Intensive blood pressure lowering may not induce true kidney disease
The findings can help improve understanding of the significance of creatinine elevations observed during hypertension therapy.
Elevations in creatinine during intensive blood pressure lowering most likely reflect benign reductions in kidney blood flow that occur naturally during treatment, rather than true kidney disease, a study found.
To compare changes in kidney damage biomarkers, researchers conducted a nested case-control study within the Systolic Blood Pressure Intervention Trial (SPRINT), including 162 adults with hypertension but no baseline kidney disease who developed incident chronic kidney disease (CKD) during trial follow-up. There were 128 patients from SPRINT's intensive therapy group (target systolic blood pressure <120 mm Hg) and 34 patients from the standard group (target systolic blood pressure <140 mm Hg). They were matched 1:1 with a control group of patients who didn't develop CKD on age, sex, race, baseline estimated glomerular filtration rate (eGFR), and randomization group. Nine urinary biomarkers of kidney damage were measured at baseline and at one year. Results were published Oct. 23 by Annals of Internal Medicine.
Higher concentrations of urinary albumin, kidney injury molecule-1, and monocyte chemoattractant protein-1 at baseline were significantly associated with greater odds of incident CKD (adjusted odds ratio per doubling, 1.50 [95% CI, 1.14 to 1.98], 1.51 [95% CI, 1.05 to 2.17], and 1.70 [95% CI, 1.13 to 2.56], respectively). After one year of blood pressure intervention, participants in the intensive group who developed CKD had significantly greater decreases in albumin-creatinine ratio, interleukin-18, anti–chitinase-3-like protein 1 (YKL-40), and uromodulin than the matched control participants. Compared with case participants in the standard group, those in the intensive group had significantly greater decreases in albumin–creatinine ratio, beta2-microglobulin, alpha1-microglobulin, YKL-40, and uromodulin.
The researchers noted that the finding of decreases, rather than elevations, in levels of kidney damage biomarkers may reflect benign changes in renal blood flow rather than intrinsic injury. Despite substantial eGFR declines in participants who developed CKD during SPRINT's first year, cases of incident CKD in the intensive treatment group were not characterized by intrinsic kidney damage.
The authors wrote, “Ultimately, these findings, in conjunction with the lower cardiovascular disease and mortality risk reported in SPRINT, should reassure clinicians who embark on evidence-based intensive blood pressure lowering for their patients.”