The Fenofibrate Role In The Fight For Kidney Function Preservation
Chronic kidney disease (CKD) and end-stage renal disease (ESRD) are increasingly significant global health concerns, with CKD now affecting an estimated 9.1% of the world’s population—a 29.3% increase since 1990. This rise has severe implications, contributing to 1.2 million deaths annually and a considerable burden of disability. While statins are widely used to manage cardiovascular risks associated with CKD, their impact on slowing kidney disease progression remains uncertain. However, emerging evidence suggests that fibrates, despite concerns about their effects on serum creatinine levels, may offer protective benefits for renal function. This study explores the potential renoprotective impacts of fenofibrate, hypothesizing that it could prevent or delay the onset of ESRD, a hypothesis tested within a large population-based cohort in Korea.
THE STUDY BACKGROUND
Chronic kidney disease (CKD) and end-stage renal disease (ESRD) are critical global health issues, with the prevalence of CKD reaching 9.1% worldwide—a significant increase of 29.3% between 1990 and 2017 [1]. The rising incidence of CKD has led to substantial public health challenges, including 1.2 million deaths annually, positioning CKD as the 12th leading cause of death globally. Additionally, CKD is responsible for 35.8 million disability-adjusted life years (DALYs), underscoring the severe impact of this condition on global health [1]. As renal function deteriorates, the risk of initiating dialysis, developing cardiovascular complications, and increased mortality becomes more pronounced, making the preservation of renal function a critical objective in managing CKD [2].
The primary treatment approach for reducing low-density lipoprotein (LDL) cholesterol levels and associated cardiovascular risks in CKD patients involves the use of statins. However, there is limited evidence supporting the efficacy of statins in slowing the progression of renal disease [3]. Fibrates, another class of lipid-lowering agents, have shown uncertain outcomes in cardiovascular risk reduction. Still, several studies have indicated that fibrates may improve renal outcomes. These improvements include reductions in albuminuria and a slower decline in estimated glomerular filtration rate (eGFR) [4–6]. Despite these findings, the potential renoprotective effects of fibrates, particularly fenofibrate, remain underexplored, especially concerning hard renal outcomes like ESRD.
Large-scale randomized controlled trials are needed to confirm the renoprotective effects of fenofibrate; however, such trials face challenges, including concerns about the potential increase in serum creatinine levels associated with fenofibrate use [7]. This has led to clinical recommendations against using fibrates in patients with reduced renal function. Despite these challenges, recent studies suggest that the elevation in serum creatinine induced by fenofibrate is reversible and not linked to tubular injury, indicating that fenofibrate may still have a role in renal protection [8,9]. Given the impracticality of large trials, well-structured observational studies are essential for providing additional evidence on the potential benefits of fenofibrate in CKD patients.
This study aims to investigate the renoprotective effects of fenofibrate by analyzing its impact on the development of ESRD in a large, nationwide, population-based cohort in Korea. The findings of this study could significantly contribute to the fields of nephrology and cardiology by providing evidence of a potential new approach to managing CKD and reducing the risk of ESRD. Additionally, the study examines the impact of concurrent statin use, as recommended for reducing cardiovascular risk in most CKD patients, to provide a comprehensive understanding of the potential benefits and risks of fenofibrate in this population [10].
THE STUDY METHOD
This research utilized data from the National Health Information Database (NHID) of South Korea, which is linked to the National Health Screening Program and National Death Registry. This comprehensive database covers 97% of the Korean population. It includes a wide array of sociodemographic details, medical records, and health screening results. The study focused on individuals who were prescribed fenofibrate for the first time between 2010 and 2017. A total of 1,465,824 individuals were initially identified. Still, after applying exclusion criteria—such as the absence of statin treatment, missing data, previous ESRD diagnosis, or development of ESRD within one year—the final analysis included 413,715 patients, evenly divided into fenofibrate user and non-user groups through 1:1 matching based on age, sex, and triglyceride levels.
Key measurements in the study included glucose, cholesterol levels, and estimated glomerular filtration rate (eGFR), which were assessed through blood samples collected after an overnight fast. The study also gathered data on lifestyle factors such as smoking status, alcohol consumption, physical activity, and socioeconomic status. Definitions for conditions like obesity, hypertension, and diabetes were based on standardized criteria, including body mass index (BMI) and blood pressure thresholds, as well as ICD-10 codes for relevant medical diagnoses.
