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World J Cardiol. Jun 26, 2026; 18(6): 119376
Published online Jun 26, 2026. doi: 10.4330/wjc.119376
Prognostic value of glomerular-filtration-rate estimated by common and modified Asian/Chinese equations for cardiovascular outcomes in elderly Chinese individuals
Atawula Aili, Department of Cardiology, The First People’s Hospital of Kashgar District, Kashgar 844000, Xinjiang Uygur Autonomous Region, China
Atawula Aili, Ayman A Mohammed, Song Zhao, Mo-Ran Li, Hao-Nan Li, Ya-Wei Xu, Yi Zhang, Department of Cardiology, Shanghai Tenth People’s Hospital, Tongji University School of Medicine, Shanghai 200072, China
Rui-Yuan Li, Department of Cardiology, Beijing Luhe Hospital, Capital Medical University, Beijing 101199, China
ORCID number: Ayman A Mohammed (0000-0003-4759-0469); Yi Zhang (0000-0001-8693-3554).
Co-first authors: Atawula Aili and Rui-Yuan Li.
Co-corresponding authors: Ayman A Mohammed and Yi Zhang.
Author contributions: Aili A and Li RY made equal contributions to this work as co-first authors; Mohammed AA, Aili A, Li RY, Zhao S, and Li MR designed and conducted the study and wrote the paper; Mohammed AA, Li RY, and Zhang Y contributed to data analysis; Li HN, Li MR, and Xu YW provided clinical advice; and Mohammed AA, Xu YW, and Zhang Y supervised the study. Mohammed AA and Zhang Y contributed equally to this work as co-corresponding authors. All authors approved the final version to be published.
Supported by National Nature Science Foundation of China, No. 82570350.
Institutional review board statement: This study was approved by the Institutional Review Board of Shanghai Tenth People’s Hospital.
Informed consent statement: All participants provided informed consent before enrollment in the study.
Conflict-of-interest statement: All the authors report no relevant conflicts of interest for this article.
STROBE statement: The authors have read the STROBE Statement-checklist of items, and the manuscript was prepared and revised according to the STROBE Statement-checklist of items.
Data sharing statement: The corresponding author will provide the dataset generated and analyzed in this study upon reasonable request.
Corresponding author: Yi Zhang, MD, PhD, Professor, Department of Cardiology, Shanghai Tenth People’s Hospital, Tongji University School of Medicine, No. 301 Yanchang Road, Shanghai 200072, China. yizshcn@gmail.com
Received: January 26, 2026
Revised: February 16, 2026
Accepted: May 9, 2026
Published online: June 26, 2026
Processing time: 143 Days and 21.5 Hours

Abstract
BACKGROUND

A simple method for evaluating renal function is the estimated glomerular filtration rate (eGFR), which reveals prognostic implications. However, it is not yet known which equation should be applied to elderly Chinese individuals.

AIM

To compare the ability of Modification of Diet in Renal Disease (MDRD), Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI), and the Asian/Chinese-modified equations and their predictive performance for clinical outcomes.

METHODS

A total of 3257 community-dwelling elderly Chinese participants (≥ 65 years) in northern Shanghai were prospectively recruited in the present study. The GFR was estimated by creatinine-based MDRD and CKD-EPI and modified Asian/Chinese (c-aMDRD, aCKD-EPI, and cCKD-EPI) equations. The outcomes included major adverse cardiovascular events (MACE), cardiovascular mortality, and all-cause mortality.

RESULTS

The prevalence of eGFR < 60 mL/minute, based on different eGFR equations, ranged from 5.7% (c-aMDRD) to 16.5% (cCKD-EPI). The rate and risk of adverse outcomes were higher in patients with eGFR < 60 mL/minute (P < 0.05). Low eGFR (< 60 mL/minute) estimated by the c-aMDRD equation was associated with MACE and cardiovascular mortality, whereas low eGFR (< 60 mL/minute) estimated by the MDRD, c-aMDRD, CKD-EPI, aCKD-EPI, and cCKD-EPI equations was associated with all-cause mortality. The CKD-EPI, aCKD-EPI, and cCKD-EPI equations demonstrated significantly better predictive abilities for outcomes than the MDRD and c-aMDRD equations.

