Serum creatinine-based estimation equations in ageing populations: A comprehensive review of accuracy and reliability

Estimating glomerular filtration rate (GFR) using serum creatinine-based equations is central to kidney function assessment in clinical practice. However, these equations face significant limitations when applied to ageing populations due to physiological changes, such as sarcopenia and nephron loss, and a higher prevalence of comorbidities. Accurate estimation of kidney function in older adults is critical for effective disease management, risk stratification, and therapeutic decision-making. This review evaluates the accuracy and reliability of widely used serum creatinine-based equations, including the Modification of Diet in Renal Disease equation, the Chronic Kidney Disease Epidemiology Collaboration equation, and the Cockcroft–Gault equation, in older adults. It highlights gaps in current practices and explores emerging alternatives to address the unique challenges posed by ageing physiology. A comprehensive analysis of the literature was conducted to assess the performance of serum creatinine-based equations in elderly cohorts. Factors such as age-related changes in renal physiology, the impact of reduced muscle mass, and biases introduced by non-standardized creatinine assays were considered. Emerging approaches, including cystatin C-based and combined equations, as well as multi-marker models, were reviewed for their potential to improve accuracy in this demographic. Current equations often misclassify kidney function in older adults, leading to over- or underestimation of GFR. Alternatives, such as cystatin C-based equations, show promise but require further validation in ageing populations. Standardisation of assays and the development of age-specific models are critical to enhancing accuracy. Tailored approaches that integrate multiple biomarkers and account for the complexities of ageing physiology are necessary to improve GFR estimation in older adults. Future research should focus on validating these methods in diverse elderly populations.