Citations

Abstract The sections in this article are: Basic Concepts—Review of Muscle Mechanics Muscle Fiber Types Mechanics of Muscle Electrical Properties of Skeletal Muscle Individual Respiratory Muscles and Their Properties General Considerations Diaphragm Intercostal Muscles Sternocleidomastoid and Scalenus Muscles Abdominal Muscles Other Respiratory Muscles Altered Respiratory Muscle Mechanical Properties in Disease Obstructive Lung Disease Diseases Characterized by Stiff Lungs Neuromuscular Diseases Severe Obesity

Abstract The sections in this article are: Mechanism of Expiratory Flow Limitation Wave‐Speed Limitation Viscous Flow Limitation Computational Model Measurement and Analysis Volume‐Time Flow‐Volume Relative Merits of Presentations Volume‐Time Flow‐Volume Additional Considerations Volume and Time History Effects of Changing Gas Properties Dysanaptic Growth Axial Bronchial Tension Thoracoabdominal Mechanics

Abstract The sections in this article are: Lung Volumes Volume‐Pressure Relations of Respiratory System During Relaxation Total Respiratory System Chest Wall and Lung Effects of Gravity and Posture Changes Throughout Life Span Volume‐Pressure Relations of Respiratory System During Static Muscular Efforts Alveolar Pressure Abdominal and Thoracic Pressures Factors Limiting Volume Extremes Upper Volume Extreme Lower Volume Extreme

Abstract Disclosure: C.A. Villavicencio Torres: None. S. Ahmadian: None. K. Moehnke: None. V.M. Fell: None. R.L. Taylor: None. S.K. Grebe: None. A.D. Maus: None. I. Bancos: None. Background: Evaluation of adrenal disorders relies on total cortisol measurements at baseline or during dynamic testing. Accurate cortisol assessment that avoids phlebotomy may simplify the work up of adrenal disorders, decrease healthcare costs, and improve patient experience. Objectives: We aimed to compare cortisol and dexamethasone concentrations between venipuncture-based (clinical) and capillary blood samples. Methodology: We conducted a cross-sectional study (July 2024-April 2025) of adults undergoing standard-of-care cortisol measurements. Capillary blood samples were collected alongside clinical samples. Capillary measurements included total cortisol and dexamethasone (mass spectrometry). Clinical samples were tested for total cortisol (Roche immunoassay) and dexamethasone (mass spectrometry). Results: Of 318 patients (243, 77% women, median age 53 years, IQR 39-66), 227 (71%) underwent dexamethasone suppression test (DST) and 88 (28%) cosyntropin stimulation test (CST). Capillary blood collection failed in 13 (4%) patients. In patients undergoing DST, median post-dexamethasone serum cortisol was 1.3 mcg/dL (IQR 0.8-2.2), and serum dexamethasone was 0.41 mcg/dL (IQR 0.27-0.59), while median capillary cortisol was 1.5 mcg/dL (IQR 1-2.5), and capillary dexamethasone was 0.33 mcg/dL (IQR 0.21-0.51). Capillary cortisol (r=0.95, 95% CI [0.93, 0.96], p<.0001) and capillary dexamethasone (r=0.93, 95% CI [0.90, 0.95], p<.0001) showed strong correlation with their respective clinical measurements. In patients undergoing CST, median baseline serum cortisol was 7.5 mcg/dL (IQR 5-10), and median baseline capillary cortisol was 8.5 mcg/dL (IQR 6-12). Median post-CST 60-minute serum cortisol was 23 mcg/dL (IQR 20-25), while capillary cortisol was 25 mcg/dL (IQR 21-28). Baseline (r=0.77, 95% CI [0.66, 0.85], p<.0001) and post-CST 60-minute capillary cortisol (r=0.88, 95% CI [0.81-92], p<.0001) strongly correlated with clinical measurements. Post-dexamethasone cortisol in paired DST samples showed that capillary measurements were higher than serum cortisol (median difference 0.20 mcg/dL (95% CI [0.12, 0.42], p<.0001), while paired capillary dexamethasone concentrations were lower than serum dexamethasone concentrations (median difference 0.04 mcg/dL (95% CI [0.03, 0.07], p<.0001). In CST, paired baseline capillary and serum cortisol concentrations were similar (median difference 0.10 mcg/dL, 95% CI [0.3, 0.3], p=.3660), while paired post-CST 60-minute capillary cortisol was higher than serum cortisol by a median of 2.8 mcg/dL (95% CI [2, 3.2], p<.0001). Conclusion: Capillary cortisol and dexamethasone concentrations demonstrate excellent correlation with venipuncture-based measurements. Following validation with at-home collection, capillary blood measurements may serve as an alternative for evaluating adrenal disorders. Presentation: Sunday, July 13, 2025

