What causes cough in pulmonary fibrosis, and how should we treat it?

PURPOSE OF REVIEW: To review the current understanding of the impact, mechanisms and treatments for cough in patients with interstitial lung disease (ILD). Evidence suggests that cough is a prevalent symptom in patients with ILD and has a significant impact on patients. RECENT FINDINGS: There is increasing interest in the role of cough hypersensitivity as seen in chronic refractory cough in patients with ILD, and encouraging recent results suggest that ILD-associated cough responds to opiate therapy. SUMMARY: Understanding the aetiology of cough in patients with ILD is crucial to continue to develop therapies which might be effective in reducing cough and increasing quality of life.

Microphthalmia with multiple ocular abnormalities in a foal.

OBJECTIVE: The aim of this report was to provide a clinical description and clinical, ultrasonographic, and histologic images of a foal with microphthalmia and multiple ocular abnormalities. ANIMALS STUDIED: A 12-h old Friesian-American Paint Horse crossbred filly presented for blindness, microphthalmia and marked ventral strabismus in both eyes. PROCEDURE: A complete ophthalmic examination was performed. Ultrasound biomicroscopy and B-mode ultrasonography were performed. The globes were submitted for histopathology. RESULTS: Ultrasound biomicroscopy demonstrated a hyperechoic cornea void of the typical epithelium, stroma, and Descemet's membrane layers. The anterior chamber was spanned by thick strands of hyperechoic tissue extending from the iris to the cornea. The lens was not visualized. B-mode ultrasound showed aphakia and mild, mottled echogenicity within the vitreous with no evidence of retinal detachment. On histopathology, both globes were microphthalmic with poorly defined corneal tissue. The anterior chambers were poorly formed and contained lacrimal glandular tissue. Portions of iridal tissue were present, but no lenses were noted. The retinas were segmentally detached and markedly atrophied with areas of retina dysplasia noted. CONCLUSIONS: This report provides a clinical, ultrasonographic and histologic description of a rare, congenital condition in a foal characterized by microphthalmia, aphakia, poorly defined corneal tissue, choristomatous differentiation of the anterior segment and retinal dysplasia.

Cough hypersensitivity and suppression in COPD.

Cough reflex hypersensitivity and impaired cough suppression are features of chronic refractory cough (CRC). Little is known about cough suppression and cough reflex hypersensitivity in cough associated with chronic obstructive pulmonary disease (COPD). This study investigated the ability of patients with COPD to suppress cough during a cough challenge test in comparison to patients with CRC and healthy subjects. This study also investigated whether cough reflex hypersensitivity is associated with chronic cough in COPD.Participants with COPD (n=27) and CRC (n=11) and healthy subjects (n=13) underwent capsaicin challenge tests with and without attempts to self-suppress cough in a randomised order over two visits, 5 days apart. For patients with COPD, the presence of self-reported chronic cough was documented, and objective 24-h cough frequency was measured.Amongst patients with COPD, those with chronic cough (n=16) demonstrated heightened cough reflex sensitivity compared to those without chronic cough (n=11): geometric mean±sd capsaicin dose thresholds for five coughs (C5) 3.36±6.88 µmol·L-1 versus 44.50±5.90 µmol·L-1, respectively (p=0.003). Participants with CRC also had heightened cough reflex sensitivity compared to healthy participants: geometric mean±sd C5 3.86±5.13 µmol·L-1 versus 45.89±3.95 µmol·L-1, respectively (p<0.001). Participants with COPD were able to suppress capsaicin-evoked cough, regardless of the presence or absence of chronic cough: geometric mean±sd capsaicin dose thresholds for 5 coughs without self-suppression attempts (C5) and with (CS5) were 3.36±6.88 µmol·L-1 versus 12.80±8.33 µmol·L-1 (p<0.001) and 44.50±5.90 µmol·L-1 versus 183.2±6.37 µmol·L-1 (p=0.006), respectively. This was also the case for healthy participants (C5 versus CS5: 45.89±3.95 µmol·L-1 versus 254.40±3.78 µmol·L-1, p=0.033), but not those with CRC, who were unable to suppress capsaicin-evoked cough (C5 versus CS5: 3.86±5.13 µmol·L-1 versus 3.34±5.04 µmol·L-1, p=0.922). C5 and CS5 were associated with objective 24-h cough frequency in patients with COPD: ρ= -0.430, p=0.036 and ρ= -0.420, p=0.041, respectively.Patients with COPD-chronic cough and CRC both had heightened cough reflex sensitivity but only patients with CRC were unable to suppress capsaicin-evoked cough. This suggests differing mechanisms of cough between patients with COPD and CRC, and the need for disease-specific approaches to its management.

