Individual FEV1 Trajectories Can Be Identified from a COPD Cohort

Lung Function Trajectories and Associated Mortality among Adults with and without Airway Obstruction

Rationale: Spirometry is essential for diagnosis and assessment of prognosis in patients with chronic obstructive pulmonary disease (COPD). Objectives: To identify FEV1 trajectories and their determinants on the basis of annual spirometry measurements among individuals with and without airway obstruction (AO) and to assess mortality in relation to trajectories. Methods: From 2002 through 2004, individuals with AO (FEV1/VC < 0.70, n = 993) and age- and sex-matched nonobstructive (NO) referents were recruited from population-based cohorts. Annual spirometry until 2014 was used in joint-survival latent-class mixed models to identify lung function trajectories. Mortality data were collected during 15 years of follow-up. Measurements and Main Results: Three trajectories were identified among the subjects with AO and two among the NO referents. Trajectory membership was driven by baseline FEV1% predicted (FEV1%pred) in both groups and also by pack-years in subjects with AO and current smoking in NO referents. Longitudinal FEV1%pred depended on baseline FEV1%pred, pack-years, and obesity. The trajectories were distributed as follows: among individuals with AO, 79.6% in AO trajectory 1 (FEV1 high with normal decline), 12.8% in AO trajectory 2 (FEV1 high with rapid decline), and 7.7% in AO trajectory 3 (FEV1 low with normal decline) (mean, 27, 72, and 26 ml/yr, respectively) and, among NO referents, 96.7% in NO trajectory 1 (FEV1 high with normal decline) and 3.3% in NO trajectory 2 (FEV1 high with rapid decline) (mean, 34 and 173 ml/yr, respectively). Hazard for death was increased for AO trajectories 2 (hazard ratio [HR], 1.56) and 3 (HR, 3.45) versus AO trajectory 1 and for NO trajectory 2 (HR, 2.99) versus NO trajectory 1. Conclusions: Three different FEV1 trajectories were identified among subjects with AO and two among NO referents, with different outcomes in terms of FEV1 decline and mortality. The FEV1 trajectories among subjects with AO and the relationship between low FVC and trajectory outcome are of particular clinical interest.

The cardiovascular phenotype of Chronic Obstructive Pulmonary Disease (COPD): Applying machine learning to the prediction of cardiovascular comorbidities

BACKGROUND

Chronic Obstructive Pulmonary Disease (COPD) is a heterogeneous group of lung conditions that are challenging to diagnose and treat. As the presence of comorbidities often exacerbates this scenario, the characterization of patients with COPD and cardiovascular comorbidities may allow early intervention and improve disease management and care.

METHODS

We analysed a 4-year observational cohort of 6883 UK patients who were ultimately diagnosed with COPD and at least one cardiovascular comorbidity. The cohort was extracted from the UK Royal College of General Practitioners and Surveillance Centre database. The COPD phenotypes were identified prior to diagnosis and their reproducibility was assessed following COPD diagnosis. We then developed four classifiers for predicting cardiovascular comorbidities.

RESULTS

Three subtypes of the COPD cardiovascular phenotype were identified prior to diagnosis. Phenotype A was characterised by a higher prevalence of severe COPD, emphysema, hypertension. Phenotype B was characterised by a larger male majority, a lower prevalence of hypertension, the highest prevalence of the other cardiovascular comorbidities, and diabetes. Finally, phenotype C was characterised by universal hypertension, a higher prevalence of mild COPD and the low prevalence of COPD exacerbations. These phenotypes were reproduced after diagnosis with 92% accuracy. The random forest model was highly accurate for predicting hypertension while ruling out less prevalent comorbidities.

CONCLUSIONS

This study identified three subtypes of the COPD cardiovascular phenotype that may generalize to other populations. Among the four models tested, the random forest classifier was the most accurate at predicting cardiovascular comorbidities in COPD patients with the cardiovascular phenotype.

