Persisting exertional dyspnea and perceived exercise intolerance after mild Covid-19: a critical role for breathing dysregulation?

Background: After mild Covid-19, a subgroup of patients reports post-acute sequelae of Covid-19 (PASC), in which exertional dyspnea and perceived exercise intolerance are common. Underlying pathophysiological mechanisms remain incompletely understood. We studied outcomes from cardiopulmonary exercise test (CPET) in these patients. Method(s): In this observational study, we included patients referred for the analysis of PASC after mild Covid-19 in whom CPET was performed after standard clinical work-up turned out unremarkable. Cardiocirculatory, ventilatory and metabolic response to, and breathing patterns during exercise at physiological limits were analyzed. Result(s): Twenty-one patients (76% female, mean age 40y) who reported severe fatigue (CIS-fatigue >= 35), dyspnea (mMRC 2 (IQR1-2)) and disability in physical role functioning (SF-36) underwent CPET at 32 weeks (IQR 22-52) after Covid-19. Mean peak oxygen uptake was 99% (SD13) of predicted with normal anaerobic thresholds at 62% (SD11) of predicted oxygen uptake. No cardiovascular or gas exchange abnormalities were detected. Twenty out of the 21 patients (95%) demonstrated breathing dysregulation, existing of ventilatory inefficiency (29%), abnormal course of breathing frequency and tidal volume (57%), and acute or chronic respiratory alkalosis in resting blood gases (67%). Conclusion(s): In the absence of deconditioning, breathing dysregulation may explain the experienced exertional dyspnea and exercise intolerance in patients with PASC after mild Covid-19.

Post-acute prevalence of occult pulmonary embolism after hospitalisation for Covid-19

Background: During hospitalization for Covid-19 the prevalence of pulmonary embolism (PE) is ~15%. Occult PE may be undiagnosed during hospitalization. Also, after discharge, factors such as residual (local) inflammation and relative physical inactivity may predispose to PE. Aim(s): To study the presence of occult PE and pulmonary perfusion defects three months after discharge from hospitalization for Covid-19. Method(s): In this prospective study we performed CT pulmonary angiography (CTPA) in adults three months after discharge from hospitalization for moderate-to-critical Covid-19. Exclusion criteria: therapeutic anticoagulation, diagnosed PE during hospitalization, CTPA contra-indications. Primary outcome measure was presence of PE. Secondary outcomes were wedge shaped perfusion defects on subtraction iodine maps, D-dimer concentration, presence of Years criteria at follow-up, and pulmonary parenchymal abnormalities. Result(s): 26 patients (65% male, 61 (SD10) y, hospital length of stay 11 (IQR9-15) days, 34% ICU treatment) underwent CTPA at 13 (SD2) weeks after discharge. 25 patients (96%) had no evidence for PE while one post-ICU patient demonstrated a suspected partial occlusion of a subsegmental pulmonary artery. No wedge shaped perfusion defects were found. D-Dimer values were <1000 ng/ml in all patients and none had Years criteria. Extent of parenchymal abnormalities decreased compared to acute phase (CT severity score 7 (SD5) vs 13 (SD5), p=0.004). Conclusion(s): Prevalence of occult PE three months after discharge from hospitalization for Covid-19 was negligible in our sample. CTPA should not be routinely performed in these patients. .

Post-Covid-19 peripheral muscle weakness is not associated with muscle ultrasound echogenicity or muscle thickness

Background: Peripheral muscle weakness has been observed in the post-acute phase of Covid-19 patients. However, it is unknown whether Covid-19 is associated with structural changes in skeletal muscles, like atrophy, inflammation or fibrosis. Aim(s): To examine whether peripheral muscle weakness in post-Covid-19 patients is associated with changes in muscle echogenicity and thickness. Method(s): Post-Covid-19 patients with objectified muscle weakness (isometric quadriceps maximal voluntary contraction (MVC) <lower limit of normal) at ~6 months after infection were cross-sectionally studied. Vastus lateralis (VL), rectus femoris (RF), tibialis anterior (TA) and gastrocnemius (GCM) were examined unilaterally using quantitative muscle ultrasound. Standardized scores (z-scores) of 2 were defined as limits of normal. Result(s): Fourteen post-Covid-19 patients were included (age 47+/-15y, 64% male, BMI 26+/-3 kg/m2). Median z-scores were determined for muscle thickness and echogenicity of VL (-1.0 [-1.3- -0.2], 0 [-0.2-1.1]), RF (-0.2 [-1.4-0.1], -0.2 [-1.3-0.6]), TA (0.1 [-0.8-0.6], 0.5 [-0.4-1.0]), and GCM (0.8 [0.1-1.0], -0.7 [-1.3- -0.1]), respectively. Thirteen patients had values within the limits of normal. One patient showed increased echogenicity of VL, but normal values for other muscles. There were significant moderate-to-strong correlations between MVC and muscle thickness of VL (r=0.670), RF (r=0.812), TA (r=0.593) and GCM (r=0.579), and between MVC and echogenicity of GCM (r=-0.588). Conclusion(s): In a cohort of post-Covid-19 patients with peripheral muscle weakness, standardized muscle ultrasound investigations did not show any evidence for structural abnormalities.

