Is decreased lung function associated with chronic kidney disease? A retrospective cohort study in Korea

Impairment of Cardiovascular Functional Capacity in Mild-to-Moderate Kidney Dysfunction

Key Points

Background

Traditional diagnostic tools that assess resting cardiac function and structure fail to accurately reflect cardiovascular alterations in patients with CKD. This study sought to determine whether multidimensional exercise response patterns related to cardiovascular functional capacity can detect abnormalities in mild-to-moderate CKD.

Methods

In a cross-sectional study, we examined 3075 participants from the Framingham Heart Study (FHS) and 451 participants from the Massachusetts General Hospital Exercise Study (MGH-ExS) who underwent cardiopulmonary exercise testing. Participants were stratified by eGFR: eGFR ≥90, eGFR 60–89, and eGFR 30–59. Our primary outcomes of interest were peak oxygen uptake (VO2Peak), VO2 at anaerobic threshold (VO2AT), and ratio of minute ventilation to carbon dioxide production (VE/VCO2). Multiple linear regression models were fitted to evaluate the associations between eGFR group and each outcome variable adjusted for covariates.

Results

In the FHS cohort, 1712 participants (56%) had an eGFR ≥90 ml/min per 1.73 m2, 1271 (41%) had an eGFR of 60–89 ml/min per 1.73 m2, and 92 (3%) had an eGFR of 30–59 ml/min per 1.73 m2. In the MGH-ExS cohort, 247 participants (55%) had an eGFR ≥90 ml/min per 1.73 m2, 154 (34%) had an eGFR of 60–89 ml/min per 1.73 m2, and 50 (11%) had an eGFR of 30–59 ml/min per 1.73 m2. In FHS, VO2Peak and VO2AT were incrementally impaired with declining kidney function (P < 0.001); however, this pattern was attenuated after adjustment for age. Percent-predicted VO2Peak at AT was higher in the lower eGFR groups (P < 0.001). In MGH-ExS, VO2Peak and VO2AT were incrementally impaired with declining kidney function in unadjusted and adjusted models (P < 0.05). VO2Peak was associated with eGFR (P < 0.05) in all models even after adjusting for age. On further mechanistic analysis, we directly measured cardiac output (CO) at peak exercise by right heart catheterization and found impaired CO in the lower eGFR groups (P ≤ 0.007).

Conclusions

Cardiopulmonary exercise testing–derived indices may detect impairment in cardiovascular functional capacity and track CO declines in mild-to-moderate CKD.

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.

Does hand stiffness reflect internal organ fibrosis in diabetes mellitus?

Fibrosis leads to irreversible stiffening of tissue and loss of function, and is a common pathway leading to morbidity and mortality in chronic disease. Diabetes mellitus (both type 1 and type 2 diabetes) are associated with significant fibrosis in internal organs, chiefly the kidney and heart, but also lung, liver and adipose tissue. Diabetes is also associated with the diabetic cheirarthropathies, a collection of clinical manifestations affecting the hand that include limited joint mobility (LJM), flexor tenosynovitis, Duypuytren disease and carpal tunnel syndrome. Histo-morphologically these are profibrotic conditions affecting various soft tissue components in the hand. We hypothesize that these hand manifestations reflect a systemic profibrotic state, and are potential clinical biomarkers of current or future internal organ fibrosis. Epidemiologically, there is evidence that fibrosis in one organ associates with fibrosis with another; the putative exposures that lead to fibrosis in diabetes (advanced glycation end product deposition, microvascular disease and hypoxia, persistent innate inflammation) are 'systemic'; a common genetic susceptibility to fibrosis has also been hinted at. These data suggest that a subset of the diabetic population is susceptible to multi-organ fibrosis. The hand is an attractive biomarker to clinically detect this susceptibility, owing to its accessibility to physical examination and exposure to repeated mechanical stresses. Testing the hypothesis has a few pre-requisites: being able to measure hand fibrosis in the hand, using clinical scores or imaging based scores, which will facilitate looking for associations with internal organ fibrosis using validated methodologies for each. Longitudinal studies would be essential in delineating fibrosis trajectories in those with hand manifestations. Since therapies reversing fibrosis are few, the onus lies on identification of a susceptible subset for preventative measures. If systematically validated, clinical hand examination could provide a low-cost, universally accessible and easily reproducible screening step in selecting patients for clinical trials for fibrosis in diabetes.

