Prevalence of renal and hepatobiliary disease, laboratory abnormalities, and potentially toxic medication exposures among persons with COPD

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.

Impact of Evolutionary Changes in Nonalcoholic Fatty Liver Disease on Lung Function Decline

Background/Aims

A relationship between fatty liver and lung function impairment has been identified, and both are independently associated with metabolic dysfunction. However, the temporal relationship between changes in fatty liver status and lung function and their genome-wide association remain unclear.

Methods

This longitudinal cohort consisted of subjects who received serial health check-ups, including liver ultrasonography and spirometry, for ≥3 years between 2003 and 2015. Lung function decline rates were classified as "slow" and "accelerated" and compared among four different sonographic changes in steatosis status: "normal," "improved," "worsened," and "persistent." A genome-wide association study was conducted between the two groups: normal/improved steatosis with a slow decline in lung function versus worsened/persistent steatosis with an accelerated decline in lung function.

Results

Among 6,149 individuals, the annual rates of decline in forced vital capacity (FVC) and forced expiratory volume measured in the first second of exhalation (FEV₁) were higher in the worsened/persistent steatosis group than in the normal/improved steatosis group. In multivariable analysis, persistent or worsened status of fatty liver was significantly associated with accelerated declines in FVC (persistent status, odds ratio [OR]=1.22, 95% confidence interval [CI]=1.04-1.44; worsened status, OR=1.30, 95% CI=1.12-1.50), while improved status of fatty liver was significantly associated with slow declines in FEV₁ (OR=0.77, 95% CI=0.64-0.92). The PNPLA3 risk gene was most strongly associated with steatosis status change and accelerated declines in FVC (rs12483959, p=2.61×10^-7) and FEV₁ (rs2294433, p=3.69×10^-8).

Conclusions

Regression of fatty liver is related to lung function decline. Continuing efforts to improve fatty liver may preserve lung function, especially for subjects with a high genetic risk.

Features of Kidney Function in Patients With Comorbidity of Arterial Hypertension and Chronic Obstructive Pulmonary Disease

Background and objective Chronic kidney disease (CKD) and hypertension are closely linked in terms of cause and effect. Decreased renal function is usually associated with increased blood pressure, and a steady increase in blood pressure accelerates the decline in renal function. In this study, we aimed to investigate laboratory parameters of renal function - blood creatinine level, urine creatinine level, urea blood level, urine albumin level, and in particular, serum cystatin C level - as early predictors of kidney damage and assess the filtration function of the kidneys based on the glomerular filtration rate (GFR) in patients with isolated arterial hypertension, those with a comorbid pathology of hypertension and chronic obstructive pulmonary disease (COPD). and those with isolated COPD. Materials and methods The study included a total of 101 patients (the final sample consisted of 88 patients) with hypertension and COPD, who were divided into three groups: Group I consisted of 38 patients with hypertension, Group II comprised 27 patients with hypertension and COPD, and Group III was made up of 23 patients with COPD. The average age of patients in groups - presented as mean [standard deviation (SD)] - was as follows - Group I: 55.7 (11.2) years, Group II: 59.3 (9.2) years, and Group III: 57.8 (9.1) years. For statistical data processing, the program Statistics 10 was used. Results The level of blood creatinine - presented as median (Me) and interquartile range (IQR) - was statistically significantly different between the groups, and the values in the three groups were as follows - Group I (patients with hypertension): 88.3 (84.2; 102.7) μmol/l, Group II (patients with comorbid pathology of arterial hypertension and COPD): 99.0 (80.0; 115.0) μmol/l, and Group III (patients with COPD): 84.6 (75.0; 94.2) μmol/l (p=0.008). The highest level was determined in patients with hypertension and comorbid COPD, while the lowest was in the comparison group, in patients with COPD. Urinary creatinine levels were as follows - Group I: 1081.0 (578.0; 1749.0) mg/l, Group II: 1318.5 (1124.0; 1817.0) mg/l, and Group III: 822.0 (625.0; 1320.5) mg/l (p=0.08). Blood urea values were as follows - Group I: 5.7 (5.2; 6.0) mmol/l, Group II: 5.7 (4.9; 6.6) mmol/l, Group III: 5.9 (4.4; 7.7) mmol/l. The calculation of GFR revealed a statistically significant difference between the three groups - Group I: 70.5 (56.0; 83.0) ml/min, Group II: 66.5 (57.0; 77.0) ml/min, and Group III: 81.5 (70.0; 88.0) ml/min (p=0.02). The cystatin C level was 1.16 (1.03; 1.27) mg/l in Group I, 1.3 (1.22; 1.38) mg/l in Group II, and 1.05 (0.96; 1.05) mg/l in Group III. Conclusions In patients of all three groups, there was a decrease in renal filtration function based on the results of creatinine and cystatin C levels. Even in the group of patients with COPD without kidney disease, a decrease in GFR was observed. We noted a negative aggravating effect of COPD on renal function in patients with hypertension, which can be attributed to increased endothelial dysfunction and increased general inflammation in this group of patients.