Abstract Disclosure: H. Ahmad: None. M. Kakakhel: None. A. Ullah: None. M. Saeed: None. J. Ikram: None. A. Qadeer: None. M. Khawar: None. H. Jawad: None. S. Haider: None. R. Haider: None. F. Ahmed: None. R.W. Kirchoff: None. Background: Type 1 diabetes mellitus (T1DM) is an autoimmune disease characterized by the destruction of insulin-producing cells in the pancreas. It is a global health concern with regional variation in incidence and prevalence. This study aims to analyze the regional incidence and prevalence of T1DM among adolescents and young adults (15-39 years) from 1990 to 2021 in 26 regions. Methods: Global Burden of Disease (GBD) data for 2021 were analyzed to assess regional incidence and prevalence of T1DM among adolescents and young adults. The Annual Average Percentage Change (AAPC) was calculated to evaluate trends from 1990 to 2021, with statistical significance determined using p-values. Results: In 2021, middle socio-demographic index (SDI) has the highest incidence (54541) as well as prevalence (1.86 million), followed by Low-middle SDI (I: 48416, P: 1.80 million) and South Asia (I: 46310, P: 1.73 million). Oceania has the lowest incidence (356) as well as prevalence (12885), followed by Andean Latin America (I: 911, P: 31954) and Caribbean regions (I: 1214, P: 54610), respectively. The largest increase in AAPC of incidence was showed by Southern Latin America (2.23, CI: 2.11-2.30), High-income Asia Pacific (2.22, CI: 2.18-2.26), and Western Europe (1.80, CI: 1.73-1.84) regions, while Western Europe (1.72, CI: 1.66-1.75), Eastern Europe (1.64, CI: 1.63-1.66), and Australasia (1.38, CI: 1.36-1.40) showed largest increase in AAPC of prevalence. The Caribbean region had the greatest decline in AAPC of prevalence (-0.11, CI: -0.08 to -0.12) followed by Eastern Sub-Saharan Africa (-0.07, CI: -0.06 to -0.09) and Central Latin America (-0.04, CI: -0.02 to -0.07). There was no region with decline in incidence. All AAPC values were statistically significant (p < 0.000001). Conclusion: Middle SDI region exhibited the highest incidence and prevalence, highlighting the vulnerability of these populations, while Oceania and Andean Latin America bore the least burden. Notably, several regions, particularly in Europe, experienced substantial increases in both incidence and prevalence, emphasizing the need for targeted interventions. Conversely, some regions, such as the Caribbean, showed encouraging declines in prevalence, suggesting that effective prevention and control strategies can be implemented. These findings underscore the importance of tailored approaches to address the evolving burden of T1DM. Presentation: Saturday, July 12, 2025

