Lung Function and Incident Kidney Disease: The Atherosclerosis Risk in Communities (ARIC) Study

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.

Association Between Decreased Renal Function and Pulmonary Function Decline in Community-dwelling Adults

BACKGROUND/AIM

Emerging evidence suggests that there is a close relationship between the human lung and kidney. This study evaluated whether decreased renal function was associated with accelerated pulmonary function decline in a large-scale community-based cohort.

PATIENTS AND METHODS

A total of 10,028 subjects of the prospective Ansung-Ansan cohort were eligible for the longitudinal analysis of changes in pulmonary function associated with decreased renal function (glomerular filtration rate <60 ml/min/1.73 m2). Logistic regression analysis was performed to evaluate factors associated with decreased baseline renal function, and a linear mixed model compared changes in pulmonary function in participants with and without decreased renal function after propensity score matching (PSM).

RESULTS

At baseline, subjects with and without decreased renal function showed distinct characteristics, and the factors associated with decreased renal function were age, baseline forced vital capacity, hypertension, and white blood cell (WBC) count. A 1:4 PSM of age, sex, body mass index, and smoking status showed that the proportion of those with hypertension and the WBC count differed between the patients with decreased and normal renal function. In the PSM population, those with decreased renal function had a greater decline in forced expiratory volume in the first second (FEV1) than those without (p=0.0402); however, these differences were not found to be evident when hypertension and WBC count were further matched (p=0.0807).

CONCLUSION

The results of our study demonstrated that decreased renal function was not directly associated with the rapid decline in pulmonary function in a community-based general population setting.

Trend and heterogeneity in forced vital capacity among Chinese students during 1985-2019: results from Chinese National Survey on Students' Constitution and Health

BACKGROUND

Forced vital capacity (FVC) reflects respiratory health, but the long-term trend and heterogeneity in FVC of Chinese students were understudied.

METHODS

Data were from Chinese National Survey on Students' Constitution and Health 1985-2019. Super Imposition by Translation and Rotation model was used to draw FVC growth curves. Sex-, region-, and nationality-heterogeneity in FVC was evaluated. Spearman correlation and generalized additive model was used to reveal influencing factors for FVC.

RESULTS

Compared to 1985, age at peak FVC velocity was 1.09, 3.17, 0.74, and 1.87 years earlier for urban male, urban female, rural male, and rural female in 2019, respectively. Peak FVC velocity first decreased and then increased during 1985-2019, only male rebounded to larger than 1985 level. FVC declined from 1985 to 2005 and then raised. Males consistently had higher FVC than females, with disparities increasing in the 13-15 age group. Urban students also had higher FVC than rural students. In 2019, FVC difference between 30 Chinese provinces and the national average showed four scenarios: consistently above national average; less than national average until age 18, then above; greater than national average until age 18, then this advantage reversed; less than national average in almost all the age. Most Chinese ethnic minority students had lower FVC levels compared to Han students. Spearman correlation and generalized additive model showed that age, sex, and height were the leading influencing factors of FVC, followed by socioeconomic and environmental factors.

CONCLUSIONS

Chinese students experienced advanced FVC spurt, and there was sex-, region- and nationality-heterogeneity in FVC. Routine measurement of FVC is necessary in less developed areas of China.

Diabetes-related perturbations in the integrity of physiologic barriers

One of the hallmarks of health is the integrity of barriers at the cellular and tissue levels. The two cardinal functions of barriers include preventing access of deleterious elements of the environment (barrier function) while facilitating the transport of essential ions, signaling molecules and nutrients needed to maintain the internal milieu (transport function). There are several cellular and subcellular barriers and some of these barriers can be interrelated. The principal physiologic barriers include blood-retinal barrier, blood-brain barrier, blood-testis barrier, renal glomerular/tubular barrier, intestinal barrier, pulmonary blood-alveolar barrier, blood-placental barrier and skin barrier. Tissue specific barriers are the result of the vasculature, cellular composition of the tissue and extracellular matrix within the tissue. Uncontrolled diabetes and acute hyperglycemia may disrupt the integrity of physiologic barriers, primarily through altering the vascular integrity of the tissues and may well contribute to the clinically recognized complications of diabetes. Although diabetes is a systemic disease, some of the organs display clinically significant deterioration in function while others undergo subclinical changes. The pathophysiology of the disruption of these barriers is not entirely clear but it may be related to diabetes-related cellular stress. Understanding the mechanisms of diabetes related dysfunction of various physiologic barriers might help identifying novel therapeutic targets for reducing clinically significant complications of diabetes.

