COPDVD: Automated classification of chronic obstructive pulmonary disease on a new collected and evaluated voice dataset

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is a severe condition affecting millions worldwide, leading to numerous annual deaths. The absence of significant symptoms in its early stages promotes high underdiagnosis rates for the affected people. Besides pulmonary function failure, another harmful problem of COPD is the systemic effects, e.g., heart failure or voice distortion. However, the systemic effects of COPD might provide valuable information for early detection. In other words, symptoms caused by systemic effects could be helpful to detect the condition in its early stages.

OBJECTIVE

The proposed study aims to explore whether the voice features extracted from the vowel "a" utterance carry any information that can be predictive of COPD by employing Machine Learning (ML) on a newly collected voice dataset.

METHODS

Forty-eight participants were recruited from the pool of research clinic visitors at Blekinge Institute of Technology (BTH) in Sweden between January 2022 and May 2023. A dataset consisting of 1246 recordings from 48 participants was gathered. The collection of voice recordings containing the vowel "a" utterance commenced following an information and consent meeting with each participant using the VoiceDiagnostic application. The collected voice data was subjected to silence segment removal, feature extraction of baseline acoustic features, and Mel Frequency Cepstrum Coefficients (MFCC). Sociodemographic data was also collected from the participants. Three ML models were investigated for the binary classification of COPD and healthy controls: Random Forest (RF), Support Vector Machine (SVM), and CatBoost (CB). A nested k-fold cross-validation approach was employed. Additionally, the hyperparameters were optimized using grid-search on each ML model. For best performance assessment, accuracy, F1-score, precision, and recall metrics were computed. Afterward, we further examined the best classifier by utilizing the Area Under the Curve (AUC), Average Precision (AP), and SHapley Additive exPlanations (SHAP) feature-importance measures.

RESULTS

The classifiers RF, SVM, and CB achieved a maximum accuracy of 77 %, 69 %, and 78 % on the test set and 93 %, 78 % and 97 % on the validation set, respectively. The CB classifier outperformed RF and SVM. After further investigation of the best-performing classifier, CB demonstrated the highest performance, producing an AUC of 82 % and AP of 76 %. In addition to age and gender, the mean values of baseline acoustic and MFCC features demonstrate high importance and deterministic characteristics for classification performance in both test and validation sets, though in varied order.

CONCLUSION

This study concludes that the utterance of vowel "a" recordings contain information that can be captured by the CatBoost classifier with high accuracy for the classification of COPD. Additionally, baseline acoustic and MFCC features, in conjunction with age and gender information, can be employed for classification purposes and benefit healthcare for decision support in COPD diagnosis.

CLINICAL TRIAL REGISTRATION NUMBER

NCT05897944.

Triple Therapy in COPD: Can We Welcome the Reduction in Cardiovascular Risk and Mortality?

Chronic obstructive pulmonary disease (COPD) is a complex disease which consists in the reduction of the airflow and leads to the disruption of the pulmonary tissue due to a chronic inflammation. The progression of the disease is characterized by an exacerbation of the symptoms and the presence of life-threatening systemic complications, such as stroke and ischemic heart disease, with a progressive decline in lung function which can deeply impact the quality of life. Mortality represents the most important COPD outcome, with an increased risk in patients with cardiovascular comorbidities. The efficacy and safety of triple inhaled therapy were demonstrated by numerous controlled trials. Above all, many robust data are now available on the effectiveness of the triple therapy to reduce mortality in COPD patients.

Electrophysiological biomarkers of central nervous system affection in cases of chronic obstructive pulmonary disease (COPD)

Background

Chronic obstructive pulmonary disease is associated with significant systemic abnormalities which includes systemic inflammation and neurohormonal activation that are considered the main mechanisms of the pathophysiology in systemic involvement. The aim of the present study was to detect the subclinical affection of the central nervous system in patients with stable chronic obstructive pulmonary disease.

Results

Forty patients with chronic obstructive pulmonary disease were enrolled in this study and 30 healthy subjects as a control group. All patients and healthy subjects were submitted to full history taking, clinical examination, arterial blood gases, spirometry, evoked potential, and electroencephalogram. Regarding to brain stem auditory evoked potentials, there was a statistically significant increase of latency of waves numbers I, III, and V, and a statistically significant increase of interpeak latencies I–III in the COPD group when compared to the control group. On the other hand, there was a statistically significant decrease of brain stem auditory evoked potential I and V amplitudes on both sides in the COPD group when compared to the control group. In visual evoked potential, there was a statistically significant increase of latency and decrease of amplitude of P100. In addition, there was a statistically significant increase of electroencephalogram changes in the COPD group when compared to the control group (20.0% vs. 3.3%, respectively).

