WASHINGTON, DC — Is chronic kidney disease (CKD) diagnosed based on a single estimated glomerular filtration rate measurement significantly different from that diagnosed using the Kidney Disease: Improving Global Outcomes (KDIGO) guideline?
That was the question addressed in a recent VA-led study. In the KDIGO guideline, the definition of CKD requires the presence of abnormal kidney structure or function for more than three months with implications for health, according to the report in the European Journal of Heart Failure.1
“CKD in patients with heart failure (HF) has not been defined using this definition, and less is known about the true health implications of CKD in these patients,” according to Washington, DC, VAMC and George Washington University researchers and colleagues. “The objective of the current study was to identify patients with HF who met KDIGO criteria for CKD and examine their outcomes.”
The Uniformed Services University and VA researchers from Providence, RI, and Palo Alto, CA, also participated in the study.
Of the 1.4 million veterans with heart failure not receiving kidney replacement therapy, 828,744 had data on more than two ambulatory serum creatinine greater than 90 days apart. CKD was defined as estimated glomerular filtration rate (eGFR) <60 ml/min/1.73 m2 (n = 185 821) or urinary albumin-to-creatinine ratio (uACR) >30 mg/g (n = 32 730) present twice >3 months apart.
On the other hand, normal kidney function (NKF) was defined as eGFR ≥60 ml/min/1.73 m2, present for >3 months, without any uACR >30 mg/g (n = 365,963).
The study team categorized patients with eGFR <60 ml/min/1.73 m2 into four stages: 45-59 (n = 72,606), 30-44 (n = 74,812), 15-29 (n = 32,077) and <15 (n = 6,326) ml/min/1.73 m2.
Results indicate that five-year all-cause mortality occurred in 40.4%, 57.8%, 65.6%, 73.3%, 69.7% and 47.5% of patients with NKF, four eGFR stages and uACR >30mg/g (albuminuria), respectively.
Compared with NKF, hazard ratios (HR) (95% confidence intervals [CI]) for all-cause mortality associated with the four eGFR stages and albuminuria were 1.63 (1.62-1.65), 2.00 (1.98-2.02), 2.49 (2.45-2.52), 2.28 (2.21-2.35) and 1.22 (1.20-1.24), respectively.
The researchers pointed out that respective age-adjusted HRs (95% CIs) were 1.13 (1.12-1.14), 1.36 (1.34-1.37), 1.87 (1.84-1.89), 2.24 (2.18-2.31) and 1.19 (1.17-1.21), and multivariable-adjusted HRs (95% CIs) were 1.11 (1.10-1.12), 1.24 (1.22-1.25), 1.46 (1.43-1.48), 1.42 (1.38-1.47) and 1.13 (1.11-1.16). Similar patterns were observed for associations with hospitalizations.
“Data needed to define CKD using KDIGO criteria were available in six out of ten patients, and CKD could be defined in seven out of ten patients with data,” according to the authors, who added, “HF patients with KDIGO-defined CKD had higher risks for poor outcomes, most of which was not explained by abnormal kidney structure or function. Future studies need to examine whether CKD defined using a single eGFR is characteristically and prognostically different from CKD defined using KDIGO criteria.”
- Patel SS, Raman VK, Zhang S, Deedwania P, et. Al. Identification and outcomes of KDIGO-defined chronic kidney disease in 1.4 million U.S. Veterans with heart failure. Eur J Heart Fail. 2024 May 3. doi: 10.1002/ejhf.3210. Epub ahead of print. PMID: 38700246.