Open Access

Update: Rationale and design of the Sodium Lowering In Dialysate (SoLID) trial: a randomised controlled trial of low versus standard dialysate sodium concentration during hemodialysis for regression of left ventricular mass

  • Joanna Leigh Dunlop1, 2,
  • Alain Charles Vandal3, 4,
  • Janak Rashme de Zoysa5,
  • Ruvin Sampath Gabriel6,
  • Imad Adbi Haloob7,
  • Christopher John Hood2,
  • Philip James Matheson8,
  • David Owen Ross McGregor9,
  • Kannaiyan Samuel Rabindranath10,
  • David John Semple11 and
  • Mark Roger Marshall1, 2, 12Email author
BMC Nephrology201516:120

DOI: 10.1186/s12882-015-0080-y

Received: 11 February 2015

Accepted: 11 February 2015

Published: 1 August 2015

Abstract

After the publication of our paper Dunlop et al. “Rationale and design of the Sodium Lowering In Dialysate (SoLID) trial: a randomised controlled trial of low versus standard dialysate sodium concentration during hemodialysis for regression of left ventricular mass”, we became aware of further data correlating left ventricular (LV) mass index at baseline and their correpsonding mass at 12 months, using cardiac margnetic resonanace imaging (MRI) in patients on hemodialysis. The original published sample size for the SoLID trial of 118 was a conservative estimate, calculated using analysis of covariance and a within person Pearson’s correlation for LV mass index of 0.75. New data communicated to the SoLID trial group has resulted in re-calcuation of the sample size, based upon a within person Pearson’s correlation of 0.8 but otherwise unchanged assumptions. As a result, the SoLID trial will now recruit 96 participants.

Update

After the publication of our paper Dunlop et al. “Rationale and design of the Sodium Lowering In Dialysate (SoLID) trial: a randomised controlled trial of low versus standard dialysate sodium concentration during hemodialysis for regression of left ventricular mass” [1], we became aware of further data correlating left ventricular (LV) mass index at baseline and their correpsonding mass at 12 months, using cardiac margnetic resonanace imaging (MRI) in patients on hemodialysis.

The original published sample size for the SoLID trial of 118 was a conservative estimate, calculated using repeated-measures analysis of covariance (ANCOVA) and a within person Pearson’s correlation for LV mass index of 0.75. The assumption of a correlation of 0.75 was based on private communication from the Jardine group (private communication P Mark 8/2/2011) [24]: in a cohort of 59 patients of their patients with repeated measures of LVMI at least 6 months apart (using cardiac MRI), correlation was 0.87 (p < 0.001) with normally distributed data. Modelling these data, and allowing for 25 % for drop outs, it was determined that 59 participants would be enrolled in each arm (power 0.8, alpha 0.05).

New data communicated to the SoLID trial group has resulted in us re-calculating sample size for the SoLID trial (private communication C McIntyre and A Odudu 30/4/2014) [5]: in a cohort of 44 patients of their patients with repeated measures of LV mass index 12 months apart (using cardiac MRI), correlation was 0.81 (p < 0.001). In 21 of these patients, there was an intervention that might have modestly affected their LV mass index; however, restricting analysis to the 23 paired values in the control group provides a similar correlation of 0.83.

Based on the data above, the sample size has been recalculated using a within person correlation of 0.8, but otherwise unchanged assumptions. It is was determined that 48 participants will be enrolled in each arm. The change in sample size has been approved by the National (New Zealand) Multi-region Ethics Committee (IRB00004663) of the New Zealand Ministry of Health (IORG0000895), and the primary funding body for this study the Health Research Council of New Zealand.

Notes

Declarations

Authors’ Affiliations

(1)
Auckland Clinical School, Faculty of Medical and Health Sciences, University of Auckland
(2)
Department of Renal Medicine, Middlemore Hospital, Counties Manukau District Health Board
(3)
Faculty of Health and Environmental Sciences, Auckland University of Technology
(4)
Ko Awatea, Middlemore Hospital, Counties Manukau District Health Board
(5)
Renal Service, North Shore Hospital, Waitemata District Health Board
(6)
Department of Cardiology, Middlemore Hospital, Counties Manukau District Health Board
(7)
Bathurst Health Service
(8)
Department of Nephrology, Wellington Hospital, Capital & Coast District Health Board
(9)
Department of Nephrology, Christchurch Hospital, Canterbury District Health Board
(10)
Department of Renal Medicine, Waikato Hospital, Waikato District Health Board
(11)
Department of Renal Medicine, Auckland City Hospital, Auckland District Health Board
(12)
Medical Affairs - Renal (Asia Pacific)

References

  1. Dunlop JL, Vandal AC, de Zoysa JR, Gabriel RS, Haloob IA, Hood CJ, et al. Rationale and design of the Sodium Lowering In Dialysate (SoLID) trial: a randomised controlled trial of low versus standard dialysate sodium concentration during hemodialysis for regression of left ventricular mass. BMC Nephrol. 2013;14:149.View ArticlePubMedPubMed CentralGoogle Scholar
  2. Mark PB, Patel RK, Jardine AG. Are we overestimating left ventricular abnormalities in end-stage renal disease? Nephrol Dial Transplant. 2007;22(7):1815–9.View ArticlePubMedGoogle Scholar
  3. Patel RK, Jardine AG, Mark PB, Cunningham AF, Steedman T, Powell JR, et al. Association of left atrial volume with mortality among ESRD patients with left ventricular hypertrophy referred for kidney transplantation. Am J Kidney Dis. 2010;55(6):1088–96.View ArticlePubMedPubMed CentralGoogle Scholar
  4. Patel RK, Oliver S, Mark PB, Powell JR, McQuarrie EP, Traynor JP, et al. Determinants of left ventricular mass and hypertrophy in hemodialysis patients assessed by cardiac magnetic resonance imaging. Clin J Am Soc Nephrol. 2009;4(9):1477–83.View ArticlePubMedPubMed CentralGoogle Scholar
  5. Odudu A, Eldehni MT, Fakis A, McIntyre CW. Rationale and design of a multi-centre randomised controlled trial of individualised cooled dialysate to prevent left ventricular systolic dysfunction in haemodialysis patients. BMC Nephrol. 2012;13:45.View ArticlePubMedPubMed CentralGoogle Scholar

Copyright

© Dunlop et al. 2015

This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.

Advertisement