Table 1 Inclusion criteria

• Males and females aged 18 years and over at the date of screening

• Subjects with CKD (reduced eGFR and/or albuminuria) defined as:

o Estimated glomerular filtration rate [eGFR] < 60 mL/min/1.73 m² for at least 90 days, and/or

o Kidney disease code on the GP electronic patient AND most recent eGFR in CKD-defining range (< 60 mL/min/1.73 m²), and/or

o Albuminuria or proteinuria (defined as urine albumin:creatinine ratio [ACR] inmg/mmol, and/or urine protein:creatinine ratio [PCR] inine mmol, and/or + protein or greater on reagent strip)*

• Subjects willing to give permission for their paper and electronic medical records to be accessed and abstracted by trial investigators for the duration of the trial

• Subjects willing to be contacted and interviewed by trial investigators should the need arise for adverse event assessment

• Subjects able to communicate well with the investigator or designee, to understand and comply with the requirements of the study and to understand and sign the written informed consent

* where albuminuria measurements are not available KDIGO state that measurements of urine protein:creatinine ratio or urine protein reagent strips can be substituted. Negative to trace on protein reagent strip is equivalent to ACR < 3 mg/mmol; trace to + is equivalent to ACR 3–30 mg/mmol [3]. The relationship between reagent strip measures and ACR depends upon urine concentration, and in this context for the purposes of ATTACK, we are regarding +protein or more as indicative of significant albuminuria. A single abnormal albuminuria/proteinuria test is required for entry to the trial: day-to-day variation in albumin excretion is substantial and the literature linking albuminuria to adverse outcomes is predicated upon single ACR readings; robust cohort data confirm that for urine ACR down to 1.7 mg/mmol multiple urine samples do not improve performance of CV mortality risk models beyond information achievable by implementation of one ACR value [57]