Assessment of risk factors responsible for rapid deterioration of lung function over a period of one year in patients with chronic obstructive pulmonary disease

Compromised lung function is a common feature of COPD patients, but certain factors increase the rate of lung function decline in COPD patients. The objective of the current study was to investigate the effect of different clinically important factors responsible for rapid deterioration of lung function quantified as ≥ 60 ml decline in FEV1 over a period of one year. COPD patients recruited from the chest clinic of Penang hospital were followed-up for one year from August 2018 to August 2019. Rapid deterioration of lung function was defined as greater than 60 ml/year decline in force expiratory volume in one second. Among 367 included patients 73.84% were male, with mean age 65.26 (9.6) years and % predicted FEV1 51.07 (11.84). 30.27% patients showed mean decline of ≥ 60 ml in FEV1. The regression analysis showed that current smoking relative risk (RR) = 2.38 (1.78-3.07), p < 0.001); GOLD Stage III& IV RR = 1.43 (1.27-1.97), p < 0.001); mMRC score 3 to 4 RR = 2.03 (1.74-2.70), p < 0.01); SGRQ-C score ≥ 10 points difference RR = 2.01 (1.58-2.73), p < 0.01); SGRQ-C symptoms Score ≥ 10 points difference RR = 1.48 (1.23-2.29), p < 0.001); 6MWT < 350 m RR = 2.29 (1.87-3.34), p < 0.01); ≥ 3 exacerbation in study year RR = 2.28 (1.58-2.42, p < 0.001); 8 or more hospital admission days (RR = 3.62 (2.66-4.20), p < 0.001); Charlson comorbidity index ≥ 3 RR = 3.18 (2.23-3.76), p < 0.01) and emphysema RR = 1.31 (1.15-1.79), p < 0.01) were significant risk factors for the rapid deterioration of lung function (FEV1 decline ≥ 60 ml). Among different factors CCI score ≥ 3, abrupt decline in health status, exacerbation frequency ≥ 3, hospital admission days ≥ 8 and emphysema were reported as risk factors for rapid deterioration of lung function.

Airway regulatory T cells are decreased in COPD with a rapid decline in lung function

Background

Differences in the expression of regulatory T cells (Tregs) have been suggested to explain why some smokers develop COPD and some do not. Upregulation of Tregs in response to smoking would restrain airway inflammation and thus the development of COPD; while the absense of such upregulation would over time lead to chronic inflammation and COPD. We hypothesized that—among COPD patients—the same mechanism would affect rate of decline in lung function; specifically, that a decreased expression of Tregs would be associated with a more rapid decline in FEV₁.

Methods

Bronchoscopy with BAL was performed in 52 subjects recruited from the longitudinal OLIN COPD study; 12 with COPD and a rapid decline in lung function (loss of FEV₁ ≥ 60 ml/year), 10 with COPD and a non-rapid decline in lung function (loss of FEV₁ ≤ 30 ml/year), 15 current and ex-smokers and 15 non-smokers with normal lung function. BAL lymphocyte subsets were determined using flow cytometry.

Results

The proportions of Tregs with regulatory function (FoxP3⁺/CD4⁺CD25^bright) were significantly lower in COPD subjects with a rapid decline in lung function compared to those with a non-rapid decline (p = 0.019). This result was confirmed in a mixed model regression analysis in which adjustments for inhaled corticosteroid usage, smoking, sex and age were evaluated. No significant difference was found between COPD subjects and smokers or non-smokers with normal lung function.

Conclusions

COPD subjects with a rapid decline in lung function had lower proportions of T cells with regulatory function in BAL fluid, suggesting that an inability to suppress the inflammatory response following smoking might lead to a more rapid decline in FEV₁.

Trial registration Clinicaltrials.gov identifier NCT02729220

Characteristics Associated with Accelerated Lung Function Decline in a Primary Care Population with Chronic Obstructive Pulmonary Disease

Background

Estimates for lung function decline in chronic obstructive pulmonary disease (COPD) have differed by study setting and have not been described in a UK primary care population.

