Restrictive lung disorder is common in patients with kidney failure and associates with protein-energy wasting, inflammation and cardiovascular disease

Uncommon Causes of Pulmonary Hypertension With Associated Cardiomyopathy: Computed Tomography and Magnetic Resonance Imaging of Cardiothoracic Manifestations

Pulmonary hypertension (PH) is a disease characterized by pathologically increased pressure in the pulmonary arteries, defined by a mean pulmonary arterial pressure (mPAP) >20 mmHg at rest measured with right heart catheterization (RHC). This definition encompasses pathologies with very different pathological backgrounds, ultimately resulting in PH. For this reason, the latter can be possibly (though seldom) accompanied by cardiomyopathies, pathologies characterized by a structural and functionally abnormal myocardium not secondary to coronary disease, hypertension, valvular disease, or congenital heart disease. Notable examples of these diseases are sarcoidosis (a multi-systemic inflammatory granulomatous disease, possibly involving the lung and the heart), systemic sclerosis (SSc) (a connective tissue disease [CTD], possibly causing interstitial lung disease [ILD], direct as well indirect involvement of the cardiovascular system), and chronic kidney disease (CKD) (a progressive pathological process involving the kidneys, with multi-systemic involvement and possible development of a peculiar form of cardiomyopathy, i.e., uremic cardiomyopathy [UC]). The diagnostic work-up of patients with coexistent PH and cardiomyopathies implies the use of multiple imaging techniques, with computed tomography (CT) and cardiovascular magnetic resonance (CMR) being among the most important. The knowledge of CT and MRI findings, together with a suggestive clinical picture, forms the basis for a correct diagnosis, therefore it is important for the radiologist to recognize them in complex clinical scenarios. The advent of new technologies (e.g., photon counting detectors) and the development of new artificial intelligence (AI) algorithms will further pave the way for improved diagnostic processes (also regarding this kind of pathologies) as well as allowing to perform a better prognostic evaluation.

Preserved ratio impaired spirometry, airflow obstruction, and their trajectories in relationship to chronic kidney disease: a prospective cohort study

Spirometry findings, such as restrictive spirometry and airflow obstruction, are associated with renal outcomes. Effects of spirometry findings such as preserved ratio impaired spirometry (PRISm) and its trajectories on renal outcomes are unclear. This study aimed to investigate the impact of baseline and trajectories of spirometry findings on future chronic kidney disease (CKD) events. This UK Biobank cohort study included participants with CKD who underwent spirometry at baseline (2006-2010). Lung function trajectories were determined using baseline and follow-up spirometry (2014-2020). Cox proportional hazards multivariate regression analysis was used to analyze the association between lung function and the incident CKD. In the baseline analysis (n = 282,354), fully adjusted hazard ratios (HRs) for PRISm participants (vs. normal spirometry) were 1.20 (1.07-1.34) for CKD and 1.51 (1.04-2.19) for end-stage renal disease (ESRD). Over an average 13.8-year follow-up period, 789 participants developed CKD. Trajectory analysis revealed higher CKD incidence with persistent AO (HR = 1.47(1.03-2.12)) and PRISm (HR = 1.28(0.88-1.88)) compared to normal lung function. Transitioning from AO to PRISm was associated with lower CKD incidence (HR = 0.27(0.08-0.93)). Recovery of normal lung function from AO could avert 16% of CKD cases. Our study indicated that baseline PRISm and airflow obstruction are associated with higher risk of incident CKD. Moreover, those with persistent AO findings had a higher risk of CKD incidence. These findings underscore the complex link between spirometry findings and renal outcomes and highlight the importance of considering respiratory and renal health in clinical assessments.

Chronic Kidney Disease-associated Lung Injury Is Mediated by Phosphate-induced MAPK/AKT Signaling

Chronic kidney disease (CKD) is associated with systemic phosphate elevations, called hyperphosphatemia. Translational studies have shown that hyperphosphatemia contributes to CKD-associated inflammation and injury in various tissues, including the kidney, heart, liver, and parathyroid gland. Mechanisms underlying pathologic actions of elevated phosphate on cells are not well understood but seem to involve uptake of phosphate through sodium phosphate cotransporters and phosphate-induced signaling via FGFR1 (fibroblast growth factor receptor 1). Clinical studies indicate patients with CKD are more likely to develop inflammatory and restrictive lung diseases, such as fibrotic interstitial lung diseases, and here we aimed to determine whether hyperphosphatemia can cause lung injury. We found that a mouse model of CKD and hyperphosphatemia, induced by an adenine-rich diet, develops lung fibrosis and inflammation. Elevation of systemic phosphate concentration by administration of a high-phosphate diet in a mouse model of primary lung inflammation and fibrosis, induced by bleomycin, exacerbated lung injury in the absence of kidney damage. Our in vitro studies identified increases of proinflammatory cytokines in human lung fibroblasts exposed to phosphate elevations. Phosphate activated ERK 1/2 (extracellular signal-related kinase 1/2) and PKB/AKT (protein kinase B) signaling, and pharmacological inhibition of ERK, AKT, FGFR1, or sodium phosphate cotransporters prevented phosphate-induced proinflammatory cytokine upregulation. In addition, inhibition of FGFR1 or sodium phosphate cotransporters decreased the phosphate-induced activation of ERK and AKT. Our study suggests that phosphate can directly target lung fibroblasts and induce an inflammatory response and that hyperphosphatemia in CKD and non-CKD models contributes to lung injury. Phosphate-lowering strategies might protect from CKD-associated lung injury.

