Etiology and treatment of cough in idiopathic pulmonary fibrosis

Drug discovery and development in idiopathic pulmonary fibrosis: the changing landscape

Idiopathic pulmonary fibrosis (IPF) is an area of high unmet clinical need and high research activity in the pharmaceutical and biotech industries. The two approved therapies, nintedanib and pirfenidone, have issues with efficacy and tolerability. Despite a considerable number of development programs reaching late-stage Phase 2b or 3 clinical trials, no drug other than nintedanib and pirfenidone has successfully demonstrated a benefit for patients. An analysis of these failures, and consideration of the trajectories of some of the current development projects, may offer novel paradigms for choosing modes-of-action and for the development of successful drugs.

The burden of cough in idiopathic pulmonary fibrosis and other interstitial lung diseases: a systematic evidence synthesis

BACKGROUND

Cough remains a persistent symptom in patients with idiopathic pulmonary fibrosis (IPF) and other interstitial lung diseases (ILDs). To inform future research, treatment and care models, we conducted the first systematic synthesis of evidence on its associated burden.

METHODS

A literature search was performed for articles published between January 2010 and October 2023 using databases including Embase, MEDLINE and the Cochrane Library. Studies in patients with IPF and other ILDs reporting cough-related measures were eligible for inclusion. Included studies were categorised based on the types of ILD they examined and their design. Study details, patient characteristics and outcomes were extracted, and the risk of bias was assessed. A narrative synthesis approach was employed to interpret the findings.

RESULTS

Sixty-one studies were included: 33 in IPF, 18 in mixed-ILDs, six in connective tissue disease-associated-ILDs and four in sarcoidosis. Across the studies, a range of tools to assess cough and its impact were used. The most frequently used measures of cough were cough severity visual analogue scale (VAS) and objective cough counts, whereas the most frequently used health-related quality of life (HRQoL)/impact measures were the St. George's Respiratory Questionnaire (SGRQ) and Leicester Cough Questionnaire (LCQ). In IPF, studies consistently reported correlations between various cough and HRQoL measures, including between cough VAS scores and objective cough counts, LCQ scores and SGRQ scores. Similar correlations were observed in studies in other ILDs, but data were more limited. Qualitative studies in both IPF and other ILDs consistently highlighted the significant cough-related burden experienced by patients, including disruption of daily activities, fatigue and social embarrassment. Although there were no studies specifically investigating the economic burden of cough, one study in patients with fibrotic ILD found cough severity was associated with workplace productivity loss.

CONCLUSIONS

Our study underscores the heterogeneity in assessing cough and its impact in IPF and other ILDs. The findings confirm the negative impact of cough on HRQoL in IPF and suggest a comparable impact in other ILDs. Our synthesis highlights the need for standardised assessment tools, along with dedicated studies, particularly in non-IPF ILDs and on the economic burden of cough.

Pharmacological treatment in Idiopathic Pulmonary Fibrosis: current issues and future perspectives

Idiopathic pulmonary fibrosis (IPF) represents a fibrotic interstitial lung disease characterized by uncertain etiology and poor prognosis. Over the years, the path to effective treatments has been marked by a series of advances and setbacks. The introduction of approved antifibrotic drugs, pirfenidone and nintedanib, marked a pivotal moment in the management of IPF. However, despite these advances, these drugs are not curative, although they can slow the natural progression of the disease. The history of drug therapy for IPF goes together with the increased understanding of the pathogenic mechanisms underlying the disease. Based on that, current research efforts continue to explore new therapies, possible personalized treatment strategies, drug combinations, and potential biomarkers for diagnosis and prognosis. In this review, we outline the route that led to the discover of the first effective therapies, ongoing clinical trials, and future directions in the search for more effective treatments.

