Proteinuria in COPD patients with and without respiratory failure

Microalbuminuria on admission for acute exacerbation of COPD as a predictor of all-cause mortality and future exacerbations

OBJECTIVES

Microalbuminuria (MAB) is a sensitive biomarker of cardiovascular risk that is directly associated with cardiovascular events and mortality. Recent studies have evaluated the presence of MAB in patients with stable chronic obstructive pulmonary disease (COPD) or hospitalised for acute exacerbation of COPD (AECOPD).

METHODS

We evaluated 320 patients admitted for AECOPD in respiratory medicine departments of two tertiary hospitals. On admission, demographic, clinical and laboratory values and COPD severity were assessed. Patients were evaluated monthly for 1 year, recording new AECOPD and death from any cause.

RESULTS

Patients with documented MAB (urinary albumin excretion of 30-300 mg/24 hours) on admission had worse lung function (forced expiratory volume in 1 s, %) (mean (SD) 34.2 (13.6)% vs 61.5 (16.7)%), higher modified Medical Research Council (3.6 (1.2) vs 2.1 (0.8)), lower 6 min walk test (171 (63) vs 366 (104)) and more hospitalisation days (9 (2.8) vs 4.7 (1.9)) (p<0.001 for all comparisons). MAB was also correlated with Global Initiative for Chronic Obstructive Lung Disease 2020 COPD stages (p<0.001). In multivariate regression analysis, MAB was a significant predictor of longer hospitalisation duration (OR 6.847, 95% CI 3.050 to 15.370, p<0.0001). Twelve-month follow-up revealed that patients with MAB experienced more AECOPDs (4.6 (3.6) vs 2.2 (3.5), p<0.0001) and deaths, n (%) (52 (36.6) vs 14 (7.8), p<0.001). Kaplan-Meier survival curves demonstrated that patients with MAB presented with increased mortality, AECOPD and hospitalisation for AECOPD risk at 1 year (p<0.001 for all comparisons).

CONCLUSIONS

The presence of MAB on admission for AECOPD was associated with more severe COPD and prolonged hospitalisation, as well as with higher rates of AECOPD and mortality risk at 1-year follow-up.

Fractional heat shock protein 27 urine excretion as a short-term predictor in acute exacerbation of chronic obstructive pulmonary disease

Background

Chronic obstructive pulmonary disease (COPD) is a major cause of morbidity and mortality and is characterized by episodes of acute exacerbations. Finding a systemic biomarker that reliably predicts outcome after an acute exacerbation remains a major challenge. Heat shock protein 27 (HSP27) has been previously studied in COPD, however, urine excretion trajectory and prognostic value after an exacerbation is unknown.

Methods

In this retrospective post hoc analysis of a prospective study that included 253 COPD patients who were hospitalized for acute exacerbation, 207 patients were analyzed. Urine and serum were sampled at admission, discharge, and 180 days after discharge; urine excretion trajectory was analyzed and correlated with clinicopathological and survival data.

Results

HSP27 urine excretion increased after an exacerbation episode [1.8% admission, 1.8% discharge, 2.3% 180 days after discharge (P=0.091)]. In severely ill patients (GOLD IV) this course was even more distinct [1.6% admission, 2.1% discharge, 2.8% 180 days after discharge (P=0.007)]. Furthermore, fractional HSP27 urine excretion at discharge was increased in GOLD IV patients (P=0.031). In Kaplan-Meier and univariable Cox proportional hazard models patients with HSP27 urine excretion below 0.845% showed significantly worse survival at 30, 90 and 180 days after discharge. In a multivariable Cox proportional hazard model including established COPD outcome parameters fractional HSP27 urine excretion remained a significant predictor of survival at 30 and 90 days after discharge. Comparing this model to our already published model that includes HSP27 serum concentration we could show that fractional HSP27 urine excretion performs better in short-term survival.

Conclusions

Our findings provide novel information about fractional HSP27 urine excretion trajectory in acute exacerbation of COPD. Fractional HSP27 urine excretion may be significantly reduced during an episode of acute exacerbation in COPD patients and may be used as a predictor of short-term all-cause mortality.