Conclusion

In patients with chronic obstructive pulmonary disease, the central nervous system could be affected subclinically as the severity of chronic obstructive pulmonary disease increased, and the patient should be electrophysiologically monitored for early detection of nervous system affection.

Neurophysiological biomarkers of peripheral nervous system affection in patients with stable chronic obstructive pulmonary disease (COPD)

Background

Chronic obstructive pulmonary disease (COPD) is accompanied by substantial systemic dysregulations that comprise systemic inflammation and neurohormonal activation in addition to many neurological involvements, such as cerebrovascular diseases, polyneuropathies, motor neuron diseases, and cognitive impairment has been described in COPD patients. The aim of the current work was to detect the subclinical affection of the peripheral nervous system in patients with stable COPD.

Results

Forty COPD patients and 30 subjects as healthy control were enrolled. All included subjects were submitted to complete medical history, clinical evaluations, investigations in the form of; arterial blood gases, spirometry, in addition to nerve conduction study. The patients with COPD were classified according to GOLD criteria for severity in grade I in 7.5% grade II in 62.5%, grade III in 20%, and grade IV in 10%. The results show a statistically significant increase in distal latency and a statistically significant decrease of amplitude and conduction velocity in patients with COPD when compared to the examined nerves of control group. The demyelinating nerve affection was the most common.

Conclusion

In COPD patients the peripheral nervous system could be affected subclinically once the severity of COPD increased and the patient should be neurophysiologically observed for early recognition of peripheral nervous system affection.

Test-Retest Reliability of Handgrip Strength in Patients with Chronic Obstructive Pulmonary Disease

The purpose of this study was to investigate the intra-rater reliability and agreement of handgrip strength (HGS) measurement using a hydraulic hand dynamometer in patients with chronic obstructive pulmonary disease (COPD). A sample of 19 COPD patients (18 males and 1 female; mean ± SD age, 66.9 ± 6.3 years) was evaluated using a hand dynamometer by the same rater in two different testing sessions with a 7-d interval. During each session, patients were asked to exert three maximal isometric contractions on the dominant hand and the mean value of the 3 efforts (measured in kilogram-force [Kgf]) was used for data analysis. The intraclass correlation coefficient (ICC_2,1), the standard error of measurement (SEM), the minimal detectable change (MDC), and Bland-Altman methods were used to estimate the degree of test-retest reliability and the measurement error, respectively. HGS in COPD patients revealed an ICC_2,1 score of 0.99, suggesting excellent test-retest reliability. The calculated SEM was relatively small (0.59 Kgf), and the MDC presented a clinically acceptable value of 1.64 Kgf. These findings, in conjunction with the narrow width of the 95% limits of agreements (95% limits of agreement, -2.5-2.1 Kgf) in the Bland-Altman plot, reflected the measurement precision and the narrow variation of the differences during the 2 testing sessions. The results of this study demonstrated an excellent test-retest reliability of HGS measurement, indicating that this method is reliable for repeated monitoring of peripheral muscle strength in patients with COPD.

Association Between Everyday Technology Use, Activities of Daily Living and Health-Related Quality of Life in Chronic Obstructive Pulmonary Disease

Purpose

A decline in the ability to perform activities of daily living (ADL) and ability to use everyday technology can pose threats to independent living, healthcare management and quality of life (QOL) of patients suffering from chronic obstructive pulmonary disease (COPD). Evidence of the relationship between these variables remains limited. The dual aim of this study was, first, to investigate if health-related QOL (HRQOL) was associated with quality in ADL performance and everyday technology use; second, to examine whether lung function, years with COPD diagnosis, living status or educational level affected physical and mental domains of HRQOL.

Methods

This cross-sectional study included (N=80) participants aged 46-87 years recruited at healthcare centres in the Northern Region of Denmark using a convenience sampling procedure. Data were gathered through standardized assessments and analysed using multiple regression analysis.