Assessment and Management of Cough in Idiopathic Pulmonary Fibrosis: A Narrative Review

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive, and fatal disease with an unknown cause. It is characterized by symptoms such as cough and breathlessness, which significantly impact patients' quality of life. Cough, in particular, has emerged as a burdensome symptom for individuals with IPF. The etiology of cough in IPF patients is believed to be complex, involving factors related to the disease itself, such as increased sensitivity of cough nerves, lung structural changes, inflammation, and genetic factors, as well as comorbidities and medication effects. Unfortunately, effective treatment options for cough in IPF remain limited, often relying on empirical approaches based on studies involving chronic cough patients in general and the personal experience of physicians. Medications such as opioids and neuromodulators are commonly prescribed but have shown suboptimal efficacy, imposing significant physical, psychological, and economic burdens on patients. However, there is hope on the horizon, as specific purinergic P2 receptor ligand-gated ion channel (P2X3) inhibitors have demonstrated promising antitussive effects in ongoing clinical trials. This review aims to provide a comprehensive overview of the evaluation and management of cough in IPF patients, as well as highlight emerging pharmacological and non-pharmacological approaches that target the cough reflex and are currently being investigated in clinical settings.

Understanding patient experience of chronic cough in interstitial lung disease

Rationale

Chronic cough is a common symptom in patients with interstitial lung disease (ILD), negatively contributing to health-related quality of life. Despite this, there is limited information and understanding on the experience of this group of patients with chronic cough. This study aimed to explore the symptom experiences for chronic cough in patients with ILD to identify its characteristics and impacts.

Methods

A qualitative study using semi-structured telephone interviews was undertaken in 16 adults with a diagnosis of ILD of any type and severity. Patients were recruited from a quaternary referral centre in Melbourne, Australia. Interviews were transcribed verbatim and coded by two researchers using thematic analysis.

Results

Patients (age range: 39-87 years, forced vital capacity: 53-107% predicted and diffusing capacity of the lung for carbon monoxide: 28-89% predicted) experienced a spectrum of cough severity and characteristics, including both dry and productive coughs. The impact of chronic cough included physical symptoms, social and emotional difficulties, and interference with work and vocational participation. Management strategies used to relieve cough included mucolytics, opiates, throat lozenges, warm drinks, pacing, breath control, relaxation exercises, movement, continuous positive airways pressure and supplemental oxygen. Patients expressed a need for further information and education regarding chronic cough, including its triggers and management.

Conclusions

This study highlights the experience and significance of chronic cough in patients with ILD. The nature and severity of chronic cough in patients with ILD appears to be more heterogeneous than previously described, with physical, social and emotional impacts contributing to symptom burden.

What Do We Need to Know About Rising Rates of Idiopathic Pulmonary Fibrosis? A Narrative Review and Update

The most common type of idiopathic interstitial pneumonia is idiopathic pulmonary fibrosis (IPF), an irreversible, progressive disorder that has lately come into question for possible associations with COVID-19. With few geographical exceptions, IPF is a rare disease but its prevalence has been increasing markedly since before the pandemic. Environmental exposures are frequently implicated in IPF although genetic factors play a role as well. In IPF, healthy lung tissue is progressively replaced with an abnormal extracellular matrix that impedes normal alveolar function while, at the same time, natural repair mechanisms become dysregulated. While chronic viral infections are known risk factors for IPF, acute infections are not and the link to COVID-19 has not been established. Macrophagy may be a frontline defense against any number of inflammatory pulmonary diseases, and the inflammatory cascade that may occur in patients with COVID-19 may disrupt the activity of monocytes and macrophages in clearing up fibrosis and remodeling lung tissue. It is unclear if COVID-19 infection is a risk factor for IPF, but the two can occur in the same patient with complicating effects. In light of its increasing prevalence, further study of IPF and its diagnosis and treatment is warranted.