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.

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.

Is There an Association Between Chronic Obstructive Pulmonary Disease and Chronic Renal Failure?

Chronic obstructive pulmonary disease (COPD) is one of the most common diseases worldwide with its prevalence increasing with age. It is commonly comorbid with other diseases and managing patients could be difficult and expensive. Chronic kidney disease (CKD) is often present in COPD patients and may be underdiagnosed, especially if it is mild. This study intended to summarize recent findings showing the correlation between the two diseases. Studies were gathered that were published in the last 11 years, from 2010 to 2021. PubMed was used as the main source of data, but papers from the references of the included other sources were added for thoroughness. Observational studies on examining the prevalence and prognosis of comorbid COPD and CKD published in the English language were included. A higher prevalence of CKD in COPD patients was found in most studies; it was found that a higher risk of mortality is present if these diseases coexist. Further research is required and more extensive prospective studies are needed with matched control groups to support the correlation.

Incidence and risk factors of chronic kidney disease: results of a nationwide study in Iceland

Background

Information on the incidence of chronic kidney disease (CKD) in the general population is scarce. This study examined the incidence and risk factors of CKD stages 1–5 in Iceland, based on multiple markers of kidney damage.

Methods

All SCr values, urine protein measurements and diagnosis codes for kidney diseases and comorbid conditions for people aged ≥ 18 years were obtained from electronic medical records of all healthcare institutions in Iceland in 2008–2016. CKD was defined according to the KDIGO criteria as evidence for kidney damage and/or eGFR &lt; 60 mL/min/1.73 m2 for &gt; 3 months. Alternatively, CKD was defined using age-adapted eGFR thresholds. Mean annual age-standardized incidence of CKD was calculated for persons without CKD at study entry. Risk factor assessment was based on ICD diagnosis codes. Incidence was reported per 100 000 population.

Results

We retrieved 1 820 990 SCr values for 206 727 persons. Median age was 45 years (range, 18–106) and 47% were men. Mean annual age-standardized incidence of CKD per 100 000 was 649 in men and 694 in women, and 480 in men and 522 in women using age-adapted eGFR thresholds. The incidence reached over 3000 in men and women aged &gt; 75 years. Traditional CKD risk factors, such as acute kidney injury, diabetes, hypertension and cardiovascular disease, as well as less well characterized risk factors, including chronic lung disease, malignancy and major psychiatric illness were associated with increased risk of CKD, and the same was true for obesity and sleep apnea in women.

Conclusion

The annual incidence of CKD, with strict adherence to the KDIGO criteria, was &lt; 0.7% but markedly lower using age-adapted eGFR thresholds. Apart from acute kidney injury, the observed risk factors comprised chronic and potentially modifiable disorders.

Obstructive spirometry pattern and the risk of chronic kidney disease: analysis from the community-based prospective Ansan-Ansung cohort in Korea

OBJECTIVE

There have been limited studies on the relationship between obstructive spirometry pattern and the development of chronic kidney disease (CKD). We investigated the association between obstructive spirometry pattern and incident CKD development in a large-scale prospective cohort study.

METHODS

We reviewed the data of 7960 non-CKD adults aged 40-69 years who participated in the Ansung-Ansan cohort, a prospective community-based cohort study. Prebronchodilation results for the ratio of forced expiratory volume per 1 s (FEV1) to forced vital capacity (FVC) were used as the primary exposure. The primary outcome was incident CKD, defined as the first event of an estimated glomerular filtration rate <60 mL/min/1.73 m². HRs and 95% CIs were calculated using multivariate Cox proportional hazard regression analysis.

