Association of bone mineral density, parameters of bone turnover, and body composition in patients with chronic obstructive pulmonary disease

Exploring the pathophysiology of anemia in COPD: Insights from chest CT and longitudinal clinical data

BACKGROUND

Although anemia has been associated with chronic obstructive pulmonary disease (COPD) severity, the underlying risk factors, such as chest imaging indicators, remain poorly understood. In this study, we aimed to investigate the relationship between anemia and clinical features, including pulmonary and extrapulmonary indicators on chest computed tomography (CT), and to clarify the pathophysiology of anemia in COPD.

METHODS

A total of 400 patients with COPD were prospectively followed for 3 years. Anemia was defined as hemoglobin <13 g/dl in males and <12 g/dl in females. Patients were categorized into the anemia and non-anemia groups, and their clinical characteristics were compared.

RESULTS

The anemia group exhibited lower percentage of predicted forced expiratory volume in 1 s (%FEV1) and body mass index (BMI) measurements, worse COPD assessment test (CAT) scores, and more frequent exacerbations. Imaging revealed more severe emphysema, lower cross-sectional areas of the pectoralis and erector spinae muscles, decreased subcutaneous fat, and more severe coronary artery calcification in this group. Additionally, echocardiography demonstrated a higher prevalence of pulmonary hypertension and reduced left ventricular ejection fraction in patients with anemia. Three-year longitudinal data analysis further showed that declining hemoglobin levels correlated with the worsening of nutritional status, a deterioration in bone mineral density (BMD), and an increase in CAT scores.

CONCLUSION

Anemia in COPD is a multifactorial comorbidity resulting in emphysema, decreased fat and muscle mass, and reduced BMD.

Leptin Levels and Bone Mineral Density: A Friend or a Foe for Bone Loss? A Systematic Review of the Association Between Leptin Levels and Low Bone Mineral Density

The introduction of CFTR modulators in the clinics has improved body mass index in cystic fibrosis (CF) individuals. Leptin is a major regulator of appetite and energy expenditure but is also involved in bone metabolism. Whether circulating leptin levels are associated with low bone mineral density (BMD) and fracture risk in CF remains unknown. Therefore, the present study aims to analyze and integrate the current evidence linking leptin and bone loss in CF. As no scientific evidence was found, we focused on secondary dysregulations of bone loss in CF that may be linked to pathologies that are similar to the various dysregulations and multisystemic manifestations in CF. Studies published from 2001 to 2022 were identified through the PubMed, Scopus, and Web of Science databases, and screening was performed following the PRISMA guidelines. The included studies were assessed using a quality checklist. From the 774 records identified, 28 studies met the inclusion criteria. Although no evidence has been found directly related to bone loss in CF individuals, some studies revealed a positive association between leptin levels and BMD, while others found an inverse association. Current evidence suggests that for circulating leptin levels to be a predictive biomarker of bone health, further research will be needed to reveal the direct and indirect mechanisms behind leptin and bone loss and to understand whether changes in leptin levels correlate with changes in BMD. Of note, studies with CF people would be of high importance to understand the role of leptin in CF-related bone disease.

Prevalence and Risk Factors for Osteoporosis in Individuals With COPD: A Systematic Review and Meta-analysis

BACKGROUND

Osteoporosis is prevalent in individuals with COPD. Updated evidence is required to complement the previous systematic review on this topic to provide best practice. The aim of this systematic review and meta-analysis was to quantitatively synthesize data from studies with respect to the prevalence and risk factors for osteoporosis among individuals with COPD.

METHODS

EMBASE, CINAHL, MEDLINE, and PubMed databases were searched for articles containing the key words "COPD," "osteoporosis," "prevalence," and "risk factor." Eligibility screening, data extraction, and quality assessment of the retrieved articles were conducted independently by two reviewers. Meta-analyses were performed to determine osteoporosis prevalence and risk factors in individuals with COPD. Meta-regression analyses were conducted to explore the sources of heterogeneity.