The Efficacy and Safety of Herbal Medicine with Pirfenidone in the Treatment of Idiopathic Pulmonary Fibrosis: A Systematic Review

Although there were randomized control trials (RCTs) that showed the considerable efficacy of herbal medicine (HM) in idiopathic pulmonary fibrosis (IPF) and systematic reviews on the value of some herbs in the treatment of IPF, there have been no systematic reviews comparing the combined use of complex HM against pirfenidone monotherapy in IPF. This review evaluated the efficacy of parallel administration of HM and pirfenidone in IPF treatment. We conducted a systematic review of RCTs that compared pirfenidone monotherapy against pirfenidone combined administration with HM in IPF. We searched the EMBASE, CENTRAL, PubMed, and CNKI databases for relevant RCTs published before July 2021. Six RCTs were eligible for inclusion. Compared with the control group, a greater recovery or a smaller reduction in forced vital capacity (FVC) and, in general, a valid improvement in the St. George’s Respiratory Questionnaire was observed in the treatment group. However, it should be noted that the risk of bias of the included RCTs was high or unclear in most categories. In IPF treatment, HM administered with pirfenidone effectively protected pulmonary function and improved the quality of life. However, given the number and quality of the included studies, the evidence was not strong enough to draw definitive conclusions. Well-designed future RCTs are warranted to evaluate the impact of HM on IPF.

ATP, an attractive target for the treatment of refractory chronic cough

Chronic cough is the most common complaint in respiratory clinics. Most of them have identifiable causes and some may respond to common disease-modifying therapies. However, there are many patients whose cough lacks effective aetiologically targeted treatments or remains unexplained after thorough assessments, which have been described as refractory chronic cough. Current treatments for refractory chronic cough are limited and often accompanied by intolerable side effects such as sedation. In recent years, various in-depth researches into the pathogenesis of chronic cough have led to an explosion in the development of drugs for the treatment of refractory chronic cough. There has been considerable progress in the underlying mechanisms of chronic cough targeting ATP, and ongoing or completed clinical studies have confirmed the promising antitussive efficacy of P2X3 antagonists for refractory cough. Herein, we review the foundation on which ATP target was developed as potential antitussive medications and provide an update on current clinical progresses.

Identification of hub genes associated with COVID-19 and idiopathic pulmonary fibrosis by integrated bioinformatics analysis

INTRODUCTION

The coronavirus disease 2019 (COVID-19), emerged in late 2019, was caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The risk factors for idiopathic pulmonary fibrosis (IPF) and COVID-19 are reported to be common. This study aimed to determine the potential role of differentially expressed genes (DEGs) common in IPF and COVID-19.

MATERIALS AND METHODS

Based on GEO database, we obtained DEGs from one SARS-CoV-2 dataset and five IPF datasets. A series of enrichment analysis were performed to identify the function of upregulated and downregulated DEGs, respectively. Two plugins in Cytoscape, Cytohubba and MCODE, were utilized to identify hub genes after a protein-protein interaction (PPI) network. Finally, candidate drugs were predicted to target the upregulated DEGs.

RESULTS

A total of 188 DEGs were found between COVID-19 and IPF, out of which 117 were upregulated and 71 were downregulated. The upregulated DEGs were involved in cytokine function, while downregulated DEGs were associated with extracellular matrix disassembly. Twenty-two hub genes were upregulated in COVID-19 and IPF, for which 155 candidate drugs were predicted (adj.P.value < 0.01).

CONCLUSION

Identifying the hub genes aberrantly regulated in both COVID-19 and IPF may enable development of molecules, encoded by those genes, as therapeutic targets for preventing IPF progression and SARS-CoV-2 infections.

Idiopathic pulmonary fibrosis: Current and future treatment

Objectives

Idiopathic pulmonary fibrosis (IPF) is a chronic fibrotic lung disease characterized by dry cough, fatigue, and progressive exertional dyspnea. Lung parenchyma and architecture is destroyed, compliance is lost, and gas exchange is compromised in this debilitating condition that leads inexorably to respiratory failure and death within 3–5 years of diagnosis. This review discusses treatment approaches to IPF in current use and those that appear promising for future development.