1,5-year course of quadriceps muscle strength following mild-to-critical Covid-19

Background: Muscle weakness is prevalent among post-Covid-19 patients, but longitudinal studies quantifying muscle strength following Covid-19 are lacking. Aim(s): To describe the course of quadriceps muscle strength over ~1,5 year following Covid-19. Method(s): A prospective analysis of 63 hospitalized (age 60+/-9y, 68% male) and 31 non-hospitalized (age 52+/-15y, 36% male) post-Covid-19 patients with persisting symptoms ('long covid') was performed. Isometric quadriceps maximal voluntary contraction (MVC) was evaluated using a computerized dynamometer at a knee angle of 60degree during 3 visits in hospitalized (89 [80-104], 215 [198-233], 434 [416-478] days after Covid-19) and non-hospitalized (138 [114-176], 282 [249-347], 540 [486-596] days after Covid-19) patients. MVC was expressed as percentage predicted and muscle weakness was defined as MVC <lower limits of normal. Result(s): Over the 3 visits, hospitalized patients had a MVC of 65+/-18, 70+/-17, and 68+/-16 %pred, and muscle weakness was present in 54, 49, 51% of cases, respectively. Similarly, non-hospitalized patients had a MVC of 70+/-16, 76+/-17, and 74+/-19 %pred, and a muscle weakness prevalence of 65, 52, and 52% was found. In both groups, MVC improved between visit 1 and 2 (p<0,05) whereas no change was observed between visit 2 and 3. The prevalence of muscle weakness in both groups did not change significantly. Conclusion(s): Quadriceps muscle strength modestly improves during the first 7-9 months following acute Covid-19 in both hospitalized and non-hospitalized 'long covid' patients. However, still half of the patients in both groups had long-term muscle weakness. Further investigation is needed into the aetiology of muscle weakness in post-Covid-19 patients.

Weight loss approaches in rural and urban u.s. adults in the international weight control registry

Background: Individuals living in rural areas have higher obesity and obesity related co-morbidities than their urban counterparts. Understanding rural-urban differences associated with weight management may inform the development of effective weight management interventions for adults living in rural areas. Methods: The International Weight Control Registry (IWCR) is an online registry designed to assess factors contributing to successes and challenges with weight loss and weight loss maintenance across the world. We examined demographics, weight history and weight management strategies in a sample of urban and rural residents in the Midwestern U.S. (IA, IL, IN, KS, MI, MN, MO, ND, NE, OH, SD, WI). Participants were classified as rural or urban by the Rural-Urban Commuting Area Code. Analyses included Chi-square tests for proportions and independent t-test and Wilcoxon rank sum test for continuous variables. Results: The sample was 45% rural (n = 78 of a total N = 174) with a mean age of 50.3 years. Rural residents were more likely to be white, non-college graduates, and have lower family income compared with urban areas (p < 0.05). Rural and urban residents reported similar weight histories and strategies for weight management. Work-related physical activity was higher and weekday sitting time was lower in rural compared to urban residents (p < 0.01). These data could potentially be impacted by the relative number of residents working from home during COVID-19 (Urban: 59% vs. Rural: 37%, p < 0.05). Rural residents were more likely to report a lack of neighborhood walkability (p < 0.01) and healthy food availability (p < 0.05) compared with urban residents. Conclusions: These data suggest rural-urban differences in demographic characteristics, opportunity for leisure time physical activity, and the availability of heathy foods should be considered in the development of weight management interventions. The consistency of the observed findings will be evaluated at the regional, national and international levels as the size of the available sample in the IWCR increases.

Pilot testing two take-home exposure prevention educational sessions with construction workers and their families

Introduction 'Take-home exposures' occur when workers accidentally bring home contaminants from work. In construction, job responsibilities may expose workers to lead and other metals, which extend to their household members via the take-home pathway. It is crucial that construction workers are aware of the take-home pathway and learn about exposure prevention strategies. Objectives This work is part of the RECLEAN Pilot Study, which aims to reduce lead in the homes of construction workers through educational and environmental interventions. Methods We developed and evaluated a suite of educational materials to train construction workers and their families on strategies to prevent take-home lead exposure. Each of the two sessions targets a specific audience, with one tailored to construction workers and the other to workers' family or household members. The sessions were originally developed to take place in person but given the COVID-19 pandemic we adapted them for online delivery as well. Results Like traditional occupational health and safety trainings, the construction worker sessions present workers with best practices to prevent take-home lead and open discussion for how such practices may fit into their own routine after work. Alternatively, the family session is designed to engage household members in discussion through a process derived from motivational interviewing. The materials for both sessions include an introduction, behavior scoring sheet, behavior wheel, and action plan. Facilitators and participants discuss strategies to prevent take-home lead, identify barriers participants (and their coworkers or families) experience when trying to change their behaviors, and ultimately prioritize a prevention goal. Conclusion The materials for both educational sessions were developed based on current literature on take-home lead and behavioral theories and in partnership with lead and construction experts from multiple organizations. Using feedback from participants, project stakeholders, and session facilitators, we evaluate the feasibility and efficacy of these educational interventions.