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.

Identification of Sputum Biomarkers Predictive of Pulmonary Exacerbations in COPD

BACKGROUND

Improved understanding of the pathways associated with airway pathophysiologic features in COPD will identify new predictive biomarkers and novel therapeutic targets.

RESEARCH QUESTION

Which physiologic pathways are altered in the airways of patients with COPD and will predict exacerbations?

STUDY DESIGN AND METHODS

We applied a mass spectrometric panel of metabolomic biomarkers related to mucus hydration and inflammation to sputa from the multicenter Subpopulations and Intermediate Outcome Measures in COPD Study. Biomarkers elevated in sputa from patients with COPD were evaluated for relationships to measures of COPD disease severity and their ability to predict future exacerbations.

RESULTS

Sputum supernatants from 980 patients were analyzed: 77 healthy nonsmokers, 341 smokers with preserved spirometry, and 562 patients with COPD (178 with Global Initiative on Chronic Obstructive Lung Disease [GOLD] stage 1 disease, 303 with GOLD stage 2 disease, and 81 with GOLD stage 3 disease) were analyzed. Biomarkers from multiple pathways were elevated in COPD and correlated with sputum neutrophil counts. Among the most significant analytes (false discovery rate, 0.1) were sialic acid, hypoxanthine, xanthine, methylthioadenosine, adenine, and glutathione. Sialic acid and hypoxanthine were associated strongly with measures of disease severity, and elevation of these biomarkers was associated with shorter time to exacerbation and improved prediction models of future exacerbations.

INTERPRETATION

Biomarker evaluation implicated pathways involved in mucus hydration, adenosine metabolism, methionine salvage, and oxidative stress in COPD airway pathophysiologic characteristics. Therapies that target these pathways may be of benefit in COPD, and a simple model adding sputum-soluble phase biomarkers improves prediction of pulmonary exacerbations.

TRIAL REGISTRY

ClinicalTrials.gov; No.: NCT01969344; URL: www.

CLINICALTRIALS

gov.

Management of the COPD Patient with Comorbidities: An Experts Recommendation Document

Background

Chronic obstructive pulmonary disease (COPD) is associated with multiple comorbidities, which impact negatively on patients and are often underdiagnosed, thus lacking a proper management due to the absence of clear guidelines.

Purpose

To elaborate expert recommendations aimed to help healthcare professionals to provide the right care for treating COPD patients with comorbidities.

Methods

A modified RAND-UCLA appropriateness method consisting of nominal groups to draw up consensus recommendations (6 Spanish experts) and 2-Delphi rounds to validate them (23 Spanish experts) was performed.

Results

A panel of Spanish internal medicine experts reached consensus on 73 recommendations and 81 conclusions on the clinical consequences of the presence of comorbidities. In general, the experts reached consensus on the issues raised with regard to cardiovascular comorbidity and metabolic disorders. Consensus was reached on the use of selective serotonin reuptake inhibitors in cases of depression and the usefulness of referring patients with anxiety to respiratory rehabilitation programmes. The results also showed consensus on the usefulness of investigating the quality of sleep, the treatment of pain with opioids and the evaluation of osteoporosis by lateral chest radiography.

Conclusion

This study provides conclusions and recommendations that are intended to improve the management of the complexity of patients with COPD and important comorbidities, usually excluded from clinical trials.

Major comorbidities lead to the risk of adverse cardiovascular events in chronic obstructive pulmonary disease patients using inhaled long-acting bronchodilators: a case-control study

BACKGROUND

While inhaled bronchodilators reduce symptoms and acute exacerbations of chronic obstructive pulmonary disease (COPD), their use is associated with increased cardiovascular events in some studies. This study investigates the risk of adverse events associated with the use of inhaled bronchodilators in COPD patients with multimorbidity.

METHODS

A case-control study was conducted between January 2015 and December 2017, and patients with spirometry-confirmed diagnosis of COPD (N = 1565) using inhaled long-acting bronchodilators were enrolled. Medical records were reviewed and clinical data, including age, gender, smoking status, major comorbidities, lung function stage, history of exacerbations, bronchodilator regimens, and treatment duration were analyzed. Major adverse cardiovascular events occurring during long-acting bronchodilator use were recorded.