RESULTS

The pooled global prevalence from 58 studies was 38% (95% CI, 34-43). The presence of COPD increased the likelihood of having osteoporosis (OR, 2.83). Other significant risk factors for osteoporosis in COPD patients were BMI < 18.5 kg/m² (OR, 4.26) and the presence of sarcopenia (OR, 3.65).

CONCLUSIONS

Osteoporosis is prevalent in individuals with COPD, and the prevalence seems to be high and similar in many countries. Patients with COPD should be screened for osteoporosis and contributing risk factors.

Analytic Morphomics Predict Outcomes After Lung Transplantation

BACKGROUND

The purpose of this study was to identify morphomic factors on standard, pretransplantation computed tomography (CT) scans associated with outcomes after lung transplantation.

METHODS

A retrospective review of 200 patients undergoing lung transplantation at a single institution from 2003 to 2014 was performed. CT scans obtained within 1 year before transplantation underwent morphomic analysis. Morphomic characteristics included lung, dorsal muscle group, bone, and subcutaneous and visceral fat area and density. Patient data were gathered from institutional and United Network for Organ Sharing databases. Outcomes, including initial ventilator support greater than 48 hours, length of stay, and survival, were evaluated using univariate and multivariable analyses.

RESULTS

On multivariable Cox regression, subcutaneous fat/total body area (hazard ratio [HR] 0.60, p = 0.001), lung density 3 volume (HR 0.67, p = 0.013), and creatinine (HR 4.37, p = 0.010) were independent predictors of survival. Initial ventilator support more than 48 hours was associated with decreased vertebral body to linea alba distance (odds ratio [OR] 0.49, p = 0.002) and Zubrod score 4 (OR 14.0, p < 0.001). Increased bone mineral density (p < 0.001) and increased cross-sectional body area (p < 0.001) were associated with decreased length of stay, whereas supplemental oxygen (p < 0.001), bilateral transplantation (p = 0.002), cardiopulmonary bypass (p < 0.001), and Zubrod score 3 (p < 0.001) or 4 (p = 0.040) were associated with increased length of stay.

CONCLUSIONS

Morphomic factors associated with lower metabolic reserve and frailty, including decreased subcutaneous fat, bone density, and body dimensions were independent predictors of survival, prolonged ventilation, and increased length of stay. Analytic morphomics using pretransplantation CT scans may improve recipient selection and risk stratification.

Role of Osteoprotegerin and Receptor Activator of Nuclear Factor-κB Ligand in Bone Loss Related to Advanced Chronic Obstructive Pulmonary Disease

Background:

Osteoporosis is a common complication of chronic obstructive pulmonary disease (COPD). Recent clinical and biological researches have increasingly delineated the biomolecular pathways of bone metabolism regulation in COPD. We extended this work by examining the specific association and potential contribution of the osteoprotegerin (OPG)/receptor activator of nuclear factor-κB ligand (RANKL) axis to the pathogenesis of osteoporosis in advanced COPD. The aim of this study was to assess the relationships of serum OPG, RANKL, and tumor necrosis factor-alpha (TNF-α) with bone turnover in men with very severe COPD.

Methods:

Pulmonary function, T-score at the lumbar spine (LS) and femoral neck (FN), serum OPG, RANKL, soluble receptor of tumor necrosis factor-alpha-I and II (sTNFR-I, sTNFR-II), osteocalcin (OC), and β-CrossLaps (βCL) levels were measured in 45 men with very severe stage COPD and 36 male non-COPD volunteers. COPD patients and healthy controls were compared using an independent t-test and Mann–Whitney U-test. The Pearson coefficient was used to assess the relationships between variables.