Nontraditional Risk Factors for Progression Through Chronic Kidney Disease Risk Categories: The Coronary Artery Risk Development in Young Adults Study

BACKGROUND

There may be nontraditional pathways of chronic kidney disease (CKD) progression that are complementary to classical pathways. Therefore, we aimed to examine nontraditional risk factors for incident CKD and its progression.

METHODS

We used the generally healthy population (n = 4382) starting at age 27-41 years in the Coronary Artery Risk Development in Young Adults (CARDIA) cohort, which is an observational longitudinal study. Nontraditional risk factors included forced vital capacity, inflammation, serum urate, and serum carotenoids. CKD risk category was classified using the estimated glomerular filtration rate (eGFR) and urinary albumin-to-creatinine ratio (UACR) measured in 1995-1996 and repeated every 5 years for 20 years: No CKD, low risk, moderate risk, high risk, and very high risk.

RESULTS

At baseline, 84.8% had no CKD (eGFR ≥60 mL/min/1.73 m2 and UACR <10 mg/g), 10.3% were in the low risk (eGFR ≥60 and UACR 10-29), and 4.9% had CKD (eGFR <60 and/or UACR ≥ 30). Nontraditional risk factors were significantly associated with the progression of CKD to higher categories. Hazard ratios per standard deviation of the predictor for incident CKD and its progression from the No CKD and low and moderate risk into CKD were inverse for forced vital capacity and serum carotenoids and positive for serum urate, GlycA, and C-reactive protein, the first 3 even after adjustment for conventional risk factors.

CONCLUSION

Several nontraditional markers were significantly associated with an increased risk of progression to higher CKD categories in generally healthy young to middle-aged adults.

Preserved Ratio Impaired Spirometry in Relationship to Cardiovascular Outcomes: A Large Prospective Cohort Study

BACKGROUND

Preserved ratio impaired spirometry (PRISm) findings are a heterogeneous condition characterized by a normal FEV₁ to FVC ratio with underlying impairment of pulmonary function. Data relating to the association of baseline and trajectories of PRISm findings with diverse cardiovascular outcomes are sparse.

RESEARCH QUESTION

How do baseline and trajectories of PRISm findings impact subsequent cardiovascular events?

STUDY DESIGN AND METHODS

In the UK Biobank cohort study, we included participants free of cardiovascular disease (CVD) with spirometry (FEV₁ and FVC values) at baseline (2006-2010). Participants with baseline spirometry and follow-up spirometry (2014-2020) were included in the lung function trajectory analysis. Cox proportional hazards multivariate regression was performed to evaluate the outcomes of major adverse cardiovascular events (MACEs), incident myocardial infarction (MI), stroke, heart failure (HF), and CVD mortality in association with lung function.

RESULTS

For baseline analysis (329,954 participants), the multivariate adjusted hazard ratios (HRs) for participants had PRISm findings (vs normal spirometry findings) were 1.26 (95% CI, 1.17-1.35) for MACE, 1.12 (95% CI, 1.01-1.25) for MI, 1.88 (95% CI, 1.72-2.05) for HF, 1.26 (95% CI, 1.13-1.40) for stroke, and 1.55 (95% CI, 1.37-1.76) for CVD mortality, respectively. A total of 22,781 participants underwent follow-up spirometry after an average of 8.9 years. Trajectory analysis showed that persistent PRISm findings (HR, 1.96; 95% CI, 1.24-3.09) and airflow obstruction (HR, 1.43; 95% CI, 1.00-2.04) was associated with a higher incidence of MACE vs consistently normal lung function. Compared with persistent PRISm findings, changing from PRISm to normal spirometry findings was associated with a lower incidence of MACE (HR, 0.42; 95% CI, 0.19-0.99).

INTERPRETATION

Individuals with baseline or persistent PRISm findings were at a higher risk of diverse cardiovascular outcomes even after adjusting for a wide range of confounding factors. However, individuals who transitioned from PRISm to normal findings showed a similar cardiovascular risk as those with normal lung function.

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.

Significant Spirometric Transitions and Preserved Ratio Impaired Spirometry Among Ever Smokers

BACKGROUND

Emerging data from longitudinal studies suggest that preserved ratio impaired spirometry (PRISm), defined by proportionate reductions in FEV₁ and FVC, is a heterogeneous population with frequent transitions to other lung function categories relative to individuals with normal and obstructive spirometry. Controversy regarding the clinical significance of these transitions exists (eg, whether transitions merely reflect measurement variability or noise).

