Browsing through the ASN's online Renal Week abstracts can be a daunting task. Over the next few weeks, NephrOnline will be highlighting abstracts we think are particularly relevant to our audience.

Every year I am awed by the staggering amount of research presented at the American Society of Nephrology's Renal Week. Each year new research helps refine clinical best practices and help take the guesswork out of treating kidney patients.

Many of the posted abstracts demonstrate the risk factors that affect the survival of hemodialysis patients. Following is a summary of just a few of these studies:


1.  Survival of patients on dialysis by incident intake volume in hemodialysis and peritoneal dialysis units

Lilyanna Trpeski, Charmaine E. Lok, Stanley S. Fenton Ontario Renal Network, Cancer Care Ontario, Toronto, ON, Canada; Nephrology Department, University Health Network, Toronto, ON, Canada

This study examined whether the intake volume of patients into a dialysis program influences overall patient survival on dialysis.

The study population consisted of patients who initiated dialysis between 1998 and 2005 in Ontario, Canada from The Renal Disease Registry (TRDR). 1,290 peritoneal dialysis (PD) and 5,587 hemodialysis (HD) patients were studied until Dec. 31, 2009 or until they were transferred to a non-TRDR site or received a transplant.

Overall 6,877 patients received HD in 12 centers and PD in 10 centers. Facilities that had an average of 75 new patients/year (>643 total/8yrs) had better 3 year survival (65.4%) than those with an average of 40 new patients/year (52.4% ). Even when adjusted for patient demographics and comorbidities, dialyzing in a facility with a high volume of incident patients was associated with improved survival. The volume of incident patients did not affect survival in PD patients.

2.  Analysis of the causes of death and mortality risk factors in patients treated with hemodialysis

Wenlv Lv, Xiaoqiang Ding, Jie Teng, Jianzhou Zou, Yimei Wang, Yihong Zhong Nephrology, Zhongshan Hospital, Fudan University, Shanghai, China

This study set out to analyze the causes of death in maintenance hemodialysis patients and followed 648 hemodialysis patients with an average age of 63 for 10 years.

The median survival time was 9.6 (0.03-156.80)months. The main causes of death were cardiovascular disease (20.3%), cerebrovascular disease(16.5%) and infection (24.9%). 33.3% of the deaths occurred within 3 months of hemodialysis. Older patients, lower blood albumin, DN, underlying cardiovascular and cerebrovascular disease, and late initiation were the risk factors of mortality.


3. Active vitamin D therapy is associated with lower mortality, especially in low 25(OH)D levels

Masatomo Taniguchi, Shunsuke Yamada, Masanori Tokumoto, Kazuhiko Tsuruya, Hideki N. Hirakata Medicine and Clinical Science, Graduate School of Medical Sciences, Kyushu University; Integrated Therapy for Chronic Kidney Disease, Graduate School of Medical Sciences, Kyushu University; Medicine, Fukuoka Dental College; Fukuoka Red Cross Hospital

This study described the 25(OH)D levels (vitamin D levels) in hemodialysis patients, and the influence of vitamin D treatment on mortality and cardiovascular disease.

Researchers measured serum 25(OH)D levels in a prospective cohort of 2,854 hemodialysis patients, and investigated two-year mortality, onset of CVD, infection- or cancer-related death. Of these patients, 78% were considered 25(OH)D insufficient (<25ng/ml) with 39% considered severely deficient (<15ng/ml).

Patients with vitamin D therapy had a significant lower risk of CVD but not that of infection- or cancer-related death. In 25(OH)D insufficient state (<25ng/ml), vitamin D treatment was associated with lower risk of mortality [HR 0.55 (0.40-0.74)], compared with untreated patients. This association was not significant in 25(OH)D levels with more than 25ng/ml [HR 0.53 (0.25-1.12)].The study suggests that vitamin D therapy contributes to a lower risk of death, especially in 25(OH)D insufficient state.

4. Obesity is a risk factor for mortality, especially among younger dialysis patients

Ellen K. Hoogeveen, Nynke Halbesma, Friedo W. Dekker, Elisabeth W. Boeschoten Internal Medicine, Jeroen Bosch Hospital, Den Bosch, Netherlands; Clinical Epidemiology, Leiden University Medical Center, Leiden, Netherlands; Clinical Epidemiology, Hans Mak Institute, Naarden, Netherlands.

According to the study authors, differences in mortality between obese young and elderly dialysis patients have not been well addressed. The  aim of this study was to investigate whether the association of BMI and mortality differs between younger (<65 y) and older (>65 y) dialysis patients.

All dialysis patients (>18 y) starting with their first dialysis treatment were included and followed until death, transplantation or a maximum of seven years . Patients were divided into eight categories based on their baseline BMI and age: <20 (7.5%), 20 to 25 (47%), 25 to 30 (34.5%) and 30 (11%) kg/m2.

In total, 1749 patients were included.Both young and elderly dialysis patients with underweight had an about 2-fold increased risk factor for mortality, although this maybe due to reverse causality. However, obesity is about 1.5-fold stronger risk factor for mortality in young compared to elderly dialysis patients.