Purpose

To describe rates of FEV₁ and FVC decline in COPD and investigate characteristics associated with accelerated decline.

Patients and Methods

Current/ex-smoking COPD patients (35 years+) who had at least 2 FEV₁ or FVC measurements ≥6 months apart were included using Clinical Practice Research Datalink. Patients were followed up for a maximum of 13 years. Accelerated rate of lung function decline was defined as the fastest quartile of decline using mixed linear regression, and association with baseline characteristics was investigated using logistic regression.

Results

A total of 72,683 and 50,649 COPD patients had at least 2 FEV₁ or FVC measurements, respectively. Median rates of FEV₁ and FVC changes or decline were -18.1mL/year (IQR: -31.6 to -6.0) and -22.7mL/year (IQR: -39.9 to -6.7), respectively. Older age, high socioeconomic status, being underweight, high mMRC dyspnoea and frequent AECOPD or severe AECOPD were associated with an accelerated rate of FEV₁ and FVC decline. Current smoking, mild airflow obstruction and inhaled corticosteroid treatment were additionally associated with accelerated FEV₁ decline whilst women, sputum production and severe airflow obstruction were associated with accelerated FVC decline.

Conclusion

Rate of FEV₁ and FVC decline was similar and showed similar heterogeneity. Whilst FEV₁ and FVC shared associations with baseline characteristics, a few differences highlighted the importance of both lung function measures in COPD progression. We identified important characteristics that should be monitored for disease progression.

Cytotoxic lymphocytes in COPD airways: increased NK cells associated with disease, iNKT and NKT-like cells with current smoking

BACKGROUND

Cytotoxic lymphocytes are increased in the airways of COPD patients. Whether this increase is driven primarily by the disease or by smoking is not clear, nor whether it correlates with the rate of decline in lung function.

METHODS

Bronchoscopy with BAL was performed in 52 subjects recruited from the longitudinal OLIN COPD study according to pre-determined criteria; 12 with COPD and a rapid decline in lung function (loss of FEV₁ ≥ 60 ml/year), 10 with COPD and a non-rapid decline in lung function (loss of FEV₁ ≤ 30 ml/year), 15 current and ex-smokers and 15 non-smokers with normal lung function. BAL lymphocyte subsets were determined using flow cytometry.

RESULTS

In BAL fluid, the proportions of NK, iNKT and NKT-like cells all increased with pack-years. Within the COPD group, NK cells - but not iNKT or NKT-like cells - were significantly elevated also in subjects that had quit smoking. In contrast, current smoking was associated with a marked increase in iNKT and NKT-like cells but not in NK cells. Rate of lung function decline did not significantly affect any of the results.

CONCLUSIONS

In summary, increased proportions of NK cells in BAL fluid were associated with COPD; iNKT and NKT-like cells with current smoking but not with COPD. Interestingly, NK cell percentages did not normalize in COPD subjects that had quit smoking, indicating that these cells might play a role in the continued disease progression seen in COPD even after smoking cessation.

TRIAL REGISTRATION

Clinicaltrials.gov identifier NCT02729220 .

Does the 2017 revision improve the ability of GOLD to predict risk of future moderate and severe exacerbation?

INTRODUCTION

In 2017 update, GOLD separated spirometry from ABCD classification.

OBJECTIVES

The aim was to investigate the predictive reliability of GOLD 2017 grading system in terms of future moderate and severe exacerbations.

METHODS

COPD patients were classified into A to D groups according to GOLD 2011 and 2017. Patients who were assigned to C/D groups according to GOLD 2011 were divided into subgroups C 1/D1, C2/D2, C3/D3 according to FEV₁ % of predicted and exacerbation history. C1/D1 patients defined as FEV₁  < 50% predicted and without ≥2 exacerbations or hospitalization in the last year.