Association between measures of kidney function and preserved ratio impaired spirometry in diabetes: NHANES 2007-2012

OBJECTIVES

This study aimed to examine the relationship between measures of kidney function and impaired lung function in individuals with diabetes and to assess all-cause mortality risk associated with having chronic kidney disease (CKD) and or impaired lung function.

DESIGN

Cross-sectional and retrospective cohort study.

SETTING

The National Health and Nutrition Examination Survey 2007-2012.

PARTICIPANTS

A total of 10 809 participants aged over 20 years were included in this study: 9503 with normal spirometry, 951 with preserved ratio impaired spirometry (PRISm) and 355 with variable obstruction (VO).

EXPOSURE AND OUTCOME MEASURES

Kidney function measures, including estimated glomerular filtration rate (eGFR) and urinary albumin to creatinine ratio (UACR), were considered exposure variables. PRISm and VO were outcome variables. PRISm was defined as a forced expiratory volume in 1 s (FEV1)<80% predicted and an FEV1/forced vital capacity (FVC) ratio≥0.7, while VO was defined as an FEV1/FVC ratio <0.7 prebronchodilator and ≥0.7 postbronchodilator. In the cross-sectional analysis, multivariate logistic regression models were used to assess the relationship between kidney function measures and spirometry findings. In the retrospective cohort analysis, Cox proportional hazards models were employed to evaluate the impact of having PRISm or VO, combined with CKD, on all-cause mortality.

RESULTS

An increase in UACR was significantly associated with higher odds of PRISm (OR (95% CI)=1.10 (1.01, 1.21), p=0.03). Additionally, eGFR <60 was associated with the odds of variable obstructive lung function (OR (95% CI)=1.72 (1.07, 2.74), p=0.03) compared with eGFR >60. After adjustments, an increase in UACR was associated with higher odds of PRISm in individuals with diabetes (OR (95% CI)=1.21 (1.08, 1.36), p=0.002), and UACR ≥300 mg/g significantly increased odds of having PRISm in idividuals with diabetes (OR (95% CI)=2.34 (1.23, 4.47), p=0.01). During a mean follow-up of 12.3 years, 10 500 deaths occurred. In the diabetic group, compared with normal spirometry without CKD, those with both PRISm and CKD had a significantly increased risk of all-cause mortality (HR (95% CI)=3.46 (1.94, 6.16), p<0.0001).

CONCLUSION

An elevated UACR and albuminuria were linked to a higher risk of PRISm. Our study emphasises that kidney and lung function are correlated. Further research is necessary to confirm our findings.

Association between pulmonary function and rapid kidney function decline: a longitudinal cohort study from CHARLS

BACKGROUND

Pulmonary function has been reported to be associated with chronic kidney disease. However, the relationship between lung function and rapid kidney function decline remains unclear.

METHODS

Participants aged ≥45 years with complete data from the 2011 and 2015 interviews of the China Health and Retirement Longitudinal Study (CHARLS) were included. Lung function, assessed by peak expiratory flow (PEF), and kidney function, assessed by estimated glomerular filtration rate (eGFR), were tested at the baseline and endpoint surveys. Rapid kidney function decline was defined as a decrease in eGFR ≥3 mL/min/1.73 m²/year, and ΔeGFR represented the difference between baseline and endpoint eGFR. Multivariate logistic regression models and linear regression models were employed to evaluate the association between PEF and the risk of rapid eGFR decline, as well as the correlation between PEF and ΔeGFR.