Abstract Disclosure: A. Ullah: None. R. Haider: None. M. Khawar: None. M. Abid: None. M. Hadeed Khawar: None. M. Shaukat: None. M. Asad Cheema: None. A. Komel: None. M. Ahmed Khan: None. R. Noureen: None. A. Batool: None. M. Mubashir: None. A. Qadeer: None. R. W. Kirchoff: None. Background: The role of dissecting the right paraesophageal lymph node (RPELN) in managing papillary thyroid carcinoma (PTC) remains a subject of debate. This meta-analysis examines both established and novel risk factors associated with RPELN metastasis. Methods: Relevant studies published up to December 2024 were retrieved using PubMed, Embase, Ovid, and Scopus search engines. Data were extracted and evaluated using the Newcastle-Ottawa scale. Statistical analysis was performed using Review Manager 5.4, with heterogeneity assessed through the Q-test and I²-test. Sensitivity analysis was conducted using the leave-one-out method, and the Egger regression test was used to generate a funnel plot for publication bias assessment. Results: Out of 2,444 articles screened, 26 studies involving 16,427 patients were included in the meta-analysis. The overall RPELN metastasis rate was 12.98% (2,133/16,427). The pooled analysis revealed significant associations between RPELN metastasis and the following factors: age under 55 years (P < 0.00001), male gender (P < 0.00001), tumor size >1 cm (P < 0.00001), multifocality (P < 0.00001), capsular invasion (P < 0.00001), vascular invasion (P < 0.00001), extra-thyroidal extension (P < 0.0001), central lymph node metastasis (P < 0.00001), lateral lymph node metastasis (P < 0.00001), Hashimoto’s thyroiditis (P = 0.002), micro-calcifications (P = 0.01), and altered echogenicity (P = 0.03). Conversely, no significant associations were observed for tumor location in the right lobe (P = 0.07), superior pole (P = 0.08), middle pole (P = 1.00), inferior pole (P = 0.28), or tumor margins (P = 0.93) (all P > 0.05). Conclusion: Factors such as age <55, male sex, tumor size >1 cm, multifocality, capsular invasion, vascular invasion, extra-thyroidal extension, central lymph node metastasis, lateral lymph node metastasis, and Hashimoto’s thyroiditis are significantly associated with RPELN metastasis. These should be carefully considered during RPELN dissection in PTC management. Presentation: Sunday, July 13, 2025

Abstract Disclosure: M. Kakakhel: None. S. Fatima: None. H. Ahmad: None. A. Ibrahim: None. W. Rahman: None. R. Haider: None. H. Jawad: None. A. Qadeer: None. M. Khawar: None. F. Ahmed: None. J. Ikram: None. R. Kirchoff: None. Background: Across the world, type 1 diabetes mellitus (T1DM) is a major health problem for teenagers and young people. This study aims to examine the incidence and prevalence of T1DM by gender in the 15-39 age range between 1990 and 2021. Methods: We analyzed data from the Global Burden of Disease (GBD) to evaluate incidence and prevalence rates of T1DM in each gender from 1990 to 2021. The Annual Percentage Change (APC) and The Annual Average Percentage Change (AAPC) was used to assess trends, with p-values determining the statistical significance. Results: From 1990 to 2021, the global prevalence of T1DM was found to be increased steadily for both genders, with the highest rates recorded in 2021: 247.32 per 100,000 for females and 246.47 per 100,000 for males. Incidence rates in 2021 showed a contrasting pattern, with males exhibiting higher rates (7.18 per 100,000) compared to females (5.98 per 100,000). AAPC analysis showed that males exhibit a faster rise in both prevalence and incidence compared to females over the study period. The difference in AAPC between males and females is more pronounced for prevalence (+0.3748%) compared to incidence (+0.1956%), with all AAPC values being statistically significant (p < 0.000001). Following the APC analysis, other significant trends were revealed. Male incidence experienced the greatest increase during 2015-2021, with an APC of +1.9033% (p < 0.000001), whereas female incidence increased most between 2011 and 2014 (APC = +1.3050%; p < 0.000001). In contrast, the most significant decline in incidence was observed in females during 1990-1992, with an APC of +0.1665% (p = 0.006799), which was the lowest increase in the dataset. For prevalence, males exhibited the highest increase during 2015-2021, with an APC of +1.3938% (p < 0.000001), whereas females had their peak increase during 2006-2009, with an APC of +0.8957% (p < 0.000001). The slowest increase in prevalence for females occurred during 2014-2019, with an APC of +0.4591% (p < 0.000001). Conclusion: The prevalence and incidence of T1DM among people aged 15-39 increased significantly between 1990 and 2021, with a greater increase in males. This highlights the need for gender-specific strategies in T1DM prevention and management, and research into the factors driving these disparities. Presentation: Sunday, July 13, 2025