The primary outcome of the study was the development of end-stage renal disease (ESRD). Incident ESRD was identified using specific ICD-10 codes and a unique “V code” that indicates the initiation of renal replacement therapy, such as dialysis or kidney transplantation. The study ensured comprehensive coverage by including all patients in South Korea who began dialysis, with data follow-up continuing until the onset of ESRD or until December 31, 2019. Exclusions were made for patients who received transplants or dialysis on the same date as an acute renal failure diagnosis, and those on continuous renal replacement therapy were also excluded.
ANALYSIS
The study used several statistical methods to analyze the data. Baseline characteristics of participants were compared using independent sample t-tests for continuous variables and χ² tests for categorical variables. ESRD incidence rates were calculated as the number of events per 1000 person-years. To assess the relationship between fenofibrate use and ESRD risk, hazard ratios (HRs) and 95% confidence intervals (CIs) were computed using Cox proportional hazards models. These models adjusted for a range of factors, including age, sex, income, smoking status, alcohol consumption, physical activity, BMI, diabetes, hypertension, HDL cholesterol, triglycerides, eGFR, and urine protein levels.
Kaplan–Meier survival curves were used to visualize and compare ESRD incidence rates among fenofibrate users and non-users, with statistical significance tested using the log-rank test. The analysis also included subgroup assessments to determine if the effect of fenofibrate on ESRD varied by factors such as income, smoking status, alcohol intake, physical activity, obesity, diabetes, hypertension, metabolic syndrome, proteinuria, CKD, and eGFR. All data analyses were conducted using SAS version 9.4, and a p-value of less than 0.05 was considered statistically significant.
RESULTS
- Baseline Characteristics:
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- Participants: The mean age was 57.7 years, with 54.0% being men.
- Fenofibrate Users vs. Non-Users:
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- Health Profile: Fenofibrate users generally had a worse health profile compared to non-users, including higher rates of obesity, smoking, heavy drinking, low income, diabetes, hypertension, metabolic syndrome, and sedentary lifestyles.
- Laboratory Measures: Users had higher glucose levels and lower HDL cholesterol but lower LDL cholesterol and prevalence of CKD compared to non-users.
- Follow-Up and Incidence Rates:
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- Follow-Up Duration: Median follow-up was 3.96 years.
- ESRD Incidence Rates:
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- Fenofibrate users had a lower ESRD incidence rate (0.885 per 1000 person-years) compared to non-users (0.960 per 1000 person-years).
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- Hazard Ratios:
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- The unadjusted HR for ESRD in fenofibrate users was 0.922.
- Multivariate-adjusted HR for ESRD in fenofibrate users was 0.763.
- Kaplan–Meier Survival Curves:
- Fenofibrate use was associated with a significantly lower risk of incident ESRD after adjusting for multiple covariates (p < 0.0001).
- Subgroup Analyses:
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- Modification by Sex and Age: The association between fenofibrate use and lower ESRD risk varied by sex and age.
- Consistency Across Subgroups: The lower risk of ESRD associated with fenofibrate was consistent across various factors, including income, smoking status, alcohol consumption, physical activity, obesity, diabetes, and metabolic syndrome.
- Variable Associations:
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- The effect was modified by hypertension, urine protein levels, and eGFR.
- Fenofibrate use was linked to a lower incidence of ESRD in subgroups with risk factors like hypertension, proteinuria, and decreased eGFR.
This analysis indicates that fenofibrate use is associated with a reduced risk of ESRD, even among individuals with adverse baseline health characteristics.
DISCUSSION
This large-scale, nationwide cohort study demonstrates that fenofibrate when added to statin therapy, is associated with a reduced risk of end-stage renal disease (ESRD) in the general population despite fenofibrate users having more risk factors for ESRD. The analysis found that fenofibrate use was linked to a lower risk of ESRD, particularly among individuals with hypertension, proteinuria, and an estimated glomerular filtration rate (eGFR) below 60 mL/min/1.73 m². This finding suggests that fenofibrate might offer protective benefits for renal health even in patients with significant renal risk factors [15–17].