The Relationship Between Cough Reflex Sensitivity and Exacerbation Frequency in Chronic Obstructive Pulmonary Disease.

BACKGROUND: Cough is predictive of exacerbations of chronic obstructive pulmonary disease (COPD). Little is known about cough reflex sensitivity during exacerbation of COPD and whether it is associated with exacerbation frequency. This pilot study aimed to investigate cough reflex sensitivity during and following recovery from exacerbation of COPD, and its association with the frequency of future exacerbations. In addition, the repeatability of cough reflex sensitivity in stable COPD was investigated. METHODS: Twenty participants hospitalised with exacerbation of COPD underwent inhaled capsaicin challenge during exacerbation and after 6 weeks of recovery. The frequency of future exacerbations was monitored for 12 months. The repeatability of cough reflex sensitivity was assessed in separate participants with stable COPD, who underwent 2 capsaicin challenge tests, 6 weeks apart. RESULTS: Cough reflex sensitivity was heightened during exacerbation of COPD. Geometric mean (SD) capsaicin concentration thresholds to elicit 5 coughs (C5) during exacerbation and after 6 weeks of recovery were 1.76 (3.73) vs. 8.09 (6.25) µmol L-1, respectively (p < 0.001). The change in C5 from exacerbation to 6-week recovery was associated with the frequency of future exacerbations (ρ = - 0.687, p = 0.003). C5 was highly repeatable over 6 weeks in stable COPD, and intraclass correlation coefficient was 0.85. CONCLUSION: Cough reflex sensitivity is heightened during exacerbation of COPD and reduces after recovery. The persistence of cough reflex hypersensitivity at recovery was associated with the frequency of future exacerbations.

Impaired cough suppression in chronic refractory cough.

Functional brain imaging in individuals with chronic cough demonstrates reduced activation in cortical regions associated with voluntary cough suppression. Little is known about the ability of patients with chronic cough to suppress cough. This study aimed to compare the ability to voluntarily suppress cough during inhaled capsaicin challenge in participants with chronic refractory cough with that in healthy controls. In addition, this study aimed to assess the repeatability of capsaicin challenge test with voluntary cough suppression.Participants with chronic refractory cough and healthy controls underwent inhaled capsaicin challenge tests while attempting to suppress their cough responses. After 5 days, either a conventional capsaicin challenge test with no cough suppression attempt, or a repeat test with an attempt at cough suppression was performed. Threshold capsaicin concentrations required to elicit one, two and five coughs were calculated by interpolation. Objective 24-h cough frequency was measured in individuals with chronic refractory cough.Healthy controls were able to suppress capsaicin-evoked cough while participants with chronic refractory cough were not. Geometric mean±sd capsaicin dose thresholds for five coughs with (CS5) and without (C5) suppression attempts were 254.40±3.78 versus 45.89±3.95 µmol·L-1, respectively, in healthy controls (p=0.033) and 3.34±5.04 versus 3.86±5.13 µmol·L-1, respectively, in participants with chronic refractory cough (p=0.922). Capsaicin dose thresholds for triggering five coughs with self-attempted cough suppression were significantly lower in participants with chronic refractory cough than in healthy controls; geometric mean±sd 4.94±4.43 versus 261.10±4.34 µmol·L-1, respectively; mean difference (95% CI) 5.72 (4.54-6.91) doubling doses (p<0.001). Repeatability of cough suppression test in both patients and healthy controls was high; intraclass correlation coefficients of log(CS5) values 0.81 and 0.87, respectively. CS5 was associated with objective cough frequency (ρ=-0.514, p=0.029).Participants with chronic refractory cough were less able to voluntarily suppress capsaicin-evoked cough compared to healthy controls. This may have important implications for the pathophysiology and treatment of chronic cough.