RESULTS

A total of 225 patients were enrolled. Among them, 25.8% were in groups C1/D1 according to GOLD 2011. These patients shifted to A/B according to GOLD 2017. C1/D1 patients had a significantly higher risk of future moderate and severe exacerbation compared to A/B (P = 0.018). The risk of future moderate and severe exacerbation was significantly higher in patients with a FEV₁  < 50% (P = 0.018).The risk of future moderate and severe exacerbation was higher in GOLD 2017 groups A and B compared to GOLD 2011 groups A and B.

CONCLUSION

Low FEV₁ was an important risk factor for future exacerbations. Downstaging of C1/D1 patients caused heterogeneity in A/B with including patients with low and high risk of future exacerbation. This resulted in a low discriminative power of GOLD 2017 regarding the risk of future exacerbation in groups A and B. This may cause underestimation of disease severity and inadequate treatment especially in A/B patients with low FEV₁ .

Long-term evolution of lung function in individuals with alpha-1 antitrypsin deficiency from the Spanish registry (REDAAT)

Background

The clinical course of alpha-1 antitrypsin deficiency (AATD) is very heterogeneous. It is estimated that 60% of individuals with severe AATD (Pi*ZZ) develop emphysema. The main objective of this study was to describe the outcomes of long-term lung function in individuals with AATD-associated emphysema after at least 8 years of follow-up.

Materials and methods

We performed a retrospective analysis of longitudinal follow-up data of AATD PiZZ patients from the Spanish registry (AATD Spanish Registry [REDAAT]). The main follow-up outcome was the annual rate of decline in forced expiratory volume in 1 second (FEV₁) calculated using the FEV₁ values at baseline and in the last post-bronchodilator spirometry available.

Results

One hundred and twenty-two AATD PiZZ patients were analyzed. The median follow-up was 11 years (interquartile range =9–14). The mean FEV₁ decline was 28 mL/year (SD=54), with a median of 33 mL/year. Tobacco consumption (β=19.8, p<0.001), previous pneumonia (β=27.8, p=0.026) and higher baseline FEV₁% (β=0.798, p=0.016) were independently related to a faster FEV₁ decline.

Conclusion

In this large cohort with a long follow-up, we observed a very variable decline of FEV₁. However, the mean FEV₁ decline was similar to that observed in large cohorts of smoking-related COPD. Tobacco consumption, previous pneumonia and better lung function at baseline were related to a faster decline in FEV₁. These results highlight the importance of early diagnosis and effective treatment.

From COPD epidemiology to studies of pathophysiological disease mechanisms: challenges with regard to study design and recruitment process: Respiratory and Cardiovascular Effects in COPD (KOLIN)

Background: Chronic obstructive pulmonary disease (COPD) is a largely underdiagnosed disease including several phenotypes. In this report, the design of a study intending to evaluate the pathophysiological mechanism in COPD in relation to the specific phenotypes non-rapid and rapid decline in lung function is described together with the recruitment process of the study population derived from a population based study. Method: The OLIN COPD study includes a population-based COPD cohort and referents without COPD identified in 2002-04 (n = 1986), and thereafter followed annually since 2005. Lung function decline was estimated from baseline in 2002-2004 to 2010 (first recruitment phase) or to 2012/2013 (second recruitment phase). Individuals who met the predefined criteria for the following four groups were identified; group A) COPD grade 2-3 with rapid decline in FEV₁ and group B) COPD grade 2-3 without rapid decline in FEV₁ (≥60 and ≤30 ml/year, respectively), group C) ever-smokers, and group D) non-smokers with normal lung function. Groups A-C included ever-smokers with >10 pack years. The intention was to recruit 15 subjects in each of the groups A-D. Results: From the database groups A-D were identified; group A n = 37, group B n = 29, group C n = 41, and group D n = 55. Fifteen subjects were recruited from groups C and D, while this goal was not reached in the groups A (n = 12) and B (n = 10). The most common reasons for excluding individuals identified as A or B were comorbidities contraindicating bronchoscopy, or inflammatory diseases/immune suppressive medication expected to affect the outcome. Conclusion: The study is expected to generate important results regarding pathophysiological mechanisms associated with rate of decline in lung function among subjects with COPD and the in-detail described recruitment process, including reasons for non-participation, is a strength when interpreting the results in forthcoming studies.