Previous studies have raised concerns about fenofibrate due to its association with increased serum creatinine levels and elevated homocysteine, which are potential risk factors for kidney damage. However, other research has highlighted fenofibrate’s potential renal benefits. For instance, the FIELD study found that while fenofibrate did not significantly impact major coronary outcomes, it reduced albuminuria progression, indicating possible renoprotective effects [5]. Similarly, detailed analyses of the FIELD study and post hoc analyses from the ACCORD Lipid Trial showed that fenofibrate could slow eGFR decline and reduce albuminuria. However, it was discontinued if eGFR dropped below 30 mL/min/1.73 m² [6,7].
The findings from this study align with those of Yen et al., who also observed a delay in permanent dialysis initiation among fenofibrate users compared to those using statins alone. This study, however, is much larger, allowing for more robust subgroup analyses and identification of characteristics that might influence the efficacy of fenofibrate in delaying ESRD [19]. Recent meta-analyses, such as those by Hadjivasilis et al., also support the notion that fenofibrate can decrease albuminuria and improve renal outcomes. However, creatinine levels might rise initially but stabilize over time [20].
Several mechanisms might explain fenofibrate’s renal protective effects. Elevated creatinine levels seen with fenofibrate use appear to be reversible and do not necessarily indicate nephrotoxicity. The drug’s ability to lower triglycerides, improve lipid profiles, and exert anti-inflammatory effects might contribute to its renal benefits. Furthermore, fenofibrate’s impact on reducing blood viscosity and improving microcirculatory dysfunction could also be beneficial in preventing kidney damage [21–25]. Current guidelines have begun to reflect these findings, suggesting that fenofibrate-induced creatinine elevation might not signify adverse renal effects and supporting further investigation into its potential benefits for patients with advanced chronic kidney disease [31,32].
The results of this study suggest that fenofibrate could be an effective option for delaying dialysis in patients with advanced CKD. However, more clinical trials are needed to validate these findings and fully understand the long-term impact of fenofibrate on renal health.
STUDY LIMITATIONS AND STRENGTHS
- Study Limitations:
- Observational Nature: The study’s observational design means causality cannot be established, and the potential for reverse causation or residual confounding exists.
- Ethnic Specificity: The study was conducted exclusively with Korean participants, which may limit the generalizability of the results to other ethnic groups. Confirmation in diverse populations is needed.
- Lack of Follow-Up Data: Follow-up test results on lipid profiles or renal function were needed. It prevented the assessment of changes over time after fenofibrate use.
- Single eGFR Measurement: eGFR was measured only once, which might overlook temporary changes in creatinine levels or acute kidney injury at the baseline.
- Missing Data on Serum Uric Acid: Data on serum uric acid levels, which fenofibrate can affect and which is associated with CKD, was not available.
- Study Strengths:
- Large-Scale Data: The study benefits from a large, nationwide population-based cohort, enhancing the reliability of the findings.
- Real-World Context: The inclusion of real-world data from patients taking statins provides practical insights into fenofibrate’s effects in typical clinical settings.
- Clinical Implications:
- The study supports the potential benefit of fenofibrate in reducing the risk of ESRD among patients on statins, particularly in those with significant renal risk factors. The findings suggest that fenofibrate may be a valuable addition to statin therapy for certain patient groups.
- Future Research Directions:
- Further research is needed to address the limitations of the current study, particularly through longitudinal studies that can track changes in renal function and lipid profiles over time. Additionally, studies involving diverse populations and data on serum uric acid levels could provide a more comprehensive understanding of fenofibrate’s impact on renal health.
CONCLUSION
The study concludes that adding fenofibrate to statin therapy is linked to a reduced risk of end-stage renal disease (ESRD) in Korean adults, with the effect being particularly significant in those with hypertension, proteinuria, or a lower estimated glomerular filtration rate (eGFR). These findings suggest a potential renoprotective role of fenofibrate for patients at high risk or with compromised kidney function. However, to solidify these observations, a large-scale randomized controlled trial focused on patients with reduced renal function is needed.
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