RESEARCH QUESTION

Are individuals with PRISm enriched for transitions associated with substantial changes in lung function?

STUDY DESIGN AND METHODS

Current and former smokers enrolled in the Genetic Epidemiology of COPD (COPDGene) study with spirometry available in phases 1 through 3 (enrollment, 5-year follow-up, and 10-year follow-up) were analyzed. Postbronchodilator lung function categories were as follows: PRISm (FEV₁ < 80% predicted with FEV₁/FVC ratio ≥ 0.7), Global Initiative for Chronic Obstructive Lung Disease grade 0 (FEV₁ ≥ 80% predicted and FEV₁/FVC ≥ 0.7), and obstruction (FEV₁/FVC < 0.7). Significant transition status was affirmative if a subject belonged to two or more spirometric categories and had > 10% change in FEV₁ % predicted and/or FVC % predicted between consecutive visits. Ever-PRISm was present if a subject had PRISm at any visit. Logistic regression examined the association between significant transitions and ever-PRISm status, adjusted for age, sex, race, FEV₁ % predicted, current smoking, pack-years, BMI, and ever-positive bronchodilator response.

RESULTS

Among subjects with complete data (N = 1,775) over 10.1 ± 0.4 years of follow-up, the prevalence of PRISm remained consistent (10.4%-11.3%) between phases 1 through 3, but nearly one-half of subjects with PRISm transitioned into or out of PRISm at each visit. Among all subjects, 19.7% had a significant transition; ever-PRISm was a significant predictor of significant transitions (unadjusted OR, 10.3; 95% CI, 7.9-13.5; adjusted OR, 14.9; 95% CI, 10.9-20.7). Results were similar with additional adjustment for radiographic emphysema and gas trapping, when lower limit of normal criteria were used to define lung function categories, and when FEV₁ alone (regardless of change in FVC % predicted) was used to define significant transitions.

INTERPRETATION

PRISm is an unstable group, with frequent significant transitions to both obstruction and normal spirometry over time.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov; No.: NCT000608764; URL: www.

CLINICALTRIALS

gov.

Echocardiographic measures and subsequent decline in kidney function in older adults: the Atherosclerosis Risk in Communities Study

AIMS

Heart failure increases the risk of kidney disease progression. However, whether cardiac function and structure are associated with the risk of incident chronic kidney disease (CKD) is not well characterized in a community setting.

METHODS AND RESULTS

Among 4188 participants (mean age 75 years and 22% blacks) of the Atherosclerosis Risk in Communities Study without prevalent CKD in 2011-13, we examined the association of echocardiographic measures of left ventricular (LV) mass index, ejection fraction, left atrial volume index (LAVi), right ventricular (RV) fractional area change, and peak RV-right atrium (RA) gradient, with the subsequent risk of incident CKD, as defined by >25% decline to estimated glomerular filtration rate (eGFR) <60 mL/min/1.73 m2, hospitalization with CKD diagnosis, or incident end-stage kidney disease. Multivariable Cox regression models were used to estimate hazard ratios (HRs). The risk of incident CKD was monotonically increased with each of higher LV mass index [adjusted HR 2.61 (1.92-3.55) for highest quartile (Q4) vs. lowest (Q1)], lower ejection fraction [1.54 (1.17-2.04) for Q1 vs. Q4], higher LAVi [2.12 (1.56-2.89) for Q4 vs. Q1], and higher peak RV-RA gradient [2.17 (1.45-3.25) for Q4 vs. Q1] but not with RV function. The associations were consistent between subgroups by sex and race.

CONCLUSION

Among community-dwelling older individuals, LV mass index, ejection fraction, LAVi, and peak RV-RA gradient were independently associated with the risk of incident CKD. Our results further support that heart disease is associated with the risk of kidney disease progression and suggest the value of echocardiography for assessing cardiac and kidney health in older populations.

Association between Comorbidities and Preserved Ratio Impaired Spirometry: Using the Korean National Health and Nutrition Examination Survey IV-VI

BACKGROUND

Preserved ratio impaired spirometry (PRISm) patients have more frequent respiratory symptoms and an increased risk of mortality. However, studies on comorbidities in these patients are lacking.

OBJECTIVES

We investigated the association between PRISm and comorbidities using the Korea National Health and Nutrition Examination Survey (KNHANES).

