-making and particularly within the regulatory context. The St George's Respiratory Questionnaire (SGRQ) is a measure of health-related quality of life widely used in clinical research. The aim of the CBQC working group on SGRQ was to construct an individual patient level database of clinical trial data that included the SGRQ, to use this to confirm the reliability and validity of the SGRQ as an outcome measure of health status, and investigate its use as a predictor of future events (exacerbations and mortality). This manuscript describes the formulation of the CBQC database and presents the baseline demographic and clinical characteristics of the integrated SGRQ database overall, and by study type (short-term [≤1 year], medium-term [2-4 years] and observational studies). Distribution of baseline SGRQ scores varied little by demographic determinants except for income region in the observational data set (low-middle income countries +10 units compared with high income, p<0.0001) and this observation held across studies. SGRQ scores increased with increasing modified Medical Research Council dyspnea scores (mean differences ranged 6.9-17.9 units) and with increasing airflow limitations (Global initiative for chronic Obstructive Lung Disease grades 1 to 4; differences ranged 4.5-16.1 units), consistent across study types. As a method of cross-sectional comparison, the SGRQ appears to be relatively free of bias from demographic factors although care should be taken when making cross sectional comparisons of scores between patients in countries at different levels of socio-economic development/.

Responder Analyses for Treatment Effects in COPD Using the St George's Respiratory Questionnaire

Background: Patient-reported outcomes data in clinical trials are usually reported as mean values, interpreted in comparison to a minimum clinically important difference (MCID) and ignoring the possibility of a sizable proportion of patients experiencing a worthwhile benefit when the majority did not. This analysis tested the reliability of calculated responder rates (from chronic obstructive pulmonary disease [COPD] patients) with the St George's Respiratory Questionnaire (SGRQ) using a range of responder cut-points above and below the MCID (4 units). Methods: Individual patient data (i.e., data from long-acting bronchodilator [LAB] and inhaled corticosteroids [ICS]/long-acting beta2-agonist [LABA] randomized clinical studies) in the COPD Biomarker Qualification Consortium database were used: short-term (≤1-year duration; 14,814 patients,) and medium-term (2-4 years; 12,043 patients). Responder rates versus placebo across SGRQ score change thresholds ranging from -1.5 to -8.0 were tested; differences were expressed as the odds ratio (OR) of a patient exceeding the threshold versus no change or deterioration. Results: The ORs measuring benefit of active treatment were similar across thresholds in short-term studies (LAB, ORs 1.40-1.42; LABA/ICS, 1.50-1.56) and medium-term LAB studies (ORs 1.34-1.43), whereas ORs in medium-term studies with LABA/ICS intervention showed a trend for higher response rates at higher values of threshold cut-points (1.64-1.79). In short-term studies, different thresholds had little effect on the OR between active drugs versus a trend for lower ORs with lower thresholds in medium-term studies. Conclusions: The OR for a treatment effect compared with placebo appears consistent across a range of responder cut-points. In medium-term trials, the treatment difference between active drugs suggests that use of a lower threshold would not increase the odds of observing a measured treatment difference.

Qualitative evaluation of the St George's Respiratory Questionnaire in patients with severe asthma

PURPOSE

Content validity is the extent to which a patient-reported outcome measure evaluates the concepts most relevant to a patient's condition and treatment. The St George's Respiratory Questionnaire (SGRQ) has been validated in a range of respiratory conditions. This study evaluated the content validity of the SGRQ in patients with severe asthma.

METHODS

A qualitative study, guided by a protocol, which included concept elicitation and cognitive debriefing of the SGRQ, was conducted in patients aged ≥18 years with history of severe asthma and blood eosinophil counts of ≥150/μL (past month) or ≥300/μL (past 12 months). Patients were recruited until saturation for concept elicitation was achieved (i.e. no additional concepts identified). Concepts identified by the patients were then mapped to the SGRQ.

RESULTS

18 patient interviews provided concept saturation. Concept elicitation confirmed that the SGRQ includes the commonly reported asthma symptoms and their impact on daily life. In total, 89-100% of patients routinely experienced cough, nighttime awakenings, shortness of breath, chest tightness, sleep difficulty, phlegm/mucus, and wheezing. Patients reported asthma impacting daily and physical activities, mood and sleep. Cognitive interviewing confirmed that patients understood the instructions, items and response options in the SGRQ. Nearly half of the concepts in the SGRQ were endorsed by ≥12 patients; of the 17 items with scoring weights ≥85, 11 were mentioned by ≥12 patients.

CONCLUSIONS

This study demonstrates that the SGRQ is a relevant, comprehensive and content-valid instrument to assess health status in patients with severe asthma.