Results

The regression model explained 50.6% (R2=0.506) of the variation in HRQOL-physical. The following four variables were statistically significantly associated with HRQOL - physical: years since COPD diagnosis (p=0.023), ability to use everyday technology (p=0.006), amount of relevant everyday technologies (p=0.015) and ADL motor ability (p<0.01). The regression model explained 22.80% (R2=0.228) of HRQOL - mental. Only the variable ability to use everyday technology was statistically significantly associated with HRQOL - mental (p=0.009).

Conclusion

Quality of ADL performance and everyday technology use seem to be associated with HRQOL in people living with COPD. The only demographic variable associated with HRQOL was years with COPD. This indicates that healthcare professionals should enhance their attention also to ADL-performance and everyday technology use when striving to increase the HRQOL of persons living with COPD.

Risk of chronic obstructive pulmonary disease in healthy individuals with high C-reactive protein levels by smoking status: a population-based cohort study in Korea

Purpose

Chronic obstructive pulmonary disease (COPD) is associated with systemic inflammation. We investigated whether elevated baseline serum C-reactive protein (CRP) levels in healthy individuals are associated with the risk of incident COPD by smoking status.

Patients and methods

This was a cohort study of 63,260 adult men and women who were older than 40 years, free of COPD at baseline, and underwent health screening from 2002 to 2016 with at least one follow-up visit through December 2016. We investigated the association between baseline high-sensitivity CRP (hsCRP) levels and incident COPD by smoking status, using flexible parametric proportional hazards models and pooled logistic regression analyses.

Results

The multivariable-adjusted hazard ratio (95% confidence interval) comparing participants in the 90th to those in the 10th percentile of hsCRP was 1.19 (1.08, 1.31). The corresponding hazard ratio in never, former, and current smokers were 1.07 (0.89, 1.29), 1.22 (1.05, 1.42), and 1.22 (1.05, 1.41), respectively. The association between hsCRP levels and incident COPD had a similar dose–response pattern in former and current smokers, but not in never smokers.

Conclusion

Higher baseline hsCRP is associated with an increased risk to develop COPD in ever smokers but not in never smokers.

Muscle Dysfunction in Smokers and Patients With Mild COPD: A SYSTEMATIC REVIEW

PURPOSE

To describe and discuss the available evidence in the literature concerning muscle function and the association between smoking and muscle dysfunction in smokers and patients with mild chronic obstructive pulmonary disease (COPD).

METHODS

The literature search involved the following databases: PubMed, Pedro, CINAHL, Cochrane Library, Lilacs, and EMBASE. Studies were included if they investigated muscle strength and/or endurance and/or cross-sectional area (CSA) in smokers and/or patients with COPD classified as Global Initiative for Obstructive Lung Disease (GOLD) I and without lung cancer. Two authors screened and identified the studies for inclusion.

RESULTS

Eighteen studies were identified. Some studies found lower values in a variety of muscle strength variables in smokers compared with nonsmoking controls, whereas others found similar values between these groups. When comparing patients with COPD classified as GOLD I with smokers, COPD patients showed lower muscle strength. Two studies found no differences in muscle CSA between smokers compared with nonsmoking controls. Some preliminary evidence also shows that patients with COPD classified as GOLD I had lower CSA in comparison with smokers.

CONCLUSION

Results concerning muscle dysfunction in smokers are divergent, since some studies have shown worse results in a variety of muscle strength variables in smokers compared with nonsmoking controls, whereas other studies have not. Moreover, there is rather preliminary evidence indicating worse muscle dysfunction and lower CSA in patients with mild COPD in comparison with healthy (or non-COPD) smokers.

Incidence and relative risk for developing cancer among patients with COPD: a nationwide cohort study in Taiwan

OBJECTIVES

This observational study aimed to examine the incidence of malignant diseases, including specific cancer types, after the diagnosis of chronic obstructive pulmonary disease (COPD) in Taiwanese patients.

SETTING

Taiwan's National Health Insurance Research Database.

PARTICIPANTS

The definition of a patient with COPD was a patient with a discharge diagnosis of COPD or at least 3 ambulatory visits for COPD. The index date was the date of the first COPD diagnosis. Patients with a history of malignancy disorders before the index date were excluded. After matching age and gender, 13 289 patients with COPD and 26 578 control participants without COPD were retrieved and analysed. They were followed from the index date to malignancy diagnosis, death or the end of study follow-up (31 December 2011), whichever came first.