CONCLUSION

eGFR is an independent predictor of long-term outcomes. When estimated by the c-aMDRD equation, eGFR predicts MACE and cardiovascular mortality, while all equations predict all-cause mortality. The CKD-EPI, aCKD-EPI, and cCKD-EPI equations might be better than MDRD and c-aMDRD for risk stratification in the elderly Chinese population.

Key Words: Clinical outcome; Estimated glomerular filtration rate; Elderly; Risk stratification; Chronic kidney disease

Core Tip: For risk stratification in elderly Chinese adults, the choice of estimated glomerular filtration rate equation is crucial. This study finds that while the modified Chinese-abbreviated Modification of Diet in Renal Disease equation specifically predicts major adverse cardiovascular events and cardiovascular death, the newer Chronic Kidney Disease Epidemiology Collaboration and its Chinese-adjusted versions are superior overall, offering the best predictive power for all-cause mortality.



INTRODUCTION

Chronic kidney disease (CKD) is a major public health concern and is associated with an increased risk of cardiovascular events and all-cause mortality[1-3]. Impaired renal function contributes to endothelial dysfunction, vascular calcification, inflammation, and accelerated atherosclerosis, thereby substantially increasing cardiovascular morbidity and mortality in affected individuals[1,4]. A simple method for evaluating renal function is the estimated glomerular filtration rate (eGFR) by several equations. For decades, the most widely used eGFR equations, including Modification of Diet in Renal Disease (MDRD) and the more recent CKD Epidemiology Collaboration (CKD-EPI), were primarily developed and validated in Caucasian populations[5,6]. Given ethnic differences in muscle mass, diet, genetic background, and creatinine metabolism, these equations may not provide optimal accuracy in Asian populations. In recent years, several Asian- and Chinese-modified eGFR equations have been developed and validated to improve renal function estimation in Chinese individuals[7-9]. Nonetheless, most validation studies have focused on cross-sectional accuracy or renal outcomes, with limited investigation into their prognostic performance for cardiovascular events, particularly in elderly populations.

Aging is associated with physiological declines in renal function and an increased prevalence of cardiovascular disease, making risk prediction in older adults especially challenging and clinically important[10-13]. Importantly, the optimal eGFR equation for predicting cardiovascular risk in elderly Chinese individuals remains uncertain[14,15]. Whether Asian/Chinese-modified equations offer superior prognostic value compared with traditional MDRD or CKD-EPI equations has not been systematically evaluated in large community-based elderly cohorts.

Therefore, in the current study, we used data from a Chinese community-based elderly cohort to examine the associations between eGFR calculated using MDRD, CKD-EPI, and Asian/Chinese-modified equations and adverse clinical outcomes. Our primary aim was to determine which eGFR equation provides the most robust prognostic information for cardiovascular risk prediction in elderly Chinese individuals.

MATERIALS AND METHODS
Study design

This analysis was part of the Northern Shanghai Study (ClinicalTrials.gov, No. NCT02368938; February 15, 2015), officially titled “Prognosis Factors of Mortality and Cardiovascular Diseases in the Elderly Chinese: The Northern Shanghai Study”[16]. The study design has been described previously in detail[16]. The inclusion criteria for the present study were: (1) Age ≥ 65 years; and (2) Ability to complete follow-up. The exclusion criteria were: (1) Missing data on baseline serum creatinine (Scr); (2) Presence of New York Heart Association class IV heart failure or end-stage renal disease; (3) Malignant tumour or life expectancy < 5 years; (4) History of stroke within the past 3 months; (5) Withdrawal from the trial due to other diseases; and (6) Protocol violations.

Data collection and laboratory tests

Data collected via questionnaire included gender, age, weight, height, smoking habits, and history of diabetes, hypertension, cardiovascular diseases, and medication use. Fasting venous blood was collected in the morning and Scr levels were measured using an enzymatic method.

eGFR

The eGFR was calculated using five creatinine-based equations: The MDRD, the CKD-EPI, the derived Chinese-abbreviated MDRD (c-aMDRD), the Asian-adapted CKD-EPI (aCKD-EPI), and the Chinese-adapted CKD-EPI (cCKD-EPI) equations. Scr is expressed in mg/dL, age in years, and eGFR in mL/minute/1.73 m²[5-8,15,17-19].

MDRD equation: eGFR MDRD = 175 × (Scr)-1.154 × (age)-0.203 × (0.742 if female).

