January/February 2017: Abstract Roundup

Chronic Kidney Disease

Coffee Consumption and Risk of CKD

International Journal of Clinical Practice. doi: 10.1111/ijcp.12919

Researchers, led by Karn Wijarnpreecha, MD, conducted a literature search and meta-analysis to assess the association between consumption of coffee and chronic kidney disease (CKD). The literature search included MEDLINE, EMBASE, and Cochrane Database of Systematic Reviews from inception to April 2016. Included studies reported odd ratios or hazard ratios to compare the risk of CKD in individuals who consumed significant amounts of coffee (defined as ≥1 cups of coffee per day) compared with those who did not consume any coffee. The analysis included four observational studies representing 14,898 individuals.

A random-effect, generic inverse variance method was used to calculate pooled risk ratios (RR) and 95% confidence interval (CI). The pooled RR in the coffee consumers was 0.71 (95% CI, 0.47-1.08). In subgroup analysis, the pooled RRs of CKD were 1.10 (95% CI, 0.94-1.29) in men and 0.81 (95% CI, 0.58-1.13) in women.
In conclusion, the researchers said, “Our study demonstrates no significant association between coffee consumption and CKD in males. However, future studies are required to assess a potential inverse association between coffee consumption and risk for developing CKD in females.”

Coronary Artery Calcification and Mortality in CKD Patients

Clinical Nephrology. doi:10.514/CN108940

Patients with chronic kidney disease on hemodialysis (CKD-5D) often experience coronary artery calcification (CAC), a predictor of mortality. However, there are few data on cardiac functional links between CAC and mortality, according to Paul Anaya, MD, PhD, and colleagues who conducted a study to test the hypothesis that CAC increases mortality by adversely affecting cardiac function.

Patients (n=157) were recruited from 37 regional dialysis centers. In 69% of participants, Agatston CAC scores were >100; 51% had a Agatston score >400. There were associations between CAC and measures of left ventricular (LV) systolic and diastolic function, peak LV systolic velocity, and estimate of LV filling pressure. Following adjustment for age, sex, left ventricular ejection fraction, and coronary artery disease, multivariate regression confirmed those relationships.

In conclusion, the researchers said, “These findings show a link between CAC, cardiac function, and mortality in CKD-5D. LV diastolic function (E:E’), peak LV systolic velocity, and global longitudinal strain are independent predictors of mortality.

Valvular calcification many be an important marker of CAC in CKD-5D. These effects on cardiac function likely explain the high mortality rate with CKD-5D and describe a potentially valuable role for echocardiography in the routine management of these patients.”

Chronotherapy and Blood Pressure Reduction in CKD Patients

International Urology and Nephrology. doi: 10.1007/s11255-016-1437-2

Researchers conducted a systemic review and meta-analysis to analyze the effects of chronotherapy on blood pressure in patients with chronic kidney disease (CKD). Following application of inclusion and exclusion criteria, researchers in China examined three randomized controlled trials representing 3380 patients. Compared with morning dosing regimen drug therapy, there was an association between chronotherapy and a significant decrease of 3.55% in sleep-time relative decline of systolic blood pressure. There was a significant decrease in nocturnal systolic blood pressure and nocturnal diastolic blood pressure in the chronotherapy group. However, there was small increase in awake systolic blood pressure in the chronotherapy group. There were no significant differences between the two groups in all-cause or cardiovascular mortality.

“This meta-analysis suggests that chronotherapy could reduce nocturnal blood pressure in hypertensive CKD patients,” the researchers said.

The VIRTUE-CKD Trail Results: Effects of Vitamin D Receptor Activation and Sodium Restriction

Journal of the American Society of Nephrology. doi: 10.1681/ASN.2016040407JASN

In a recent multicenter, randomized, placebo-controlled, crossover trial, Martin de Borst, MD, PhD, and colleagues examined the individual and combined effects of the vitamin D receptor activator paricalcitol and dietary sodium restriction on residual albuminuria in chronic kidney disease (CKD). In the study, 45 patients with nondiabetic CKD stages 1 to 3 and albuminuria >300 mg/24 hours despite treatment with Ramipril at 10 mg/day and blood pressure <140/90 mmHg were treated for four 8-week periods with paricalcitol, each combined with a low-sodium or regular-sodium diet.

In the intention-to-treat analysis, albuminuria was 1060 mg/24 hours during regular-sodium diet plus placebo compared with 990 mg/24 hours during regular-sodium plus paricalcitol. Albuminuria was reduced to 717 mg/24 hours with low sodium plus placebo and to 683 mg/24 hours with low sodium plus paricalcitol. The reduction by paricalcitol beyond the effect of low sodium was nonsignificant. In the per-protocol analysis that was restricted to patients with ≥95% compliance with the study medication, there was no further reduction in albuminuria with paricalcitol.

The researchers said, “In conclusion, moderate dietary sodium restriction substantially reduced residual albuminuria during fixed dose angiotensin-converting enzyme inhibition. The additional effect of paricalcitol was small and nonsignificant.”


Dialysis

Assessing Cardiovascular Responses in Hemodialysis and Hemodiafiltration

Journal of the American Society of Nephrology. doi: 10.1681/ASN.2016060686JASN

Recurrent segmental ischemic injury (myocardial stunning) that drives cumulative cardiac damage results from hemodynamic stress during hemodialysis. Using intradialytic cardiac magnetic resonance imaging (MRI), Charlotte Buchanan and colleagues conducted a study of the cardiovascular effect of dialysis sessions to assess the comparative effects of standard hemodialysis compared with hemodiafiltration in stable patients.