RESULTS

Over a mean follow-up period of 11.7 years, incident CKD developed in 511 subjects (6.4%). An increase of 0.1 in FEV1/FVC was associated with a decreased risk of incident CKD (HR 0.76, 95% CI 0.68 to 0.84, p<0.001). Compared with the fourth quartile, the HR (95 % CI) of the first quartile of FEV1/FVC ratio was 1.81 (1.39 to 2.36, p<0.001). In the restricted cubic spline curve, the renal hazard associated with a decreased FEV1/FVC ratio was evident at FEV1/FVC values <0.80, showing a U-shaped relationship. In subgroup analysis, the renal hazard associated with a decreased FEV1/FVC ratio was particularly evident in people without metabolic syndrome (p for interaction=0.018).

CONCLUSION

Decreased FEV1/FVC ratio was independently associated with an increased risk of incident CKD development, particularly in people without metabolic syndrome. Future studies need to be conducted to confirm these results.

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).

Longitudinal Analysis of Lung Function in Pregnant Women with and without Asthma

BACKGROUND

Spirometry is commonly used to assess and monitor lung function. It may also be a useful tool to monitor maternal health during pregnancy. However, large studies examining lung function across gestation are limited. Also, whether spirometry values follow the same pattern during pregnancy in women with and without asthma is unknown.

OBJECTIVE

To investigate the effect of advancing gestation, and its interaction with asthma, on lung function in a large well-defined cohort of pregnant women.

METHODS

Data were obtained from prospective cohorts involving women with (n = 770) and without (n = 259) asthma (2004-2017), recruited between 12 and 22 weeks' gestation. Lung function (forced vital capacity [FVC], FEV₁, FEV₁:FVC%) was assessed periodically during pregnancy using spirometry. Multilevel mixed-effect regression models were used to assess changes in lung function over gestation.

RESULTS

Asthma had a significant effect on baseline lung function (FEV₁%, -9%; FVC%, -3%; FEV₁:FVC%, -4%). FVC% decreased with advancing gestation (-0.07%/wk; 95% CI, -0.10 to -0.04]), as did FEV₁%, but only among those without asthma (women without asthma: -0.14%/wk, 95% CI, -0.22 to -0.06%; compared with women with asthma: 0.02%/wk, 95% CI, -0.01 to 0.06). FEV₁:FVC% remained relatively stable for women without asthma (0.03%/wk; 95% CI, -0.08 to 0.02), but increased for women with asthma (0.06%/wk; 95% CI, 0.04 to 0.16).

CONCLUSIONS

Data suggest that advancing gestation negatively affects FVC% and FEV₁%. This is consistent with extrapulmonary restriction from advancing pregnancy. Yet, the presence of asthma altered the trajectories of FEV₁% and FEV₁:FVC%. Optimal asthma management during pregnancy might have opposed the negative effects of gestation on lung function.

Cardiovascular Functional Changes in Chronic Kidney Disease: Integrative Physiology, Pathophysiology and Applications of Cardiopulmonary Exercise Testing

The development of cardiovascular disease during renal impairment involves striking multi-tiered, multi-dimensional complex alterations encompassing the entire oxygen transport system. Complex interactions between target organ systems involving alterations of the heart, vascular, musculoskeletal and respiratory systems occur in Chronic Kidney Disease (CKD) and collectively contribute to impairment of cardiovascular function. These systemic changes have challenged our diagnostic and therapeutic efforts, particularly given that imaging cardiac structure at rest, rather than ascertainment under the stress of exercise, may not accurately reflect the risk of premature death in CKD. The multi-systemic nature of cardiovascular disease in CKD patients provides strong rationale for an integrated approach to the assessment of cardiovascular alterations in this population. State-of-the-art cardiopulmonary exercise testing (CPET) is a powerful, dynamic technology that enables the global assessment of cardiovascular functional alterations and reflects the integrative exercise response and complex machinery that form the oxygen transport system. CPET provides a wealth of data from a single assessment with mechanistic, physiological and prognostic utility. It is an underutilized technology in the care of patients with kidney disease with the potential to help advance the field of cardio-nephrology. This article reviews the integrative physiology and pathophysiology of cardio-renal impairment, critical new insights derived from CPET technology, and contemporary evidence for potential applications of CPET technology in patients with kidney disease.

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.