Accurate GFR in obesity-protocol for a systematic review

Area of Science:

• Nephrology
• Metabolic Disorders
• Diagnostic Accuracy

Background:

• Obesity is a growing global health concern with a strong link to chronic kidney disease (CKD).
• Current methods for estimating kidney function, primarily using creatinine-based equations like CKD-EPI, are crucial for clinical decisions but may be inaccurate in obese individuals.
• The impact of obesity on the reliability of these estimations is not well understood.

Purpose of the Study:

• To systematically review diagnostic studies comparing estimated glomerular filtration rate (eGFR) equations with measured kidney function in obese individuals.
• To assess the accuracy of commonly used creatinine-based equations in estimating kidney function in the context of obesity and CKD.
• To inform clinical practice regarding the most suitable equations for CKD management in obese patients.

Main Methods:

• A comprehensive systematic search of electronic databases (MEDLINE, EMBASE, Cochrane Library) will be conducted.
• Data extraction will include study characteristics, participant demographics, reference standards, index tests, and measures of agreement (e.g., proportion within 10-50% of measured GFR) and bias.
• Meta-analysis will be performed if study quality and risk of bias are adequate, with heterogeneity assessed using I² statistics and meta-regression for sensitivity analyses.

Main Results:

• Preliminary searches identified a substantial number of relevant citations across databases.
• The review will quantify the proportion of estimated GFR (eGFR) values falling within specified percentages of measured GFR.
• Bias between eGFR and measured GFR will be analyzed, with potential for meta-regression to explore influencing factors.

Conclusions:

• This systematic review aims to provide evidence-based guidance for clinicians on the optimal use of kidney function estimation equations in obese patients with CKD.
• The findings will assist in accurate CKD staging and appropriate medication dosing.
• If current equations prove inadequate, this review will highlight the need for developing and validating new GFR estimation methods for obese populations.