RESULTS

A total of 6159 participants were included, with 1157 (18.78%) individuals experiencing a rapid decline in eGFR. After adjusting for potential covariates, higher baseline PEF (Quartile 4 vs Quartile 1, OR=0.95, 95% CI 0.92 to 0.98) and elevated PEF % predicted (OR=0.96, 95% CI 0.94 to 0.99) were found to be associated with a lower risk of rapid eGFR decline. ΔeGFR decreased by 0.217 and 0.124 mL/min/1.73 m² for every 1 L/s increase in baseline PEF (β (95% CI): -0.217 (-0.393 to -0.042)) and 10% increase in PEF % predicted (β (95% CI): -0.124 (-0.237 to -0.011)), respectively. During the follow-up period, ΔeGFR decreased as PEF increased over time among participants in Quartile 1 (β per 1 L/s increase in ΔPEF=-0.581, 95% CI -1.003 to -0.158; β per 10% increase in ΔPEF % predicted=-0.279, 95% CI -0.515 to -0.043).

CONCLUSIONS

Higher PEF was associated with a slower longitudinal eGFR decline in middle-aged and older adults.

Respiratory sarcopenia screening in dialysis patients: cross-sectional and multicentre study protocol

BACKGROUND

Respiratory sarcopenia is characterized by the weakness of respiratory muscles associated with sarcopenia due to aging or systemic diseases such as chronic kidney disease (CKD). Patients with CKD undergoing dialysis are particularly susceptible to respiratory muscle weakness caused by factors such as fluid overload and electrolyte imbalance. This weakness not only affects ventilation but also impairs oxygen uptake and delivery to muscle tissue, potentially leading to severe sarcopenia. Thus, the objective of this study is to conduct a respiratory sarcopenia screening in patients with CKD undergoing haemodialysis (HD) and peritoneal dialysis (PD).

METHODS

This is an observational, cross-sectional and multicentre study conducted between March 2023 and March 2025. The study was approved by the Research Ethics Committee at two centres. Sarcopenia diagnosis is determined based on low handgrip strength and amount of appendicular skeletal muscle mass, assessed through bioelectrical impedance analysis. Respiratory sarcopenia is diagnosed in patients with sarcopenia who have low inspiratory muscle strength, evaluated through a manovacuometry test. The severity of sarcopenia and respiratory sarcopenia is defined, respectively, by low physical performance (measured using the Short Physical Performance Battery and Timed-Up and Go test) and pulmonary performance (measured through spirometry). Thus, this study will include 81 patients undergoing dialysis (41 on HD and 40 on PD) from three participating centres.

DISCUSSION

The literature has been focused on respiratory function in CKD; however, the relationship with sarcopenia remains understudied. We believe that, similar to appendicular skeleton muscles, the axial skeleton muscles are also likely to weaken with the presence of chronic disease, such as CKD.

Phosphate induces inflammation and exacerbates injury from cigarette smoke in the bronchial epithelium

An elevation in serum phosphate-also called hyperphosphatemia-is associated with reduced kidney function in chronic kidney disease (CKD). Reports show CKD patients are more likely to develop lung disease and have poorer kidney function that positively correlates with pulmonary obstruction. However, the underlying mechanisms are not well understood. Here, we report that two murine models of CKD, which both exhibit increased serum levels of phosphate and fibroblast growth factor (FGF) 23, a regulator of phosphate homeostasis, develop concomitant airway inflammation. Our in vitro studies point towards a similar increase of phosphate-induced inflammatory markers in human bronchial epithelial cells. FGF23 stimulation alone does not induce a proinflammatory response in the non-COPD bronchial epithelium and phosphate does not cause endogenous FGF23 release. Upregulation of the phosphate-induced proinflammatory cytokines is accompanied by activation of the extracellular-signal regulated kinase (ERK) pathway. Moreover, the addition of cigarette smoke extract (CSE) during phosphate treatments exacerbates inflammation as well as ERK activation, whereas co-treatment with FGF23 attenuates both the phosphate as well as the combined phosphate- and CS-induced inflammatory response, independent of ERK activation. Together, these data demonstrate a novel pathway that potentially explains pathological kidney-lung crosstalk with phosphate as a key mediator.

Targeting Lung-Gut Axis for Regulating Pollution Particle-Mediated Inflammation and Metabolic Disorders

Cigarette smoking (CS) or ambient particulate matter (PM) exposure is a risk factor for metabolic disorders, such as insulin resistance (IR), increased plasma triglycerides, hyperglycemia, and diabetes mellitus (DM); it can also cause gut microbiota dysbiosis. In smokers with metabolic disorders, CS cessation decreases the risks of serious pulmonary events, inflammation, and metabolic disorder. This review included recent studies examining the mechanisms underlying the effects of CS and PM on gut microbiota dysbiosis and metabolic disorder development; one of the potential mechanisms is the disruption of the lung-gut axis, leading to gut microbiota dysbiosis, intestinal dysfunction, systemic inflammation, and metabolic disease. Short-chain fatty acids (SCFAs) are the primary metabolites of gut bacteria, which are derived from the fermentation of dietary fibers. They activate G-protein-coupled receptor (GPCR) signaling, suppress histone deacetylase (HDAC) activity, and inhibit inflammation, facilitating the maintenance of gut health and biofunction. The aforementioned gut microbiota dysbiosis reduces SCFA levels. Treatment targeting SCFA/GPCR signaling may alleviate air pollution-associated inflammation and metabolic disorders, which involve lung-gut axis disruption.