CKD-EPI equation: eGFR CKD-EPI = 141 × min (Scr/κ, 1)α × max (Scr/κ, 1)-1.209 × 0.993age × (1.018 if female), where κ = 0.7 for females and 0.9 for males, and α = -0.329 for females and -0.411 for males.

c-aMDRD equation: eGFR c-aMDRD = 175 × (Scr)-1.234 × (age)-0.179 × (0.79 if female).

aCKD-EPI equation: eGFR aCKD-EPI = eGFR CKD-EPI × Asian correction factor, where the Asian correction factor is 0.813.

cCKD-EPI equation: eGFR cCKD-EPI = eGFR CKD-EPI × Chinese correction coefficient, where the Chinese-specific coefficient is 1.1.

Follow-up and outcomes

The primary endpoint of this study was the occurrence of major adverse cardiovascular events (MACE). MACE were defined as a composite endpoint of non-fatal myocardial infarction, non-fatal stroke, cardiovascular revascularization stent or coronary artery bypass grafting, and cardiovascular death. The secondary endpoint was the all-cause death. All-cause death was defined as mortality from any cause, including cardiac-related. Cardiovascular death was identified as mortality due to fatal arrhythmia, cardiac arrest, myocardial infarction, or heart failure. Mortality data and causes of death up to October 25, 2022, were obtained from the Shanghai Health Statistics Center. We obtained hospitalization records for all participants from the Shanghai Medical Insurance Bureau up to October 25, 2022. MACE events were identified using International Classification of Diseases, 10th Revision codes, such as I63 for ischemic stroke, I60-I61 for haemorrhagic stroke, I64 for unspecified stroke, and I21 for myocardial infarction. For participants without follow-up data from the Shanghai Medical Insurance Bureau and Shanghai Health Statistics Center, follow-up was conducted via telephone.

Statistical analysis

Baseline demographic and clinical characteristics are presented as medians (interquartile ranges) for continuous variables and n (%) for categorical variables. Comparisons of categorical variables between groups were performed using the χ2 test, while non-normally distributed continuous variables were compared using the non-parametric tests. The Kaplan Meier time-to-event curve and the log-rank test were used to determine the significance of time to endpoints in patients with eGFR ≥ and < 60 mL/minute. Cox proportional hazard models were used to assess the risk associated with different CKD categories, based on various GFR estimation equations, for MACE, cardiovascular death, and all-cause mortality. The models were adjusted for significant known risk factors (covariates with P < 0.1 in the univariate models), including gender, smoking status, hypertension, diabetes, body mass index, age, coronary heart disease, blood leukocyte, serum albumin, uric acid, and stroke history. Odds ratios for the absence of MACE during follow-up were estimated using logistic regression, with the same model adjustments. The prognostic performance of the five eGFR equations was compared by evaluating goodness-of-fit and discrimination of different models after adjusting for confounding variables. To quantify the goodness-of-fit, the Akaike information criterion (AIC) was calculated. The discriminative power of the eGFR equations was assessed using the area under of the receiver operating characteristic curve (AUC). Differences in AUCs between equations were calculated and compared using the z-test. Two-tailed P values < 0.05 were considered statistically significant. All statistical analyses were conducted using SPSS v.26.0 and GraphPad v.8.0.1.

RESULTS

From July 2014 to September 2019, the research team invited 3590 individuals to participate in the North Shanghai Study. After applying the exclusion criteria and obtaining informed consent, 3363 (93.7%) participants were initially enrolled. For the current analysis, we further excluded participants who were younger than 65 years (n = 61), lacked baseline creatinine measurements (n = 39), or were lost to follow-up (n = 6). The final analytic cohort comprised 3257 participants (Figure 1).

Figure 1
Figure 1 Flow chart of the screening process for the study population from the Northern Shanghai Study.

The median age of the cohort was 70 years (interquartile range: 67-75 years), and 44% were male. The prevalence of eGFR < 60 mL/minute was 7.7% using the MDRD, 5.7% using the c-aMDRD, 10.2% using the CKD-EPI, 7.7% using the aCKD-EPI, and 16.5% using the cCKD-EPI equations. Table 1 and Supplementary Table 1 summarize the baseline characteristics of the study population, stratified by eGFR ≥ 90 and < 90 mL/minute. Compared with participants with eGFR ≥ 90 mL/minute, those with eGFR < 90 mL/minute were older and more frequently male, current smokers, and had a higher prevalence of hypertension and coronary heart disease. They also had higher leukocyte counts, uric acid levels, and body mass index, but a lower prevalence of diabetes (all P < 0.05). Total cholesterol and low-density lipoprotein differed significantly between groups only when eGFR was estimated using the MDRD equation.