Twelve patients 32 to 72 years of age who were on hemodialysis were randomly allocated to either hemodialysis or hemodiafiltration. Following stabilization after 2 weeks on the modality, patients underwent serial cardiac MRI assessment during dialysis. They then crossed over to the other modality and were rescanned after 2 weeks. Cardiac MRI measures of interest were cardiac index, stroke volume index, global and regional contractile function (myocardial strain), coronary artery flow, and myocardial perfusion. None of the cardiovascular responses were influenced by treatment modality.

The researchers added, “In conclusion, in this randomized, crossover study, there was no significant difference in the cardiovascular response to hemodiafiltration or hemodialysis with cooled dialysate as assessed with intradialytic MRI.”

Simple Exercise Program Improves Functioning and Quality of Life for Dialysis Patients

Journal of the American Society of Nephrology. doi: 10.1681/ASN.2016060686JASN

Results of the Exercise Introduction to Enhance Performance in Dialysis trial were reported by Carmine Zoccali, MD, and colleagues. The study was designed to determine whether a simple, personalized walking exercise program managed by dialysis staff and conducted at home would improve functional status in adults on dialysis. Primary study outcomes of interest were change in physical performance at 6 months (measured by the 6minute walking test and the five times sit-to-stand test), and quality of life (measured by the Kidney Disease Quality of Life Short Form).

Study participants were randomized to either normal physical activity (n=145) or walking exercise (n=151); of those, 104 in the exercise group and 123 in the control group completed the 6-month evaluations. In the exercise group, the distance covered during the 6-minute walking test improved from baseline. There was no improvement in the control group. The five times sit-to-stand test also showed improvement in the exercise group but not in the control group. Scores on the KDQOL-SF also improved in the exercise group but not in the control group.

“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 researchers said.

Oral Calcitriol Lowers PTH in Hemodialysis Patients

International Urology and Nephrology. doi:10.1007/s11255-016-1446-1

Controversy remains surrounding the optimal vitamin D3 therapy for treating patients on chronic hemodialysis with secondary hyperparathyroidism (SHPT). Based on recent studies suggesting that uremia in end-stage renal disease is associated with enzymatic hepatic dysfunction altering 25-hydroxylation of vitamin D3, Sandrine Rauscher, MD, and colleagues designed a study to compare the efficacy of calcitriol, the fully hydroxylated active form of vitamin D3, with alfacalcidol, which requires 25-hydroxylation to be effective, in the treatment of that patient population.

The retrospective review included 45 chronic hemodialysis patient who were switched from oral alfacalcidol to oral calcitriol for treatment of SHPT. Following the switch to calcitriol, the mean dose of active vitamin D3 was decreased from 3.50 mcg/week (baseline) to 2.86 mcg. There was a significant decrease in parathyroid hormone (PTH) (from 94.4 to 82.6 pmol), and mean corrected calcium increased from 2.17 to 2.25 mmol/L. There was no clinically significant hypercalcemia, and phosphorus levels were stable.

In conclusion the researchers said, “According to our study, calcitriol in equal dosage is more effective than alfacalcidol in lowering serum PTH level in chronic hemodialysis patients. This suggests that calcitriol may be the optimal active vitamin D3 for the treatment of SHPT in chronic hemodialysis patients.”

Managing Infections in Peritoneal Dialysis Patients with Computed Tomography

Clinical Nephrology. doi: 10.5414/CN108928

Researchers in Tokyo, led by Keina Nozaki, recently conducted a study to assess the effectiveness of computed tomography (CT) for the detection of exit-site and tunnel infections with a Tenckhoff catheter. The study included nine patients with exit-site or tunnel infections and 15 control cases.

Attenuation around the catheter was detected by CT in all cases; ultrasonography detected a hypoechoic area in only one case with abscess formation. In all cases, one or two sites with increased fat density were observed focally along the catheter; these areas did not always extend directly from the exit site.

“In this retrospective study comprising a small number of cases, increased attenuation of fatty tissue around the Tenckhoff catheter correlated with exit-site or tunnel infections. CT might be an auxiliary tool for diagnosis, although CT costs much more than ultrasonography and is not always available in general practice. Further studies are needed,” the researchers said.


Transplantation

Poorly HLA-matched Living Donor Kidney Improves Outcomes Compared with Deceased Donor Organ

Transplantation. 2016;100(12):2717-2722

Approximately half of renal transplants in pediatric patients involve a living donor, resulting in improved renal allograft survival. Matko Marlais, MRCPCH, and colleagues recently conducted a study designed to examine the effect of human leukocyte antigen (HLA) matching in deceased and living donor renal allograft outcomes in pediatric transplant recipients.
The researchers utilized data from the United Kingdom Transplant Registry on all children who received a donation after brain death or living donor kidney-only transplant between 2000 and 2011. HLA-A, HLA-B, and HAL-DR mismatches were stratified into four levels and two groups.

The study included 1378 pediatric renal transplant recipients. Of those, 58% (n=804) received a deceased donor kidney and 42% (n=574) received a kidney from a living donor. Allograft survival at 5 years was superior among the patients receiving a poorly HLA-matched living donor kidney transplant (88%; 95% confidence interval [CI], 84-91%) compared with patients who received a well HLA-matched donation after brain death kidney transplant (83%; 95% CI, 80-86%); log rank rest P=.03).
Five-year renal allograft survival was superior for children who received a living donor kidney with one or two HLA-DR mismatches (88%; 95% CI, 84-91%) compared with those who received a donation after brain death kidney with zero HLA-DR mismatches (83%; 95% CI, 80-86%; log rank test P=.03).

In conclusion, the researchers said, “In children, poorly HLA-matched living donor renal transplant outcomes are not inferior when compared with well HLA-matched donation after brain death renal transplants. It is difficult to justify preferentially waiting for an improved HAL-matched donation after brain death kidney when a poorer HLA-matched living donor kidney transplant is available.”