Physical Inactivity in Pulmonary Sarcoidosis.

PURPOSE: Reduced physical activity in many chronic diseases is consistently associated with increased morbidity. Little is known about physical activity in sarcoidosis. The aim of this study was to objectively assess physical activity in patients with pulmonary sarcoidosis and investigate its relationship with lung function, exercise capacity, symptom burden, and health status. METHODS: Physical activity was assessed over one week in 15 patients with pulmonary sarcoidosis and 14 age-matched healthy controls with a tri-axial accelerometer (ActivPal™) and the International Physical Activity Questionnaire (IPAQ). All participants underwent pulmonary function tests, 6-min walk test (6MWT) and completed the Fatigue Assessment Scale (FAS), Medical Research Council (MRC) Dyspnoea Scale and the King's Sarcoidosis Questionnaire (KSQ). RESULTS: Patients with sarcoidosis had significantly lower daily step counts than healthy controls; mean (SD) 5624 (1875) versus 10,429 (2942) steps (p < 0.01) and a trend towards fewer sit-to-stand transitions each day (p = 0.095). Only two patients (13%) self-reported undertaking vigorous physical activity (IPAQ) compared to half of healthy individuals (p < 0.01). Daily step count was significantly associated with 6MWT distance in sarcoidosis (r = 0.634, p = 0.01), but not with forced vital capacity (r = 0.290), fatigue (r = 0.041), dyspnoea (r = -0.466) or KSQ health status (r = 0.099-0.484). Time spent upright was associated with fatigue (r = -0.630, p = 0.012) and health status (KSQ Lung scores r = 0.524, p = 0.045), and there was a significant correlation between the number of sit-to-stand transitions and MRC dyspnoea score (r = -0.527, p = 0.044). CONCLUSION: Physical activity is significantly reduced in sarcoidosis and is associated with reduced functional exercise capacity (6MWD). Fatigue, exertional symptoms and health status were more closely associated with time spent upright and the number of bouts of physical activity, as compared to step counts. Further studies are warranted to identify the factors that determine different physical activity profiles in sarcoidosis.

Alternative access for transcatheter aortic valve replacement in older adults: A collaborative study from France and United States.

BACKGROUND: We examined the outcomes of older adults undergoing nontrans-femoral (non-TF) transcatheter aortic valve replacement (TAVR) procedures including trans-apical (TA), trans-aortic (TAo), trans-subclavian (TSub), and trans-carotid (TCa) techniques. METHODS AND RESULTS: This is an observational study of all consecutive older patients who underwent non-TF TAVR for symptomatic severe AS with Edwards Sapien (ES), Medtronic CoreValve, ES3 or Lotus Valve at three centers in France and the United States from 04/2008 to 02/2017. Baseline characteristics and clinical outcomes were defined according to VARC-2 criteria. Of 857 patients who received TAVR, 172 (20%) had an alternative access procedure. Of these, 45 (26%) were TA, 67 (39%) TAo, 17 (10%) TSub, and 43 (25%) TCa procedures. The preference for non-TF access site was different between the two countries (US: TA 39%, TAo 52%, TSub 9%; TCa 0% vs. France: TA 9%, TAo 23%, TSub 11%, and TCa 57%, P-value < .001). Most patients who underwent TAo TAVR were older women (median age: TA 82, TAo 84, TSub 81, TCa 81, P-value = 0.043; female gender: TA 32 (27%), TAo 30 (55%), TSub 10 (41%), TCa 27 (37%), P-value = .021). The predicted Society of Thoracic Surgery risk of mortality was similar among groups (TA 7%, TAo 7%, TSub 6%, TCa 7%, P-value= .738). No differences were observed in the frequency of para-valvular leak, intra-procedural bleeding, vascular complications, conversion to open-heart surgery, or development of acute kidney injury. The highest in-hospital mortality was observed in the TAo group (TA 2%, TAo 15%, TSub 0%, TCa 2%, P-value = .014). However, hospital length of stay, one-month, and one-year mortality were similar among non-TF techniques. CONCLUSION: Although regional differences exist in the choice of alternative access techniques, centers with high technical expertise can provide a safe alternative to traditional TF TAVR. TAo TAVR was associated with higher in-hospital mortality than other non-TF approaches, and this may have reflected patient rather than procedural factors. All alternative access techniques had similar mortality rates and clinical outcomes at one-year follow-up. Trans-carotid access is safe and feasible compared to other non-TF access techniques.