Table 1 Baseline characteristics based on estimated glomerular filtration rate values estimated with different equations, n (%)/median (interquartile range).
Variable
Total (n = 3257)
MDRD, < 90 mL/minute (n = 2069, 63.5%)
c-aMDRD, < 90 mL/minute (n = 1466, 45.0%)
CKD-EPI, < 90 mL/minute (n = 2436, 74.8%)
aCKD-EPI, < 90 mL/minute (n = 1878, 57.7%)
cCKD-EPI, < 90 mL/minute (n = 3112, 95.5%)
Age70 (67-75)71a (68-77)72a (68-78)71a (68-77)72a (68-78)70a (67-75)
Male1430 (43.9)906 (43.8)788a (53.1)1125a (46.2)855a (45.5)1428a (45.9)
Hypertension1740 (53.4)1147a (55.4)848a (57.8)1349a (55.4)1074a (57.2)1674 (53.8)
Diabetes639 (19.6)374a (18.1)283 (19.3)454a (18.6)351 (18.7)599a (19.2)
CHD1050 (32.2)703a (34)511a (34.9)838a (34.4)665a (35.4)1008 (32.4)
Stroke612 (18.8)394 (19)285 (19.4)458 (18.8)355 (18.9)588 (18.9)
Smoking807 (24.8)518 (25)430a (29.3)606 (24.9)475 (25.3)805a (25.9)
Alcoholic556 (17.1)334 (16.1)236 (16.1)409 (16.8)303 (16.1)537 (17.3)
BMI24.4 (22.2-26.6)24.4a (22.4-26.8)24.6a (22.5-26.9)24.4a (22.3-26.7)24.5a (22.5-26.9)24.4 (22.2-26.6)
TC5.04 (4.41-5.73)5.06a (4.45-5.75)5.02 (4.40-5.71)5.04 (4.42-5.74)5.04 (4.44-5.74)5.03 (4.40-5.73)
LDL3.09 (2.53-3.70)3.11a (2.57-3.72)3.08 (2.55-3.68)3.09 (2.55-3.71)3.10 (2.56-3.71)3.08 (2.53-3.69)
HDL1.35 (1.13-1.61)1.34 (1.13-1.61)1.34 (1.11-1.62)1.34 (1.13-1.62)1.34 (1.12-1.63)1.34 (1.13-1.61)
TG1.38 (1.04-1.90)1.35 (1.03-1.87)1.36 (1.03-1.88)1.36 (1.03-1.88)1.36 (1.03-1.88)1.38 (1.04-1.90)
WBC5.66 (4.83-6.66)5.74a (4.92-6.72)5.78a (4.99-6.84)5.7a (4.87-6.71)5.75a (4.93-6.74)5.66 (4.83-6.66)
Albumin47 (45-49)47a (45-49)47a (45-48)47a (45-49)47a (45-48)47 (45-49)
Uric acid325 (275-380)340a (290-400)355a (301-416)335a (286-393)343a (292-403)327a (279-382)

During a median follow-up of 5.4 years (interquartile ranges: 4.1-7.3), 343 participants (10.53%) experienced MACE including non-fatal myocardial infarction (36, 1.11%), non-fatal stroke (93, 2.86%), cardiovascular revascularization (137, 4.21%), and cardiovascular death (77, 2.36%). The secondary endpoint (all-cause mortality) occurred in 202 participants (6.20%), including non-cardiovascular death (125, 3.84%) and cardiovascular death (77, 2.36%). The incidence of MACE, cardiovascular mortality, and all-cause mortality increased with decreasing eGFR across all five equations (all P < 0.05; Table 2). Kaplan-Meier analyses demonstrated that participants with a low eGFR (< 60 mL/minute) had a significantly higher risk of MACE, cardiovascular mortality, and all-cause mortality compared with those with eGFR ≥ 60 mL/minute for all equations (log-rank P < 0.05), as shown in Figure 2 and Supplementary Figures 1 and 2.