METHOD

This cross-sectional study included participants aged ≥50 years from the KNHANES (2007-2015). Participants who did not undergo spirometry or performed inadequately were excluded. We classified participants into 3 groups according to spirometry: PRISm (forced expiratory volume in one second [FEV1] /forced vital capacity [FVC] ≥ 0.7 and FEV1 <80%), chronic obstructive pulmonary disease (COPD) (FEV1/ FVC <0.7), and normal. Multivariate logistic regression analyses were used to evaluate the risk of comorbidities in the PRISm group compared to that in the normal group.

RESULT

The study included 17,515 participants: 12,777 (73.0%), 1,563 (8.9%), and 3,175 (18.1%) in normal, PRISm, and COPD groups, respectively. After adjustment for known risk factors of each disease, hypertension (adjusted odds ratio [95% confidence interval]; 1.31 [1.14-1.50]), diabetes (1.51 [1.29-1.78]), hypercholesterolemia (1.20 [1.04-1.37]), obesity (1.31 [1.15-1.48]), ischemic heart disease (1.58 [1.13-2.22]), chronic renal disease (2.31 [1.09-4.88]), and thyroid disease (1.41 [1.09-1.83]) risks were significantly higher in the PRISm group than in the normal group. The average number of comorbidities was 2.45 in the PRISm group, which was higher than that in the normal (2.1) and COPD (2.03) groups (p < 0.05).

CONCLUSION

The number of comorbidities was significantly higher in the PRISm group than in others. Hypertension, diabetes, obesity, ischemic heart disease, chronic renal disease, and thyroid disease were associated with PRISm after adjustment for risk factors.

Longitudinal change in lung function and subsequent risks of cardiovascular events: evidence from four prospective cohort studies

BACKGROUND

Lung function is constantly changing over the life course. Although the relation of cross-sectional lung function measure and adverse outcomes has been reported, data on longitudinal change and subsequent cardiovascular (CV) events risks are scarce. Therefore, this study is to determine the association of longitudinal change in lung function and subsequent cardiovascular risks.

METHODS

This study analyzed the data from four prospective cohorts. Subjects with at least two lung function tests were included. We calculated the rate of forced respiratory volume in 1 s (FEV1) and forced vital capacity (FVC) decline for each subject and categorized them into quartiles. The primary outcome was CV events, defined as a composite of coronary heart disease (CHD), chronic heart failure (CHF), stroke, and any CV death. Cox proportional hazards regression and restricted cubic spline models were applied.

RESULTS

The final sample comprised 12,899 participants (mean age 48.58 years; 43.61% male). Following an average of 14.79 (10.69) years, 3950 CV events occurred. Compared with the highest FEV1 quartile (Q4), the multivariable HRs for the lowest (Q1), 2nd (Q2), and 3rd quartiles (Q3) were 1.33 (95%CI 1.19, 1.49), 1.30 (1.16, 1.46), and 1.07 (0.95, 1.21), respectively. Likewise, compared with the reference quartile (Q4), the group that experienced a faster decline in FVC had higher HRs for CV events (1.06 [95%CI 0.94-1.20] for Q3, 1.15 [1.02-1.30] for Q2, and 1.28 [1.14-1.44] for Q1). The association remained robust across a series of sensitivity analyses and nearly all subgroups but was more evident in subjects < 60 years.

CONCLUSIONS

We observed a monotonic increase in risks of CV events with a faster decline in FEV1 and FVC. These findings emphasize the value of periodic evaluation of lung function and open new opportunities for disease prevention.

Kidney function and obstructive lung disease: a bidirectional Mendelian randomisation study

BACKGROUND

Additional study is warranted to investigate the causal effects between kidney function and obstructive lung disease.

METHODS

This study was a bidirectional two-sample Mendelian randomisation (MR) analysis. The CKDGen genome-wide association study (GWAS) meta-analysis for estimated glomerular filtration rate (eGFR) including individuals of European ancestry (N=567 460) provided the genetic instrument for kidney function and outcome summary statistics. A GWAS for FEV1/FVC including individuals of European ancestry from the UK Biobank (N=321 047) provided the genetic instrument for FEV1/FVC and outcome data. A polygenic score (PGS) analysis was performed to test the causal estimates from kidney function to binary obstructive lung disease outcomes, including chronic obstructive pulmonary disease (COPD), asthma, and FEV1/FVC<70%, and to perform non-linear MR with individual-level UK Biobank data.

