Claudia Torino

Pulmonary Congestion Predicts Cardiac Events and Mortality in ESRD

Pulmonary congestion is highly prevalent and often asymptomatic among patients with ESRD treated with hemodialysis, but whether its presence predicts clinical outcomes is unknown. Here, we tested the prognostic value of extravascular lung water measured by a simple, well validated ultrasound B-lines score (BL-US) in a multicenter study that enrolled 392 hemodialysis patients. We detected moderate-to-severe lung congestion in 45% and very severe congestion in 14% of the patients. Among those patients with moderate-to-severe lung congestion, 71% were asymptomatic or presented slight symptoms of heart failure. Compared with those patients having mild or no congestion, patients with very severe congestion had a 4.2-fold risk of death (HR=4.20, 95% CI=2.45-7.23) and a 3.2-fold risk of cardiac events (HR=3.20, 95% CI=1.75-5.88) adjusted for NYHA class and other risk factors. Including the degree of pulmonary congestion in the model significantly improved the risk reclassification for cardiac events by 10% (P<0.015). In summary, lung ultrasound can detect asymptomatic pulmonary congestion in hemodialysis patients, and the resulting BL-US score is a strong, independent predictor of death and cardiac events in this population.

Assessment of obesity in chronic kidney disease: what is the best measure?

Purpose of reviewObesity is a major driver of the current epidemic of chronic kidney disease (CKD), but metrics of obesity in the CKD population have been studied sparsely. This review updates knowledge on this issue. Recent findingsMeasures of abdominal obesity, waist circumference and waist-to-hip ratio (WHR), are better predictors than BMI of the high risk of mortality in predialysis and dialysis patients and waist circumference reliably reflects visceral fat in CKD patients. Skinfold thickness and WHR are superior to BMI for the classification of obesity in CKD patients. Multifrequency body impedance analysis (BIA) provides valid estimates of fat mass in hemodialysis patients. SummarySkinfold thickness,WHR and multifrequency BIA are superior to BMI for measuring body fat in CKD patients and measures of abdominal obesity are stronger predictors of adverse clinical outcomes than the BMI. These metrics should be preferentially applied for the assessment of obesity in CKD, but it remains unproven that these techniques offer real advantages over the BMI in clinical practice in CKD patients.

Chest ultrasound and hidden lung congestion in peritoneal dialysis patients

BACKGROUND Chest ultrasound (US) is a non-invasive well-validated technique for estimating extravascular lung water (LW) in patients with heart diseases and in end-stage renal disease. We systematically applied this technique to the whole peritoneal dialysis (PD) population of five dialysis units. METHODS We studied the cross-sectional association between LW, echocardiographic parameters, clinical [pedal oedema, New York Heart Association (NYHA) class] and bioelectrical impedance analysis (BIA) markers of volume status in 88 PD patients. RESULTS Moderate to severe lung congestion was evident in 41 (46%) patients. Ejection fraction was the echocardiographic parameter with the strongest independent association with LW (r = -0.40 P = 0.002). Oedema did not associate with LW on univariate and multivariate analysis. NYHA class was slightly associated with LW (r = 0.21 P = 0.05). Among patients with severe lung congestion, only 27% had pedal oedema and the majority (57%) had no dyspnoea (NYHA Class I). Similarly, the prevalence of patients with BIA, evidence of volume excess was small (11%) and not significantly different (P = 0.79) from that observed in patients with mild or no congestion (9%). CONCLUSIONS In PD patients, LW by chest US reveals moderate to severe lung congestion in a significant proportion of asymptomatic patients. Intervention studies are necessary to prove the usefulness of chest US for optimizing the control of fluid excess in PD patients.

Asymptomatic Pulmonary Congestion and Physical Functioning in Hemodialysis Patients

BACKGROUND AND OBJECTIVES Poor physical performance is common in patients with kidney failure on dialysis (CKD-5D). Whether lung congestion, a predictable consequence of cardiomyopathy and fluid overload, may contribute to the low physical performance of CKD-5D patients has not been investigated in hemodialysis patients. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS This study investigated the relationship between the physical functioning scale of the Kidney Disease Quality of Life Short Form and a validated ultrasonographic measure of lung water in a multicenter survey of 270 hemodialysis patients studied between 2009 and 2010. RESULTS Moderate to severe lung congestion by lung ultrasonography was observed in 156 (58%) patients; among these, 60 (38%) were asymptomatic (New York Heart Association [NYHA] class I). On univariate analysis, physical functioning was inversely associated with lung water in the whole group (r=-0.22; P<0.001) and in the subgroup of asymptomatic patients (r=-0.40; P=0.002). Age (r=-0.45; P<0.001) and past cardiovascular events (r=-0.22; P=0.002) were also inversely associated with physical functioning, whereas albumin (r=0.23; P<0.001) was directly associated with the same parameter. NYHA class correlated strongly with physical functioning (r=-0.52; P<0.001). In a multiple regression analysis, both NYHA class and lung water maintained an independent association with physical functioning, whereas albumin and background cardiovascular events failed to independently relate with the same outcome. CONCLUSIONS Symptomatic and asymptomatic lung congestion is associated with poor physical functioning in hemodialysis patients. This association is independent of NYHA, suggesting that this measurement and NYHA may have complementary value to explain the variability in physical performance in hemodialysis patients.