Data Source

The data were obtained from the Randomized Controlled Trials and scientific studies published in English literature. We used search terms related to IPF, antifibrotic treatment, lung transplant, and management.

Results

Etiopathogenesis of IPF is not fully understood, and treatment options are limited. Pathological features of IPF include extracellular matrix remodeling, fibroblast activation and proliferation, immune dysregulation, cell senescence, and presence of aberrant basaloid cells. The mainstay therapies are the oral antifibrotic drugs pirfenidone and nintedanib, which can improve quality of life, attenuate symptoms, and slow disease progression. Unilateral or bilateral lung transplantation is the only treatment for IPF shown to increase life expectancy.

Conclusion

Clearly, there is an unmet need for accelerated research into IPF mechanisms so that progress can be made in therapeutics toward the goals of increasing life expectancy, alleviating symptoms, and improving well‐being.

Phase 2b Study of Inhaled RVT-1601 for Chronic Cough in Idiopathic Pulmonary Fibrosis: SCENIC Trial: Multi-Center, Randomized, Placebo-Controlled Study

RATIONALE

Chronic cough remains a major and often debilitating symptom for patients with idiopathic pulmonary fibrosis (IPF). In a phase 2a study, inhaled RVT-1601 reduced daytime cough and 24-hour average cough counts in patients with IPF.

OBJECTIVES

To determine the efficacy, safety and optimal dose of inhaled RVT-1601 for the treatment of chronic cough in patients with IPF.

METHODS

In this multicenter, randomized, placebo-controlled phase 2b study, patients with IPF and chronic cough for ≥8 weeks were randomized (1:1:1:1) to receive 10, 40, and 80 mg RVT-1601 three times daily or placebo for 12 weeks. The primary endpoint was change from baseline to end of treatment in log-transformed 24-hour cough count. Key secondary endpoints were change from baseline in cough severity and cough specific quality of life. Safety was monitored throughout the study.

MEASUREMENTS AND MAIN RESULTS

The study was prematurely terminated due to the impact of COVID-19 pandemic. Overall, 108 patients (mean age 71.0 years, 62.9% males) received RVT-1601 10 mg (n = 29), 40 mg (n = 25), 80 mg (n = 27), or matching placebo (n = 27); 61.1% (n = 66) completed double-blind treatment. No statistically significant difference was observed in the least-squares mean change from baseline in log-transformed 24-hour average cough count, cough severity, and cough-specific quality of life score between the RVT-1601 groups and placebo. The mean percentage change from baseline in 24-hour average cough count was 27.7% in the placebo group. Treatment was generally well tolerated.

CONCLUSIONS

Treatment with inhaled RVT-1601 (10, 40 and 80 mg TID) did not provide benefit over placebo for the treatment of chronic cough in patients with IPF. Clinical trial registration available at www.clinicaltrials.gov, ID: NCT03864328.

Management of musculoskeletal pain in patients with idiopathic pulmonary fibrosis: a review

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive, fibrotic, and fatal interstitial lung disease (ILD) of unknown etiology that primarily affects the elderly. Patients with IPF suffer from a heavy symptom burden and usually have a poor quality of life. Dyspnea and dry cough are predominant symptoms of IPF. Although pain is not considered one of the main symptoms of IPF, it can occur for a variety of reasons, such as hypoxia, coughing, muscle and nerve damage, deconditioning, and steroid use. The prevalence of pain in IPF patients varies greatly, ranging from around 30 to 80%, with the prevalence being estimated mostly among patients in the end-of-life period. It manifests itself in the form of muscle pain, joint discomfort, or back and chest pain. Approaches to the treatment of chronic musculoskeletal pain in patients with IPF include pharmacological and non-pharmacological measures that are also important to optimize the treatment of other symptoms (dyspnea and cough) and the optimal treatment of comorbidities. Given the scarcity of data on this symptom in the literature, this article summarizes what is currently known about the etiology and treatment of musculoskeletal pain in IPF.