Physiotherapy and Speech and Language therapy intervention for chronic cough.

There are few effective pharmacological therapies available to treat refractory chronic cough. Functional MRI studies of the brain have recently shown that patients with chronic cough have dysfunctional inhibitory control of cough. Self-management therapies delivered by physiotherapists or speech therapists are effective at suppressing cough. They enable patients to consciously suppress the urge to cough. The intervention consists of education, laryngeal hygiene, cough suppression and distraction measures and behaviour modification. The efficacy of Physiotherapy and Speech And Language Intervention (PSALTI) has been confirmed in two randomised control trials. In one trial, there was a 41% reduction in cough frequency with PSALTI, assessed objectively with the Leicester Cough Monitor, and a clinically significant improvement in quality of life. Importantly, the improvement in cough was sustained when therapy was discontinued. The addition of the Speech Pathology Treatment to neuromodulator drug therapy, Pregabalin has also been evaluated in a clinical trial. There was a clinically significant improvement in quality of life, and this was sustained when therapy was discontinued. The mechanism of action of PSALTI is not known and this should be investigated in future. Further studies are needed to identify the components of PSALTI that deliver the most benefit, and determine whether PSALTI is effective in cough associated with other chronic lung disorders.

Qualitative assessment of sensations and triggers in chronic cough.

Qualitative interviews show a wide range of cough triggers and sensations in patients with refractory chronic cough. Knowledge of these may help us manage this complicated and impactful condition. https://bit.ly/41k9Ot5.

Practicality and Safety of Electrical Pulmonary Vein Isolation and Left Atrial Appendage Ligation in Lung Transplant Recipients With Pretransplant Atrial Fibrillation.

Background: Lung transplant surgery creates surgical pulmonary vein isolation (PVI) as a routine part of the procedure. However, many patients with pretransplant atrial fibrillation continue to have atrial fibrillation at 1 y. We hypothesized that the addition of electrical PVI and left atrial appendage isolation/ligation (LAL) to the lung transplant procedure restores sinus rhythm at 1 y in patients with pretransplant atrial fibrillation. Methods: We retrospectively reviewed all adult lung transplant recipients at the University of California Los Angeles from April 2006 to August 2021. All patients with pretransplant atrial fibrillation underwent concomitant PVI/LAL and were compared with lung transplant recipients without preoperative atrial fibrillation. In-hospital outcomes; 1-y survival; and the incidence of stroke, cardiac readmissions, repeat ablations, and sinus rhythm (composite endpoint) were examined at 1 y for the PVI/LAL cohort. Results: Sixty-one lung transplant recipients with pretransplant atrial fibrillation underwent concomitant PVI/LAL. No patient in the PVI/LAL cohort required cardiac-related readmission or catheter ablation for atrial fibrillation within 1 y of transplantation. Freedom from the composite endpoint of death, stroke, cardiac readmission, and repeat ablation for atrial fibrillation at 1 y was 85% (95% confidence interval, 73%-92%) for lung transplant recipients treated with PVI/LAL. Conclusions: The addition of PVI/LAI to the lung transplant operation in patients with pretransplant atrial fibrillation was safe and effective in maintaining sinus rhythm and baseline risk of stroke at 1 y.

