Cohort profile: Alliance for Quality Assessment in Healthcare-Dialysis (AQuAH-D) prospective cohort study of patients on haemodialysis in Japan

PURPOSE: The global burden of kidney failure is increasing, but the treatment of kidney failure varies widely between patients, between dialysis facilities and over time. The Alliance for Quality Assessment in Healthcare-Dialysis (AQuAH-D) aims to conduct efficient and timely cohort studies on associations between those variations and clinical and patient-reported outcomes. PARTICIPANTS: Included are outpatients aged 20 years old or older who are undergoing haemodialysis and have consented to participate. A total of 2895 patients were enrolled from 25 facilities in Japan between August 2018 and July 2020 and are to be followed until 31 December 2026. Chart review and annual questionnaires are used to collect data on patient characteristics and on outcomes including quality of life. Data on medications, haemodialysis prescriptions and blood tests are obtained from existing electronic records. Data are collected retrospectively from 1 January 2017 to patient enrolment, and prospectively from patient enrolment until the end of December 2026. FINDINGS TO DATE: To date, the mean age is 68.3 (SD 12.2) years and 35.2% are female. The most common cause of kidney failure is diabetic nephropathy (37.4%). In January 2020, the facilities’ median weekly doses of erythropoietin stimulating agent (ESA) and of intravenous vitamin D ranged from 1846 to 9692 IU (epoetin alfa equivalent) and 0.78 to 2.25 µg (calcitriol equivalent), respectively. The facilities’ percentages of patients to whom calcimimetics are prescribed varied from 19% to 79%. During the retrospective period (averaging 1.85 years per participant), the incidence rates of any hospitalisation and of hospitalisation due to cardiovascular disease were 67.2 and 12.0 per 100 person-years, respectively. FUTURE PLANS: AQuAH-D data will be updated every 6 months and will be available for studies addressing a wide range of research questions, using the advantages of granular data and quality-of-life measurement of ageing patients on haemodialysis.