Management of cough in patients with idiopathic interstitial lung diseases in primary care

Importance: Cough is a common symptom in idiopathic interstitial lung diseases (ILDs), there is little information of its management in primary care. The objective of this study was to explore the frequency of cough-related consultations and the medications prescribed to patients with ILDs in primary care. Methods: This retrospective cohort study used electronic medical records (EMR) from Manitoba primary care providers participating in the Manitoba Primary Care Research Network repository (2014–2019). Cough-related consults and the subsequent medications prescribed to patients with ILDs were identified in the EMR. Results: 295 patients with ILDs were identified, 73 (25%) of them had 141 cough-related consultations (mean 1.9, SD 1.3) during the period studied. In 50 (35%) of the consultations, patients were prescribed one or more of the following: inhaled bronchodilators (34%), nasal corticoids (18%), codeine/opiates (18%), antibiotics (14%), inhaled corticoids (14%), proton pump inhibitors (8%), cough preparations (6%), antihistamines (4%), and oral corticoids (2%). 13 (26%) subsequent cough-related consultations were identified within 6 months, mainly among patients who were prescribed cough preparations, nasal corticoids, antihistamines, and antibiotics. Conclusion: One-quarter of patients with ILDs consulted primary care due to cough, and about a third of them received a prescription to address potentially underlying causes of cough. Although further studies are required to explore the effect of the medications prescribed, recurrent cough consultations suggested that cough preparations, nasal corticoids, and antihistamines are among the least effective treatments. More research is needed to understand the causes and optimal treatment of cough in patients with ILDs.

How We Do It: Managing Cough in Idiopathic Pulmonary Fibrosis

In many studies, more than one-half of patients with idiopathic pulmonary fibrosis (IPF) endorse cough. In IPF (as in other conditions), when chronic, cough may be frustrating and lead to significant impairments in quality of life. In patients with IPF, comorbid conditions such as gastroesophageal reflux can cause or contribute to cough; when stemming from IPF itself, chronic cough likely arises from multiple mechanisms including mechanical and neurosensory changes. In this article, we review our approach at attempting to identify causes of chronic cough in patients with IPF; these include gastroesophageal reflux disease or upper airway cough syndrome and IPF itself. We cursorily summarize the current evidence for the treatment of chronic cough in IPF, briefly review data on the treatment of unexplained chronic cough and extrapolate it to the treatment of refractory cough in IPF, but we focus our attention on our approaches to evaluation and management, recognizing that some may not be supported by a robust cache of data.

Treatment of Persistent Cough in Subjects with Idiopathic Pulmonary Fibrosis (IPF) with Gefapixant, a P2X3 Antagonist, in a Randomized, Placebo-Controlled Clinical Trial

INTRODUCTION

Chronic cough is a highly problematic symptom for patients with idiopathic pulmonary fibrosis (IPF); limited therapeutic options are available. We evaluated gefapixant, a P2X3 receptor antagonist, for the treatment of chronic cough in IPF.

METHODS

This randomized, double-blind, placebo-controlled, crossover study included subjects with IPF. Sequence A included gefapixant 50 mg BID (period 1; 14 days) followed by placebo (period 2; 14 days); sequence B had the opposite sequence of treatments. This regimen was specified in a protocol amendment that modified the original active treatment regimen of gefapixant 50 mg BID for 10 days and 150 mg BID for 4 days. Patients randomized to the original treatment regimen were excluded from efficacy analyses but included in safety assessments. The primary efficacy endpoint was change from baseline in awake cough frequency (coughs/hour) from periods 1 and 2 combined. Adverse events (AEs) were monitored throughout the study.

RESULTS

A total of 51 subjects were randomized, 44 of whom were randomized to treatment sequences evaluated in the primary efficacy analysis (i.e., 22 subjects in sequence A and 22 subjects in sequence B); seven subjects received the treatment assigned before the protocol amendment and were excluded from efficacy analyses. The change from baseline in awake cough frequency from periods 1 and 2 combined (mixed model for repeated measures analysis) did not demonstrate a significant reduction versus placebo in cough at day 14 (p = 0.90); in a post hoc analysis of log-transformed data p value for reduction versus placebo at day 14 was 0.07. The most common AEs were related to taste (dysgeusia and ageusia).