Study of microalbuminuria in chronic obstructive pulmonary disease patients at tertiary care teaching hospital

Background:

Hypoxemia-induced endothelial dysfunction leads to microalbuminuria. Microalbuminuria (MAB) has also been used as a parameter to assess the risk of cardiovascular events in an individual. The aim of this study was to observe the relationship of MAB in patients with chronic obstructive pulmonary disease (COPD) and to correlate MAB with different stages of COPD.

Materials and Methods:

This cross sectional study included 140 patients with COPD selected according to GOLD guidelines based on COPD test assessment score and the number of exacerbations who had smoking pack years of more than 10 years. Urine albumin creatinine ratio (UACR) more than 30 mg/gm represents MAB.

Results:

The UACR increases as the severity of groups of COPD increases with significant differences in UACR values among different COPD groups. Significant differences were seen among various groups of COPD when compared for different clinical parameters such as SPO2, PaO2, PaCO2, pH, and C-reactive protein (CRP). Pearson correlation analysis revealed that UACR was significantly inversely related with PaO2 (r = -0.514, P < 0.001), SPO2 (r = –0.397, P < 0.001) and FEV1 (r = –0.441, P < 0.001) and it was significantly positively correlated with PaCO2 (r = 0.675, P < 0.001).

Conclusion:

This study indicates that there is strong relationship of MAB in patients with COPD and the levels of MAB increase as the severity of COPD increases due to hypoxia and endothelial dysfunction. As MAB is a marker for cardiovascular risk, patients with COPD can be routinely evaluated for the urine test of MAB specially who are at increased risk for cardiovascular events.

Study the association of chronic obstructive pulmonary disease with early endothelial dysfunction and its impact on cardiovascular system by estimating urinary albumin creatinine ratio

Background:

Chronic obstructive pulmonary disease (COPD) attribute to systemic inflammation which is responsible for microalbuminuria reflecting endothelial dysfunction, could be a significant surrogate marker of potential cardiovascular morbidity.

Objective:

The aim of our study was to find out the possible association of COPD with early cardiovascular changes in the form of renal endothelial dysfunction.

Settings and Design:

Case–control, multi-group, cross-sectional hospital-based study was designed and conducted in the Department of Respiratory Medicine of BPS Government Medical College for Women, Khanpur Kalan, Sonipat, Haryana.

Subjects and Methods:

The study included 150 subjects, comprising of three groups with each having 50 subjects: Group 1 – acute exacerbation of COPD, Group 2 – stable COPD patients, Group 3 – asymptomatic smokers. Pulmonary function test, urine albumin creatinine ratio (UACR) and brachio-ankle pulse wave velocity were measured in all the subjects.

Statistical Analysis:

Data were analyzed using SPSS ver 20 (IBM, USA) software. Continuous variables were compared by unpaired Student's t-test while correlation was measured by Pearson correlation test, P < 0.05 was considered statistically significant.

Results:

The mean urine albumin creatinine ratio UACR value in acute exacerbation of COPD (283.30 mg/g; standard deviation [SD] ±871.98) was found significantly higher compare to control subjects (24.17 mg/g; SD ± 32.105;) P = 0.038. Besides this COPD patients with Type 2 respiratory failure having robust positive correlation in between UACR and arterial blood pH (r = 0.559; P = 0.030) while it was inverse and moderate with partial pressure of arterial oxygen (r = −0.470; P = 0.077).

Conclusions:

Acute state of COPD with or without Type 2 respiratory failure is having a significant impact on cardiovascular system in the form of early microvascular changes.

Microalbuminuria in chronic obstructive pulmonary disease

BACKGROUND

Microalbuminuria is an important risk factor for cardiovascular diseases. Microalbuminuria may be seen due to hypoxemia in patients with chronic obstructive pulmonary disease (COPD).

OBJECTIVES

In this study, we investigated prevalence and relationship of microalbuminuria with clinical and physiological parameters in patients with COPD.

METHOD

During the research, 66 consecutive patients with COPD and 40 cases smokers with normal spirometry were included. The urinary albumin creatinin ratio (UACR) was calculated according to previously described formula. The presence of microalbuminuria was defined as UACR being ≥20 in men and ≥30 in women. The severity index of chronic diseases was evaluated by using MCIRS.