Figure 2
Figure 2 Kaplan-Meier curves show the relationship between estimated glomerular filtration rate and survival free from major cardiovascular events. eGFR: Estimated glomerular filtration rate; MDRD: Modification of Diet in Renal Disease; c-aMDRD: Chinese-abbreviated Modification of Diet in Renal Disease; CKD-EPI: Chronic Kidney Disease Epidemiology Collaboration; aCKD-EPI: Asian-adapted Chronic Kidney Disease Epidemiology Collaboration; cCKD-EPI: Chinese-adapted Chronic Kidney Disease Epidemiology Collaboration; MACE: Major adverse cardiovascular events.
Table 2 Association between clinical outcomes and estimated glomerular filtration rate calculated with different equations, n (%).
Equation
Event
eGFR(mL/minute)
P value
≥ 90
60-90
< 60
MDRDMACE113 (9.5)190 (10.5)40 (15.9)10.011
Cardiovascular mortality16 (1.3)42 (2.3)19 (7.6)1< 0.001
All-cause mortality54 (4.5)95 (5.2)53 (21.1)1< 0.001
Event-free1037 (87.3)1575 (86.6)177 (70.5)1< 0.001
c-aMDRDMACE170 (9.5)137 (10.7)36 (19.4)1< 0.001
Cardiovascular mortality32 (1.8)27 (2.1)18 (9.7)1< 0.001
All-cause mortality82 (4.6)75 (5.9)45 (24.2)1< 0.001
Event-free1571 (87.7)1095 (85.5)123 (66.1)1< 0.001
CKD-EPIMACE71 (8.6)224 (10.7)48 (14.4)10.015
Cardiovascular mortality7 (0.9)246 (2.2)24 (7.2)1< 0.001
All-cause mortality26 (3.2)2111 (5.3)65 (19.5)1< 0.001
Event-free731 (89)21814 (86.3)244 (73.3)1< 0.001
aCKD-EPIMACE122 (8.8)2180 (11.1)41 (16.3)10.001
Cardiovascular mortality12 (0.9)245 (2.8)20 (7.9)1< 0.001
All-cause mortality45 (3.3)2102 (6.3)55 (21.8)1< 0.001
Event-free1224 (88.8)21389 (85.4)176 (69.8)1< 0.001
cCKD-EPIMACE12 (8.3)254 (9.9)77 (14.3)10.006
Cardiovascular mortality1 (0.7)41 (1.6)35 (6.5)1< 0.001
All-cause mortality6 (4.1)109 (4.2)87 (16.2)1< 0.001
Event-free128 (88.3)2252 (87.5)409 (76.0)1< 0.001

Table 3 and Figure 3 depict the association between CKD stage and MACE. Compared to participants with an eGFR of 60-90 mL/minute, those with an eGFR < 60 mL/minute estimated using the c-aMDRD equation had a significantly increased risk of MACE [hazard ratio (HR) = 1.59, 95% confidence interval (CI): 1.06-2.38, P = 0.026]. In contrast, the risk of MACE associated with eGFR < 60 mL/minute was not statistically significant when estimated using the MDRD, CKD-EPI, aCKD-EPI, or cCKD-EPI equations. Likewise, MACE risk did not differ significantly between participants with an eGFR ≥ 90 and 60-90 mL/minute across all equations. Furthermore, participants with an eGFR < 60 mL/minute estimated using the c-aMDRD equation had a significantly higher risk of cardiovascular mortality compared to those with an eGFR of 60-90 mL/minute (HR = 2.86, 95%CI: 1.47-5.56; Supplementary Table 2 and Supplementary Figure 3A). This association was not observed with other equations.

Figure 3
Figure 3 Prediction of major cardiovascular events by estimated glomerular filtration rate calculated using different equations. eGFR: Estimated glomerular filtration rate; MDRD: Modification of Diet in Renal Disease; c-aMDRD: Chinese-abbreviated Modification of Diet in Renal Disease; CKD-EPI: Chronic Kidney Disease Epidemiology Collaboration; aCKD-EPI: Asian-adapted Chronic Kidney Disease Epidemiology Collaboration; cCKD-EPI: Chinese-adapted Chronic Kidney Disease Epidemiology Collaboration; HR: Hazard ratio; CI: Confidence interval.
Table 3 Prediction of major adverse cardiovascular events by estimated glomerular filtration rate calculated with different equations.
eGFR (mL/minute)
Equation
Cox
≥ 90
60-90
< 60
MDRDEvent113/1188190/181840/251
HR1.0811.15
95%CI0.84-1.390.79-1.67
P value0.540.46
c-aMDRDEvent170/1791137/128036/186
HR1.1811.59
95%CI0.92-1.511.06-2.38
P value0.180.026
CKD-EPIEvent71/821224/210348/333
HR1.2110.87
95%CI0.89-1.650.62-1.24
P value0.210.45
aCKD-EPIEvent122/1379180/162641/252
HR1.1411.12
95%CI0.87-1.480.77-1.62
P value0.340.55
cCKD-EPIEvent12/145254/257477/538
HR1.1710.79
95%CI0.62-2.180.58-1.08
P value0.630.14

