Abstract Background Sarcopenia is common in chronic obstructive pulmonary disease (COPD) and contributes to adverse outcomes. Alpha-1 antitrypsin deficiency (AATD) is the most common genetic cause of COPD, but its impact on skeletal muscle remains to be determined. Methods We performed a retrospective analysis of 487,207 participants in the UK Biobank with available SERPINA1 genotyping. Associations between AAT genotypes and measures of skeletal muscle mass were determined using multivariable linear and logistic regression models. Models adjusted for age, sex, smoking status, genetic principal components, lung function (FEV₁% predicted), and liver fibrosis risk (FIB-4). We determined that the Z-allele was associated with sarcopenia and mortality using regression models and mediation analysis. Results Compared with PI*MM individuals, carriers of the Z allele (PI*MZ, PI*SZ, PI*ZZ) demonstrated significantly lower fat free mass index (FFMI) and appendicular skeletal muscle index (ASMI), as well as higher odds of sarcopenia by binary definition. Associations persisted after adjustment for lung and liver function. A dose-dependent relationship was observed, with the greatest reductions in muscle mass and highest sarcopenia associated with PI*ZZ individuals (adjusted OR for FFMI-defined sarcopenia 2.02, 95% CI 1.16-3.32). Each additional Z allele was associated with increased mortality risk (adjusted OR 1.09, 95% CI 1.02-1.16), with sarcopenia mediating a modest proportion (∼2.6%) of this association. Conclusions. The SERPINA1 Z allele is associated with reduced muscle mass and increased risk for sarcopenia independent of lung and liver disease. Our findings expand the phenotypic spectrum of AATD-related diseases to include skeletal muscle as a modifiable target for intervention.
Social Determinants of Health Contribute to Adverse Clinical Outcomes in COPD Patients With Sarcopenia and Frailty
Abstract Background. Sarcopenia (i.e. skeletal muscle loss) is a significant contributor to adverse clinical outcomes in patients with COPD. Nutritional intake and physical activity influence sarcopenia and frailty. There is increasing recognition that social determinants of health (SDOH) play critical roles in nutritional status. We evaluated the impact of SDOH on clinical outcomes in hospitalized patients with COPD and sarcopenia and/or frailty. Design. The Nationwide Inpatient Sample (NIS) (years 2018-2020) was analyzed to study adult hospitalized patients with a primary diagnosis of COPD (J43, J44). SDOH was defined by ICD-10 Z-codes as a composite sum of problems related to housing and economic status, unemployment, occupation, psychosocial, family, and healthcare access. Sarcopenia and frailty were defined by a composite of ICD10 codes that have been previously validated in the literature. Multivariate regression models were generated to determine the impact of sarcopenia, frailty, and sarcopenia+frailty on clinical outcomes in COPD patients, which were adjusted for age, race, sex, SDOH, and comorbidities (cardiovascular disease, anemia, coagulopathy, HIV, depression, diabetes mellitus). Results. Of the 282,164 COPD patients that were analyzed, 7254 (2.6%) had codes related to SDOH, 21,035 (7.5%) had sarcopenia, 106,995 (37.9%) had frailty, and 11,293 (4%) had both sarcopenia and frailty. The predominant SDOH code was related to housing (70.9%) followed by social environment (11.5%). SDOH codes were more prevalent in patients with sarcopenia alone (3.6%), compared with frailty (2.5%) or sarcopenia+frailty (2.6%) (p<0.001). When adjusted for demographics including age, race, and sex, SDOH was associated with greater odds of sarcopenia (adj OR 1.64, 95% CI: 1.51-1.79), frailty (adj OR 1.17, 95% CI: 1.11-1.24), and sarcopenia+frailty (adj OR 1.72; 95% CI: 1.54-1.90). COPD patients with sarcopenia+frailty had the greatest association with adverse clinical outcomes (i.e. in-hospital mortality, higher healthcare cost, and higher length of stay), followed by frailty alone, and sarcopenia alone (Table 1). Conclusion. In COPD patients, SDOH increased the odds for a diagnosis of sarcopenia, frailty, and sarcopenia+frailty. Sarcopenia+frailty had the greatest association with adverse outcomes in COPD patients, followed by frailty alone, and sarcopenia alone.