RESULTS

The causal estimates by summary-level MR indicated that genetically predicted increased kidney function was significantly associated with increased FEV1/FVC Z scores [10% increase in eGFR, beta 0.055 (0.024, 0.086)]. The PGS for increased eGFR showed a significant association with a reduced risk of FEV1/FVC<70% [OR 0.93 (0.87, 0.99)], COPD [OR 0.93 (0.87, 0.99)] and late-onset (≥50 years old) asthma [OR 0.93 (0.88, 0.99)]. The non-linear MR demonstrated that the causal effect from eGFR to FEV1/FVC was apparent in eGFR ranges lower than 60 mL/min/1.73 m². On the other hand, genetically predicted FEV1/FVC showed nonsignificant causal estimates of eGFR change [beta 0.568% (-0.458, 1.605%)].

CONCLUSION

This study supports kidney function impairment would be a causative factor for obstructive lung disease.

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.

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.

Modulation of the Association of Hypobicarbonatemia and Incident Kidney Failure With Replacement Therapy by Venous pH: A Cohort Study

RATIONALE & OBJECTIVE

Studies showing an association between lower bicarbonate levels and worse kidney disease prognosis have not accounted for the influence of pH. It remains unknown whether this association is consistent across a wide range of blood pH values. This study sought to assess how pH modifies the relationship between hypobicarbonatemia and incident kidney failure requiring kidney replacement therapy (KFRT).

STUDY DESIGN

Retrospective cohort study.

SETTING & PARTICIPANTS

1,058 Japanese patients with estimated glomerular filtration rates<60mL/min/1.73m².

EXPOSURE

Baseline venous bicarbonate levels and venous pH.

OUTCOME

KFRT defined as initiation of kidney replacement therapy (hemodialysis, peritoneal dialysis, and kidney transplantation).

ANALYTICAL APPROACH

Cox proportional hazards model assessing the interaction between baseline bicarbonate levels and venous pH on incident KFRT.

RESULTS

In the lowest bicarbonate quartile (≤21.5 mEq/L), 59% of patients had acidemia (pH<7.32), whereas 38% had venous pH within the normal range and 3% had alkalemia (pH>7.42). During a median follow-up of 3.0 years, 374 patients developed KFRT. Venous pH modified the association between bicarbonate level and rate of KFRT (P for interaction=0.04). After adjustment for potential confounders, including capacity for respiratory compensation, the lowest (vs the highest) bicarbonate quartile was associated with a 2.29-fold (95% CI, 1.10-4.77; P=0.03) higher rate of KFRT among patients with acidemia (pH<7.32). In contrast, among patients without acidemia (pH≥7.32), no significant association was found between bicarbonate level and KFRT. In an exploratory analysis, patients with higher respiratory compensation capacity had a lower rate of KFRT (HR per 0.1 increase in respiratory compensation capacity, 0.90; 95% CI, 0.87-0.94; P<0.001).

LIMITATIONS

Observational study design; blood gas measurements were performed in a select patient population.

CONCLUSIONS

Venous pH modified the association of hypobicarbonatemia with progression of chronic kidney disease to KFRT. Measurement of venous pH may be valuable for identifying patients with chronic kidney disease and hypobicarbonatemia and may inform treatment.

Relationship between pulmonary function and albuminuria in type 2 diabetic patients with preserved renal function

BACKGROUND

Albuminuria is the early manifestation of the pathogenesis of diabetic nephropathy (DN). The current study was to investigate the relationship of pulmonary function with albuminuria in type 2 diabetic patients with preserved renal function to evaluate the role of pulmonary function in the early stage of DN.

METHODS

A total of 326 patients with type 2 diabetes mellitus (T2DM) including 270 without albuminuria and 56 with albuminuria, and 265 non-diabetic patients were enrolled. The patients' general information, and the parameters of pulmonary function, including forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1), FEV1/FVC, total lung capacity (TLC), diffusion capacity for carbon monoxide of lung (DLCO) were compared between T2DM and control groups, as well as T2DM patients with and without albuminuria groups. All pulmonary function parameters were expressed as a percentage of those predicted (%pred). Logistic regression models were constructed to test the association of albuminuria and pulmonary function.

RESULTS

The values of FVC%pred, FEV1%pred, TLC%pred and DLCO%pred were lower, and the proportion of subjects with FVC%pred < 80, FEV1%pred < 80, and DLCOc%pred < 80 was higher in T2DM subjects than controls (all P < 0.05). Subgroup analysis of diabetic patients showed that the values of FVC%pred, FEV1%pred, TLC%pred, and DLCOc%pred (97.18 ± 13.45, 93.95 ± 14.51, 90.64 ± 9.97, 87.27 ± 13.13, respectively) were significantly lower in T2DM subjects with albuminuria than those without albuminuria (103.94 ± 14.12, 99.20 ± 14.25, 93.79 ± 10.36, 92.62 ± 13.45, all P < 0.05). There was a significantly negative correlation between the urine albumin-to-creatinine ratio (UACR) and DLCOc%pred (r = - 0.143, P = 0.010) in spearman linear correlation test. In logistic regression analysis, the FVC%pred (OR 0.965, 95%CI 0.944-0.988), FEV1%pred (OR 0.975, 95%CI 0.954-0.996), and DLCOc%pred (OR 0.974, 95%CI 0.951-0.998) were independently associated with albuminuria after adjustments for smoking index, duration, HbA1c, FBG, and TG.