Abstract Disclosure: M. Kakakhel: None. S. Fatima: None. H. Ahmad: None. M. Khan: None. A. Rai: None. A. Qadeer: None. R. Haider: None. M. Khawar: None. U. Habib: None. H. Jawad: None. J. Ikram: None. F. Ahmed: None. R. Kirchoff: None. Introduction: Type 1 Diabetes Mellitus (T1DM) is a disease that affects people all over the world. This condition causes significant morbidity, as measured by Disability-Adjusted Life Years (DALYs) and mortality rates, and its severity varies worldwide. The purpose of this study is to examine trends in T1DM-related death rates and DALYs across 26 geographical areas from 1990 to 2021 in order to provide a current picture of the disease's consequences and identify regional differences. Methods: This study examined DALYs and mortality rates per 100,000 people in individuals aged 15-39 years using data from the Global Burden of Disease Study from 1990 to 2021. Trends were assessed using the Average Annual Percentage Change (AAPC), with p-values used to define statistical significance. The study examined 26 regions with varied socioeconomic development indices (SDI). Using confidence intervals to account for data uncertainty, DALYs and mortality were examined to investigate the disease burden across time. Results: In 1990, the Middle SDI region had the highest DALYs at 298,352 (95% CI: 256,144 -349,670), which reached 382,857 (95% CI: 213,704-317,664) by 2021 (AAPC = 0.15, P-value < 0.000001). The region with the highest DALYs in 2021 was the Low-Middle SDI, with 419,772 (95% CI: 344,307- 495,496) cases (AAPC = -2.93, P-value = <0.000001). From 1990 to 2021, Oceania consistently had the lowest DALYs of 1,895 (95% CI: 1,264-2,577) and 4,210(95% CI: 3,011-5,724), respectively (AAPC= 0.15, P-value = 0.0004). Mortality rates in 1990 were highest in the Middle SDI area with 3,758 deaths (95% CI: 3,343-4,332) (AAPC= -1.23, P-value = <0.000001), but by 2021, South Asia had the highest mortality rate at 5,189(95% CI: 4,272-6,087) (AAPC= -0.49). Oceania had the lowest mortality rate of 25 deaths (95% CI 145-35) (AAPC = 0.193, P-value = <0.0004) in 1990, whereas Australasia had the lowest mortality rate of 28 deaths (95% CI 26-29) in 2021 (AAPC = -0.93, P-value = <0.000001). Conclusion: From 1990 to 2021, the global burden of type 1 diabetes—as indicated by DALYs and death rates—underwent a substantial shift, with significant rises in several regions. DALYs were highest in the Middle SDI region in 1990 but have migrated to the Low-Middle SDI region by 2021, reflecting shifting healthcare issues and demographics. Mortality rates followed a similar pattern, with South Asia and the Low-Middle SDI regions experiencing the highest rates in 2021. Over both time periods, however, Oceania and Australasia consistently had the lowest DALYs and death rates. These findings emphasise the critical need for targeted interventions in high-burden areas. Addressing these differences is crucial for decreasing the global burden of T1DM. Presentation: Sunday, July 13, 2025

Abstract Disclosure: H. Ahmad: None. S. Fatima: None. M. Kakakhel: None. I. khan: None. A. Raza: None. Z. Khan: None. R. Haider: None. A. Qadeer: None. M. Khawar: None. F. Ullah: None. H. Jawad: None. J. Ikram: None. F. Ahmed: None. R.W. Kirchoff: None. Background: Type 1 diabetes mellitus (T1DM) is an autoimmune condition, characterized by the destruction of pancreatic beta cells, resulting in lifelong dependency on insulin. It is a significant health burden in adolescents and young adults, with long-term complications affecting quality of life and survival. We aim to explore sex-stratified trends in mortality and disability-adjusted life years (DALYs) due to T1DM from 1990 to 2021. Methods: We obtained sex-stratified data for adolescents and young adults (15-39 years) with T1DM from the Global Burden of Disease (GBD) from 1990 to 2021. The mortality rates were age-standardized and expressed per 100,000 deaths. Trends were analyzed as annual percentage change (APC) and average APC (AAPC) using Joinpoint Regression. Results: From 1990 to 2021, deaths due to T1DM in adolescent and young adult males increased globally from 7,123 to 9,244 per annum, with age-standardized mortality rates (ASMRs) decreasing from 0.64 to 0.61 and standardized DALYs rising from 49.56 to 51. In females, deaths rose from 6,160 to 6,892, with ASMRs declining from 0.57 to 0.47 and DALYs declining from 47.12 to 43.11. Despite the apparent rise in deaths, ASMRs exhibited a significant decline in both sexes, with an AAPC of -0.16% (95% CI: -0.20 to -0.12) in males and -0.62% (-0.68 to -0.55) in females, four times that of in males. The DALYs showed a significant decline in females with an AAPC of -0.31% (-0.35 to -0.26) but a significant increase in males with an AAPC of 0.09% (0.04 to 0.12). Males showed the greatest APC increase in ASMRs of 1.34% from 1990 to 1994, while females showed the greatest APC increase of 0.45% from 1990 to 2000, three times less and over twice the period seen in males. This was followed by the greatest APC decline of -1.14% in females from 2001 to 2011, and a non-significant decline of -0.14% till 2021. Males experienced the greatest decline of -1.14% from 2000 to 2013. It then increased significantly from 2013 to 2018 (APC: 0.73%), followed by a significant decline of -0.62% till 2021, almost four times that in females. DALYs showed a similar trend in females with the greatest increase of 0.45% from 1990 to 2000, followed by the greatest decrease of -1.14% till 2011, and then a non-significant decline of -0.14 till 2021. Males showed the greatest increase of 1.24% from 1990 to 1994 and the greatest decrease of 0.63% from 2000 to 2013, followed by a much smaller decline. Conclusion: Although ASMRs declined, the recent decline in ASMRs in females is becoming less pronounced highlighting the importance of ongoing monitoring and improvement strategies. The disparity in DALYs between males and females also demands the need for targeted interventions addressing male-specific challenges to reduce the burden of T1DM. Presentation: Sunday, July 13, 2025