Feasibility and performance of the chronic obstructive pulmonary disease population screener and chronic obstructive pulmonary disease screening questionnaire in a Chinese physical examination center.

Background: Chronic obstructive pulmonary disease (COPD) affects up to 13% of the Chinese population, though it is under diagnosed throughout China. Screening among asymptomatic individual as part of routine health checks in China can facilitate early diagnosis and intervention to prevent disease progress. The COPD Population Screener (COPD-PS) or COPD Screening Questionnaire (COPD-SQ) has yet to be applied in Chinese physical examination centers (PECs) for COPD screening, and their feasibility and effectiveness should be clarified before full-scale implementation. This study is the first to apply the COPD-PS and COPD-SQ in a public hospital PEC in China to assess their feasibility and effectiveness and to identify their optimal cutoff values. Methods: People aged ≥40 years who attended the Second Affiliated Hospital of Shantou University PECs from September 2021 to December 2022 were asked to complete the COPD-PS and COPD-SQ and to undergo spirometry. The optimal cutoff values of the two questionnaires at the maximal Youden index were found, and the sensitivity and specificity were calculated. Results: Data from 198 participants were analyzed; mean [standard deviation (SD)] age of patients was 63.52 (10.94) years. Twenty-five participants (12.63%) were diagnosed with COPD. The number of COPD patients classified as Global Initiative for Chronic Obstructive Lung Disease (GOLD) grades 1 to 4 were 8, 12, 4, and 1, respectively. The area under the curves (AUCs) of the COPD-PS and COPD-SQ were 0.730 and 0.738, respectively. The optimal COPD-PS cutoff value of 4 points corresponded to a sensitivity of 72.00% and a specificity of 60.10%. The COPD-SQ optimal cutoff value of 15 points corresponded to a sensitivity of 76.00% and a specificity of 63.60%. Conclusions: Applying the COPD-PS and COPD-SQ in Chinese PECs is feasible, cost-effective and effective. COPD-PS and COPD-SQ can facilitate the early diagnosis of COPD, and whether they can improve the participants' quality of life would benefit a further study. It is recommended that the COPD-PS or COPD-SQ questionnaires be added to the screening of the physical examination program in PECs as part of health checks for people over 40 years old.

Chronic cough: is the end nigh?

Chronic cough (lasting more than 8 weeks) is a common condition with substantial psychosocial impact. Despite huge efforts following robust guidelines, chronic cough in many patients remains refractory or unexplained (RU-CC). Recent insights support a significant role for cough hypersensitivity in RU-CC, including neuropathophysiological evidence from inhalational cough challenge testing, functional magnetic resonance imaging, and airway nerve biopsy. Along with improved approaches to measuring cough, this knowledge has developed in tandem with repurposing neuromodulator medications, including gabapentin, and evidence for non-pharmacological treatments. Most significantly, there is now a pipeline for novel classes of drugs specifically for chronic cough. The P2X3 receptor antagonist gefapixant is the first such drug to be approved in Europe. However, challenges persist. The field of chronic cough needs more robust epidemiological data, enhanced diagnostic tools, further well-designed clinical trials accounting for the effects of placebo, and treatments with minimal side-effects. Addressing these challenges are novel chronic cough registries, improved International Classification of Diseases (10th revision) coding, genetic testing options and further mechanistic studies. This Viewpoint article discusses these facets and considers how, whilst the end of chronic cough may not be imminent for all patients, the evolving landscape looks increasingly optimistic.

Cough in chronic lung disease: a state of the art review.