Interestingly, participants with an eGFR ≥ 90 mL/minute estimated using the c-aMDRD equation also exhibited a higher cardiovascular mortality risk compared to those with an eGFR of 60-90 mL/minute (HR = 1.85, 95%CI: 1.05-3.25), whereas no significant differences were observed with other equations. For all-cause mortality (Supplementary Table 3 and Supplementary Figure 3B), eGFR < 60 mL/minute was consistently associated with an increased risk across all equations: MDRD (HR = 2.45; 95%CI: 1.69-3.56), c-aMDRD (HR = 2.82; 95%CI: 1.86-4.27), CKD-EPI (HR = 1.86; 95%CI: 1.31-2.64), aCKD-EPI (HR = 2.11; 95%CI: 1.47-3.03), and cCKD-EPI (HR = 1.57; 95%CI: 1.11-2.22). In contrast, eGFR ≥ 90 mL/minute was not associated with all-cause mortality compared with the reference group across all equations.

Table 4 summarizes the comparative discrimination performance of the eGFR equations. Compared to the MDRD equation, the CKD-EPI, aCKD-EPI, and cCKD-EPI equations demonstrated significantly better discrimination for MACE, cardiovascular mortality, and all-cause mortality, with AUC differences ranging from 0.024 to 0.059 (all P < 0.001; Figure 4A). Similarly, compared to the c-aMDRD equation, the CKD-EPI, aCKD-EPI, and cCKD-EPI equations showed superior discrimination for all outcomes (AUC differences, 0.018 to 0.061; all P < 0.001; Figure 4B).

Figure 4
Figure 4 Comparison of predictive ability of different estimated glomerular filtration rate equations. A: Compared to the Modification of Diet in Renal Disease equation; B: Compared to the Chinese-abbreviated Modification of Diet in Renal Disease equation. AUC: Area under of the receiver operating characteristic curves; MACE: Major adverse cardiovascular events; MDRD: Modification of Diet in Renal Disease; c-aMDRD: Chinese-abbreviated Modification of Diet in Renal Disease; CKDEPI: Chronic Kidney Disease Epidemiology Collaboration; aCKDEPI: Asian-adapted Chronic Kidney Disease Epidemiology Collaboration; cCKDEPI: Chinese-adapted Chronic Kidney Disease Epidemiology Collaboration.
Table 4 Assessment of the discrimination ability of different estimated glomerular filtration rate equations.
MACE
CV mortality
All-cause mortality
Event-free
ΔAUC
P value
ΔAUC
P value
ΔAUC
P value
ΔAUC
P value
MDRD and c-aMDRD-0.060.0890.0020.744-0.0040.372-0.0070.027
MDRD and CKD-EPI-0.025< 0.001-0.059< 0.001-0.051< 0.001-0.032< 0.001
MDRD and aCKD-EPI-0.024< 0.001-0.059< 0.001-0.049< 0.001-0.030< 0.001
MDRD and cCKD-EPI-0.034< 0.001-0.057< 0.001-0.050< 0.001-0.041< 0.001
c-aMDRD and CKD-EPI-0.019< 0.001-0.061< 0.001-0.047< 0.001-0.025< 0.001
c-aMDRD and aCKD-EPI-0.0180.001-0.061< 0.001-0.046< 0.001-0.024< 0.001
c-aMDRD and cCKD-EPI-0.028< 0.001-0.059< 0.001-0.047< 0.001-0.035< 0.001
CKD-EPI and aCKD-EPI0.0010.0750.0000.8760.0010.0690.0020.003
CKD-EPI and cCKD-EPI-0.0090.1180.0020.8700.0000.981-0.0090.067
aCKD-EPI and cCKD-EPI-0.0100.0930.0020.887-0.0010.885-0.0110.038

Model fit was assessed using the AIC and the Bayesian Information Criterion across different endpoints (Supplementary Table 4). The AIC and Bayesian Information Criterion values for the CKD-EPI, aCKD-EPI, and cCKD-EPI equations were lower than those of the other two equations, suggesting that the fit of the CKD-EPI, aCKD-EPI, and cCKD-EPI equations were better than that of the MDRD and c-aMDRD equations.

