Low eGFR linked to high mortality rate but not to cardiovascular events in older patients
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Key takeaways:
- Researchers evaluated the risk of adverse outcomes in older patients across categories of eGFR.
- The database used by researchers was from the Systolic Blood Pressure Intervention Trial.
Among older adults participating in the Systolic Blood Pressure Intervention Trial, a low eGFR without albuminuria was associated with a higher mortality rate but not with increased risk of cardiovascular events, results showed.
Researchers concluded that additional studies are needed to evaluate an adapted chronic kidney disease stage-based risk stratification for older adults. ”We believe that age should be taking into consideration when staging CKD, especially for older adults who have minimal or no albuminuria, and who might have low eGFR due to aging rather than kidney disease,” Ana C. Ricardo, MD, with the department of internal medicine at Advocate
Q6 Christ Medical Center and the division of nephrology in the department of medicine at University of Illinois at Chicago and a co-author on the paper, told Healio. “In addition to age, the CKD stage should take into account social determinants of health, which play an important role in how patients manage their disease and interact with the health care system.”
Ricardo and colleagues, including lead author Valentina Turbay-Caballero, MD, reviewed data from 2,509 participants aged 75 years and older from the Systolic Blood Pressure Intervention Trial (SPRINT). The primary outcome for SPRINT was a composite of myocardial infarction, other acute coronary syndromes, stroke, heart failure or death from cardiovascular causes, along with all-cause death.
In the analysis by Turbay-Caballero and colleagues, mean eGFR was 64 mL/min/1.73 m2, and the median urine albumin-to-creatinine ratio (UACR) was 13.1 mg/g for patients in the study group.
Researchers found no statistically significant difference in the risk of the primary outcome among participants with an eGFR 45 mL/min/1.73 m2 to 59 mL/min/1.73 m2, or an eGFR of 15 mL/min/1.73 m2 to 44 mL/min/1.73 m2 and a UACR less than 30 mg/g.
Patients who had a UACR greater than 30 mg/g in the two eGFR groups, however, did have a higher risk for the SPRINT primary outcome of all-cause mortality; the risk was higher for each category of abnormal eGFR and UACR, with the highest risk among those patients with eGFR 15 mL/min/1.73 m2 to 44 mL/min/1.73 m2 and UACR of 30 mg/g or greater.
“Our findings of higher risk for all-cause death among participants with low eGFR, even those with normal or mildly increased albuminuria, is in contrast with prior studies that have shown that among older adults, GFR reduction attributed to aging is not associated with higher mortality,” the authors wrote. “These discordant results might be attributed to differences in the populations studied as well as the methods used to estimate GFR. “Additional studies with larger samples are needed to evaluate this further,” they wrote.
One of the limitations of the study and SPRINT, Ricardo told Healio, is that it does not include patients with diabetes. “Diabetes and proteinuria are associated with heightened cardiovascular risk; therefore, we might observe that older individuals with diabetes and/or proteinuria, especially those with high levels of proteinuria (and therefore true CKD), might have risk of cardiovascular events and mortality related to kidney disease, independent of their age,” Ricardo said.