RESULTS

The most common comorbidities were cardiovascular disease (CVD) (53.6%) and chronic kidney disease (CKD) (25.8%). We observed that CVD (odds ratio [OR], 5.77), CKD (OR, 2.02) and history of frequent exacerbations (OR, 2.37) were independent risk factors for cardiovascular events, regardless of the type of bronchodilators use. Moreover, COPD patients with both CKD and CVD had higher risk (6.32-fold) of adverse cardiovascular effects than those with neither comorbidity. Eighty-seven of 1565 (5.56%) COPD patients died during this study period. Of them, 21.8% (19/87) were cardiovascular-related and 73.6% (64/87) patients were respiratory-related mortality. Among COPD patients using long-acting bronchodilators, CKD was the only risk factor to predict cardiovascular events and cardiovascular-related mortality (OR, 4.87; 95% confidence interval [CI], 1.75-13.55].

CONCLUSIONS

COPD patients had higher risk of cardiovascular events were associated with their CVD and/or CKD comorbidities and history of frequent exacerbations, rather than associated with their use of inhaled bronchodilators.

Consequences of chronic kidney disease in chronic obstructive pulmonary disease

Background

The combination of chronic obstructive pulmonary disease (COPD) and chronic kidney disease (CKD) is associated with a higher prevalence of comorbidities and increased mortality. The impact of kidney function on patient-centered outcomes in COPD has not been evaluated.

Methods

Patients from the German COPD and Systemic Consequences - Comorbidities Network (COSYCONET) cohort COPD were analysed. CKD was diagnosed if the estimated glomerular filtration rate (eGFR) measurements were < 60 mL/min/1.73m² at study inclusion and six month later. The effect of CKD, on comorbidities, symptoms [modified British Medical Research Council dyspnoea scale], physical capacity [six-minute walk test, and timed up and go] and St George’s Respiratory Questionnaire were analysed. Restricted cubic spline models were used to evaluate a nonlinear relationship between eGFR with patient-centered outcomes, cox survival analysis was applied to evaluate mortality.

Results

2274 patients were analysed, with CKD diagnosed in 161 (7.1%). Spline models adjusted for age, gender, BMI, FEV₁ and cardiovascular comorbidities revealed independent associations between eGFR with modified British Medical Research Council dyspnoea scale, St George’s Respiratory Questionnaire, (p < 0.001 and p = 0.011), six-minute walk test (p = 0.015) and timed up and go (p < 0.001). CKD was associated with increased mortality, independently from for other cardiovascular comorbidities (hazard ratio 2.3; p < 0.001).

Conclusion

These data show that CKD is a relevant comorbidity in COPD patients which impacts on patient-centered outcomes and mortality.

Trial registration

NCT01245933

Electronic supplementary material

The online version of this article (10.1186/s12931-019-1107-x) contains supplementary material, which is available to authorized users.

Chronic Obstructive Pulmonary Disease and Hepatitis C

Chronic obstructive pulmonary disease (COPD) is a preventable, treatable disease with significant extrapulmonary manifestations that could affect negatively its course in some patients. Hepatitis C virus infection (HCV), on the other hand, is associated with a number of extrahepatic manifestations. COPD patients have increased prevalence of HCV and patients with HCV, especially older ones, have increased prevalence and faster progression of COPD. HCV infection exerts long-term effects on lung tissue and is an additional risk factor for the development of COPD. The presence of HCV is associated with an accelerated loss of lung function in COPD patients, especially in current smokers. COPD could represent extrahepatic manifestation associated with HCV infection. The aim of this article was to review the literature on prevalence of HCV in COPD and vice versa, pathogenetic link and the consequences of their mutual existence.

Association between non-alcoholic fatty liver disease and decreased lung function in adults: A systematic review and meta-analysis

AIM

] and forced vital capacity [FVC]).

METHODS

We searched publication databases using predefined keywords to identify studies (published up to October 4, 2018), in which NAFLD was diagnosed by imaging or biochemistry (no studies with biopsy-proven NAFLD were available). Data from selected studies were extracted, and meta-analysis was performed using random-effects modelling.

RESULTS

and FVC at baseline were also independently associated with a ∼ 15% increased risk of incident NAFLD (n = 1 study in Korean individuals). Subgroup analyses did not materially modify these findings.