DISCUSSION
Key findings

This study examined the impact of renal impairment on long-term outcomes in an elderly Chinese population. Several key findings emerged. First, when different equations were used to calculate eGFR, the prevalence of eGFR < 60 mL/minute/1.73 m2 varied widely, ranging from 5.7% to 16.5%. Second, irrespective of the equation applied and despite differences in prevalence across equations, participants with an eGFR < 60 mL/minute/1.73 m2 had a significantly higher risk of MACE, cardiovascular mortality, and all-cause mortality. Third, a significant association between eGFR and outcomes was observed when using the c-aMDRD equation, with lower eGFR independently associated with MACE and cardiovascular mortality. In addition, reduced eGFR was consistently associated with all-cause mortality across all equations. Finally, the CKD-EPI, aCKD-EPI, and cCKD-EPI equations demonstrated superior prognostic performance for MACE, cardiovascular mortality, all-cause mortality, and event-free survival compared with the MDRD and c-aMDRD equations.

Previous literature on renal dysfunction and clinical outcomes

Interest in the association between renal impairment and the risks of mortality and cardiovascular disease has increased substantially in recent years. GFR is the most comprehensive index of renal function in both healthy and diseased states[20]. Although eGFR is an established predictor of clinical outcomes in older populations, evidence regarding the comparative prognostic performance of different eGFR equations remains limited and inconsistent. Prior studies have suggested that the CKD-EPI equation provides more accurate GFR estimation and superior risk prediction compared with the MDRD equation[7,21,22]. However, to our knowledge, no previous study compared the prognostic value of Asian- or Chinese-modified equations with conventional equations in an elderly Chinese population. Our findings provide novel evidence that, in older Chinese individuals, all eGFR equations independently predicted all-cause mortality, whereas only the c-aMDRD equation retained independent prognostic value for MACE and cardiovascular mortality. These results highlight potential differences in equation performance for cardiovascular vs non-cardiovascular outcomes and underscore the need for population-specific calibration when using eGFR for cardiovascular risk stratification.

In Western populations, the prevalence of CKD is approximately 10% at age 65 and increases to nearly 60% among individuals aged ≥ 80 years[12,13]. A large retrospective cohort study in Spain (n = 130233; median age 70 years) reported that 13.5% of participants overall and 29% of those aged ≥ 75 years had an eGFR < 60 mL/minute using the CKD-EPI equation[10]. Similarly, in a Belgian cohort of individuals aged ≥ 80 years, the prevalence of eGFR < 60 mL/minute was 44%-45% based on the MDRD and CKD-EPI equations[23]. Moreover, the mean eGFR estimated by the MDRD and CKD-EPI equations were 64 ± 22 mL/minute and 61 ± 19 mL/minute, respectively. In our study, the prevalence of eGFR < 60 mL/minute ranged from 5.7% to 16.5% across equations and the mean eGFR was 94 ± 24, 85 ± 20, 83 ± 15, 79 ± 14, and 71 ± 12 mL/minute when using the c-aMDRD, MDRD, aCKD-EPI, CKD-EPI, and cCKD-EPI equations, respectively, suggesting age- and equation-dependent variability. In contrast, Matsushita et al[21] reported that the median eGFR calculated using the CKD-EPI equation was higher than that calculated using the MDRD equation (97.6 mL/minute vs 88.8 mL/minute) in the Atherosclerosis Risk in Communities Study. Scr, the basis of these equations, is influenced not only by GFR but also by muscle mass, diet, sex, race, and aging, which may partly explain inter-equation and population differences in estimated renal function.