Exercise in Patients on Dialysis: A Multicenter, Randomized Clinical Trial.

Previous studies have suggested the benefits of physical exercise for patients on dialysis. We conducted the Exercise Introduction to Enhance Performance in Dialysis trial, a 6-month randomized, multicenter trial to test whether a simple, personalized walking exercise program at home, managed by dialysis staff, improves functional status in adult patients on dialysis. The main study outcomes included change in physical performance at 6 months, assessed by the 6-minute walking test and the five times sit-to-stand test, and in quality of life, assessed by the Kidney Disease Quality of Life Short Form (KDQOL-SF) questionnaire. We randomized 296 patients to normal physical activity (control; n=145) or walking exercise (n=151); 227 patients (exercise n=104; control n=123) repeated the 6-month evaluations. The distance covered during the 6-minute walking test improved in the exercise group (mean distance±SD: baseline, 328±96 m; 6 months, 367±113 m) but not in the control group (baseline, 321±107 m; 6 months, 324±116 m; P<0.001 between groups). Similarly, the five times sit-to-stand test time improved in the exercise group (mean time±SD: baseline, 20.5±6.0 seconds; 6 months, 18.2±5.7 seconds) but not in the control group (baseline, 20.9±5.8 seconds; 6 months, 20.2±6.4 seconds; P=0.001 between groups). The cognitive function score (P=0.04) and quality of social interaction score (P=0.01) in the kidney disease component of the KDQOL-SF improved significantly in the exercise arm compared with the control arm. Hence, a simple, personalized, home-based, low-intensity exercise program managed by dialysis staff may improve physical performance and quality of life in patients on dialysis.

The Agreement between Auscultation and Lung Ultrasound in Hemodialysis Patients: The LUST Study

BACKGROUND AND OBJECTIVES Accumulation of fluid in the lung is the most concerning sequela of volume expansion in patients with ESRD. Lung auscultation is recommended to detect and monitor pulmonary congestion, but its reliability in ESRD is unknown. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS In a subproject of the ongoing Lung Water by Ultra-Sound Guided Treatment to Prevent Death and Cardiovascular Complications in High Risk ESRD Patients with Cardiomyopathy Trial, we compared a lung ultrasound-guided ultrafiltration prescription policy versus standard care in high-risk patients on hemodialysis. The reliability of peripheral edema was tested as well. This study was on the basis of 1106 pre- and postdialysis lung ultrasound studies (in 79 patients) simultaneous with standardized lung auscultation (crackles at the lung bases) and quantification of peripheral edema. RESULTS Lung congestion by crackles, edema, or a combination thereof poorly reflected the severity of congestion as detected by ultrasound B lines in various analyses, including standard regression analysis weighting for repeated measures in individual patients (shared variance of 12% and 4% for crackles and edema, respectively) and κ-statistics (κ ranging from 0.00 to 0.16). In general, auscultation had very low discriminatory power for the diagnosis of mild (area under the receiver operating curve =0.61), moderate (area under the receiver operating curve =0.65), and severe (area under the receiver operating curve =0.68) lung congestion, and the same was true for peripheral edema (receiver operating curve =0.56 or lower) and the combination of the two physical signs. CONCLUSIONS Lung crackles, either alone or combined with peripheral edema, very poorly reflect interstitial lung edema in patients with ESRD. These findings reinforce the rationale underlying the Lung Water by Ultra-Sound Guided Treatment to Prevent Death and Cardiovascular Complications in High Risk ESRD Patients with Cardiomyopathy Trial, a trial adopting ultrasound B lines as an instrument to guide interventions aimed at mitigating lung congestion in high-risk patients on hemodialysis.