CONCLUSIONS

and FVC in Asian and United States adults, and such small, but significant, reductions of lung volumes at baseline may be also associated with increased NAFLD incidence in Asian individuals. Further research is needed to better elucidate the link between NAFLD and impaired lung volumes.

Revealing Methodological Challenges in Chronic Obstructive Pulmonary Disease Studies Assessing Comorbidities: A Narrative Review

Beyond respiratory impairment, patients with chronic obstructive pulmonary disease (COPD) often suffer from comorbidities which are associated with worse health status, higher health care costs and worse prognosis. Reported prevalences of comorbidities largely differ between studies which might be explained by different assessment methods (objective assessment, self-reported assessment, or assessment by medical records), heterogeneous study populations, inappropriate control groups, incomparable methodologies, etc. This narrative review demonstrates and further evaluates the variability in prevalence of several comorbidities in patients with COPD and control individuals and discusses several shortcomings and pitfalls which need to be considered when interpreting comorbidity data. Like in other chronic organ diseases, the accurate diagnosis and integrated management of comorbidities is a key for outcome in COPD. This review highlights that there is a need to move from the starting point of an established index disease towards the concept of the development of multimorbidity in the elderly including COPD as an important and highly prevalent pulmonary component.

Relationship between obstructive lung disease and non-alcoholic fatty liver disease in the Korean population: Korea National Health and Nutrition Examination Survey, 2007-2010

Purpose

Previous studies have shown that progressive forms of non-alcoholic fatty liver disease (NAFLD) occur frequently in patients with obstructive lung disease (OLD). However, few studies have written about this relationship. This study aimed to investigate the relationship between OLD and NAFLD.

Subjects and methods

The Korea National Health and Nutrition Examination Survey is a national population-based, cross-sectional surveillance program that was initiated to assess the health and nutritional status of the Korean population. From 2007 to 2010, 11,738 subjects were enrolled. The subjects were defined as having NAFLD when they had scores higher than -0.640 in a NAFLD liver fat score prediction model, which was a previously validated prediction score. Individuals with forced expiratory volume in one second/forced vital capacity <0.7 were considered to have OLD. The subjects were divided into non-OLD and OLD groups and non-NAFLD and NAFLD groups. All analyses were performed using sample weighting using the complex samples plan.

Results

The prevalences of NAFLD and OLD were 30.2% and 8.9%, respectively. Although not statistically significant, subjects in the NAFLD group involved a higher tendency of having OLD than did those in the non-NAFLD group (8.5% vs 10.0%, respectively, P=0.060). Subjects with OLD showed a higher tendency to have NAFLD than non-OLD subjects (30.0% vs 33.7%, respectively, P=0.060). NAFLD subjects were at higher odds of OLD (odds ratio=1.334; 95% confidence interval=1.108-1.607, P=0.002) than non-NAFLD subjects, after adjusting for age, sex, and smoking history. OLD subjects were at higher odds of NAFLD (odds ratio=1.556; 95% confidence interval=1.288-1.879, P<0.001) than non-OLD subjects, after adjusting for age, sex, and smoking history.

Conclusion

This study showed that NAFLD is related to OLD. Clinicians should be aware of possible liver comorbidities in OLD patients and that extrahepatic disease in NAFLD patients may vary more than previously thought.

Determination of colistin-related nephrotoxicity and risk factors in intensive care unit

OBJECTIVE:

Colistin is a cationic polypeptide antibiotic with a cyclic structure that belongs to the polymyxin group. It was banned from clinical use because of its significant renal side effects, such as nephrotoxicity. However, the administration of colistin has recently been initiated again in the treatment of multi-drug resistant pathogens, such as Acinetobacter baumannii and Pseudomonas aeruginosa. Nephrotoxicity and neurotoxicity are the main problems encountered in the clinical use of polymyxins. The aim of this study was to determine the frequency and risk factors of colistin-related nephrotoxicity in the adult intensive care unit (ICU).

METHODS:

In this study, a retrospective review of patients who were followed up between January 1 and December 31, 2016 and who received colistin treatment in the adult ICU was performed. Retrospective computer records of age, sex, site of infection and microorganism breeding, daily creatinine values, and additional diseases were recorded and examined. Nephrotoxicity was assessed using the Risk, Injury, Failure, Loss, and End-stage kidney disease criteria.