Previous studies have consistently demonstrated that reduced eGFR is associated with increased all-cause mortality and cardiovascular morbidity[24-26]. However, findings in older populations have been inconsistent. In NHANES II, eGFR < 70 mL/minute (MDRD) was associated with increased all-cause and cardiovascular mortality[24], whereas in the Atherosclerosis Risk in Communities study, an eGFR of 15-59 mL/minute was linked to higher cardiovascular risk[26]. Similar results were obtained in a cohort of older adults (≥ 65 years old) for an eGFR of 15-59 mL/minute (MDRD)[25]. In contrast, NHANES I did not observe a significant association between eGFR 30-60 mL/minute and mortality[27]. Large population-based studies from the United States, Iceland, and the United Kingdom further demonstrated that eGFR < 60 mL/minute was independently associated with mortality and cardiovascular outcomes[1,28,29]. Using the CKD-EPI equation, Shastri et al[2] reported that eGFR < 43 mL/minute predicted mortality in older adults, and Van Pottelbergh et al[23] showed that risks were particularly pronounced when eGFR < 30 mL/minute.

In our study, eGFR < 60 mL/minute estimated by all equations was significantly associated with all-cause mortality, whereas eGFR < 60 mL/minute predicted MACE and cardiovascular mortality only when calculated using the c-aMDRD equation. These discrepancies may reflect differences in eGFR equations and population characteristics. Notably, we observed a U-shaped association between eGFR (c-aMDRD) and cardiovascular mortality, consistent with prior studies reporting increased mortality at higher eGFR levels[2,10], potentially reflecting confounding by frailty, hyperfiltration, or creatinine-related bias.

Our findings indicate that the CKD-EPI, aCKD-EPI, and cCKD-EPI equations demonstrated superior discrimination for MACE, cardiovascular mortality, and all-cause mortality compared with the MDRD and c-aMDRD equations in an elderly Chinese community-based population. Consistent with our results, previous work from the North Shanghai Study showed that eGFR estimated using the aCKD-EPI and cCKD-EPI equations was more strongly associated with preclinical target organ damage[9]. These differences are not unexpected, as some equations were derived and validated in Western populations, whereas others were developed in Asian or Chinese cohorts.

The CKD-EPI equation, a newer GFR estimation method, has consistently shown greater accuracy than the MDRD equation across diverse populations and clinical settings[6]. The four-level ethnicity-based CKD-EPI equation further reduced estimation bias in Asian populations[7], including Chinese individuals, and CKD-EPI-derived eGFR has been shown to better predict adverse outcomes in Asian cohorts[3,30,31]. Accordingly, the aCKD-EPI equation may provide more accurate risk stratification in elderly Chinese individuals. The superior performance of the cCKD-EPI equation may reflect its derivation in a Chinese population with an age distribution like our cohort, highlighting the importance of population- and age-specific calibration of eGFR equations for cardiovascular risk prediction.

Strengths and limitations

This study is the first to compare eGFR equations in relation to adverse outcomes in elderly Chinese individuals. A major advantage of our study is that it utilized data from a population-based, prospective cohort study. This study also has limitations. The Scr concentrations were measured using the enzymatic method and the eGFR was based on the initial creatinine value observed at admission, but variations in creatinine concentrations within subjects should be considered. The absence of a reference standard for measuring the true GFR, as well as the eGFR cutoff of 60 mL/minute utilized to define CKD in older people in this study, is frequently debated because some age-related decline renal function might result from physiological changes rather than true pathology. Our participants were recruited from northern Shanghai; therefore, the findings may not apply to other races. Finally, the cross-sectional design of this study cautions against overinterpretation of the data.

CONCLUSION

The different eGFR values showed poor agreement, with the prevalence of renal dysfunction (eGFR < 90 mL/minute) ranging from 45%-95%. A low eGFR estimated by c-aMDRD is associated with MACE and cardiovascular mortality and with all-cause mortality by all equations in community-dwelling elderly Chinese individuals. The CKD-EPI, aCKD-EPI, and cCKD-EPI equations demonstrated better predictive ability for long-term outcomes than the MDRD and c-aMDRD equations in this populations.

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Footnotes

Peer review: Externally peer reviewed.

Peer-review model: Single blind

Specialty type: Cardiac and cardiovascular systems

Country of origin: China

Peer-review report’s classification

Scientific quality: Grade B, Grade B

Novelty: Grade B, Grade C

Creativity or innovation: Grade C, Grade C

Scientific significance: Grade A, Grade C

P-Reviewer: Zhou XD, MD, Associate Chief Physician, China S-Editor: Wu S L-Editor: Wang TQ P-Editor: Xu J

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