The Oxford Renal (OxRen) cross-sectional study of chronic kidney disease in the UK

Introduction: Chronic kidney disease (CKD) diagnosed with objective measures of kidney damage and function has been recognised as a major public health burden. Independent of age, sex, ethnicity and comorbidity, strong associations exist between cardiovascular disease, mortality, morbidity and CKD, defined by reduced glomerular filtration rate and increased urinary albumin excretion. Detection of CKD within the population is therefore a priority for health systems. Methods and analysis: 15 000 patients aged 60 years or over meeting the inclusion criteria will be invited to the study. Recruitment will be stratified to represent the distribution of socioeconomic position in the UK general population. Patients will be excluded if terminally ill (expected survival <1 year), or if they have received a solid organ transplant. Patients will attend up to two screening visits, to determine if they have CKD, followed by an assessment visit where demographic and physiological parameters will be recorded alongside questionnaires on exercise, diet, cognitive assessment and quality of life. Blood and urine specimens will be taken for immediate routine assays as well as for freezing pending peptide and genetic studies. Patients will have office and home blood pressure measurements as well as pulse wave velocity assessment. Healthcare costs of screening and subsequent monitoring will be calculated. Ethics and dissemination: The protocol and related documents have been approved by NRES Committee South Central-Oxford B-Reference 13/SC/0020.