RESULTS:

A total of 48 patients were included in the study. Of these, 50% were male. The mean age of the patients with nephrotoxicity was 59.73±22.38 years, and the mean age of those without nephrotoxicity was 58.00±22.39 years. A. baumanni was observed to be the causative microorganism in all patients, and the most frequent infection was pneumonia. Nephrotoxicity was investigated in 54.2% (n=26) of the patients. In this study, when risk factors for nephrotoxicity were evaluated, it was found that the presence of nephrotoxicity was greater in cases with chronic obstructive pulmonary disease, malignancy, or abdominal surgery in patients older than 65 years. In addition, mortality was greater in those who developed nephrotoxicity, although it was not statistically significant.

CONCLUSION:

In this study, the rate of nephrotoxicity was 54.2% in patients who received colistin in the ICU. Therefore, patients in the adult ICU receiving colistin therapy should be carefully monitored for the development of nephrotoxicity as a side effect.

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

BACKGROUND

Reduced lung function is associated with clinical outcomes such as cardiovascular disease. However, little is known about its association with incident end-stage renal disease (ESRD) and chronic kidney disease (CKD).

STUDY DESIGN

Prospective cohort study.

SETTING & PARTICIPANTS

14,946 participants aged 45 to 64 years at baseline (1987-1989) in the Atherosclerosis Risk in Communities (ARIC) Study (45.0% men and 25.2% black), with follow-up through 2012.

PREDICTORS

Race- and sex-specific quartiles of percent-predicted forced vital capacity (FVC) and the proportion of forced expiratory volume in 1 second of expiration to FVC (FEV1/FVC) at baseline determined with spirometry.

OUTCOMES

Incident ESRD (defined here as renal replacement therapy or death due to CKD) as the primary outcome and incident CKD (defined here as ESRD, ≥25% decline in estimated glomerular filtration rate to a level <60mL/min/1.73m2, or CKD-related hospitalizations/deaths) as the secondary outcome.

RESULTS

During a median follow-up of 23.6 years, 526 (3.5%) participants developed ESRD. After adjusting for potential confounders, the cause-specific HR of incident ESRD for the lowest (vs highest) quartile was 1.72 (95% CI, 1.31-2.26) for percent-predicted FVC and 1.33 (95% CI, 1.03-1.73) for FEV1/FVC. Compared to a high-normal lung function pattern, a mixed pattern (ie, percent-predicted FVC<80% and FEV1/FVC<70%; 3.4% of participants) demonstrated the highest adjusted cause-specific HR of ESRD at 2.28 (95% CI, 1.50-3.45), followed by the restrictive pattern (ie, percent-predicted FVC<80% and FEV1/FVC≥70%; 4.8% of participants) at 2.03 (95% CI, 1.47-2.81), obstructive pattern (ie, percent-predicted FVC≥80% and FEV1/FVC<70%; 18.9% of participants) at 1.47 (95% CI, 1.09-1.99), and low-normal pattern (ie, percent-predicted FVC 80%-<100% and FEV1/FVC≥70%, or percent-predicted FVC≥80% and FEV1/FVC 70%-<75%; 44.3% of participants) at 1.21 (95% CI, 0.94-1.55). Similar associations were seen with incident CKD.

LIMITATIONS

Limited number of participants with moderate/severe lung dysfunction and spirometry only at baseline.

CONCLUSIONS

Reduced lung function, particularly lower percent-predicted FVC, is independently associated with CKD progression. Our findings suggest a potential pathophysiologic contribution of reduced lung function to the development of CKD and a need for monitoring kidney function in persons with reduced lung function.

Impact of chronic kidney disease among Korean adults with chronic obstructive pulmonary disease

PURPOSE

Chronic kidney disease (CKD) is an emerging issue in patients with chronic obstructive pulmonary disease (COPD). In COPD, loss of muscle mass is relatively common finding, and diagnosis of CKD should be based on measured or estimated GFR (Cavailles et al. Eur Respir Rev 22:454-475, 2013; Gosker et al. Am J Clin Nutr 71:1033-1047, 2000; Delanaye and Mariat Nat Rev Nephrol 9:513-522, 2013). We aimed to determine the prevalence and impact of CKD, defined by using chronic kidney disease epidemiology collaboration (CKD-EPI) equation, in COPD patients.

METHODS

This study analyzed data of 3393 adults 40 years of age or older who completed pulmonary function tests in the fifth Korea National Health and Nutritional Examination Survey 2012. Participants with normal lung function (NLF) and COPD were included. CKD was defined as an eGFR <60 mL/min/1.73 m². Multivariate logistic regression analysis was performed to evaluate the relationship between CKD and COPD.