Increased Exacerbations and Hospitalizations Among PI[asterisk]MZ Compared to PI[asterisk]MM Individuals: An Electronic Health Record Analysis
Abstract RATIONALE The best described endotype of COPD is alpha-1 antitrypsin (AAT) deficiency, which is due to a genetic abnormality in the SERPINA1 gene. Homozygotes for the Z allele (PI[asterisk]ZZ individuals) carry the genotype most commonly associated with severe AAT deficiency, but a highly prevalent endotype is the heterozygous state (PI[asterisk]MZ individuals). Here we test the hypothesis that individuals with PI[asterisk]MZ genotype are at higher risk for COPD exacerbation and healthcare utilization compared to those with no pathogenic variants in the SERPINA1 gene (PI[asterisk]MM individuals). METHODS Real-world data on 4,456 individuals with available AAT genotyping were extracted from the Cleveland Clinic Health System (CCHS) electronic health records (EHR) and analyzed to compare the risk of moderate COPD exacerbation (defined as a short-term steroid prescription), all-cause emergent care (defined as an express care visit, urgent care visit, or emergency department visit), and all-cause hospitalization between individuals with PI[asterisk]MZ vs. PI[asterisk]MM genotypes. Cox proportional hazards models were used to adjust for age, sex, race, BMI, smoking status, comorbidity count, liver disease diagnosis, and median income by zip code.To assess the effect of AAT levels on outcomes, we categorized participants into three groups based on AAT level and used 90 mg/dL as a threshold given it is the lower limit of the normal reference range and genotype: MM individuals with an AAT level >90 mg/dL, MZ >90 mg/dL and MZ <90 mg/dL. To assess the effect of PI[asterisk]MZ genotype among individuals with pre-existing lung disease, we performed a subgroup analysis of individuals with at least a six-month inhaler prescription. RESULTS In this cohort, 308 individuals had a PI[asterisk]MZ genotype. PI[asterisk]MZ was associated with increased risk for moderate COPD exacerbations (adjusted HR [95% CI]: 1.66 [1.27, 2.17]) and hospitalizations (adjusted HR [95% CI]: 1.44 [1.19, 1.75]) compared to PI[asterisk]MM. The risk of hospitalization was higher among PI[asterisk]MZ individuals with AAT levels <90 mg/dL (adjusted HR [95% CI]: 1.59 [1.14, 2.23]) but not in those with AAT levels >90 mg/dL, as compared to PI[asterisk]MM. Sensitivity analysis in those treated with inhaler therapy showed overall similar results. CONCLUSIONS Increased hospitalizations and moderate COPD exacerbations among PI[asterisk]MZ individuals compared to PI[asterisk]MM individuals merit future prospective studies to better characterize the longitudinal course and healthcare utilization among those with an PI[asterisk]MZ genotype. Given the high prevalence of these carriers globally, PI[asterisk]MZ represents a COPD phenotype that invites additional investigation to identify biomarkers of worse disease and treatable traits.
Nocturnal Hypoxemia is Associated with Sarcopenia in Patients with Chronic Obstructive Pulmonary Disease
Abstract Rationale Chronic obstructive pulmonary disease (COPD) is the third leading cause of death worldwide. Our previous studies have identified that nocturnal hypoxemia causes skeletal muscle loss (i.e., sarcopenia) in in vitro models of COPD. Objectives We aimed to extend our preclinical mechanistic findings by analyzing a large sleep registry to determine whether nocturnal hypoxemia is associated with sarcopenia in patients with COPD. Methods Sleep studies from patients with COPD (n = 479) and control subjects without COPD (n = 275) were analyzed. Patients with obstructive sleep apnea, as defined by apnea–hypopnea index ⩾ 5, were excluded. Pectoralis muscle cross-sectional area (PMcsa) was quantified using computed tomography scans performed within 1 year of the sleep study. We defined sarcopenia as less than the lowest 20% residuals for PMcsa of control subjects, which was adjusted for age and body mass index (BMI) and stratified by sex. Youden’s optimal cut-point criteria were used to predict sarcopenia based on mean oxygen saturation during sleep. Additional measures of nocturnal hypoxemia were analyzed. The pectoralis muscle index (PMI) was defined as PMcsa normalized to BMI. Results On average, males with COPD had a 16.6% lower PMI than control males (1.41 ± 0.44 vs. 1.69 ± 0.56 cm2/BMI; P < 0.001), whereas females with COPD had a 9.4% lower PMI than control females (0.96 ± 0.27 vs. 1.06 ± 0.33 cm2/BMI; P < 0.001). Males with COPD with nocturnal hypoxemia had a 9.5% decrease in PMI versus COPD with normal O2 (1.33 ± 0.39 vs. 1.47 ± 0.46 cm2/BMI; P < 0.05) and a 23.6% decrease compared with control subjects (1.33 ± 0.39 vs. 1.74 ± 0.56 cm2/BMI; P < 0.001). Females with COPD with nocturnal hypoxemia had an 11.2% decrease versus COPD with normal O2 (0.87 ± 0.26 vs. 0.98 ± 0.28 cm2/BMI; P < 0.05) and a 17.9% decrease compared with control subjects (0.87 ± 0.26 vs. 1.06 ± 0.33 cm2/BMI; P < 0.001). These findings were largely replicated using multiple measures of nocturnal hypoxemia. Conclusions We defined sarcopenia in the pectoralis muscle using residuals that take into account age, BMI, and sex. We found that patients with COPD have a lower PMI than patients without COPD and that nocturnal hypoxemia was associated with an additional decrease in the PMI of patients with COPD. Additional prospective analyses are needed to determine a protective threshold of oxygen saturation to prevent or reverse sarcopenia due to nocturnal hypoxemia in COPD.
Unsupervised Machine Learning Demonstrates a Transcriptomic Signature Associated With Lower Skeletal Muscle Mass in COPDGene
B70. COPD IN THE SPOTLIGHT: INSIGHTS INTO DISEASE PATHOGENESIS | April 30, 2024 | Volume: No volume available | Issue: No issue available | Pages: A4280-A4280