Intensive BP control may delay kidney replacement therapy in patients with advanced CKD
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Using intensive blood pressure control in patients with stages 4 to 5 chronic kidney disease may delay the onset of kidney replacement therapy, according to data published in the Journal of the American Society of Nephrology.
“The Kidney Disease Improving Global Outcomes guidelines recently changed their recommendation to treat all patients with CKD to a target clinic systolic BP of [less than] 120 mmHg (level 2C evidence), assuming that clinic BP is measured using a standardized approach,” Elaine Ku, MD, MAS, from the departments of medicine and pediatrics in the divisions of nephrology at the University of California, and colleagues wrote. “To date, there are an insufficient number of clinical trials designed to test intensive BP lowering exclusively in populations at very elevated risk of progression to [kidney failure requiring replacement therapy] KFRT or death, such as those with stage 4 or 5 disease or severe albuminuria, although some high-risk individuals were included in select trials.”
In a pooled analysis, researchers examined 5,823 patients with eGFR of less than 60 mL/min per 1.73 m2 to determine if the effects of intensive BP control improved kidney or mortality outcomes. Specifically, researchers compared the impacts on patients with CKD stage 4 or 5 to those with CKD stage 3.
- Data were derived from the following seven trials:
- Modification of Diet in Renal Disease Trial;
- African American Study of Kidney Disease and Hypertension;
- Action to Control Cardiovascular Risk in Diabetes;
- Systolic Blood Pressure Intervention Trial;
- Secondary Prevention of Small Subcortical Strokes Trial;
- Effect of Strict Blood Pressure Control and ACE inhibition on the Progression of Chronic Renal Failure in Pediatric Patients (ESCAPE);
- and Ramipril in Efficacy in Nephropathy (REIN-2) Trial.
The onset of kidney replacement therapy (KRT) before death during the parent trial served as the primary outcome.
Researchers pooled all data, then used Cox proportional hazard regression models to analyze the correlation between the randomized assignment to the BP intervention and risk of onset KRT. Death was also examined with follow-up censored at the time of KFRT.
Overall, 526 patients required KRT during the parent trial and 382 died. Although it did not make a significant impact, intensive BP control compared with the usual was associated with a lower risk of the kidney outcome and death in unadjusted analysis. Researchers noted that a patient’s eGFR at baseline affected the impact of the intervention on the kidney outcome.
Compared with usual BP control, intensive BP control correlated with a 20% reduced risk of the primary kidney outcome in patients with stage 4 to 5 CKD, but not stage 3 CKD.
“Although our analyses are post-hoc, there is no evidence of harm in this high-risk population from either the kidney or the mortality standpoint. However, we acknowledge that these data require further confirmation in adequately powered clinical trials,” Ku and colleagues wrote. “Efforts should be devoted to including such underrepresented populations in clinical trials, and to test interventions in those with advanced CKD (based on eGFR or albuminuria) who are at high-risk for progression to KFRT to provide more definitive evidence on the appropriate BP targets in such populations.”
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