CONCLUSIONS

Gefapixant was generally well tolerated but was not associated with a significant improvement in chronic cough in subjects with IPF as defined by the primary endpoint in this study.

TRIAL REGISTRATION

NCT02502097.

Azithromycin for the Treatment of Chronic Cough in Idiopathic Pulmonary Fibrosis: A Randomized Controlled Cross-over Trial

RATIONALE

Patients with idiopathic pulmonary fibrosis (IPF) frequently suffer from difficult to treat chronic cough, which substantially affects their quality of life. Azithromycin has been demonstrated to relieve chronic cough in some populations, however this has not been investigated in IPF.

OBJECTIVES

To determine the safety and efficacy of azithromycin for the treatment of chronic cough in patients with IPF.

METHODS

In a double-blind randomized controlled cross-over trial, patients with IPF underwent two 12-week intervention periods (azithromycin 500mg or placebo 3 times per week). The primary outcome was change in cough-related quality of life measured by the Leicester cough questionnaire (LCQ). Secondary outcomes included cough severity measured using Visual Analog Scale (VAS), health-related quality of life assessed by the St. George's Respiratory Questionnaire (SGRQ), and objective cough frequency using audiovisual readings from 24h respiratory polygraphy.

RESULTS

25 patients were randomized (23 men, 2 women), 20 patients completed the study. Mean (standard deviation, SD) age was 67 (8) years, mean (SD) forced vital capacity (FVC) was 65 (16) %-predicted, and diffusion capacity (DLCO) 43 (16) %-predicted. Mean (SD) baseline LCQ was 11.7 (3.7) and 11.3 (3.3) for the azithromycin and the placebo period, respectively, and the corresponding mean (SD) cough VAS 5.6 (2.3) and 5.8 (2.1). There was no significant change in LCQ and VAS with azithromycin or placebo. Similarly, there was no significant difference in change in polygraphy measured cough frequency between the azithromycin and placebo periods. Gastrointestinal adverse effects were more frequent with azithromycin than with placebo (diarrhea 43% vs 5%, p=0.03).

CONCLUSIONS

This randomized controlled trial does not support the use of low dose azithromycin for chronic cough in patients with IPF. Clinical trial registered with ClinicalTrials.gov (NCT02173145).

Palliative care in pulmonary medicine

Palliative care was initially developed for patients with advanced cancer. The concept has evolved and now encompasses any life-threatening chronic disease. Studies carried out to compare end-of-life symptoms have shown that although symptoms such as pain and dyspnea are as prevalent in patients with lung disease as in patients with cancer, the former receive less palliative treatment than do the latter. There is a need to refute the idea that palliative care should be adopted only when curative treatment is no longer possible. Palliative care should be provided in conjunction with curative treatment at the time of diagnosis, by means of a joint decision-making process; that is, the patient and the physician should work together to plan the therapy, seeking to improve quality of life while reducing physical, psychological, and spiritual suffering.

Idiopathic Pulmonary Fibrosis: A Review of Disease, Pharmacological, and Nonpharmacological Strategies With a Focus on Symptoms, Function, and Health-Related Quality of Life

