MedicalResearch.com Interview with:
Michael G. Shlipak, MD, MPH
Scientific Director , Kidney Health Research Collaborative (khrc.ucsf.edu)
Professor of Medicine, Epidemiology & Biostatistics
University of California, San Francisco
Associate Chief of Medicine for Research Development
San Francisco VA Medical Center
MedicalResearch.com: What is the background for this study?
- Our study represents major advancements in our understanding of whether kidney tissue damage accompanies the diagnosis of chronic kidney disease during hypertension therapy.
- The Systolic Blood Pressure Intervention Trial (SPRINT) was a landmark clinical trial that demonstrated that more intensive systolic blood pressure management (target <120 mmHg) reduced rates of major cardiovascular events and mortality compared with standard therapy (<140 mmHg). A recent announcement indicated that the lower systolic blood pressure target also slowed the rate of cognitive decline and dementia incidence.
- The major concern with intensive blood pressure lowering in SPRINT is the 3-fold incidence of chronic kidney disease, as defined using the clinical standard of serum creatinine levels. This detrimental impact on the kidney was surprising because hypertension is a predominant risk factor for kidney disease, and hypertension therapy should reduce CKD risk.
- Given the lower blood pressure targets in the recently-updated national hypertension guidelines, there has been substantial concern that guideline implementation of blood pressure targets could cause an epidemic of CKD and the attendant suffering from its downstream consequences of cardiovascular disease, heart failure, and kidney failure.
- In our study, we compared SPRINT participants who developed CKD with matched controls, using a panel of validated urinary biomarkers of kidney damage. These urine tests can measure actual kidney damage, rather than relying on the creatinine which is an indirect reflection of the kidney’s filtering function.
- In the group undergoing intensive blood pressure lowering in SPRINT, we found that the new cases of CKD had an overall lowering of the kidney damage biomarkers compared with the controls, contrary to what would have been expected if they were developing “real” CKD.
- In contrast, the new CKD cases that developed in the standard treatment group did have overall elevations in the urinary biomarkers of kidney damage; 5 of the 9 biomarkers significantly increased relative to the CKD cases in the intensive treatment group.