RESULTS

Among 3393 participants, 528 (15.6%) were classified as COPD. The prevalence values of participants with eGFR level ≥90, 60-90, and <60 mL/min/1.73 m² were 54.1, 43.6, and 2.2% in those with NLF and 39.8, 51.5, and 8.7% in those with COPD (p = 0.000). We analyzed the relationship between COPD and all factors that had a statistically significant association with COPD. The significant factors were older age, lower education, BMI, pulmonary tuberculosis, current bronchial asthma, smoking, and CKD.

CONCLUSIONS

In a Korean population ≥40 years old, the prevalence of participants with COPD is 15.6%. CKD is an independent risk factor for COPD. In addition to CKD, older age, lower education, BMI, pulmonary tuberculosis, current bronchial asthma, and smoking are significantly associated with COPD.

Prevalence of chronic kidney disease in patients with chronic obstructive pulmonary disease: a systematic review and meta-analysis

Background

The incidence and prevalence of chronic kidney disease (CKD) continue to rise worldwide. Increasing age, diabetes, hypertension, and cigarette smoking are well-recognized risk factors for CKD. Chronic obstructive pulmonary disease (COPD) is characterized by chronic airway inflammation leading to airway obstruction and parenchymal lung destruction. Due to some of the common pathogenic mechanisms, COPD has been associated with increased prevalence of CKD.

Methods

Systematic review of medical literature reporting the incidence and prevalence of CKD in patients with COPD using the Cochrane Collaboration Methodology, and conduct meta-analysis to study the cumulative effect of the eligible studies. We searched Medline via Ovid, PubMed, EMBASE and ISI Web of Science databases from 1950 through May, 2016. We included prospective and retrospective observational studies that reported the prevalence of CKD in patients with COPD.

Results

Our search resulted in 19 eligible studies of which 9 have been included in the meta-analysis. The definition of CKD was uniform across all the studies included in analysis. COPD was found to be associated with CKD in the included epidemiological studies conducted in many countries. Our meta-analysis showed that COPD was found to be associated with a significantly increased prevalence of CKD (Odds Ratio [OR] = 2.20; 95% Confidence Interval [CI] 1.83, 2.65). Study limitations: Studies included are observational studies. However, given the nature of our research question there is no possibility to perform a randomized control trial.

Conclusions

Patients with COPD have increased odds of developing CKD. Future research should investigate the pathophysiological mechanism behind this association, which may lead to better outcomes.

Electronic supplementary material

The online version of this article (doi:10.1186/s12890-016-0315-0) contains supplementary material, which is available to authorized users.

Prevalence and burden of comorbidities in Chronic Obstructive Pulmonary Disease

The classical definition of Chronic Obstructive Pulmonary Disease (COPD) as a lung condition characterized by irreversible airway obstruction is outdated. The systemic involvement in patients with COPD, as well as the interactions between COPD and its comorbidities, justify the description of chronic systemic inflammatory syndrome. The pathogenesis of COPD is closely linked with aging, as well as with cardiovascular, endocrine, musculoskeletal, renal, and gastrointestinal pathologies, decreasing the quality of life of patients with COPD and, furthermore, complicating the management of the disease. The most frequently described comorbidities include skeletal muscle wasting, cachexia (loss of fat-free mass), lung cancer (small cell or non-small cell), pulmonary hypertension, ischemic heart disease, hyperlipidemia, congestive heart failure, normocytic anemia, diabetes, metabolic syndrome, osteoporosis, obstructive sleep apnea, depression, and arthritis. These complex interactions are based on chronic low-grade systemic inflammation, chronic hypoxia, and multiple common predisposing factors, and are currently under intense research. This review article is an overview of the comorbidities of COPD, as well as their interaction and influence on mutual disease progression, prognosis, and quality of life.

Obstructive and Restrictive Lung Function Measures and CKD: National Health and Nutrition Examination Survey (NHANES) 2007-2012

BACKGROUND

Prevalence and factors associated with obstructive and restrictive lung function in people with chronic kidney disease (CKD) are unknown.

STUDY DESIGN

Cross-sectional and longitudinal analyses.

SETTING & PARTICIPANTS

Participants aged 40 to 79 years from NHANES (National Health and Nutrition Examination Survey) 2007 to 2012 who underwent spirometry testing.

PREDICTOR

CKD (estimated glomerular filtration rate [eGFR] >15-<60mL/min/1.73m(2) or urinary albumin-creatinine ratio ≥ 30mg/g).

OUTCOMES

Restrictive lung function (defined as FEV1/FVC≥0.70 and baseline FVC<80% predicted), obstructive lung function (defined as FEV1/FVC<0.70 based on postbronchodilator spirometric results), and mortality data (available for 2007-2008 and 2009-2010 survey periods).