Despite several advances in treatment, idiopathic pulmonary fibrosis (IPF) remains a progressive, symptomatic, and terminal disease in patients not suitable for lung transplantation. With disease progression, IPF often leads to a constellation of symptoms, including dyspnea, cough, anxiety, and depression. Palliative care is appropriate to support these patients. However, traditional curriculum in palliative care has often focused on supporting patients with malignant disease, and clinicians are not universally trained to manage patients with progressive nonmalignant diseases such as IPF. Current antifibrotic therapies aim to slow disease progression but are not able to reduce symptoms or improve daily function and health-related quality of life (HRQL). Palliative care in this patient group requires an understanding of the clinical characteristics of IPF, comorbidities, common medications used, and nonpharmacological strategies that can be undertaken to improve daily function and HRQL. This review focuses on IPF management strategies and their effects on symptoms, exercise tolerance, HRQL, and survival. Pharmacological interactions and considerations related to commonly used palliative care medications are also reviewed. This review highlights the needs of patients with IPF and caregivers, psychosocial function, patient-reported assessment tools, and topics related to advance care planning.

A Cross-sectional Survey of the Clinical Manifestations and Underlying Illness of Cough

AIM

The aim of this study was to identify factors affecting the final diagnosis of cough.

MATERIALS AND METHODS

This study recruited 463 consecutive patients who visited five Japanese general hospitals due to cough from October 2006 to September 2007. Of these, 418 patients (90%) who completed a questionnaire designed to acquire data regarding clinical manifestations of cough were included.

RESULTS

Most patients with bronchial asthma had cough with seasonal variation and wheezing. Patients with gastro esophageal reflux disease suffered from heartburn and cough without daily or seasonal variation. Cough associated with sinobronchial syndrome was only observed in females and was linked to increased sputum. Patients with whooping cough were bothered by cough interrupting sleep and talking. Patients with cardiogenic cough had exertional dyspnea.

CONCLUSION

The specific items on our questionnaire relating to patient characteristics, complications, and triggers of cough, represent useful tools for diagnosing the primary disease producing cough.

Cough in pulmonary tuberculosis: Existing knowledge and general insights

Cough is a prominent symptom of pulmonary tuberculosis (TB), one of the oldest and most prevalent infectious diseases. Coughing probably has a pivotal role in transmission of the causative organism Mycobacterium tuberculosis. Despite this, little research to date has addressed this subject. Current knowledge of the mechanisms of cough in TB and how exactly coughing patterns predict infectiousness is scant, but this is changing. This overview summarises the existing evidence for the infectiousness of cough in TB, clinical correlates, and possible causes of cough in TB. Potential unique characteristics of cough in the disease are discussed, as is treatment and the subjective awareness of coughing in the disease.

Randomised, double-blind, placebo-controlled pilot trial of omeprazole in idiopathic pulmonary fibrosis

Background

Cough is a common, disabling symptom of idiopathic pulmonary fibrosis (IPF), which may be exacerbated by acid reflux. Inhibiting gastric acid secretion could potentially reduce cough. This study aimed to determine the feasibility of a larger, multicentre trial of omeprazole for cough in IPF, to assess safety and to quantify cough.

Methods

Single-centre, double-blind, randomised, placebo-controlled pilot trial of the proton pump inhibitor (PPI) omeprazole (20 mg twice daily for 3 months) in patients with IPF. Primary objectives were to assess feasibility and acceptability of trial procedures. The primary clinical outcome was cough frequency.

Results

Forty-five participants were randomised (23 to omeprazole, 22 to placebo), with 40 (20 in each group) having cough monitoring before and after treatment. 280 patients were screened to yield these numbers, with barriers to discontinuing antacids the single biggest reason for non-recruitment. Recruitment averaged 1.5 participants per month. Geometric mean cough frequency at the end of treatment, adjusted for baseline, was 39.1% lower (95% CI 66.0% lower to 9.3% higher) in the omeprazole group compared with placebo. Omeprazole was well tolerated and adverse event profiles were similar in both groups, although there was a small excess of lower respiratory tract infection and a small fall in forced expiratory volume and forced vital capacity associated with omeprazole.

Conclusions

A large randomised controlled trial of PPIs for cough in IPF appears feasible and justified but should address barriers to randomisation and incorporate safety assessments in relation to respiratory infection and changes in lung function.