PRIMARY OUTCOME MEASURES

Patients were diagnosed with cancer (n=1681, 4.2%; 973 (7.3%) for patients with COPD and 728 (2.7%) for patients without COPD). The risk of 7 major cancer types, including lung, liver, colorectal, breast, prostate, stomach and oesophagus, between patients with COPD and patients without COPD was also estimated.

RESULTS

The mean age of all study participants was 57.9±13.5 years. The average length of follow-up to cancer incidence was 3.9 years for patients with COPD and 5.0 years for patients without COPD (p<0.01). Patients with COPD were diagnosed with cancer (n=973, 73%) at a significantly higher rate than patients without COPD (n=708, 2.7%; p<0.01). The HR for developing cancer in patients with COPD was 2.8 (95% CI 2.6 to 3.1) compared with patients without COPD after adjusting for age, sex and comorbidities. The most common cancers in patients with COPD include lung, liver, colorectal, breast, prostate and stomach cancers.

CONCLUSIONS

The risk of developing cancer is higher in patients with COPD compared with patients without COPD. Cancer screening is warranted in patients with COPD.

Comorbidity associated with referral to pulmonary rehabilitation in people hospitalized with chronic obstructive pulmonary disease

PURPOSE

Comorbid conditions are common in people with chronic obstructive pulmonary disease (COPD) and may affect therapeutic management. The aim of this study was to examine the association of comorbidity in people with COPD with referral to a pulmonary rehabilitation (PR) program.

METHODS

An analysis of data was conducted from an observational study of 88 people admitted to hospital with a primary diagnosis of COPD. Demographic and admission-related data were extracted and comorbidity scores (Charlson and Rx-Risk-V) were calculated.

RESULTS

Total comorbidity scores were not associated with referral to PR; however specific comorbid conditions were. The presence of anxiety (from medical records) was more frequent in those referred to PR (χ = 4.20; P = .04; OR, 7.0; 95% CI, 0.8-59.0). The presence of hypertension (as determined by Rx-Risk-V) was more likely to result in PR referral (χ = 6.69; P = .01; OR, 6.8; 95% CI, 1.6-29.1), and, in those with arrhythmia, PR referral was less likely (χ = 4.22; P = .04; OR, 0.28; 95% CI, 0.08-0.99). Patients who had been referred to PR had lower forced expiratory volume in 1 second (FEV1 percent predicted) (P < .001) and greater hospital bed days in previous 3 years (P = .051). In a multivariate analysis, FEV1 percent predicted, bed days in the last 3 years, and Rx-Risk-V categories of hypertension and arrhythmia accounted for 25% of variance in referral to PR.

CONCLUSIONS

In addition to COPD disease severity and hospital utilization, specific comorbidities identified with a comprehensive system (ie, the Rx-Risk score) were associated with referral to PR in this sample.

Activity of α1-antitrypsin and some lysosomal enzymes in the blood serum of patients with chronic obstructive pulmonary disease after smoking cessation

The activity of α₁-antitrypsin (AAT) and the lysosomal enzymes, cathepsin D (CTS D), arylsulfatase (ASA), and acid phosphatase, (AcP) was determined in patients with COPD (GOLD category A). Moreover, the diagnostic usefulness of these parameters in blood serum was assessed along with establishing whether smoking cessation affects these parameters. The study included 70 patients with COPD who ceased smoking (study group) and two control groups of 33 subjects each: nonsmokers without COPD (control I) and patients with COPD who continued smoking (control II). In control I, blood was taken once and in control II, at the start of the experiment and after the 1st, 2nd, and 3rd months. AAT in the patients exhibited higher activity than in the healthy subjects at all time points. AAT activity in the patients before the start of the experiment was ~80% higher (P < 0.001) than in control I. No statistically significant differences in CTS D, ASA, and AcP activity were found. COPD involves increased AAT activity and unchanged activities of the assessed lysosomal enzymes. Three-month tobacco abstinence does not affect these parameters in peripheral blood. Determining the AAT levels in blood serum can be used in the diagnostics of COPD.