Effect of respiratory muscle training in patients with chronic kidney disease: A systematic review and meta-analysis of randomized controlled trials

OBJECTIVE

This systematic review and meta-analysis aimed to evaluate the effect of respiratory muscle training on respiratory muscle strength, lung function, cardiopulmonary fitness, and quality of life for chronic kidney disease patients.

METHODS

PubMed, Embase, Web of Science Core Collection, and Cochrane Central Register of Controlled Trials published randomized controlled trials that evaluated the effect of respiratory muscle training for chronic kidney disease patients from inception to December 2021, and rerun on September 2022. The quality of included studies was evaluated according to the Cochrane Collaboration's risk of bias tool-2. The outcomes were analyzed as mean differences with a fixed/random effect model. The strength of evidence was evaluated with the Grading of Recommendation, Assessment, Development, and Evaluation approach.

RESULTS

Eleven randomized controlled trials were included. All but two of the studies were in hemodialysis patients. The follow-up time range was 4 to 12 weeks. Compared to controls, respiratory muscle training significantly improved maximal expiratory pressure (mean difference = 17.36, p = 0.013), maximal inspiratory pressure (mean difference = 18.26, p = 0.002), forced expiratory volume at 1 second (mean difference = 0.20, p= 0.020), forced vital capacity (mean difference = 0.26, p = 0.008), but not for 6-minute walk test (mean difference = 39.85, p= 0.138).

CONCLUSIONS

As a non-pharmacological therapy, respiratory muscle training can effectively improve maximal expiratory pressure, maximal inspiratory pressure, forced expiratory volume at 1 second, and forced vital capacity in patients with chronic kidney disease and is safe for such populations.

Respiratory complications and sleep disorders in children with chronic kidney disease: A correlation often underestimated

Chronic Kidney Disease (CKD) is characterized by a progressive and irreversible loss of kidney function which gradually leads to end-stage kidney disease (ESKD). Virtually all the organs are damaged by the toxicity of uremic compounds. The lungs may be affected and the impaired pulmonary function may be the direct result of fluid retention and metabolic, endocrine and cardiovascular alterations, as well as systemic activation of the inflammation. An increased prevalence in sleep disorders (SD) is also reported in patients with CKD, leading to a further negative impact on overall health and quality of life. While these complex relationships are well documented in the adult population, these aspects remain relatively little investigated in children. The aim of this review is to provide a brief overview of the pathophysiology between lung and kidney and to summarize how CKD may affect respiratory function and sleep in children.

Lung Dysfunction and Chronic Kidney Disease: A Complex Network of Multiple Interactions

Chronic kidney disease (CKD) is a progressive disease that affects > 10% of the total population worldwide or >800 million people. CKD poses a particularly heavy burden in low- and middle-income countries, which are least able to cope with its consequences. It has become one of the leading causes of death worldwide and is one of the few non-communicable diseases where the number of related deaths has increased over the last two decades. The high number of people affected, and the significant negative impact of CKD should be a reason to increase efforts to improve prevention and treatment. The interaction of lung and kidney leads to highly complex and difficult clinical scenarios. CKD significantly affects the physiology of the lung by altering fluid homeostasis, acid-base balance and vascular tone. In the lung, haemodynamic disturbances lead to the development of alterations in ventilatory control, pulmonary congestion, capillary stress failure and pulmonary vascular disease. In the kidney, haemodynamic disturbances lead to sodium and water retention and the deterioration of renal function. In this article, we would like to draw attention to the importance of harmonising the definitions of clinical events in pneumology and renal medicine. We would also like to highlight the need for pulmonary function tests in routine clinical practise for the management of patients with CKD, in order to find new concepts for pathophysiological based disease-specific management strategies.

Influence of mild pulmonary congestion on diaphragmatic mobility and activities of daily living in chronic kidney disease: An experimental and clinical study

BACKGROUND

Pulmonary congestion is a strong predictor of mortality and cardiovascular events in chronic kidney disease (CKD); however, the effects of the mild form on functionality have not yet been investigated. The objective of this study was to assess the influence of mild pulmonary congestion on diaphragmatic mobility (DM) and activities of daily living (ADL) in hemodialysis (HD) subjects, as well as compare ADL behavior on dialysis and non-dialysis days. In parallel, experimentally induce CKD in mice and analyze the resulting pulmonary and functional repercussions.