The pathogenetic mechanisms of cough in idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis is a peripheral subpleural interstitial lung disorder limited to the lung not involving the airways. It has a poor prognosis (survival less than 5 years) and commonly an interstitial pneumonia radiological pattern. Patients complain of a chronic dry cough in 80% of cases. A cough is often the first symptom of this rare disease, preceding dyspnea by years, and is associated with a poor prognosis, high dyspnea scores and low FVC percentages. The pathogenetic mechanisms leading to coughing in IPF are unclear. This review focuses on recent evidence of cough pathophysiology in this disease. Gastroesophageal reflux may promote coughing in IPF patients; bile salts and pepsin may be abundant in BAL of these patients, inducing overproduction of TGF-β by airway epithelial cells and mesenchymal transition with fibroblast recruitment/activation and extracellular matrix deposition. Patients have an enhanced cough reflex to capsaicin and substance P with respect to control subjects. Moreover, patients with the MUC5B polymorphism show more severe coughing as MUC5B encodes for the dominant mucin in the honeycomb cysts of IPF patients. Comorbidities, including asthma, gastroesophageal reflux, hypersensitivity pneumonitis, bronchiectasis, chronic obstructive pulmonary disease and emphysema, can induce coughing in IPF patients. There is no clear explanation of the causes of coughing in IPF. Further research into the pathophysiology of IPF and the pathogenetic mechanisms of coughing is necessary to improve survival and quality of life.

Gastroesophageal Reflux Disease in Idiopathic Pulmonary Fibrosis: Uncertainties and Controversies

The mechanisms of idiopathic pulmonary fibrosis (IPF), a rare, devastating disease with a median survival of 3-5 years, are not fully understood. Gastroesophageal reflux disease (GERD) is a frequent comorbidity encountered in IPF. Hypothetically, GERD-associated microaspiration may lead to persistent inflammation impairing lung infrastructure, thereby possibly accelerating the progression of IPF. IPF may increase intrathoracic pressure, which can aggravate GERD and vice versa. On the basis of the possible beneficial effects of antireflux or antacid therapy on lung function, acute exacerbation, and survival, the recent international IPF guideline recommends antacid therapies for patients with IPF, regardless of symptomatic GERD. However, due to newer conflicting data, several national guidelines do not support this recommendation. Elucidation of these questions by further clinical and bench-to-bedside research may provide us with rational clinical diagnostic and therapeutic approaches concerning GERD in IPF. The present review aims to discuss the latest data on the controversial association of IPF and GERD.

Managing patients with chronic cough: challenges and solutions

Chronic cough is a common complaint and a frequent cause of medical consultation. Its management can be difficult. We present here an overview of the current guidelines for the management of chronic cough. Different steps are detailed, including the initial research of an obvious etiology and alert signs that should lead to further investigation of underlying condition. The diagnosis of the most frequent causes: asthma, non-asthmatic eosinophilic bronchitis, gastroesophageal reflux disease and upper airway cough syndrome should be considered, assessed and treated accordingly. Recent advances have been made in the comprehension of refractory chronic cough pathophysiology as well as its pharmacologic and non-pharmacologic treatment, especially speech pathology therapy.

Best supportive care for idiopathic pulmonary fibrosis: current gaps and future directions

Best supportive care (BSC) is generally defined as all the interventions and the multiprofessional approach aimed to improve and optimise quality of life (QoL) in patients affected by progressive diseases. In this sense, it excludes and might be complementary to other interventions directly targeting the disease. BSC improves survival in patients with different types of cancer. Patients with idiopathic pulmonary fibrosis (IPF) experience a vast range of symptoms during the natural history of the disease and might have a beneficial effect of BSC interventions. This review highlights the current evidence on interventions targeting QoL and gaps for the clinical assessment of BSC in the treatment of IPF patients. Very few interventions to improve QoL or improve symptom control are currently supported by well-designed studies. Sound methodology is paramount in evaluating BSC in IPF, as well as the use of validated tools to measure QoL and symptom control in this specific group of patients.