Chronic cough (CC; ≥8 weeks in duration) is a common and burdensome feature of respiratory diseases. The understanding of cough has progressed significantly in recent years, albeit largely in refractory (unexplained) chronic cough (RCC) in the absence of other respiratory conditions. The prevalence of CC in respiratory diseases is poorly described, but estimates have been reported: asthma (8-58%), chronic obstructive pulmonary disease (COPD; 10-74%), bronchiectasis (82-98%), interstitial lung disease (ILD; 50-89%) and sarcoidosis (3-64%). CC in respiratory conditions generally predicts impaired health status and more severe disease. It is associated with increased symptom burden and disease severity in asthma, COPD, bronchiectasis and ILD, higher exacerbation frequency in asthma and bronchiectasis, and increased mortality and lung transplantation in idiopathic pulmonary fibrosis (IPF). Physiologically, heightened cough reflex sensitivity (CRS) has been reported and postulated to be mechanistic in isolated RCC. Cough reflex hypersensitivity (CRH) has also been reported in asthma, COPD, bronchiectasis, ILD and sarcoidosis. Unlike recent advances in isolated RCC, there are limited studies and understanding of central cough neuropathways in other respiratory conditions. Of note, dysfunctional central voluntary cough suppression neuropathways and physiology were observed in isolation in RCC; cough suppression is preserved in COPD. Understanding in the mechanism of RCC cannot be simply extrapolated to other respiratory conditions. The restricted understanding of cough mechanisms in these conditions has limited cough-specific therapeutic options in this context. There is currently an unmet need to expand our understanding of cough in chronic respiratory conditions, both in order to improve the quality of life of patients, and to improve knowledge of cough in general. This review aims to describe the prevalence, impact, pathophysiology and management of CC in asthma, COPD, bronchiectasis, ILD and sarcoidosis.

Patient Global Impression of Severity Scale in Chronic Cough: Validation and Formulation of Symptom Severity Categories.

BACKGROUND: The Patient Global Impression of Severity (PGI-S) scale is a self-reported, single-item categorical scale that is increasingly used when assessing chronic cough (CC). OBJECTIVE: This study aimed to establish validity, repeatability, and responsiveness of the PGI-S scale in CC and use the scale to define discrete categories of severity when measured with other commonly used patient-reported outcome (PRO) tools. METHODS: Consecutive patients with CC completed the PGI-S scale, cough severity and urge to cough visual analog scales (VAS), and cough-specific health status Leicester Cough Questionnaire (LCQ) at a clinic visit. Validity, repeatability, and responsiveness were assessed, and threshold scores for PRO severity categories determined. RESULTS: A total of 482 participants completed the assessments; the median (interquartile range [IQR]) age was 57 (46-67) years, 71% were female, and the median (IQR) duration of cough was 48 (24-120) months. They reported a median (IQR) PGI-S score of 3 (3-4; moderate severity), cough severity VAS of 57 (31-75) mm, urge to cough VAS of 62 (40-81) mm, and LCQ of 11.5 (8.7-14.4). There were strong associations between PGI-S scores and cough severity VAS (ρ = 0.81), urge to cough VAS (ρ = 0.73), and LCQ (ρ = -0.73) (all P < .001). Repeatability of the PGI-S scale was high (n = 77); the intraclass correlation coefficient (95% confidence interval) was 0.85 (0.77-0.91) (P < .001). The PGI-S scale was responsive in participants with a treatment response (P < .001). The suggested PRO thresholds to define severe cough are ≥61 mm (cough severity VAS), ≥71 mm (urge to cough VAS), and ≤10 (LCQ). CONCLUSION: The PGI-S scale is a simple and valid tool that characterizes cough severity and is repeatable and responsive in CC. The proposed categorical severity thresholds for VAS and LCQ can provide intuitive meaning for patients and clinicians.

Safety and efficacy of delaying lung transplant surgery to a morning start.