The quality of reporting in clinical research: the CONSORT and STROBE initiatives

Inaccurate reporting of data hampers the generalizability and the correct interpretation of results of scientific medical papers. The Consolidated Standards of Reporting Trials (CONSORT) and Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) initiatives, both included in the Enhancing the Quality and Transparency of Health Research (EQUATOR) international network, have elaborated appropriate guidelines in order to improve the transparence, clearness and completeness of scientific literature. The CONSORT statement consists of a 25 items checklist and a flow-chart diagram which provide guidance to Authors on how to report randomized clinical trials. The STROBE is a checklist of 22 items which should be addressed when observational studies (case–control, cohort and cross-sectional) are made up. Many editorial committees and prestigious international journals have now embraced these guidelines to improve the quality and methodology of their scientific reports.

PULMONARY CONGESTION AND PHYSICAL FUNCTIONING IN PERITONEAL DIALYSIS PATIENTS

♦ Purpose: Decline in physical function is commonly observed in patients with kidney failure on dialysis. Whether lung congestion, a predictable consequence of cardiomyopathy and fluid overload, may contribute to the low physical functioning of these patients has not been investigated. ♦ Methods: In 51 peritoneal dialysis (PD) patients, we investigated the cross-sectional association between the physical functioning scale of the Kidney Disease Quality of Life Short Form (KDQOL-SF: Rand Corporation, Santa Monica, CA, USA) and an ultrasonographic measure of lung water recently validated in dialysis patients. The relationship between physical functioning and lung water was also analyzed taking into account the severity of dyspnea measured using the New York Heart Association (NYHA) classification currently used to grade the severity of heart failure. ♦ Results: Evidence of moderate-to-severe lung congestion was evident in 20 patients, and this alteration was asymptomatic (that is, NHYHA class I) in 11 patients (55%). On univariate analysis, physical functioning was inversely associated with lung water (r = -0.48, p < 0.001), age (r = -0.44, p = 0.001), previous cardiovascular events (r = -0.46, p = 0.001), and fibrinogen (r = -0.34, p = 0.02). Physical functioning was directly associated with blood pressure, the strongest association being with diastolic blood pressure (r = 0.38, p = 0.006). The NYHA class correlated inversely with physical functioning (r = -0.51, p < 0.001). In multiple regression analysis, only lung water and fibrinogen remained independent correlates of physical functioning. The NYHA class failed to maintain its independent association. ♦ Conclusions: This cross-sectional study supports the hypothesis that symptomatic and asymptomatic lung congestion is a relevant factor in the poor physical functioning of patients on PD.

An overview on standard statistical methods for assessing exposure-outcome link in survival analysis (Part II): the Kaplan-Meier analysis and the Cox regression method.

The Kaplan-Meier and the Cox regression methods are the most used statistical techniques for performing “time to event analysis” in epidemiological and clinical research. The Kaplan-Meier analysis allows to build up one or more survival curves describing the occurrence of the outcome of interest over time according to the presence/absence of one or more exposures. The Cox regression method models the relationship between a specific exposure (either a continuous one like age, and systolic blood pressure or a categorical one like diabetes, degree of obesity, etc.) and the occurrence of a given outcome taking into account multiple confounders and/or predictors.

Moderator's view: Ambulatory blood pressure monitoring and home blood pressure for the prognosis, diagnosis and treatment of hypertension in dialysis patients

Major health agencies now recommend the systematic application of ambulatory blood pressure monitoring (ABPM) for the diagnosis of hypertension. Given the exceedingly high prevalence of nocturnal hypertension, masked and white coat hypertension and the overt inadequacy of peridialysis (pre-, intra- and post-dialysis) BP measurements, more extensive application of ABPM for the diagnosis of hypertension in dialysis patients would appear logical. In a recent survey performed in NDT Educational, organizational problems and/or cognitive resistance emerged as important factors hindering more extensive application of ABPM and home BP by nephrologists. External validation of observations made in landmark studies in a single institution about hypertension subcategorization by ABPM is urgently needed. Furthermore, apparent cognitive resistance by nephrologists may be justified by the fact that these techniques have been insufficiently tested in the dialysis population for applicability in everyday clinical practice, tolerability, organizational impact and cost-effectiveness. We should be more resolute in abandoning peridialysis measurements for diagnosing and treating hypertension in haemodialysis patients. Home BP is a formidable educational instrument for patient empowerment and self-care, and evidence exists that this technique is superior to peridialysis values to better hypertension control as defined on the basis of ABPM. We should strive to promote more extensive application of home BP monitoring to diagnose and manage hypertension in haemodialysis patients. ABPM with novel, user friendly and better tolerated techniques is to be awaited in the near future.