Timing of dialysis initiation and choice of dialysis modality

Timing of peritoneal dialysis initiation and mortality: analysis of the Canadian Organ Replacement Registry

BACKGROUND

Several observational studies of hemodialysis patients show an association between early dialysis therapy initiation and increased mortality. Few studies have examined this association among peritoneal dialysis patients.

STUDY DESIGN

Retrospective cohort study.

SETTING & PARTICIPANTS

A cohort of 8,047 incident peritoneal dialysis patients who started dialysis therapy in 2001-2009 and were treated in Canada.

PREDICTOR

Estimated glomerular filtration rate (eGFR) at dialysis therapy initiation. Defined early, mid, and late starts as eGFR>10.5, 7.5-10.5, and <7.5mL/min/1.73m(2), respectively.

OUTCOMES

Time to death.

MEASUREMENTS

Proportional piecewise exponential survival models to compare mortality (overall and early) for the 3 predictor groups.

RESULTS

Between 2001 and 2009, the proportion of patients starting peritoneal dialysis therapy as early starts increased from 29% (95% CI, 26%-32%) to 44% (95% CI, 41%-47%). Compared with the late-start group, the overall mortality rate was not higher for the early- (adjusted HR, 1.08; 95% CI, 0.96-1.23) or mid-start (adjusted HR, 0.96; 95% CI, 0.86-1.09) groups. However, when examined yearly, patients in the early-start group were significantly more likely to die within the first year of dialysis therapy compared with those in the late-start group (adjusted HR, 1.38; 95% CI, 1.10-1.73), but not in subsequent years.

LIMITATIONS

Bias and residual confounding may have influenced the observed relationship between predictor and outcome.

CONCLUSIONS

Patients are initiating peritoneal dialysis therapy at increasingly higher eGFRs. Contrary to most observational studies assessing hemodialysis, the early initiation of peritoneal dialysis therapy, at eGFR>10.5mL/min/1.73m(2), is not associated with increased mortality.

Peritoneal dialysis--current status and future challenges

Peritoneal dialysis is now a well established, mature treatment modality for advanced chronic kidney disease. The medium term (at least 5 year) survival of patients on peritoneal dialysis is currently equivalent to that of those on haemodialysis, and is particularly good in patients who are new to renal replacement therapy and have less comorbidity. Nevertheless the modality needs to keep pace with the constantly evolving challenges associated with the provision and delivery of health care. These challenges, which are gradually converging at a global level, include ageing of the population, multimorbidity of patients, containment of cost, increasing self care and environmental issues. In this context, peritoneal dialysis faces particular challenges that include multiple barriers to the therapy and unsatisfactory and poorly defined technique survival as well as limitations relating to intrinsic aspects of the therapy, such as peritoneal membrane longevity and hypoalbuminaemia. To move the therapy forward and favourably influence health-care policy, the peritoneal dialysis community needs to integrate their research effort more effectively by undertaking clinically meaningful studies-with a strong focus on technique survival--that are supported by multidisciplinary expertise in patient-centred outcomes, study design and analysis.

Systematic review and meta-analysis of the relation between body mass index and short-term donor outcome of laparoscopic donor nephrectomy

In this era of organ donor shortage, live kidney donation has been proven to increase the donor pool; however, it is extremely important to make careful decisions in the selection of possible live donors. A body mass index (BMI) above 35 is generally considered as a relative contraindication for donation. To determine whether this is justified, a systematic review and meta-analysis were carried out to compare perioperative outcome of live donor nephrectomy between donors with high and low BMI. A comprehensive literature search was performed in MEDLINE, Embase, and CENTRAL (the Cochrane Library). All aspects of the Preferred Reporting Items for Systematic Reviews and Meta-analyses statement were followed. Of 14 studies reviewed, eight perioperative donor outcome measures were meta-analyzed, and, of these, five were not different between BMI categories. Three found significant differences in favor of low BMI (29.9 and less) donors with significant mean differences in operation duration (16.9 min (confidence interval (CI) 9.1-24.8)), mean difference in rise in serum creatinine (0.05 mg/dl (CI 0.01-0.09)), and risk ratio for conversion (1.69 (CI 1.12-2.56)). Thus, a high body mass index (BMI) alone is no contraindication for live kidney donation regarding short-term outcome.

Estimated glomerular filtration rate at reinitiation of dialysis and mortality in failed kidney transplant recipients

BACKGROUND

Recent observational studies and a controlled trial suggest more favorable outcomes upon later dialysis initiation in chronic kidney disease. The role of estimated glomerular filtration rate (eGFR) in predicting outcome at reinitiation of dialysis in failed kidney transplant recipients is unclear.

METHODS

Five-year data in a large dialysis organization was linked to the 'Scientific Registry of Transplant Recipients' to identify 747 failed kidney transplant patients with CKD Stage 5, who had restarted dialysis therapy. A propensity score for early (eGFR>10.5 mL/min/1.73 m2) versus late reinitiation of dialysis was fit by logistic regression. The mortality hazard ratio (HR) was estimated across tertiles of the fitted score.

RESULTS

Patients were 44±14 years old and included 42% women. Male gender {odds ratio (OR), [95% confidence interval (CI)]: 1.82 (1.22-2.73)}, diabetes mellitus [OR: 1.75 (1.14-2.68)] and peripheral vascular disease [OR: 3.55 (1.17-10.77)] were associated with higher odds of early dialysis reinitiation. Each mL/min/1.73 m2 higher eGFR was associated with 6% higher death risk in unadjusted model [HR: 1.06 (1.01-1.11)], and although not significant in fully adjusted models [HR: 1.02 (0.96-1.07)], it was significant in some subgroups including women and younger patients. The death HR of higher eGFR across lowest to highest tertiles of propensity score of early dialysis initiation (corresponding healthiest to sickest patients) were 1.10 (0.98-1.24), 1.00 (0.91-1.10) and 0.99 (0.92-1.07), respectively (P for trend<0.05), indicating a trend toward higher mortality risk with earlier dialysis initiation in the healthiest patients.

CONCLUSIONS

Earlier return to dialysis therapy in failed kidney transplant patients tends to correlate with worse dialysis survival especially among healthiest and younger patients and women. Additional studies need to verify these findings.

Timing of dialysis initiation in transplant-naive and failed transplant patients

Over the past two decades, most guidelines have advocated early initiation of dialysis on the basis of studies showing improved survival in patients starting dialysis early. These recommendations led to an increase in the proportion of patients initiating dialysis with an estimated glomerular filtration rate (eGFR) >10 ml/min/1.73 m(2), from 20% in 1996 to 52% in 2008. During this period, the percentage of patients starting dialysis with an eGFR ≥15 ml/min/1.73 m(2) increased from 4% to 17%. However, recent studies have failed to substantiate a benefit of early dialysis initiation and some data have suggested worse outcomes for patients starting dialysis with a higher eGFR. Several reasons for this seemingly paradoxical observation have been suggested, including the fact that patients requiring early dialysis are likely to have more severe symptoms and comorbidities, leading to confounding by indication, as well as biological mechanisms that causally relate early dialysis therapy to adverse outcomes. Patients with a failing renal allograft who reinitiate dialysis encounter similar problems. However, unique factors associated with a failed allograft means that the optimal timing of dialysis initiation in failed transplant patients might differ from that in transplant-naive patients with chronic kidney disease. In this Review, we discuss studies of dialysis initiation and compare risks and benefits of early versus late initiation and reinitiation of dialysis therapy.