RESULTS

The rate of presence of microalbuminuria and UACR were higher in patients with COPD than smokers with normal spirometry. Pearson correlation analysis showed a significant inverse relationship between UACR and PaO2, FEV1%, FVC%. On the other hand, there was a positive relationship between UACR and BODE index. There was a significant relationship between the presence of microalbuminuria with PaO2 and BODE index. In the linear regression model, there was a negative relationship between UARC and PaO2 yet there was a significantly positive relationship between UARC and MCIRS score, BODE index. In the logistic regression model, the presence of microalbuminuria showed significant associations with PaO2, BODE index.

CONCLUSION

Microalbuminuria may be seen in patients with COPD, depending on the severity of disease and hypoxemia. Microalbuminuria in patients with severe COPD should be examined in regular periods for risk of cardiovascular morbidity or mortality.

Clinical validity of plasma and urinary desmosine as biomarkers for chronic obstructive pulmonary disease

BACKGROUND

Although an increased concentration of degraded elastin products in patients with chronic obstructive pulmonary disease (COPD) has been reported for many years, its clinical validity and utility remain uncertain due to technical difficulties, small study groups and the unknown relationship between exacerbation and elastin degradation. The objectives of this study were to determine the validity of urinary and blood total desmosine/isodesmosine in patients with COPD and asthma and to evaluate their relationship to exacerbation status and lung function.

METHODS

Urinary and blood desmosine levels were measured using validated isotopic dilution liquid chromatography-tandem mass spectrometry methods.

RESULTS

390 study participants were recruited from the following groups: healthy volunteers, stable asthma, stable and 'during an exacerbation' COPD. Compared with healthy non-smokers, we found increased urinary or blood desmosine levels in patients with COPD, but no differences in patients with asthma or healthy smokers. The elevation of urinary desmosine levels was associated with the exacerbation status in patients with COPD. Approximately 40% of patients with stable and 'during an exacerbation' COPD showed elevated blood desmosine levels. Blood desmosine levels were strongly associated with age and were negatively correlated with lung diffusing capacity for carbon monoxide.

CONCLUSION

The results suggest that urinary desmosine levels are raised by exacerbations of COPD whereas blood desmosine levels are elevated in a subgroup of patients with stable COPD and reduced lung diffusing capacity. The authors speculate that a raised blood desmosine level may identify patients with increased elastin degradation suitable for targeted therapy. Future prospective studies are required to investigate this hypothesis.

Microalbuminuria and hypoxemia in patients with chronic obstructive pulmonary disease

RATIONALE

Microalbuminuria (MAB), a marker of endovascular dysfunction, is a predictor of cardiovascular events and all-cause mortality in the general population. There is evidence of vascular dysfunction in patients with chronic obstructive pulmonary disease (COPD).

OBJECTIVES

To assess the prevalence and relationship of MAB with clinical and physiological parameters in stable patients with COPD.

METHODS

We measured urinary albumin rate (urinary albumin to creatinine ratio: UACR), smoking history, arterial blood pressure, gas exchange, body mass index, lung function, BODE index (body mass index, airflow obstruction, dyspnea, exercise performance), and comorbidity index in 129 patients with stable COPD and 51 smokers with normal spirometry without known cardiovascular disease. MAB levels were compared between groups. A multivariate analysis was performed to determine the best determinants of MAB levels.

MEASUREMENTS AND MAIN RESULTS

MAB was higher in patients with COPD than in control smokers (8 [5th-95th percentile (P₅₋₉₅), 2.9-113] vs. 4.2 [P₅₋₉₅, 1.8-22.7] mg/g, P < 0.001]). The difference remained significant even after using the standard pathologic threshold (MAB, 30-299 mg/g in women and 20-299 mg/g in men; 24% in patients with COPD vs. 6% in control smokers; P = 0.005). In patients with COPD, there was a negative correlation between Pa(O₂) and MAB (r = -0.40, P < 0.001). Using multivariate analysis, MAB was only associated with the Pa(O₂) (relative risk, 0.934; 95% confidence interval, 0.880-0.992; P < 0.001) and with the systolic arterial blood pressure (relative risk, 1.034; 95% confidence interval, 1.011-1.057; P = 0.003).

CONCLUSIONS

MAB is frequent in patients with COPD and is associated with hypoxemia independent of other cardiovascular risk factors. Further studies are necessary to investigate whether MAB could be an early simple biomarker of cardiovascular compromise in patients with COPD.