RESULTS

7,610 participants (CKD=1,338; non-CKD=6,272) were included. Prevalences of obstructive lung function adjusted to the mean age of 55 years and 50% men in the CKD and non-CKD groups were 15.6% and 13.3%, respectively (P=0.2). Similarly, adjusted prevalences of restrictive lung function in the CKD and non-CKD groups were 9.8% and 6.7%, respectively (P=0.01). Presence of albumin-creatinine ratio ≥ 30mg/g was associated with obstructive (OR, 1.42; 95% CI, 1.07-1.88) and restrictive lung function (OR, 1.43; 95% CI, 1.01-2.03) in the entire study cohort. eGFR<60mL/min/1.73m(2) was associated with higher odds of obstructive lung function. In a multivariable Cox model, age (HR, 1.07; 95% CI, 1.04-1.11) and presence of obstructive lung function (HR, 2.68; 95% CI, 1.80-3.97), but not CKD measures, were associated with death.

LIMITATIONS

Small proportion of participants with advanced kidney disease.

CONCLUSIONS

In a representative sample of US adults, impaired lung function is common in those with and without CKD. Albuminuria was independently associated with both obstructive and restrictive lung function, and eGFR<60mL/min/1.73m(2) was associated with higher odds of obstructive lung function. Older age and obstructive lung function were associated with higher likelihood of death. Further studies examining the burden of lung disease in advanced CKD are needed.

Impact of renal dysfunction on in-hospital mortality of patients with severe chronic obstructive pulmonary disease: a single-center Italian study

BACKGROUND

We conducted a study, based on discharge hospital sheets [International Classification of Diseases, 9th Revision, Clinical Modification (ICD-9-CM)], in order to evaluate the relationship between chronic kidney disease (CKD), acute kidney injury (AKI), multi-morbidity, and in-hospital mortality (IHM).

METHODS

This study included all hospital admissions for chronic obstructive pulmonary disease (COPD) exacerbations between January 1, 2000, and December 31, 2013, recorded in the database of the University Hospital St. Anna of Ferrara. Age, sex, and diagnosis of CKD and AKI were collected, and Charlson comorbidity index (CCI) was calculated by ICD-9-CM codes. IHM was our main outcome.

RESULTS

We analyzed 7073 subjects with COPD exacerbation; they were more frequently male (56.9 vs 43.1 %), and mean age was 76.7 ± 9.8 years. Diagnosis of CKD was present in 771 patients (10.9 %), while AKI was diagnosed in 354 cases (5 %). A total of 554 patients (7.8 %) died during hospitalization, and LOS was 10.3 ± 11.2 days (median 8 days); the CCI corrected for CKD was 2.30 ± 1.65. Univariate analysis showed that IHM group had higher age (81.2 ± 7.9 vs 76.3 ± 9.9 years, p < 0.001), CCI (2.61 ± 2.21 vs 2.28 ± 1.62, p = 0.001), and LOS (11.1 ± 15.1 vs 10.3 ± 10.8 days, p = 0.001) and developed AKI more frequently (16.6 vs 4 %, p < 0.001) than survivors. Multivariate logistic regression analysis showed an independent association of IHM with age (OR 1.063; 95 % CI 1.050-1.075, p < 0.001), male sex (OR 1.229; 95 % CI 1.016-1.486, p = 0.033), logCCI (OR 2.051; 95 % CI 1.419-2.964, p < 0.001), and AKI (OR 3.849; 95 % CI 2.874-5.155, p < 0.001).

CONCLUSIONS

Acute kidney injury (AKI) represents a very important predictive factor of IHM in male older adult with multi-morbidity admitted because of COPD exacerbations.

Economic Burden of COPD in the Presence of Comorbidities

BACKGROUND

The morbidity and mortality associated with COPD exacts a considerable economic burden. Comorbidities in COPD are associated with poor health outcomes and increased costs. Our objective was to assess the impact of comorbidities on COPD-associated costs in a large administrative claims dataset.

METHODS

This was a retrospective observational study of data from the Truven Health MarketScan Commercial Claims and Encounters and the MarketScan Medicare Supplemental Databases from January 1, 2009, to September 30, 2012. Resource consumption was measured from the index date (date of first occurrence of non-rule-out COPD diagnosis) to 360 days after the index date. Resource use (all-cause and disease-specific [ie, COPD- or asthma-related] ED visits, hospitalizations, office visits, other outpatient visits, and total length of hospital stay) and health-care costs (all-cause and disease-specific costs for ED visits, hospitalizations, office visits, and other outpatient visits and medical, prescription, and total health-care costs) were assessed. Generalized linear models were used to evaluate the impact of comorbidities on total health-care costs, adjusting for age, sex, geographic location, baseline health-care use, employment status, and index COPD medication.