CONCLUSION

Our results demonstrated albuminuria is associated with a restrictive pulmonary function as well as pulmonary diffusion function in T2DM with preserved renal function, which remind us to be alert of the pulmonary function decline even in the early stage of DN.

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.

Prediction of the mechanisms of action of Shenkang in chronic kidney disease: A network pharmacology study and experimental validation

ETHNOPHARMACOLOGICAL RELEVANCE

Traditional Chinese medicine provides a unique curative treatment of complex chronic diseases, including chronic kidney disease (CKD), which is not effectively treated with the current therapies. The pharmacological mechanisms of Shenkang (SK), a herbal medicine containing rhubarb (Rheum palmatum L. or R. tanguticum Maxim. ex Balf.), red sage (Salvia miltiorrhiza Bunge), safflower (Carthamus tinctorius L.), and astragalus (Astragalus mongholicus Bunge), widely used to treat CKD in China, are still unclear.

AIM OF THE STUDY

In this study, the comprehensive approach used for elucidating the pharmacological mechanisms of SK included the identification of the effective constituents, target prediction and network analysis, by investigating the interacting pathways between these molecules in the context of CKD. These results were validated by performing an in vivo study and by comparison with literature reviews.

MATERIALS AND METHODS

This approach involved the following main steps: first, we constructed a molecular database for SK and screened for active molecules by conducting drug-likeness and drug half-life evaluations; second, we used a weighted ensemble similarity drug-targeting model to accurately identify the direct drug targets of the bioactive constituents; third, we constructed compound-target, target-pathway, and target-disease networks using the Cytoscape 3.2 software and determined the distribution of the targets in tissues and organs according to the BioGPS database. Finally, the resulting drug-target mechanisms were compared with those proposed by previous research on SK and validated in a mouse model of CKD.

RESULTS

By using Network analysis, 88 potential bioactive compounds in the four component herbs of SK and 85 CKD-related targets were identified, including pathways that involve the nuclear factor-κB, mitogen-activated protein kinase, transient receptor potential, and vascular endothelial growth factor, which were categorized as inflammation, proliferation, migration, and permeability modules. The results also included different tissues (kidneys, liver, lungs, and heart) and different disease types (urogenital, metabolic, endocrine, cardiovascular, and immune diseases as well as pathological processes) closely related to CKD. These findings agreed with those reported in the literature. However, our findings with the network pharmacology prediction did not account for all the effects reported for SK found in the literature, such as regulation of the hemodynamics, inhibition of oxidative stress and apoptosis, and the involvement of the transforming growth factor-β/SMAD3, sirtuin/forkhead box protein O (SIRT/FOXO) and B-cell lymphoma-2-associated X protein pathways. The in vivo validation experiment revealed that SK ameliorated CKD through antifibrosis and anti-inflammatory effects, by downregulating the levels of vascular cell adhesion protein 1, vitamin D receptor, cyclooxygenase-2, and matrix metalloproteinase 9 proteins in the unilateral ureteral obstruction mouse model. This was consistent with the predicted target and pathway networks.

CONCLUSIONS

SK exerted a curative effect on CKD and CKD-related diseases by targeting different organs, regulating inflammation and proliferation processes, and inhibiting abnormal extracellular matrix accumulation. Thus, pharmacological network analysis with in vivo validation explained the potential effects and mechanisms of SK in the treatment of CKD. However, these findings need to be further confirmed with clinical studies.