Renal failure in high altitude: renal functions, renal pathology and bone mineralization in rats with ablation nephropathy at 1200 m altitude

The effect of altitude on renal failure and bone mineralization is not well known. This topic is studied in a 5/6 nephrectomy rat model. After hemoglobin, creatinine clearance and proteinuria were determined in 28 Wistar rats. Two 5/6 nephrectomy (Nx1-Nx2, n=7 each) and two sham (Sh1-Sh2, n=7 each) groups were formed. The Nx1-Sh1 and Nx2-Sh2 groups were kept at sea level and at 1200 m altitude, respectively. The same analyses were performed after 3 months just before sacrifices in order to harvest kidneys and femurs for histopathologic examination. Hemoglobin, creatinine clearance, and proteinuria were similar in all groups at the onset. Final hemoglobin was higher in Nx2-Sh2, but only Sh2 vs. Sh1 was significant (p=0.001). Creatinine clearance decreased (p=0.001 for Nx1) and proteinuria increased (p=0.002 for Nx1 and p=0.005 for Nx2) after 5/6 nephrectomy, but Nx1 vs. Nx2 was similar. Histopathological changes in the remnant kidneys were prominent, but Nx1 vs. Nx2 was not different. Although the relative osteoid volume increased in Nx groups, only Nx1 vs. Sh1 was different (p=0.006). In conclusion, exposure to 1200 m altitude, compared to the sea level, preserved the creatinine clearance better in 5/6 nephrectomized rats. No change was observed in proteinuria, renal histopathology, and bone mineralization.

Microalbuminuria, von Willebrand factor and fibrinogen levels as markers of the severity in COPD exacerbation

In COPD, the systemic effects of the disease reflect the structural and/or biochemical alterations occurring in the structures or organs other than the lungs in relation to the characteristics of the primary disease. The disorders of endothelial structures due to COPD may lead vascular pathologies, such as ischemic heart disease, stroke, to occur more commonly in those with COPD. On consideration of the fact that the vascular endothelium is a major site in which the systemic effect of the inflammation occurs, should von Willebrand Factor, a clotting factor of endothelium origin, and the plasma level of fibrinogen vary with the severity of the disease in COPD, the variability of arterial blood gas values, and the stability or exacerbation of the disease? Considering the fact that microalbuminuria is an indirect manifestation of the renal endothelial permeability and/or renal perfusion; should there be an association between microalbuminuria and the severity of COPD? Therefore, in order to assess the effect of the systemic inflammation in COPD on the vascular endothelium, we compared the levels of the plasma vWF, fibrinogen, 24-h urine microalbuminuria of those with stable COPD (33 patients) and exacerbation of COPD (26 patients) with those of the controls (16 healthy subjects). The mean age was 63.42 -/+ 10.29, 68.00 -/+ 9.77 and 59.63 -/+ 14.10 years in SCOPD, COPDAE, and CG, respectively. The level of microalbuminuria was found to increase significantly in COPDAE group, compared to that of the controls (P = 0.004). When we investigated the relation between smoking burden and microalbuminuria, vWF, fibrinogen levels, the amount of consumption and positive relationship were found significant. (r = 0.336, P = 0.003 between smoking pack-years and vWF, r = 0.403, P = 0.001 between smoking pack-years and fibrinogen, and r = 0.262, P = 0.02 between smoking pack-years and microalbuminuria). The levels of vWF and fibrinogen are AECOPD > SCOPD > CG, with the highest being in AECOPD, and the difference among the groups was statistically significant. The relationship between the level of hypoxemia and microalbuminuria, fibrinogen and vWF was found to be significant (r = -0.360, P = 0.005 between oxygen saturation and microalbuminuria, r = -0.359, P = 0.005 between the level of PaO(2) and fibrinogen, and r = -0.336, P = 0.009 between PaO(2) and vWF). In conclusion, the levels of plasma vWF, fibrinogen, and microalbuminuria may be helpful in grading the severity of COPD exacerbation. The related increase in these markers may represent a possible pathophysiological mechanism behind the increased vascular morbidity of patients with COPD and detecting indirectly the endothelial dysfunction as a manifestation of systemic outcomes due to COPD and in detecting earlier the cases in which the risk for developing the associated complications are higher. We suggest that further studies are necessary to investigate the impact of antithrombotic treatment on microalbuminuria, plasma vWF and fibrinogen as markers of endothelial dysfunction coexisting COPD exacerbation.