Serum potassium as a predictor of adverse clinical outcomes in patients with chronic kidney disease: new risk equations using the UK clinical practice research datalink

Fig. 1. Study participation flow diagram. CKD: chronic kidney disease; CPRD: Clinical Practice Research Datalink; eGFR: estimated glomerular filtration rate; HF: heart failure; ICD: International Classification of Diseases

Fig. 2. Adjusted incident rate ratios for death (a), MACE (b) and RAASi discontinuation (c) as a function of serum potassium in CKD patients. Black: full patient-intervals; grey: patient-intervals restricted to 30 days. Incident rate ratios were adjusted to account for confounding patient demographics, clinical histories and comorbidities, clinical measurements, and medication usage, as reported in Table 4 and Additional file 1: Table S3. CKD: chronic kidney disease; MACE: major adverse cardiac event; RAASi: renin-angiotensin-aldosterone system inhibitor. Error bars represent 95% confidence intervals

Fig. 3. Predicted incidence rates of death, disaggregated by age (a), RAASi usage (b), time from index (c) and eGFR (d). a light grey line: 60 years, dark grey line: 70 years, black line: 80 years. b grey line: not prescribed, black line: prescribed. c light grey line: 1 year, dark grey line: 5 years, black line: 10 years. d light grey line: 15 mL/min/1.73m2, dark grey line: 30 mL/min/1.73m2, black line: 60 mL/min/1.73m2. The four most important variables for each event (according to the absolute value of the t statistic) were varied, with all other baseline covariates reflective of the cohort average: female; aged 72 years; non-smoker; no history of comorbidities; no medications prescribed; 1066 days elapsed since initial CKD event; no history of heart failure during follow-up period; eGFR 51 mL/min/1.73m2; BMI 29 kg/m2; haemoglobin 13.6 g/dL; total cholesterol 4.98 mmol/L. BMI: body mass index; CKD: chronic kidney disease; eGFR: estimated glomerular filtration rate; RAASi: renin-angiotensin-aldosterone system inhibitor

Fig. 4. Predicted incidence rates of MACE, disaggregated by age (a), history of MACE (b), time from index (c) and sex (d). a light grey line: 60 years, dark grey line: 70 years, black line: 80 years. b grey line: yes, black line: no. c light grey line: 1 year, dark grey line: 5 years, black line: 10 years. d grey line: male, black line: female. The four most important variables for each event (according to the absolute value of the t statistic) were varied, with all other baseline covariates reflective of the cohort average: female; aged 72 years; non-smoker; no history of comorbidities; no medications prescribed; 1066 days elapsed since initial CKD event; no history of heart failure during follow-up period; eGFR 51 mL/min/1.73m2; BMI 29 kg/m2; haemoglobin 13.6 g/dL; total cholesterol 4.98 mmol/L. BMI: body mass index; CKD: chronic kidney disease; eGFR: estimated glomerular filtration rate; MACE: major adverse cardiac event

Fig. 5. Predicted incidence rates of RAASi discontinuation, disaggregated by eGFR (a), diuretics usage (b), presence of diabetes (c), and sex (d). a light grey line: 15 mL/min/1.73m2, dark grey line: 30 mL/min/1.73m2, black line: 60 mL/min/1.73m2. b grey line: yes, black line: no. c grey line: yes, black line: no. d grey line: male, black line: female. The four most important variables for each event (according to the absolute value of the t statistic) were varied, with all other baseline covariates reflective of the cohort average: female; aged 72 years; non-smoker; no history of comorbidities; no medications prescribed; 1066 days elapsed since initial CKD event; no history of heart failure during follow-up period; eGFR 51 mL/min/1.73m2; BMI 29 kg/m2; haemoglobin 13.6 g/dL; total cholesterol 4.98 mmol/L. BMI: body mass index; CKD: chronic kidney disease; eGFR: estimated glomerular filtration rate; RAASi: renin-angiotensin-aldosterone system inhibitor