METHODS

Thirty subjects in HD underwent thoracic and abdominal ultrasonography, anthropometric assessment, lung and kidney function, respiratory muscle strength assessment and symptoms analysis. To measure ADL a triaxial accelerometer was used over seven consecutive days. Twenty male mice were randomized in Control and CKD group. Thoracic ultrasonography, TNF-α analysis in kidney and lung tissue, exploratory behavior and functionality assessments were performed.

RESULTS

Mild pulmonary congestion caused a 26.1% decline in DM (R²=.261; P=.004) and 20% reduction in walking time (R²=.200; P=.01), indicating decreases of 2.23mm and 1.54min, respectively, for every unit increase in lung comet-tails. Regarding ADL, subjects exhibited statistically significant differences for standing (P=.002), walking (P=.034) and active time (P=.002), and number of steps taken (P=.01) on days with and without HD. In the experimental model, CKD resulted in increased levels of TNF-α on kidneys (P=.037) and lungs (P=.02), attenuation of exploratory behavior (P=.01) and significant decrease in traveled distance (P=.034). Thoracic ultrasonography of CKD mice showed presence of B-lines.

CONCLUSION

The mild pulmonary congestion reduced DM and walking time in subjects undergoing HD. Individuals were less active on dialysis days. Furthermore, the experimental model implies that the presence of pulmonary congestion and inflammation may play a decisive role in the low physical and exploratory performance of CKD mice.

Eplerenone ameliorates lung fibrosis in unilateral ureteral obstruction rats by inhibiting lymphangiogenesis

Chronic kidney disease (CKD) involves progressive and irreversible loss of renal function, often causing complications and comorbidities and impairing the function of various organs. In particular, lung injury is observed not only in advanced CKD but also in early-stage CKD. The present study investigated the potential involvement of mineralocorticoid receptors (MRs) and lymphatic vessels in lung injury using a 180-day unilateral ureteral obstruction (UUO) model for CKD. Changes in lung associated with lymphangiogenesis and inflammatory were analyzed in UUO rats. The pathology of the lung tissue was observed by hematoxylin and eosin and Masson's staining. Detection of the expression of lymphatic vessel endothelial hyaluronic acid receptor-1 (LYVE-1), Podoplanin, vascular endothelial growth factor receptor-3 (VEGFR-3) and VEGF C to investigate lymphangiogenesis. The mRNA and protein expression levels of IL-1β, monocyte chemotactic protein 1, tumor necrosis factor-α, nuclear factor κB, phosphorylated serum and glucocorticoid-induced protein kinase-1 and MR were evaluated using western blot, reverse transcription-quantitative PCR, immunohistochemical staining and immunofluorescence staining. In the present study, long-term UUO caused kidney damage, which also led to lung inflammation, accompanied by lymphangiogenesis. However, treatment with eplerenone, an MR blocker, significantly reduced the severity of lung injury and lymphangiogenesis. Therefore, lymphangiogenesis contributed to lung fibrosis in UUO rats due to activation of MRs. In addition, transdifferentiation of lymphatic epithelial cells into myofibroblasts may also be involved in lung fibrosis. Collectively, these findings provided a potential mechanism for lung fibrosis in CKD and suggested that the use of eplerenone decreased kidney damage and lung fibrosis.

Lung-kidney interactions and their role in chronic kidney disease-associated pulmonary diseases

Chronic illnesses rarely present in a vacuum, devoid of other complications, and chronic kidney disease is hardly an exception. Comorbidities associated with chronic kidney disease lead to faster disease progression, expedited dialysis dependency, and a higher mortality rate. Although chronic kidney disease is most commonly accompanied by cardiovascular diseases and diabetes, there is clear cross talk between the lungs and kidneys pH balance, phosphate metabolism, and immune system regulation. Our present understanding of the exact underlying mechanisms that contribute to chronic kidney disease-related pulmonary disease is poor. This review summarizes the current research on kidney-pulmonary interorgan cross talk in the context of chronic kidney disease, highlighting various acute and chronic pulmonary diseases that lead to further complications in patient care. Treatment options for patients presenting with chronic kidney disease and lung disease are explored by assessing activated molecular pathways and the body's compensatory response mechanisms following homeostatic imbalance. Understanding the link between the lungs and kidneys will potentially improve health outcomes for patients and guide healthcare professionals to better understand how and when to treat each of the pulmonary comorbidities that can present with chronic kidney disease.

