DIALysis or not: Outcomes in older kidney patients with GerIatriC Assessment (DIALOGICA): rationale and design
Authors: van Oevelen Mathijs , Abrahams Alferso C. , Bos Willem Jan W. , Emmelot-Vonk Mariëlle H. , Mooijaart Simon P. , van Diepen Merel , van Jaarsveld Brigit C. , van Eck van der Sluijs Anita , Voorend Carlijn G. N. , van Buren Marjolijn ,   on behalf of the DIALOGICA study group, van der Net J. B. , Cnossen T. T. , Goossens K. , Krepel H. P. , Logtenberg S. J. J. , Susanto C. R. , Severs D. , Polinder-Bos H. A. , Siezenga M. A. , Bogers R. , Hoogeveen E. K. , Kerckhoffs A. P. M. , Cornelis T. , Jonker J. T. , Joosten J. M. H. , Litjens E. J. R. , Adema A. Y. , Bontemps-Visser A. , Bosma R. J. , Romijn M. D. M. , Boom H. , van Kempen G. , Klein H. H. T. I. , Snoep J. D. , Schuurmans M. H. P. J. , Nauta F. L. , Franssen C. F. M. , Molenaar F. M. , Wauters I. 
Published: January 2021

Abstract
Background
The incidence and prevalence of older patients with kidney failure who are dependent on dialysis is increasing. However, observational studies showed limited or no benefit of dialysis on mortality in subgroups of these patients when compared to conservative care. As the focus is shifting towards health-related quality of life (HRQoL), current evidence of effects of conservative care or dialysis on HRQoL in older patients is both limited and biased. Dialysis comes with both high treatment burden for patients and high costs for society; better identification of patients who might not benefit from dialysis could result in significant cost savings. The aim of this prospective study is to compare HRQoL, clinical outcomes, and costs between conservative care and dialysis in older patients.

Methods
The DIALysis or not: Outcomes in older kidney patients with GerIatriC Assessment (DIALOGICA) study is a prospective, observational cohort study that started in February 2020. It aims to include 1500 patients from 25 Dutch and Belgian centres. Patients aged ≥70 years with an eGFR of 10–15 mL/min/1.73m2 are enrolled in the first stage of the study. When dialysis is initiated or eGFR drops to 10 mL/min/1.73m2 or lower, the second stage of the study commences. In both stages nephrogeriatric assessments will be performed annually, consisting of questionnaires and tests to assess most common geriatric domains, i.e. functional, psychological, somatic, and social status. The primary outcome is HRQoL, measured with the Twelve-item Short-Form Health Survey. Secondary outcomes are clinical outcomes (mortality, hospitalisation, functional status, cognitive functioning, frailty), cost-effectiveness, and decisional regret. All outcomes are (repeated) measures during the first year of the second stage. The total follow-up will be a maximum of 4 years with a minimum of 1 year in the second stage.

Discussion
By generating more insight in the effects of conservative care and dialysis on HRQoL, clinical outcomes, and costs, findings of this study will help patients and physicians make a shared decision on the best individual treatment option for kidney failure.

Trial registration
The study was registered in the Netherlands Trial Register (NL-8352) on 5 February 2020.