Declining Kidney function linked to cognitive impairment in high BP patients
USA: Declining kidney function in hypertension patients may increase the risk for dementia and mild cognitive impairment (MCI), according to a recent study in the Journal of the American Society of Nephrology.
Intensive hypertension treatment may be beneficial for cardiovascular disease and cognitive function but this comes at the cost of reduced kidney function. Manjula Kurella Tamura, Division of Nephrology, Stanford University School of Medicine, Palo Alto, California, and colleagues investigated markers of kidney function and the effect of intensive hypertension treatment on the incidence of dementia and MCI.
The study included 9361 participants from the randomized Systolic Blood Pressure Intervention Trial -- which compared intensive versus standard systolic BP lowering (targeting <120 mm Hg versus <140 mm Hg, respectively). The participants were categorized according to baseline and longitudinal changes in eGFR and urinary albumin-to-creatinine ratio. Primary outcomes were the occurrence of adjudicated probable dementia and MCI.
Key findings of the study include:
- Among 8563 participants who completed at least one cognitive assessment during follow-up (median 5.1 years), probable dementia occurred in 325 (3.8%) and MCI in 640 (7.6%) participants.
- In multivariable adjusted analyses, there was no significant association between baseline eGFR <60 ml/min per 1.73 m2 and risk for dementia or MCI.
- In time-varying analyses, eGFR decline ≥30% was associated with a higher risk for probable dementia.
- Incident eGFR <60 ml/min per 1.73 m2 was associated with a higher risk for MCI and a composite of dementia or MCI.
- Although these kidney events occurred more frequently in the intensive treatment group, there was no evidence that they modified or attenuated the effect of intensive treatment on dementia and MCI incidence.
- Baseline and incident urinary ACR ≥30 mg/g were not associated with probable dementia or MCI, nor did the urinary ACR modify the effect of intensive treatment on cognitive outcomes.
"Among hypertensive adults, declining kidney function measured by eGFR is associated with increased risk for probable dementia and MCI, independent of the intensity of hypertension treatment," concluded the authors.
The study, "Kidney Disease, Intensive Hypertension Treatment, and Risk for Dementia and Mild Cognitive Impairment: The Systolic Blood Pressure Intervention Trial," is published in the Journal of the American Society of Nephrology.