Effects of chronic obstructive pulmonary disease and obstructive sleep apnea on cognitive functions: evidence for a common nature

Patients with chronic obstructive pulmonary disease (COPD) and obstructive sleep apnea syndrome (OSAS) show similar neurocognitive impairments. Effects are more apparent in severe cases, whereas in moderate and mild cases the effects are equivocal. The exact mechanism that causes cognitive dysfunctions in both diseases is still unknown and only suggestions have been made for each disease separately. The primary objective of this review is to present COPD and OSAS impact on cognitive functions. Secondly, it aims to examine the potential mechanisms by which COPD and OSAS can be linked and provide evidence for a common nature that affects cognitive functions in both diseases. Patients with COPD and OSAS compared to normal distribution show significant deficits in the cognitive abilities of attention, psychomotor speed, memory and learning, visuospatial and constructional abilities, executive skills, and language. The severity of these deficits in OSAS seems to correlate with the physiological events such as sleep defragmentation, apnea/hypopnea index, and hypoxemia, whereas cognitive impairments in COPD are associated with hypoventilation, hypoxemia, and hypercapnia. These factors as well as vascocerebral diseases and changes in systemic hemodynamic seem to act in an intermingling and synergistic way on the cause of cognitive dysfunctions in both diseases. However, low blood oxygen pressure seems to be the dominant factor that contributes to the presence of cognitive deficits in both COPD and OSAS.

The association between co-morbidities and physical performance in people with chronic obstructive pulmonary disease

A systematic review was conducted to examine the association between co-morbidity and physical performance in people with chronic obstructive pulmonary disease (COPD). MEDLINE, EMBASE, CINAHL, SCOPUS and Cochrane Central Register of Controlled Trials were searched from inception to end-February 2013, using keywords ‘COPD’, ‘exercise’, ‘physical activity’, ‘rehabilitation’, ‘co-morbidity’ and individual co-morbid conditions. Studies reporting associations of co-morbidities in COPD with at least one objective measure of physical performance were included. Study quality was appraised using the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) checklist. Nine studies met inclusion criteria. Mean (standard deviation (SD)) STROBE score was 16 (3) (maximum score = 21). Four studies examined anxiety as a co-morbid condition; three examined depression; two examined obesity and two examined a range of conditions. Reduced physical performance was associated with higher Charlson score (odds ratio (OR) = 0.72, 95% confidence interval (CI) = 0.54–0.98), metabolic disease (OR = 0.58, 95% CI = 0.49–0.67), anxiety (OR = 0.37, 95% CI = 0.23–0.59) and osteoporosis (OR = 0.28, 95% CI = 0.11–0.70). Depression had minimal association with physical performance but was associated with higher dropout rates from pulmonary rehabilitation programmes. Obesity was negatively associated with baseline physical performance but not with change from an exercise intervention. The presence of co-morbid conditions in people with COPD may negatively affect physical performance and should be identified and accounted for analysis of interventions.

Smoke extract impairs adenosine wound healing: implications of smoke-generated reactive oxygen species

Adenosine concentrations are elevated in the lungs of patients with asthma and chronic obstructive pulmonary disease, where it balances between tissue repair and excessive airway remodeling. We previously demonstrated that the activation of the adenosine A2A receptor promotes epithelial wound closure. However, the mechanism by which adenosine-mediated wound healing occurs after cigarette smoke exposure has not been investigated. The present study investigates whether cigarette smoke exposure alters adenosine-mediated reparative properties via its ability to induce a shift in the oxidant/antioxidant balance. Using an in vitro wounding model, bronchial epithelial cells were exposed to 5% cigarette smoke extract, were wounded, and were then stimulated with either 10 μM adenosine or the specific A2A receptor agonist, 5'-(N-cyclopropyl)-carboxamido-adenosine (CPCA; 10 μM), and assessed for wound closure. In a subset of experiments, bronchial epithelial cells were infected with adenovirus vectors encoding human superoxide dismutase and/or catalase or control vector. In the presence of 5% smoke extract, significant delay was evident in both adenosine-mediated and CPCA-mediated wound closure. However, cells pretreated with N-acetylcysteine (NAC), a nonspecific antioxidant, reversed smoke extract-mediated inhibition. We found that cells overexpressing mitochondrial catalase repealed the smoke extract inhibition of CPCA-stimulated wound closure, whereas superoxide dismutase overexpression exerted no effect. Kinase experiments revealed that smoke extract significantly reduced the A2A-mediated activation of cyclic adenosine monophosphate-dependent protein kinase. However, pretreatment with NAC reversed this effect. In conclusion, our data suggest that cigarette smoke exposure impairs A2A-stimulated wound repair via a reactive oxygen species-dependent mechanism, thereby providing a better understanding of adenosine signaling that may direct the development of pharmacological tools for the treatment of chronic inflammatory lung disorders.

