Comparative effectiveness of an individualized model of hemodialysis vs conventional hemodialysis: a study protocol for a multicenter randomized controlled trial (the TwoPlus trial)
Authors: Murea Mariana , Raimann Jochen G. , Divers Jasmin , Maute Harvey , Kovach Cassandra , Abdel-Rahman Emaad M. , Awad Alaa S. , Flythe Jennifer E. , Gautam Samir C. , Niyyar Vandana D. , Roberts Glenda V. , Jefferson Nichole M. , Shahidul Islam , Nwaozuru Ucheoma , Foley Kristie L. , Trembath Erica J. , Rosales Merlo L. , Fletcher Alison J. , Hiba Sheikh I. , Huml Anne , Knicely Daphne H. , Hasan Irtiza , Makadia Bhaktidevi , Gaurav Raman , Lea Janice , Conway Paul T. , Daugirdas John T. , Kotanko Peter ,   on behalf of the Two Plus Research Consortium, Funes Denisse A. , Guillaume Jessica , Shoyelu Victoria , Vergara Katherine , Lyman Lyn B. , Salmi Fatima , Adams Erika , Farrell Jessica , Ginsberg Nancy , Howard Christa , Shabdue Suzanne , Jackson Shawanna , Johnson Seth , Blackie Randall D. , Chaudhuri Sheetal , Desai Priya , Hamilton Kristy , Shumilin Igor , Clynes Diana , Gonzalez Valerie , Kahle Erin , Mitchell Marie , Rate Jennifer , Burciu Brindusa , Serrano Lilliana , Peluso Alexandra , Bittencourt Valeria G. , Forghani Zohreh , Ghalechi Elnaz R. , Green Allison , Markovic Marina , Martin Debra , Poulton Caroline , Singh Simran , Stiles Katlyn , Trapuzzano Ashleigh , Baker Joni , Trynosky Susan 
Published: June 2024

Abstract
Background
Most patients starting chronic in-center hemodialysis (HD) receive conventional hemodialysis (CHD) with three sessions per week targeting specific biochemical clearance. Observational studies suggest that patients with residual kidney function can safely be treated with incremental prescriptions of HD, starting with less frequent sessions and later adjusting to thrice-weekly HD. This trial aims to show objectively that clinically matched incremental HD (CMIHD) is non-inferior to CHD in eligible patients.

Methods
An unblinded, parallel-group, randomized controlled trial will be conducted across diverse healthcare systems and dialysis organizations in the USA. Adult patients initiating chronic hemodialysis (HD) at participating centers will be screened. Eligibility criteria include receipt of fewer than 18 treatments of HD and residual kidney function defined as kidney urea clearance ≥3.5 mL/min/1.73 m2 and urine output ≥500 mL/24 h. The 1:1 randomization, stratified by site and dialysis vascular access type, assigns patients to either CMIHD (intervention group) or CHD (control group). The CMIHD group will be treated with twice-weekly HD and adjuvant pharmacologic therapy (i.e., oral loop diuretics, sodium bicarbonate, and potassium binders). The CHD group will receive thrice-weekly HD according to usual care. Throughout the study, patients undergo timed urine collection and fill out questionnaires. CMIHD will progress to thrice-weekly HD based on clinical manifestations or changes in residual kidney function. Caregivers of enrolled patients are invited to complete semi-annual questionnaires. The primary outcome is a composite of patients’ all-cause death, hospitalizations, or emergency department visits at 2 years. Secondary outcomes include patient- and caregiver-reported outcomes. We aim to enroll 350 patients, which provides ≥85% power to detect an incidence rate ratio (IRR) of 0.9 between CMIHD and CHD with an IRR non-inferiority of 1.20 (α = 0.025, one-tailed test, 20% dropout rate, average of 2.06 years of HD per patient participant), and 150 caregiver participants (of enrolled patients).

Discussion
Our proposal challenges the status quo of HD care delivery. Our overarching hypothesis posits that CMIHD is non-inferior to CHD. If successful, the results will positively impact one of the highest-burdened patient populations and their caregivers.

Trial registration
Clinicaltrials.gov NCT05828823. Registered on 25 April 2023.