Results:

OPG and OC were lower in male COPD patients than in control subjects whereas RANKL, serum βCL, TNF-α, and its receptors were higher. OPG directly correlated with forced expiratory volume in 1 s (FEV1) % predicted (r = 0.46, P < 0.005), OC (r = 0.34, P < 0.05), LS (r = 0.56, P < 0.001), and FN T-score (r = 0.47, P < 0.01). In contrast, serum RANKL inversely associated with LS and FN T-score (r = −0.62, P < 0.001 and r = −0.48, P < 0.001) but directly correlated with βCL (r = 0.48, P < 0.001). In addition, OPG was inversely correlated with RANKL (r = −0.39, P < 0.01), TNF-α (r = −0.56, P < 0.001), and sTNFR-I (r = −0.40, P < 0.01).

Conclusion:

Our results suggest that serum OPG and RANKL levels are inversely associated with bone loss in men with advanced stage COPD.

Effects of therapies for regulating and reinforcing lung and kidney on osteoporosis in rats with chronic obstructive pulmonary disease

OBJECTIVE

To evaluate the efficacy and long-term effects of the three therapies for regulating and reinforcing lung and kidney (reinforcing lung and invigorating spleen, reinforcing lung and replenishing kidney, and supplementing Qi and nourishing kidney) in Traditional Chinese Medicine (TCM) on osteoporosis in rats with chronic obstructive pulmonary disease.

METHODS

Totally 120 rats were randomly divided into control, model, Bufeijianpi, Bufeiyishen, Yiqizishen, aminophyline groups. Repeated smoke inhalations and bacterial infections were used to duplicate the stable Chronic obstructive pulmonary disease rat model. Normal saline was given to the air control and model groups, while Bufeijianpi granule, Bufeiyishen granule, and Yiqizishen granule, and aminophylline were administrated to rats in the Bufeijianpi, Bufeiyishen, Yiqizishen, and aminophylline groups respectively from weeks 9 through 20. Another 12 weeks without medicines to observe the long-term effect. Rats were sacrificed at week 20 and week 32. Bone mass density (BMD), bone mineral content (BMC), morphology of the femoral head, lung function, and levels of serum interleukin (IL)-1β, IL-6, and tumor necrosis factor-α were detected.

RESULTS

At weeks 20 and 32, tidal volume, peak expiratory flow and expiratory flow at 50% tidal volume in the three TCM-treated groups were higher than those in the model group (P < 0.05). Femur weight, BMD, and BMC were significantly higher in the three TCM-treated groups and the aminophylline-treated group compared with the model group (P < 0.01), except for BMC in the Yiqizishen-treated group at week 20.

CONCLUSION

Bufeijianpi, Bufeiyishen, and Yiqizishen granules show good effects in the prevention and treatment of osteoporosis, which can alleviate airflow limitations and inflammation, improve BMD and BMC of the femur, and have favorable long-term effects.

Body fat, lean mass and bone density of the spine and forearm in women

The aim of this study was to determine the relative contributions of fat mass and lean mass to the variability of bone mineral density (BMD) of the lumbar spine and proximal 1/3 forearm in Bulgarian women. 180 women aged 21 through 76 years participated (mean age 50.8 ± 9.7 years). 130 of them were postmenopausal. Lumbar spine and forearm BMD were measured by dual-energy X-ray absorptiometry, followed by a whole-body scan for body composition examination (Hologic QDR 4500 A device, software version 1.26). The strongest linear correlation was found with body weight (r2=0.231, p<0.001). Using this model, 18.1 % of the variability of lumbar spine BMD was attributable to fat mass and 16.0 % to lean mass. The relative influence of fat mass on L1-L4 BMD was greater than that of lean mass (standardized regression coefficient 0.291 versus 0.199). There were weak correlations of body weight, fat and lean mass with the forearm BMD. Lean mass correlated slightly better (r=0.187, p=0.050) to forearm BMD than fat mass (r=0.162, p=0.055). In conclusion, the differentiation between fat and lean mass does not strengthen the BMD correlations beyond that with total body weight.