Albuminuria may be sole kidney marker of stroke risk
MedWire News: Albuminuria is the only kidney function marker that is significantly associated with the risk for incident stroke, research suggests.
The results emerge from an analysis of 3287 participants in the Cardiovascular Health Study, which includes community-dwelling people aged at least 65 years from four US communities.
Between 1996 and 2006, 390 of these people suffered a stroke, of which 81% were ischemic, 12% hemorrhagic, and 7% unclassified.
The researchers report in the journal Neurology that the risk for any stroke was a significant 2.10-fold higher in participants in the fifth quintile of baseline urinary albumin-to-creatinine ratio (UACR; >29.8) than those in the first quintile (≤4.7).
The corresponding risk increases for ischemic and hemorrhagic stroke were 1.86 and 3.22 fold, respectively. However, Maria Aguilar (Mayo Clinic Arizona, Phoenix, USA) and colleagues note that the limited number of hemorrhagic strokes means that this association should be treated with caution.
Each standard deviation increase in UACR (1.32) was associated with a significant 32% increase in risk for any stroke, and significant 28% and 61% increases in risk for ischemic and hemorrhagic stroke, respectively.
All associations were independent of clinical variables including cystatin C levels.
In contrast, neither increasing quintiles of cystatin C nor decreasing quintiles of estimated glomerular filtration rate were associated with stroke risk, after accounting for confounders including UACR.
Studies based on other cohorts have reported similar findings for cardiovascular mortality and cardiac events, say the researchers.
"Taken together, these findings support the hypothesis that albuminuria and reduced filtration function are separate pathologic processes, with albuminuria conferring the risk of incident stroke independent of filtration function."
They conclude: "Assuming these findings are confirmed, we need to learn more about how albuminuria could affect risk through hemodynamic and nonhemodynamic effects, seeking novel preventative strategies."
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By Eleanor McDermid