Trajectory and mortality of preserved ratio impaired spirometry: the Rotterdam Study

Preserved ratio impaired spirometry (PRISm) is a heterogeneous condition but its course and disease progression remain to be elucidated. We aimed to examine its prevalence, trajectories and prognosis in the general population.In the Rotterdam Study (population-based prospective cohort) we examined prevalence, trajectories and prognosis of subjects with normal spirometry (controls; forced expiratory volume in 1 s (FEV₁)/forced vital capacity (FVC) ≥0.7, FEV₁  ≥80%), PRISm (FEV₁/FVC ≥0.7, FEV₁ <80%) and chronic obstructive pulmonary disease (COPD) (FEV₁/FVC <0.7) at two study visits. Hazard ratios with 95% confidence intervals for mortality (until December 30, 2018) were adjusted for age, sex, body mass index, current smoking and pack-years.Of 5487 subjects (age 69.1±8.9 years; 7.1% PRISm), 1603 were re-examined after 4.5 years. Of the re-examined PRISm subjects, 15.7% transitioned to normal spirometry and 49.4% to COPD. Median lung function decline was highest in subjects with incident PRISm (FEV₁ -92.8 mL·year^-1, interquartile range (IQR) -131.9- -65.8 mL·year^-1; FVC -93.3 mL·year^-1, IQR -159.8- -49.1 mL·year^-1), but similar in persistent PRISm (FEV₁ -30.2 mL·year^-1, IQR -67.9- -7.5 mL·year^-1; FVC -20.1 mL·year^-1, IQR -47.7-21.7 mL·year^-1) and persistent controls (FEV₁ -39.6 mL·year^-1, IQR -64.3--12.7 mL·year^-1; FVC -20.0 mL·year^-1, IQR -55.4-18.8 mL·year^-1). Of 5459 subjects with informed consent for follow-up, 692 (12.7%) died during 9.3 years (maximum) follow-up: 10.3% of controls, 18.7% of PRISm subjects and 20.8% of COPD subjects. Relative to controls, subjects with PRISm and COPD Global Initiative for Chronic Obstructive Lung Disease (GOLD) 2-4 had increased all-cause mortality (PRISm: HR 1.6, 95% CI 1.2-2.0; COPD GOLD 2-4: HR 1.7, 95% CI 1.4-2.1) and cardiovascular mortality (PRISm: HR 2.8, 95% CI 1.5-5.1; COPD 2-4: HR 2.1, 95% CI 1.2-3.6). Mortality within <1 year was highest in PRISm, with patients often having cardiovascular comorbidities (heart failure or coronary heart disease; 70.0%).PRISm is associated with increased mortality and this population encompasses at least three distinct subsets: one that develops COPD during follow-up, a second with high cardiovascular burden and early mortality, and a third with persistent PRISm and normal age-related lung function decline.

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.

Metabolomics Identifies Novel Blood Biomarkers of Pulmonary Function and COPD in the General Population

Determination of metabolomic signatures of pulmonary function and chronic obstructive pulmonary disease (COPD) in the general population could aid in identification and understanding of early disease processes. Metabolome measurements were performed on serum from 4742 individuals (2354 African-Americans and 1529 European-Americans from the Atherosclerosis Risk in Communities study and 859 Europeans from the Cooperative Health Research in the Region of Augsburg study). We examined 368 metabolites in relation to cross-sectional measures of forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC), their ratio (FEV1/FVC) and COPD using multivariable regression followed by meta-analysis. At a false discovery rate of 0.05, 95 metabolites were associated with FEV1 and 100 with FVC (73 overlapping), including inverse associations with branched-chain amino acids and positive associations with glutamine. Ten metabolites were associated with FEV1/FVC and seventeen with COPD (393 cases). Enriched pathways of amino acid metabolism were identified. Associations with FEV1 and FVC were not driven by individuals with COPD. We identified novel metabolic signatures of pulmonary function and COPD in African and European ancestry populations. These may allow development of biomarkers in the general population of early disease pathogenesis, before pulmonary function has decreased to levels diagnostic for COPD.

Reduced forced vital capacity is independently associated with ethnicity, metabolic factors and respiratory symptoms in a Caribbean population: a cross-sectional study

Background

Relationships between low forced vital capacity (FVC), and morbidity have previously been studied but there are no data available for the Caribbean population. This study assessed the association of low FVC with risk factors, health variables and socioeconomic status in a community-based study of the Trinidad and Tobago population.

Methods

A cross-sectional survey was conducted using the Burden of Obstructive Lung Disease (BOLD) study protocol. Participants aged 40 years and above were selected using a two-stage stratified cluster sampling. Generalized linear models were used to examine associations between FVC and risk factors.

Results

Among the 1104 participants studied a lower post-bronchodilator FVC was independently associated with a large waist circumference (− 172 ml; 95% CI, − 66 to − 278), Indo-Caribbean ethnicity (− 180 ml; 95% CI, − 90 to − 269) and being underweight (− 185 ml; 95% CI, − 40 to − 330). A higher FVC was associated with smoking cannabis (+ 155 ml; 95% CI, + 27 to + 282). Separate analyses to examine associations with health variables indicated that participants with diabetes (p = 0∙041), history of breathlessness (p = 0∙007), and wheeze in the past 12 months (p = 0∙040) also exhibited lower post-bronchodilator FVC.

