Associations With Baseline Blood Pressure Control in NURTuRE-CKD

glomerular filtration

stroke, myocardial infarction, coronary artery bypass surgery, peripheral vascular disease or amputation either self-reported or from medical notes and recorded on the case record form.Sex was self-reported at baseline by participants.Stored samples from the baseline visit were analysed centrally for serum creatinine and urine albumin to creatinine ratio (UACR) at Geneva University Hospitals Switzerland to give a baseline eGFR and UACR for each participant.Estimated glomerular filtration rate (eGFR) was calculated using the CKD-EPI equation ( 2009) without the ethnicity variable as recommended by NICE.Anti-hypertensive medications were recorded at baseline by the research teams and categorized by their method of action.Preparations containing two agents were separated into medication classes.
Data were kept centrally in a database held in the UK Renal Registry (UKRR).

Blood Pressure Control
Baseline mean systolic and diastolic BP values were compared against three guidelines; two applicable to participants at time of recruitment: the 2014 NICE guideline S2 , and the international KDIGO 2012 S3 guideline.NICE recommended different targets by albuminuria and diabetes status (<140/90 mmHg without diabetes, <130/80 mmHg with diabetes or UACR ≥70 mg/mmol) and KDIGO by albuminuria status only (<140/90 mmHg, unless high risk ACR >30 mg/g then <130/80 mmHg.In 2021 KDIGO issued an updated guideline S4 suggesting a target of <120 mmHg systolic based on findings from the intensive versus standard blood pressure intervention (SPRINT) trial S1 and BP control was assessed against the lower target to gauge the proportion of the recruited population that would meet it.
BP control was defined as systolic and/or diastolic reading at baseline below the recommended target for each.

Statistical Analysis
Continuous data are presented as mean ± standard deviation (SD) where normally distributed and otherwise as median and interquartile range (IQR).Categorical variables are presented as counts and percentages.Comparison of mean systolic and diastolic BP were performed by independent t-test or 1 way analysis of variance (ANOVA).
To investigate factors associated with BP control, univariable logistic regression analysis was performed with achievement of each BP target as the dependent variable.To identify independent associations, multivariable logistic regression analysis for BP control by guideline was performed adjusting for age (<65 years), sex, ethnicity, diabetes, history of atherosclerotic cardiovascular disease, body mass index (BMI), smoking status, employment, number of antihypertensives, renin angiotensin system inhibition (RAASi), albuminuria status and eGFR.Variables to be included in the models were selected based on previously reported associations with BP control S5-S8 or significant associations in the univariable analyses.Odds ratios are reported with 95% confidence intervals with a p value of <0.05 considered statistically significant.
All statistical analysis was performed using IBM SPSS v 28.01 eGFR-estimated glomerular filtration rate, urinary albumin creatinine ratio uACR.

Figure S7 .
Mean systolic and diastolic BP by number of antihypertensives in the NURTuRE-CKD cohort Supplementary Figure S6.Pattern of use of the three most commonly prescribed antihypertensives at baseline in the NURTuRE-CKD cohort BMI-body mass index, CVD -cardiovascular disease, CKD -chronic kidney disease, eGFR -estimated glomerular filtration rate, GCSE -general certificate of secondary education, IMD-index of multiple deprivation, NVQ-national vocational qualification, RAASi -renin angiotensin system inhibition, SILS -single-item literacy screener where a score of >2 suggested Blood pressure in the NURTuRE-CKD cohort according to KDIGO CKD risk categories (n=2683, data are median (IQR))

Table S2 .
Univariate associations with BP control by guideline BMI-body mass index, CVD -cardiovascular disease, eGFR -estimated glomerular filtration rate, GCSE -general certificate of secondary education, IMD-index of multiple deprivation, NVQ-national vocational qualification, RAASi -renin angiotensin system inhibition, UACR -urinary albumin creatinine ratio