Vitamin D deficiency: What does it mean for chronic obstructive pulmonary disease (COPD)? a compherensive review for pulmonologists

OBJECTIVES

Vitamin D deficiency and Chronic Obstructive Pulmonary Disease (COPD) are both under-recognized health problems, world-wide. Although Vitamin D has long been known for calcemic effects it also has less known noncalcemic effects. Recent data have shown that Vitamin D deficiency is highly prevalent in patients with COPD and correlates with forced expiratory volume in one second (FEV₁ ) and FEV₁ decline. The objective of this work was to review the current literature on vitamin D deficiency in relation with COPD.

DATA SOURCE

A literature search, using the words "vitamin D" and "COPD", was undertaken in Pubmed database.

RESULTS

The noncalcemic effects of vitamin D relating with COPD may be summarised as increasing antimicrobial peptide production, regulation of inflammatory response and airway remodelling. Vitamin D inhibits the production of several proinflammatory cytokines and leads to suppression Th1 and Th17 responses which may be involved in the pathogenesis of COPD. Vitamin D insufficiency may also contribute to chronic respiratory infections and airway colonization so returning vitamin D concentrations to an optimal range in patients with COPD might reduce bacterial load and concomitant exacerbations.Vitamin D is also important for COPD-related comorbodities such as osteoporosis, muscle weakness and cardiovascular diseases. Data about the effect of Vitamin D supplementation on those comorbidities in relation with COPD are been scarce.

CONCLUSION

Improving the blood level of Vitamin D into the desired range may have a beneficial effect bones and muscles, but more studies are needed to test to test that hypothesis.

Interpreting patient-reported outcomes from clinical trials in COPD: a discussion

One of the challenges faced by the practising physician is the interpretation of patient-reported outcomes (PROs) in clinical trials and the relevance of such data to their patients. This is especially true when caring for patients with progressive diseases such as COPD. In an attempt to incorporate the patient perspective, many clinical trials now include assessments of PROs. These are formalized methods of capturing patient-centered information. Given the importance of PROs in evaluating the potential utility of an intervention for a patient with COPD, it is important that physicians are able to critically interpret (and critique) the results derived from them. Therefore, in this paper, a series of questions is posed for the practising physician to consider when reviewing the treatment effectiveness as assessed by PROs. The focus is on the St George's Respiratory Questionnaire for worked examples, but the principles apply equally to other symptom-based questionnaires. A number of different ways of presenting PRO data are discussed, including the concept of the minimum clinically important difference, whether there is a ceiling effect to PRO results, and the strengths and weaknesses of responder analyses. Using a worked example, the value of including a placebo arm in a study is illustrated, and the influence of the study on PRO results is considered, in terms of the design, patient withdrawal, and the selection of the study population. For the practising clinician, the most important consideration is the importance of individualization of treatment (and of treatment goals). To inform such treatment, clinicians need to critically review PRO data. The hope is that the questions posed here will help to build a framework for this critical review.

Improvements in Lung Diffusion Capacity following Pulmonary Rehabilitation in COPD with and without Ventilation Inhomogeneity

BACKGROUND

Lung diffusing capacity (DLCO) and lung volume distribution predict exercise performance and are altered in COPD patients. If pulmonary rehabilitation (PR) can modify DLCO parameters is unknown.

OBJECTIVES

To investigate changes in DLCO and ventilation inhomogeneity following a PR program and their relation with functional outcomes in patients with COPD.

METHODS

This was a prospective, observational, multicentric study. Patients were evaluated before and after a standardized 3-week PR program. Functional assessment included body plethysmography, DLCO, transfer factor (KCO) and alveolar volume (VA), gas exchange, the 6-min walking test (6MWT) and exercise-related dyspnea. Patients were categorized according to the severity of airflow limitation and presence of ventilation inhomogeneity, identified by a VA/TLC <0.8.

RESULTS

Two hundred and fifty patients completed the study. Baseline forced expiratory volume in 1 s (FEV1) % predicted (mean ± SD) was 50.5 ± 20.1 (76% males); 137 patients had a severe disease. General study population showed improvements in 6MWT (38 ± 55 m; p < 0.01), DLCO (0.12 ± 0.63 mmol × min-1 kPa-1; p < 0.01), lung function and dyspnea. Comparable improvements in DLCO were observed regardless of the severity of disease and the presence of ventilation inhomogeneity. While patients with VA/TLC <0.8 improved the DLCO increasing their VA (177 ± 69 ml; p < 0.01), patients with VA/TLC >0.8 improved their KCO (8.1 ± 2.8%; p = 0.019). The latter had also better baseline lung function and higher improvements in 6MWT (14.6 ± 6.7 vs. 9.0 ± 1.8%; p = 0.015). Lower DLCO at baseline was associated with lower improvements in 6MWT, the greatest difference being between subjects with very severe and mild DLCO impairment (2.7 ± 7.4 vs. 14 ± 2%; p = 0.049).

CONCLUSIONS

In COPD patients undergoing a PR program, different pathophysiological mechanisms may drive improvements in DLCO, while ventilation inhomogeneity may limit improvements in exercise tolerance.