Conclusion

These findings suggest that low FVC in this Caribbean population is associated with ethnicity, low body mass index (BMI), large waist circumference, chronic respiratory symptoms, and diabetes.

Electronic supplementary material

The online version of this article (10.1186/s12890-019-0823-9) contains supplementary material, which is available to authorized users.

Prevalence and factors associated with self-reported kidney disease among Serbian adults: Results of 2013 National Health Survey

BACKGROUND

Data from developing countries on the rates of kidney disease are scarce. The study aimed to estimate population-based prevalence of self-reported kidney disease (SRKD) in Serbia, describe co-occurrence of chronic diseases/conditions/functional limitations in respondents with SRKD and explore association between SRKD and possible risk factors.

METHODS

We performed a secondary analysis of 2013 National Health Survey data. Data on a total of 14,587 respondents aged 15 years or older were analyzed using means of descriptive statistics, principal component analysis and logistic regression analysis.

RESULTS

Out of all study respondents, 5.6% (95%CI 5.2-6.0) reported presence of kidney disease. Prevalence of all analyzed morbidities and functional limitations was higher in respondents with SRKD, and they had 8 times higher likelihood of being diagnosed with cirrhosis, 6.3 times higher likelihood of being diagnosed with urinary incontinence, more than 3 times higher likelihood of being diagnosed with degenerative disorder of bone and joint system. For cardiovascular diseases we obtained odds ratios (ORs) from 2.27 (95%CI 2.32-3.44) for heart attack to 2.95 (95%CI 2.43-3.57) for coronary heart disease. Number of co-occurrence patterns of kidney and other chronic diseases/conditions varied depending on inclusion of obesity in models. Logistic regression analysis showed that age explained most part of variability in the prevalence of SRKD and in the prevalence of two morbidities in respondents with SRKD, whereas the presence of three or more morbidities were associated with female gender, aging and low education level.

CONCLUSIONS

Our study provided evidence that the presence of kidney disease was significantly associated with socio-demographic, lifestyle characteristics and a number of morbidities in Serbia. There is a need for integrated care and public health interventions, tackling management of NCDs and their risk factors. Detailed well-designed studies, as part of cost-effective preventive approach, are needed for chronic kidney disease screening.

Lung Dysfunction and Mortality in Patients with Chronic Kidney Disease

BACKGROUND/AIMS

Lung dysfunction associates with increased mortality but the impact of chronic kidney disease (CKD) is less clear. We evaluated lung function and its association with mortality among individuals with normal to severely reduced glomerular filtration rate (GFR).

METHODS

404 individuals representing GFR category G1 (n=31; GFR >90 mL/min/1.73 m2), G2 (n=46), G3 (n=33), G4 (n=49) and G5 (n=245; GFR< 15 mL/min/1.73 m2) underwent spirometry yielding lung function indices forced vital capacity (FVC), forced expiratory volume in the first second (FEV1) and peak expiratory flow (PEF). Associations of lung function indices expressed as percentages of predicted values (%FEV1, %FVC and %PEF) with 5-year mortality were analyzed by competing-risk regression models.

RESULTS

The prevalence of obstructive (6% in G1 and 11% in G5) and especially restrictive (9% in G1 to 36% in G5) lung dysfunction increased with declining GFR and with higher comorbidity burden. In patients (n=22) with protein-energy wasting, inflammation and cardiovascular disease, the prevalence of restrictive lung function was 64%. The highest tertiles of % FEV1 and %FVC associated with lower sub-hazard ratios (sHR) for all-cause mortality, 0.49 (95% CI, 0.27-0.88)) and 0.56 (95% CI, 0.32-0.98), and that of %FEV1 also with lower cardiovascular mortality risk (sHR 0.16; 95%CI 0.04-0.69) after adjusting for multiple confounders. Restrictive lung dysfunction (FEV1/FVC ≥ 0.70, and %FVC < 80) associated with increased mortality risk (sHR 1.80, 95%CI, 1.04-3.13) while the association with obstructive lung impairment was not statistically significant.

CONCLUSION

Lung dysfunction and in particular restrictive lung dysfunction associates with degree of renal function impairment and presence of comorbidities, and is an independent predictor of increased mortality in CKD patients.