Evaluation of clinical variables according to follow-up times in COPD: results from ON-SINT cohort

Background: COPD is a chronic disease traditionally associated with increased symptoms as lung function deteriorates. Follow-up times in previous cohort studies were limited to a few years. Interestingly, newer longer observational studies show a more comprehensive picture on disease progression over time. Therefore, the question on the relevancy of the follow-up time in cohort studies remains open.

Methods: The ON-SINT study is an observational, retrospective, nationwide, real-life cohort study, in which patients diagnosed with COPD were recruited between December 2011 and April 2013 by primary care (PC) and secondary care (SC) physicians. Patients were evaluated at the inclusion visit and at the initial visit when the diagnosis of COPD was first established. Distribution of lung function decline over the years was studied comparing those cases with longer follow-up times, with the median of the distribution as the cutoff point.

Results: The sample included 1214 patients of which 857 (70.6%) were recruited by PC and 357 (29.4%) by SC physicians. Median follow-up time was 6.26 years. Mean annual change in the complete cohort were –4.5 (222) ml year^–1 for FVC and 5.5 (134) ml year^–1 for FEV₁. We confirm the variable distribution of FEV₁ decline and found that longer follow-up periods reduce this variability. Of note, FEV₁ decline was different between groups (shorter: 19.7 [180.4] vs longer: –9.7 [46.9]; p = 0.018). Further, our data revealed differences in the clinical presentation according to follow-up times, with special emphasis on dyspnea (OR: 1.035; 95%CI: 1.014–1.056), exacerbations (OR 1.172; 95%CI 1.045–1.315) and CAT scores (OR 1.047; 95%CI 1.019–1.075) being associated with longer follow-up times.

Conclusions: This study describes the impact of follow-up periods on lung function variability, and reveals differences in clinical presentation according to follow-up times, with special emphasis on dyspnea, exacerbations and CAT scores.

Characteristics and longitudinal progression of chronic obstructive pulmonary disease in GOLD B patients

Background

The characteristics and natural history of GOLD B COPD patients are not well described. The clinical characteristics and natural history of GOLD B patients over 1 year in a multicentre cohort of COPD patients in the COPDMAP study were assessed. We aimed to identify the subgroup of patients who progressed to GOLD D (unstable GOLD B patients) and identify characteristics associated with progression.

Methods

Three hundred seventy COPD patients were assessed at baseline and 12 months thereafter. Demographics, lung function, health status, 6 min walk tests and levels of systemic inflammation were assessed. Students t tests and Mann Whitney-U tests were used.

Results

One hundred seven (28.9%) of patients were categorised as GOLD B at baseline. These GOLD B patients had similar FEV1 to GOLD A patients (66% predicted). More GOLD B patients were current smokers (p = 0.031), had chronic bronchitis (p = 0.0003) and cardiovascular comorbidities (p = 0.019) compared to GOLD A. At 12 months, 25.3% of GOLD B patients progressed to GOLD D. These patients who progressed (unstable patients) had worse health status and symptoms (SGRQ-C Total, 50.0 v 41.1, p = 0.019 and CAT, 21.0 v 14.0, p = 0.006) and lower FEV₁ (60% v 69% p = 0.014) at baseline compared to stable patients who remained in GOLD B.

Conclusions

Unstable GOLD B patients who progressed to GOLD D had a higher level of symptoms at baseline. A high symptom burden may predict an increased likelihood of disease progression in GOLD B patients.

Electronic supplementary material

The online version of this article (doi:10.1186/s12890-017-0384-8) contains supplementary material, which is available to authorized users.