Pulmonary function, muscle strength, and quality of life have differed between chronic kidney disease patients and healthy individuals

Chronic kidney disease (CKD) patients have lower pulmonary function, respiratory and peripheral muscle strength values when compared to the general population, which reflects negatively in the quality of life (QoL). The aim of this study was to compare the pulmonary function, respiratory and peripheral muscle strength, and QoL between CKD patients and healthy individuals. Cross-sectional study with a consecutive sample of 39 individuals separated into three groups: nondialysis-dependent CKD in stage 5 (CKD-5), HD group (CKD-HD), and healthy individuals. The tests performed were spirometry, manovacuometry, handgrip strength (HGS), and Medical Outcomes Short-Form Health Survey (SF-36). A significant difference between groups was observed in forced expiratory volume in 1 second (FEV₁ ) and its predicted value (p = 0.004 and p < 0.001, respectively), forced vital capacity (FVC), and its predicted value (p = 0.008 and p < 0.001, respectively), peak expiratory flow (PEF) and its predicted value (p = 0.004 and p < 0.001, respectively), maximal inspiratory pressure (MIP) and its predicted value (p = 0.022), maximal expiratory pressure (MEP) and its predicted value (p = 0.030 and p = 0.009, respectively) in which CKD-5 presented the worst values, followed by CKD-HD and healthy group. The CKD-5 had worse pulmonary function, respiratory muscle strength, and QoL. Moreover, CKD-HD also showed some impairment in pulmonary function and QoL when compared with healthy individuals. Even with the peripheral muscle strength preserved, its decrease is proportional to the pulmonary impairment in the evaluated CKD patients.

A Spectrum of Pulmonary Complications Occurring in End-Stage Renal Disease Patients on Maintenance Hemodialysis

Objective

To investigate the trends of end-stage renal disease (ESRD) in patients undergoing maintenance hemodialysis (MHD) and find the correlation with effects on the pulmonary system in such patients.

Methodology

A multicentric prospective study was conducted in the city of Solapur, India. Data were collected from 250 patients through interpersonal interrogation using a questionnaire to capture basic demographic details, the history of ESRD, and relevant respiratory symptoms like breathlessness, cough, fever, etc. related to their disease. Symptoms that are likely associated with the pulmonary system were analyzed and referred to the pulmonology department. Appropriate diagnoses were made using relevant diagnostic tools like X-rays and sputum studies. The association between various disease attributes and pulmonary diagnoses was analyzed using the chi-square (χ2) test, with a p-value of value less than or equal to 0.05 considered statistically significant. Various socio-demographic variables, existing comorbidities, occupation-related risk factors, smoking history, past or current history of any respiratory conditions, the association between the causes of ESRD, time since the first dialysis and sociodemographic factors, and frequency of pulmonary complications were the other covariates in the study.

Results

Our study reports that 31.6% of our patients had significant impairment in their functioning due to respiratory complaints. The prevalence of respiratory complications was 27.2%. Major contributors were pleural effusion (33.8), pneumonia (25), pulmonary edema (20.58), pleuritis (11.76), collapse (8.8), tuberculosis (5.8), fibrosis (4.4), pericardial effusion (4.4), calcification (2.9), and hydrothorax (1.47). We report one case of Urinothorax as a rare cause of hydrothorax in such patients. Overall, our analysis found a significant association between non-reporting of respiratory complaints and acute admissions to the intensive care unit (ICU) with a respiratory cause at p-value 0.0076 with a greater predilection toward the rural populations.

Conclusion

Our study results highlight the prevalence of pulmonary complications in ESRD patients. The occurrence of pulmonary complications, irrespective of the presence of symptoms and a greater association between non-reporting of respiratory symptoms and acute admissions to the ICU, is a hallmark to consider the importance of history and clinical vigilance during patient visits.

Patient-Reported Measures and Lifestyle Are Associated With Deterioration in Nutritional Status in CKD Stage 4-5: The EQUAL Cohort Study

OBJECTIVE

The aim of this study was to explore the changes in nutritional status before dialysis initiation and to identify modifiable risk factors of nutritional status decline in older adults with advanced renal disease.

DESIGN AND METHODS

The European Quality Study on treatment in advanced chronic kidney disease (EQUAL) is a prospective, observational cohort study involving six European countries. We included 1,103 adults >65 years with incident estimated glomerular filtration rate <20 mL/min/1.73 m² not on dialysis, attending nephrology care. Nutritional status was assessed with the 7-point Subjective Global Assessment tool (7-p SGA), patient-reported outcomes with RAND-36 and the Dialysis Symptom Index. Logistic regression was used to estimate the associations between potential risk factors and SGA decline.