RESULTS

Among 183,681 patients with COPD, the most common comorbidities were cardiovascular disease (34.8%), diabetes (22.8%), asthma (14.7%), and anemia (14.2%). Most patients (52.8%) had one or two comorbidities of interest. The average all-cause total health-care costs from the index date to 360 days after the index date were highest for patients with chronic kidney disease ($41,288) and anemia ($38,870). The impact on total health-care costs was greatest for anemia ($10,762 more, on average, than a patient with COPD without anemia).

CONCLUSIONS

Our analysis demonstrated that high resource use and costs were associated with COPD and multiple comorbidities.

Managing comorbidities in COPD

Chronic obstructive pulmonary disease (COPD) is a leading cause of morbidity and mortality worldwide. Age and smoking are common risk factors for COPD and other illnesses, often leading COPD patients to demonstrate multiple coexisting comorbidities. COPD exacerbations and comorbidities contribute to the overall severity in individual patients. Clinical trials investigating the treatment of COPD routinely exclude patients with multiple comorbidities or advanced age. Clinical practice guidelines for a specific disease do not usually address comorbidities in their recommendations. However, the management and the medical intervention in COPD patients with comorbidities need a holistic approach that is not clearly established worldwide. This holistic approach should include the specific burden of each comorbidity in the COPD severity classification scale. Further, the pharmacological and nonpharmacological management should also include optimal interventions and risk factor modifications simultaneously for all diseases. All health care specialists in COPD management need to work together with professionals specialized in the management of the other major chronic diseases in order to provide a multidisciplinary approach to COPD patients with multiple diseases. In this review, we focus on the major comorbidities that affect COPD patients. We present an overview of the problems faced, the reasons and risk factors for the most commonly encountered comorbidities, and the burden on health care costs. We also provide a rationale for approaching the therapeutic options of the COPD patient afflicted by comorbidity.

Anaemia in chronic obstructive pulmonary disease: an insight into its prevalence and pathophysiology

Chronic obstructive pulmonary disease (COPD) is a major health problem, with increasing morbidity and mortality. There is a growing literature regarding the extra-pulmonary manifestations of COPD, which can have a significant impact on symptom burden and disease progression. Anaemia is one of the more recently identified co-morbidities, with a prevalence that varies between 4.9% and 38% depending on patient characteristics and the diagnostic criteria used. Systemic inflammation seems to be an important factor for its establishment and repeated bursts of inflammatory mediators during COPD exacerbations could further inhibit erythropoiesis. However, renal impairment, malnutrition, low testosterone levels, growth hormone level abnormalities, oxygen supplementation, theophylline treatment, inhibition of angiotensin-converting enzyme and aging itself are additional factors that could be associated with the development of anaemia. The present review evaluates the published literature on the prevalence and significance of anaemia in COPD. Moreover, it attempts to elucidate the reasons for the high variability reported and investigates the complex pathophysiology underlying the development of anaemia in these patients.

Renal and hepatobiliary dysfunction in chronic obstructive pulmonary disease

PURPOSE OF REVIEW

This review examines the associations between chronic obstructive pulmonary disease (COPD) and renal and hepatobiliary diseases, with emphasis on the epidemiology and clinical outcomes, along with current information on pathophysiologic mechanisms and risk factors.

RECENT FINDINGS

Glomerular filtration, sodium retention, and waste excretion are abnormal in COPD and sensitive to hypoxemia and hypercarbia, but variably responsive to oxygen administration and angiotensin-converting enzyme inhibition. Newer concepts about the role of hypoxia on the progression of chronic renal failure, and improved understanding about the relationships between COPD, decreased arterial compliance, and renal glomerular injury, are bringing new insights about potential causal mechanisms between COPD and kidney diseases. Other than the well known relationship between cor pulmonale and passive liver congestion, little was known about the relationships between COPD and liver diseases until recent population-based surveys demonstrated that COPD patients have substantially elevated risk for specific hepatobiliary system diseases.

SUMMARY

Renal complications of COPD are common especially among patients with hypoxemia and hypercarbia. Renal-endocrine mechanisms, tissue hypoxia, and vascular rigidity have roles in the pathophysiology, but understanding of causal relationships is not precise. COPD patients have increased risk for hepatobiliary diseases and asymptomatic elevations of hepatic transaminases, which fortunately have relatively low prevalence.