22 Sep Chronic Kidney Disease: Lower Blood Pressure May Equal Higher Mortality
Medical Research: What are the main findings of the study?
Dr. Kovesdy: We applied the structure of a clinical trial of hypertension management to our cohort of >600,000 patients with prevalent Chronic Kidney Disease (CKD). We first identified patients with baseline uncontrolled hypertension (using the definition applied by the SPRINT trial), then isolated the ones who had a decline in their baseline systolic blood pressure to two different levels (<120 and 120-139 mmHg) in response to a concomitant increase in prescribed antihypertensives, similar to what would happen in a trial examining two different systolic blood pressure targets. We then matched patients in the two groups to end up with identical baseline characteristics, similar to a randomized trial. When we examined the all-cause mortality of these two groups, we found that the group with follow-up systolic blood pressure of <120 had a 70% higher mortality.
Medical Research: What was most surprising about the results?
Dr. Kovesdy: The fact that patients treated to lower blood pressure targets have higher mortality is surprising. Past guidelines have recommended stricter blood pressure control in patients at high risk for cardiovascular disease, such as those with CKD. However, clinical trial evidence for this has been lacking, therefore more recent clinical guidelines rec blood pressure rommend identical BP treatment goals for patients with CKD. Our results suggest that lowering blood pressure to more stringent targets may in fact be deleterious.
Medical Research: What should clinicians and patients take away from your report?
Dr. Kovesdy: Clinicians should head the recommendations from JNC8 and use a blood pressure target of <140/90 for patients with Chronic Kidney Disease. There is now mounting evidence (including our study) suggesting a potential deleterious effect of over-treating BP in hypertensive individuals with Chronic Kidney Disease.
Medical Research: What recommendations do you have for future research as a result of this study?
Dr. Kovesdy: Our study is observational, hence it cannot provide conclusive evidence about the effects of systolic blood pressure treatment targets. Ultimately we will need clinical trials to determine what the ideal (i.e. affective and safe) BP targets should be in CKD. The SPRINT trial is examining outcomes in hypertensive patients treated to systolic blood pressure goals of <120 and 120-139, and it enrolls a large number of patients with CKD; hence its results (due to be available after 2018) should help clarify this question.