RESULTS

The majority of the patients had a normal nutritional status at baseline, 28% were moderately malnourished (SGA ≤5). Overall, mean SGA decreased by -0.18 points/year, (95% confidence interval -0.21; -0.14). More than one-third of the study participants (34.9%) deteriorated in nutritional status (1 point decline in SGA) and 10.9% had a severe decline in SGA (≥2 points). The proportion of patients with low SGA (≤5) increased every 6 months. Those who dropped in SGA also declined in estimated glomerular filtration rate and mental health score. Every 10 points decrease in physical function score increased the odds of decline in SGA by 23%. Lower physical function score at baseline, gastrointestinal symptoms, and smoking were risk factors for impaired nutritional status. There was an interaction between diabetes and physical function on SGA decline.

CONCLUSIONS

Nutritional status deteriorated in more than one-third of the study participants during the first year of follow-up. Lower patient-reported physical function, more gastrointestinal symptoms, and current smoking were associated with decline in nutritional status.

The oxygen cascade in patients treated with hemodialysis and native high-altitude dwellers: lessons from extreme physiology to benefit patients with end-stage renal disease

Patients treated with hemodialysis (HD) repeatedly undergo intradialytic low arterial oxygen saturation and low central venous oxygen saturation, reflecting an imbalance between upper body systemic oxygen supply and demand, which are associated with increased mortality. Abnormalities along the entire oxygen cascade, with impaired diffusive and convective oxygen transport, contribute to the reduced tissue oxygen supply. HD treatment impairs pulmonary gas exchange and reduces ventilatory drive, whereas ultrafiltration can reduce tissue perfusion due to a decline in cardiac output. In addition to these factors, capillary rarefaction and reduced mitochondrial efficacy can further affect the balance between cellular oxygen supply and demand. Whereas it has been convincingly demonstrated that a reduced perfusion of heart and brain during HD contributes to organ damage, the significance of systemic hypoxia remains uncertain, although it may contribute to oxidative stress, systemic inflammation, and accelerated senescence. These abnormalities along the oxygen cascade of patients treated with HD appear to be diametrically opposite to the situation in Tibetan highlanders and Sherpa, whose physiology adapted to the inescapable hypobaric hypoxia of their living environment over many generations. Their adaptation includes pulmonary, vascular, and metabolic alterations with enhanced capillary density, nitric oxide production, and mitochondrial efficacy without oxidative stress. Improving the tissue oxygen supply in patients treated with HD depends primarily on preventing hemodynamic instability by increasing dialysis time/frequency or prescribing cool dialysis. Whether dietary or pharmacological interventions, such as the administration of L-arginine, fermented food, nitrate, nuclear factor erythroid 2-related factor 2 agonists, or prolyl hydroxylase 2 inhibitors, improve clinical outcome in patients treated with HD warrants future research.

Duration of hemodialysis associated with cardio-respiratory dysfunction and breathlessness: a multicenter study

Background

Patients with hemodialysis suffer with protein-energy wasting and uremic myopathy lead to lack of physical activity and poor functional performance. However, ventilation abnormality in patients undergone hemodialysis remains controversial regarding the respiratory impairment. Therefore, the study aimed to determine the effect of duration of dialysis on respiratory function.

Methods

A multicenter study with cross-sectional study was designed in four hemodialysis outpatient clinics. Respiratory muscle strength (i.e., maximal inspiratory pressure (MIP) and maximal expiratory pressure (MEP)) pulmonary function test (i.e., forced vital capacity (FVC), forced expiratory volume in one second (FEV₁) and FEV₁/FVC ratio), functional capacity (6-minute walk test) and sensation of breathlessness were assessed prior to dialysis.

Results

A total of 100 hemodialysis patients were recruited with 38 females and 62 males. An average of duration of hemodialysis was 5.93± 4.96 years. Decreased MIP values, FEV₁ values, FVC values, %FEV₁ and %FVC were noted in patients with long duration of dialysis (defined as ≥ 5 years of dialysis) compared to those with short duration of dialysis (p_s < .05). In addition, increased sensation of breathlessness was observed in patients with long duration of dialysis (p < .05). Furthermore, participants with long duration of dialysis had an increased risk of ventilatory restriction (OR 6.093, p = .007).

Changes in pulmonary restrictive parameters by intensive home hemodialysis: a case report

Background

Patients with End-Stage Renal Disease (ESRD) are at an increased risk for restrictive lung disease due to accumulation of uremic toxins and volume overload. Hemodialysis is the preferred treatment for improving lung function in dialysis patients. However, the effects of fluid removal and solute clearance by hemodialysis on lung function remain unclear.

Case presentation

We report a case of restrictive lung disorder in a hemodialysis patient, who showed improvement in both clinical and spirometric lung function after initiation of intensive home hemodialysis (32 h per week).

Conclusion

Intensive hemodialysis augments fluid removal and solute clearance, which in turn may improve restrictive lung function.

