Current equations estimating glomerular filtration rate in primary care: comparison and determinants

Area of Science:

• Nephrology
• Primary Care Medicine
• Epidemiology

Background:

• Accurate estimation of glomerular filtration rate (eGFR) is crucial for diagnosing and managing chronic kidney disease (CKD).
• The Modification of Diet in Renal Disease (MDRD) and Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equations are widely used for eGFR estimation.
• Primary care settings manage a significant proportion of patients with or at high risk of CKD.

Purpose of the Study:

• To compare eGFR estimations between MDRD and CKD-EPI equations in a primary care population.
• To evaluate the concordance in CKD staging using both eGFR equations.
• To identify patient factors influencing discrepancies between MDRD and CKD-EPI eGFR values.

Main Methods:

• An observational study involving 803 patients with CKD, hypertension, or diabetes managed in primary care.
• Calculation of eGFR using both MDRD and CKD-EPI equations for 1534 instances.
• Bland-Altman analysis was employed to quantify bias and precision between the two equations.

Main Results:

• The mean eGFR(MDRD) was slightly higher than eGFR(CKD-EPI) by 0.8 ± 3.6 ml/min/1.73 m(2).
• CKD staging agreement between MDRD and CKD-EPI was high, occurring in 93.3% of cases.
• Factors such as age and extreme eGFR values influenced the differences between the equations.

Conclusions:

• No clinically significant differences were observed between MDRD and CKD-EPI eGFR estimations in this primary care cohort.
• Both equations demonstrated high agreement in classifying CKD stages.
• The established MDRD equation is recommended for primary care use due to its simplicity and comparable performance to CKD-EPI.