Table 1.

PICOS eligibility criteria for the identification of studies.

	Inclusion criteria	Exclusion criteria
Population	Patients with CKD∗	Patients without CKD Patients with cancer Patients with MDS Paediatric patients
Intervention and comparators	NA	NA
Outcomes	Incidence or prevalence of anaemia† alongside associated risk factors Anaemia or Hb concentration as a predictor of event incidence (probability, odds or rate, hazard ratio (HR), incident rate ratio (IRR), or odds ratio (OR)) for stroke, MI, heart failure, MACE, eGFR decline and/or CKD progression, progression to dialysis, death, or hospitalisation	Outcomes of interest not reported
Study	Randomised controlled trial, nonrandomised controlled trial, prospective study, longitudinal study, retrospective study, observational study, and cohort study	Economic evaluation, clinical practice or treatment guidelines, case reports, letter, editorial, and review
Language restrictions	English language only	Studies published in languages other than English
Date restrictions	2002 onwards (15-year time horizon)	Prior to 2002

CKD: chronic kidney disease; ESRD: end-stage renal disease; Hb: haemoglobin; HR: hazard ratio; IRR: incident rate ratio; MACE: major adverse cardiovascular events; MDS: myelodysplastic syndrome; MI: myocardial infarction; NA: not applicable; OR: odds ratio. ^∗Patients with comorbidities were included, with the exception of CKD patients with cancer or MDS. ^†Anaemia was defined as low Hb in the blood or low red blood cell production. Other types of anaemia such as chemotherapy-induced anaemia and sickle cell anaemia were excluded.