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Main Trial Design and Trial Status

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1 Main Trial Design and Trial Status
Walter T. Ambrosius, PhD SPRINT Coordinating Center Wake Forest School of Medicine

2 American Society of Hypertension, Inc. (ASH)
Disclosure of Relationships Over the past 12 months Over the last 12 months, Walter T. Ambrosius, PhD, has received research support from the National Heart, Lung, and Blood Institute (NHLBI), the National Eye Institute (NEI), the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), and the National Institute on Aging (NIA) of the National Institutes of Health (NIH).

3 Outline SPRINT Locations SPRINT Outcomes
Primary and secondary analyses Subgroups Event rate justification Sample size calculations Power summary Ancillary studies Current recruitment status

4 SPRINT Networks and Sites

5 Primary Outcome Composite (CVD)
CVD mortality Myocardial infarction Non-MI acute coronary syndrome Stroke Heart Failure

6 Key Secondary Objectives
Total mortality Progression of CKD Probable dementia Cognitive impairment White matter lesions detected by MRI

7 Other Planned Analyses
Achieved blood pressure Adverse events Health related quality of life Cost Various laboratory assays Chemistry profile, fasting glucose, lipid profile

8 Primary Analysis Primary analysis will use a Cox proportional hazards model (time to event) Stratified by clinical site Intention to treat principle will be used Jackson says I should delete this for a clinical audience. I’ve deleted 2 of the 5 bullets but I think what remains is important.

9 Subgroups Motivated by biologically plausible hypotheses: Others:
CKD vs. non-CKD <75 vs. 75+ years of age Black vs. non-black Others: CVD vs. no prior CVD Gender SBP tertiles at baseline

10 Primary Outcomes in Subgroups
Formal tests within subgroups are not planned Interactions between subgroup indicators and intervention arm will be tested Regardless of interaction test, overall conclusion applies to all subgroups

11 Event Rate Calculations for Primary Outcome
Based on ALLHAT data provided by ALLHAT, all three arms not stopped early, without diabetes at baseline 4.39 %/yr (using hospitalized angina rather than non-MI ACS) Need to modify the rate for the SPRINT population

12 Modifications from ALLHAT
Factors increasing event rate: SPRINT will have older participants Use of Framingham risk score of ≥15% Oversampling of stage 3 and 4 CKD Factors decreasing event rate: Temporal trend towards reduced rate in other studies More rigorous definition of non-MI ACS Exact impact of these is unclear To be conservative, we halved ALLHAT’s rate and assumed 2.2 %/yr

13 Comparison to ACCORD ACCORD event rate was 2.09 %/yr in standard BP and 1.87 %/yr in intensive BP ACCORD: Excluded people with CKD due to concerns about metformin for glycemia question Did not recruit age >80 years in the main trial Lipid trial enrolled almost all people with low HDL, excluding these high risk people from the BP trial Did not include non-fatal heart failure or non-MI acute coronary syndrome Thus, we believe SPRINT will have a higher event rate than ACCORD

14 SPRINT Assumptions The event rate for the SPRINT composite outcome is
2.2 %/yr in the standard BP arm 4 %/yr for standard BP participants with eGFR <60 ml/min/1.73m2 3.5 %/yr for standard BP participants ≥75 years old

15 SPRINT Assumptions, Cont.
Sample sizes: 9250 participants in SPRINT (primary outcome and incident dementia) 4300 participants with eGFR < 60 ml/min/1.73m2 3250 participants ≥75 years old Uniform recruitment over 2 years Minimum follow-up is 3 years, 10 months (assumes that closeout visits occur uniformly over a 4 month period) Two-sided tests at the 0.05 level are used Annual loss to follow-up is 2 %/yr 3 %/yr for incident dementia

16 SPRINT Power Summary: Primary Outcomes
88.7% power to detect a treatment effect of 20% of intensive BP vs. standard BP 81.9% power to detect a treatment effect of 20% of intensive BP vs. standard BP among participants with eGFR of <60 ml/min/1.73m2 at baseline 84.5% power to detect a treatment effect of 25% of intensive BP vs. standard BP among participants at least 75 years old at baseline

17 Funded Ancillary Studies
SPRINT FAST (Factors affecting Atherosclerosis Study), Srini Beddhu, MD, University of Utah (NIDDK) MYH9 and other validated CKD genes in SPRINT, Barry Freedman, MD, Wake Forest (NIDDK) SPRINT HEART, Dalane Kitzman, MD, Wake Forest (NHLBI) Reduction in Pulse wave velocity as a predictor of CV outcomes in SPRINT, Mark Supiano, MD, U of Utah (NHLBI) SPRINT MIND The Kidneys, Manju Tamura, MD, Stanford (NIDDK)

18 Current Trial Status DSMB has evaluated enrollment and adherence and recommended continuation Currently recruiting at or above our weekly target Anticipate meeting our target of 9250, over 58% complete

19 Take Home Message SPRINT is a randomized clinical trial of systolic blood pressure lowering from usual goal to lower-than-usual goal in 9250 participants with 88.7% power to detect a 20% reduction in the primary composite CVD outcome

20 American Society of Hypertension, Inc. (ASH)
Disclosure of Relationships Over the past 12 months Over the last 12 months, Walter T. Ambrosius, PhD, has received research support from the National Heart, Lung, and Blood Institute (NHLBI), the National Eye Institute (NEI), the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), and the National Institute on Aging (NIA) of the National Institutes of Health (NIH).


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