Objective: We aimed to evaluate the safety and efficacy of delaying lung transplantation until morning for donors with cross-clamp times occurring after 1:30 am. Methods: All consented adult lung transplant recipients between March 2018 and May 2022 with donor cross-clamp times between 1:30 am and 5 am were enrolled prospectively in this study. Skin incision for enrolled recipients was delayed until 6:30 am (Night group). The control group was identified using a 1:2 logistic propensity score method and included recipients of donors with cross-clamp times occurring at any other time of day (Day group). Short- and medium-term outcomes were examined between groups. The primary endpoint was early mortality (30-day and in-hospital). Results: Thirty-four patients were enrolled in the Night group, along with 68 well-matched patients in the Day group. As expected, donors in the Night group had longer cold ischemia times compared to the Day group (344 minutes vs 285 minutes; P < .01). Thirty-day mortality (3% vs 3%; P = .99), grade 3 primary graft dysfunction at 72 hours (8% vs 4%; P = .40), postoperative complications (26% vs 38%; P = .28), and hospital length of stay (15 days vs 14 days; P = .91) were similar in the 2 groups. No significant differences were noted between groups in 3-year survival (70% vs 77%; P = .30) or freedom from chronic lung allograft dysfunction (91% vs 95%; P = .75) at 3 years post-transplantation. The median follow-up was 752.5 days (interquartile range, 487-1048 days). Conclusions: Lung transplant recipients with donor cross-clamp times scheduled after 1:30 am may safely have their operations delayed until 6:30 am with acceptable outcomes. Adoption of such a policy in clinically appropriate settings may lead to an alternative workflow and improved team well-being.

Healthcare utilization and costs in chronic cough.

BACKGROUND: Chronic cough is a common reason for medical consultations and is associated with considerable physical and psychological morbidity. This study investigated healthcare use and cost in chronic cough and assessed its relationship with cough severity, health status, objective cough frequency (CF), and anxiety and depression. METHODS: This was a prospective study of consecutive patients with chronic cough from a specialist clinic who completed a cough severity visual analogue scale (VAS), cough-specific health status (Leicester Cough Questionnaire; LCQ) and general health status EuroQol EQ-5D-5L, Generalized Anxiety Disorder (GAD7), Patient Health Questionnaire (PHQ9), and 24-hour objective CF monitoring with Leicester Cough Monitor (LCM). Case notes were reviewed for cough-specific healthcare use 12 months before and after the first cough clinic consultation. Resource use included general practitioner and hospital clinic visits, investigations, and treatments. Unit costs for healthcare use were derived predominantly from National Health Service Reference Costs. RESULTS: One hundred participants with chronic cough were recruited (69% female, median duration 3 years, mean age 58 years). The diagnoses of cough were unexplained (57%), refractory (27%), and other (16%). Cough severity, health status, and CF were: median (IQR) VAS = 59.5 (30-79) mm, mean (SD) LCQ = 11.9 (4.0), mean (SD) EQ-5D-5L = 0.846 (0.178), and geometric mean (SD) CF = 15.3 (2.5) coughs/hr, respectively. The mean (SD) total cost per individual for cough-related healthcare utilization was £1,663 (747). Diagnostic investigations were the largest contributor to cost (63%), followed by cough clinic consultations (25%). In multivariate analysis, anxiety (GAD7) and cough-related health status (LCQ) were associated with increased cost (p ≤.001 and .037). CONCLUSION: Healthcare cost associated with chronic cough are largely due to diagnostic investigations and clinic consultations. The predictors of costs were health status (LCQ) and anxiety. Further studies should investigate the optimal management protocols for patients with chronic cough.

Demographic Imbalances Resulting From the Bring-Your-Own-Device Study Design.

Digital health technologies, such as smartphones and wearable devices, promise to revolutionize disease prevention, detection, and treatment. Recently, there has been a surge of digital health studies where data are collected through a bring-your-own-device (BYOD) approach, in which participants who already own a specific technology may voluntarily sign up for the study and provide their digital health data. BYOD study design accelerates the collection of data from a larger number of participants than cohort design; this is possible because researchers are not limited in the study population size based on the number of devices afforded by their budget or the number of people familiar with the technology. However, the BYOD study design may not support the collection of data from a representative random sample of the target population where digital health technologies are intended to be deployed. This may result in biased study results and biased downstream technology development, as has occurred in other fields. In this viewpoint paper, we describe demographic imbalances discovered in existing BYOD studies, including our own, and we propose the Demographic Improvement Guideline to address these imbalances.

