Greater variability in estimated glomerular filtration rate (eGFR) is independently associated with higher death risk among individuals with hypertension and elevated cardiovascular risk (CV), according to new research.

The risk for all-cause mortality is a significant 29% higher in these patients, Joachim H. Ix, MD, MAS, of the University of California, San Diego, and colleagues reported in the American Journal of Kidney Diseases.

The relationship between eGFR and mortality was not a reflection of rapid kidney decline in some individuals nor was it mediated by CKD status, baseline eGFR, albuminuria, use of angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, and diuretic medications, or changes in systolic blood pressure, according to sensitivity and other analyses.

For the study, the investigators calculated the coefficient of eGFR variation for 7520 patients (mean age 68 years; 65% male; 58% White) in the Systolic Blood Pressure Intervention Trial (SPRINT) trial. The SPRINT excluded patients with diabetes mellitus, stroke, or proteinuria exceeding 1 g/d. The investigators further excluded patients with a recent CV event. They used eGFR values (based on the 4-variable Modification of Diet in Renal Disease equation) obtained at the 6-, 12-, and 18-month health care visits. Mean eGFR was 73 mL/min/1.73 m2 at 6 months.


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Over 2.4 years, 154 patients died and 370 experienced CV events. Dr Ix’s team found no relationship between eGFR variability and the risk for CV events.

“Collectively, these findings demonstrate that variability in eGFR measurements observed within individuals over time holds important physiological and prognostic information, above and beyond the severity of CKD and presence of related risk factors,” Dr Ix and his peers stated.

The investigators suggested that eGFR variability may be a marker of impaired homeostatic/homeodynamic control in renal blood flow, thereby reflecting a “vascular aging” phenotype associated with multiple disease processes and causes of death.

Disclosure: Several study authors declared affiliations with the pharmaceutical industry. Please see the original reference for a full list of authors’ disclosures.

Reference

Malhotra R, Katz R, Jotwani V, et al. Estimated GFR variability and risk of cardiovascular events and mortality in SPRINT (Systolic Blood Pressure Intervention Trial). Am J Kid Dis. doi:10.1053/j.ajkd.2020.10.016