Use of an Australian quality of life tool in patients with COPD

COPD is a leading chronic disease, increasing globally. Given this condition's irreversible and progressive nature, health-related quality of life (HRQOL) is increasingly a primary end-point in COPD management. We evaluated several HRQOL tools with a primary goals of (1) investigating how the generic Assessment Quality of Life (AQOL) functions compared to the Medical Outcomes Study 36-item Short Form Health Survey (SF36) and the St. Georges Respiratory Questionnaire (SGRQ); and (2) considering the extent to which clinical disease severity, as measured by the BODE index, predicts variation in HRQOL reports.

METHODS

134 consecutive patients entering a pulmonary rehabilitation program were recruited. Participants completed two generic measures of HRQOL (SF36 and AQOL) and one disease specific measure (SGRQ). The clinical severity of COPD was assessed using a composite global COPD severity score, BODE.

RESULTS

Significant associations were demonstrated between AQOL and both the SF36 (r = .68) and SGRQ (r = -.60). BODE significantly predicted AQOL scores (R = -.31); mMRC (R = -.36) and 6MWD (R = .39) were stronger contributors to these predictions than were FEV(1) or BMI.

CONCLUSIONS

This study establishes convergent validity between AQOL, and the SF36 and SGRQ in patients with COPD. For future studies wishing to examine HRQOL from a generic perspective, we have shown that during cross-sectional analyses AQOL performs similarly to the SF36. In addition we identified that the clinical severity of COPD, as assessed by BODE, significantly influences reports of quality of life made using AQOL. The components of BODE that most strongly contributed to predicting HRQOL were dsypnea and exercise tolerance.

Chronic obstructive pulmonary disease and cancer risk: a Danish nationwide cohort study

INTRODUCTION

Little is known about the risk of cancer in patients with chronic obstructive pulmonary disease (COPD), including which cancer sites are most affected. We examined the short- and long-term risk of lung and extrapulmonary cancer in a nationwide cohort of COPD patients.

METHODS

We linked the Danish National Registry of Patients and the nationwide cancer registry, and examined the incidence of various cancers in 236,494 individuals with a first incident hospital contact with COPD during 1980-2008. The observed cancer incidence in this cohort was compared with the expected incidence in the general population on the basis of national age-, sex-, and site-specific incidence rates.

RESULTS

Median follow-up was 3.5 years. During the first year of follow-up, 9434 cancers were diagnosed in COPD patients [standardized incidence ratio (SIR) = 3.1; 95% CI 3.0 to 3.2]. The 1-year SIR was 8.5 (8.2-8.9) for lung cancer, 5.1 (5.0-5.2) for all tobacco-related cancers, and 1.9 (1.9-2.0) for other cancers. In the following years, cancer incidence was increased 1.4-fold (1.4-1.5) in COPD patients. These patients had an increased risk of developing tobacco-related cancers (SIR = 2.1; 95% CI 2.0-2.1), including cancers of the lung, larynx, tongue, oral cavity, pharynx, esophagus, stomach, liver, pancreas, cervix uteri, and urinary tract (with SIRs ranging between 1.3 and 2.8).

CONCLUSIONS

Patients with first-time hospital-diagnosed COPD are at considerably increased risk of developing both lung cancer and extrapulmonary cancers. Physicians should be aware of cancer in COPD patients.

The possible role of granzyme B in the pathogenesis of chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a highly prevalent inflammatory lung condition characterized by airways disease and emphysema, and the precise mechanism of pathogenesis is poorly understood. The consistent features of COPD include protease-antiprotease imbalance, inflammation and accelerated aging caused by apoptosis or senescence. One family of molecules involved in all of these processes is the granzymes, serine proteases with the best-known member being granzyme B (GzmB). The majority of GzmB is released unidirectionally towards target cells, but GzmB can also be released nonspecifically and escape into the extracellular environment. GzmB is capable of cleaving extracellular matrix (ECM) proteins in vitro, and the accumulation of GzmB in the extracellular milieu during chronic inflammation in COPD could contribute to ECM degradation and remodelling and, consequently, the emphysematous phenotype in the lung. Preliminary studies suggest that increased GzmB expression is associated with increased COPD severity, and this may represent a promising new target for drug and biomarker discovery in COPD. In this paper, we review the potential pathogenic contributions of GzmB to the pathogenesis of COPD.