Noninvasive Assessment of Neuromechanical and Neuroventilatory Coupling in COPD.

This study explored the use of parasternal second intercostal space and lower intercostal space surface electromyogram (sEMG) and surface mechanomyogram (sMMG) recordings (sEMGpara and sMMGpara, and sEMGlic and sMMGlic, respectively) to assess neural respiratory drive (NRD), neuromechanical (NMC) and neuroventilatory (NVC) coupling, and mechanical efficiency (MEff) noninvasively in healthy subjects and chronic obstructive pulmonary disease (COPD) patients. sEMGpara, sMMGpara, sEMGlic, sMMGlic, mouth pressure (Pmo), and volume (Vi) were measured at rest, and during an inspiratory loading protocol, in 16 COPD patients (8 moderate and 8 severe) and 9 healthy subjects. Myographic signals were analyzed using fixed sample entropy and normalized to their largest values (fSEsEMGpara%max, fSEsMMGpara%max, fSEsEMGlic%max, and fSEsMMGlic%max). fSEsMMGpara%max, fSEsEMGpara%max, and fSEsEMGlic%max were significantly higher in COPD than in healthy participants at rest. Parasternal intercostal muscle NMC was significantly higher in healthy than in COPD participants at rest, but not during threshold loading. Pmo-derived NMC and MEff ratios were lower in severe patients than in mild patients or healthy subjects during threshold loading, but differences were not consistently significant. During resting breathing and threshold loading, Vi-derived NVC and MEff ratios were significantly lower in severe patients than in mild patients or healthy subjects. sMMG is a potential noninvasive alternative to sEMG for assessing NRD in COPD. The ratios of Pmo and Vi to sMMG and sEMG measurements provide wholly noninvasive NMC, NVC, and MEff indices that are sensitive to impaired respiratory mechanics in COPD and are therefore of potential value to assess disease severity in clinical practice.

A method for intelligent allocation of diagnostic testing by leveraging data from commercial wearable devices: a case study on COVID-19.

Mass surveillance testing can help control outbreaks of infectious diseases such as COVID-19. However, diagnostic test shortages are prevalent globally and continue to occur in the US with the onset of new COVID-19 variants and emerging diseases like monkeypox, demonstrating an unprecedented need for improving our current methods for mass surveillance testing. By targeting surveillance testing toward individuals who are most likely to be infected and, thus, increasing the testing positivity rate (i.e., percent positive in the surveillance group), fewer tests are needed to capture the same number of positive cases. Here, we developed an Intelligent Testing Allocation (ITA) method by leveraging data from the CovIdentify study (6765 participants) and the MyPHD study (8580 participants), including smartwatch data from 1265 individuals of whom 126 tested positive for COVID-19. Our rigorous model and parameter search uncovered the optimal time periods and aggregate metrics for monitoring continuous digital biomarkers to increase the positivity rate of COVID-19 diagnostic testing. We found that resting heart rate (RHR) features distinguished between COVID-19-positive and -negative cases earlier in the course of the infection than steps features, as early as 10 and 5 days prior to the diagnostic test, respectively. We also found that including steps features increased the area under the receiver operating characteristic curve (AUC-ROC) by 7-11% when compared with RHR features alone, while including RHR features improved the AUC of the ITA model's precision-recall curve (AUC-PR) by 38-50% when compared with steps features alone. The best AUC-ROC (0.73 ± 0.14 and 0.77 on the cross-validated training set and independent test set, respectively) and AUC-PR (0.55 ± 0.21 and 0.24) were achieved by using data from a single device type (Fitbit) with high-resolution (minute-level) data. Finally, we show that ITA generates up to a 6.5-fold increase in the positivity rate in the cross-validated training set and up to a 4.5-fold increase in the positivity rate in the independent test set, including both symptomatic and asymptomatic (up to 27%) individuals. Our findings suggest that, if deployed on a large scale and without needing self-reported symptoms, the ITA method could improve the allocation of diagnostic testing resources and reduce the burden of test shortages.