Impact of Age-related Diseases on Pulmonary Function Tests in Older Japanese Adults: A Cross-sectional Pilot Study

Introduction:

A widely used reference range for pulmonary function testing was derived from middle-aged, healthy, non-smoking adults in Japan. This study examined the effect of age-related diseases on pulmonary function tests for older Japanese adults.

Methods:

All patients aged ≥65 years who underwent spirometry before general and orthopedic surgeries in Itoigawa General Hospital (Niigata, Japan) from January 2014 to June 2019 were identified, and their charts were reviewed.

Results:

This study included 1050 Japanese patients (median age: 75 years). The median spirometric values of vital capacity, forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1), and FEV1/FVC in all patients were 2.66 L [interquartile range; 2.24, 3.25], 2.57 L [2.13, 3.13], 1.98 L [1.66, 2.37], and 77.5% [72.2, 81.9], respectively. Multiple regression analyses revealed that spirometric values were significantly affected by age, body height, sex, smoking status, social dependency, dyslipidemia, diabetes, history of heart failure, peripheral artery disease, end-stage renal disease, neuromuscular disease, and psychiatric disorders. Male sex and height were positively correlated with FVC and FEV1. Other factors, such as a history of heart failure, neuromuscular disease, and independent physical activity, were negatively correlated with FVC and FEV1 to almost the same extent as that of age.

Conclusions:

These data will provide clinically useful information to accurately interpret pulmonary function test results in older Japanese adults.

Low lung function and the risk of incident chronic kidney disease in the Malmö Preventive Project cohort

BACKGROUND

Although the prevalence of kidney disease is higher in those with reduced lung function, the longitudinal relationship between low lung function and future risk of chronic kidney disease (CKD) has not been widely explored.

METHODS

Baseline lung function was assessed in 20,700 men and 7325 women from 1974 to 1992. Mean age was 43.4 (±6.6) and 47.5 (±7.9) for men and women respectively. Sex-specific quartiles of FEV1 and FVC (L) were created (Q4: highest, reference) and the cohort was also divided by the FEV1/FVC ratio (≥ or < 0.70). Cox proportional hazards regression was used to determine the risk of incident CKD events (inpatient or outpatient hospital diagnosis of CKD) in relation to baseline lung function after adjustment for various confounding factors.

RESULTS

Over 41 years of follow-up there were 710 and 165 incident CKD events (main diagnosis) in men and women respectively. Low FEV1 was strongly associated with future risk of CKD in men (Q1 vs Q4 adjusted HR: 1.46 (CI:1.14-1.89), p-trend 0.002). Similar findings were observed for FVC in men (1.51 (CI:1.16-1.95), p-trend 0.001). The adjusted risks were not found to be significant in women, for either FEV1 or FVC. FEV1/FVC < 0.70 was not associated with increased incidence of CKD in men or women.

CONCLUSION

Low FEV1 and FVC levels at baseline are a risk factor for the development of future incident CKD in men. Monitoring kidney function in those with reduced vital capacity in early life could help with identifying those at increased risk of future CKD.

Glomerular hyperfiltration may be a novel risk factor of restrictive spirometry pattern: Analysis of the Korea National Health and Nutrition Examination Survey (KNHANES) 2009-2015

BACKGROUND AND OBJECTIVES

There have been limited studies regarding the association between glomerular hyperfiltration (GHF) and restrictive spirometry pattern (RSP) in Korean adults.

METHODS

We used data of 23,189 adults from the Korea National Health and Nutritional Examination Survey 2009-2015 with a complete data set including spirometry, serum creatinine, and anthropometric measurements. Spirometry data included the forced expiratory volume in one second (FEV1) and forced vital capacity (FVC). We defined GHF as the >90th percentile of age & sex adjusted estimated glomerular filtration rate (eGFR), and RSP was defined as an FVC <80%-predicted value and an FEV1/FVC ratio ≥0.7.

RESULTS

Participants with RSP showed higher blood pressure, fasting glucose, and triglyceride, reduced high density lipoprotein cholesterol, and central obesity, which resulted in a higher prevalence of metabolic syndrome (MetS) compared to those without RSP. Multivariate logistic regression revealed that the odds for RSP were significantly increased with an increased number of MetS components. In addition, increased eGFR was associated with decreased FVC, showing an inverted J-shaped relationship in a multivariate generalized additive model analysis. In the multivariate logistic regression analysis, the adjusted odds ratio and 95% confidence interval of GHF for RSP was 1.184 (1.026-1.368, P = 0.021), which was evident in groups without metabolic disorders.

CONCLUSIONS

We concluded that GHF was associated with increased odds for RSP, particularly in groups without metabolic disorders. Further prospective studies are needed to confirm our study results.