Abstract Disclosure: J.R. Hewlett: None. J.G. Sfeir: None. R.A. Wermers: None. J.J. Schmitz: None. Percutaneous ethanol ablation (PEA) is a non-surgical technique used in the management of hyperparathyroidism (HPT) since the 1980s. Previously published cohorts are small and/or focused on patients with primary hyperparathyroidism (PHPT) in the setting of multiple endocrine neoplasia type 1 (MEN1). New randomized controlled trial data suggests similar response rates between parathyroidectomy and PEA (98.5% vs 91.1%) for uniglandular disease, and a previously published cohort of PEA in patients with MEN1 and recurrent multiglandular PHPT at our institution reported post-PEA normocalcemia in 74.5% of patients. This retrospective cohort study examined the treatment response to PEA in those with PHPT (including MEN1) and tertiary HPT (THPT) at a single institution between 1997-2023. Those with secondary hyperparathyroidism or eucalcemic PHPT were excluded. The primary outcome was a serum calcium ≤10.1 mg/dL at 3-6 months and secondary outcomes included number and volume of ethanol injections, time to recurrence of HPT, and complications of PEA. A total of 83 patients were included. Most were women (62.7%) and the median age at diagnosis of HPT was 40 years. The majority had PHPT (90.4%), and many (86.7%) had previously undergone surgery. The most common indications for PEA were risk for hypoparathyroidism with additional surgery (72.3%) poor surgical candidacy (16.9%), and patient preference (8.4%). The mean calcium was 10.7 mg/dL (95% CI 10.56-10.85) and the mean PTH was 164 pg/mL (95% CI 120.6-208.3) prior to PEA. The mean number of ethanol injections was 3.0 (95% CI 2.6 – 3.4) and the cumulative volume of ethanol was 1.2 mL (95% CI 1.0-1.4). At 3-6 months, 68.3% of treated patients had calcium ≤10.1 mg/dL with a mean value of 9.4 mg/dL (95% CI 9.1-9.6). Of those, 42% did not have recurrence at most recent follow-up. Of those with recurrence, a post-PEA calcium ≤10.1 mg/dL at 3-6 months was associated with a longer time to recurrence than those without (36.9 months versus 3.75 months; P=0.0009). There was no significant difference between the number of times (P=0.56) or the volume (P=0.41) of ethanol injected between those with calcium of ≤10.1 mg/dL at 3-6 months and those without. Hypocalcemia was observed in 8 (9.6%; transient in 75%), hypoparathyroidism in 3 (3.6%; transient in 66.7%), laryngeal nerve injury in 2 (2.4%; transient in 50%), and hoarseness in 9 (10.8%; transient in 100%) patients. This is the largest North American cohort of patients who received PEA for HPT and represents a broader review of HPT than previously published. Our rate of post-PEA eucalcemia is lower than previously reported, however this cohort was complex with a high proportion of multiglandular disease (80.7%), MEN1 (39.8%) and prior surgeries (mean 1.7 per person; 95% CI 1.5-1.9). PEA remains a safe and effective treatment for patients with recurrent HPT, especially those at high risk of post-surgical hypoparathyroidism. Presentation: Monday, July 14, 2025