Abstract
Objective. To increase the accuracy of estimated GFR (eGFR) from creatinine overall and at measured GFR ≥90 mL/min per 1.73 m2 by revising the Lund-Malmö (LM) equations, to elaborate on more complex forms to improve the LM and CKD-EPI equations further, and to assess benefits of adding lean body mass (LBM). Material and methods. Swedish Caucasians (n = 850, 376 women; median 60, range 18–95 years) referred for GFR measurement (plasma iohexol-clearance: median 55, range 5–173 mL/min/1.73 m2) constituted the Lund-Malmö Study cohort. Bias, precision, accuracy, expressed as median absolute percentage difference and percentage of estimates ±10% (P10) and ±30% (P30) of measured GFR, and classification ability with respect to five GFR stages were compared with the original LM, CKD-EPI and MDRD equations. Results. LM Revised overall performed better than LM Original without LBM due to increased accuracy at measured GFR ≥90 mL/min/1.73 m2. Further extensions of the CKD-EPI or LM equations did not substantially improve overall performance. In particular, the performance of LM Revised at measured GFR ≥90 mL/min/1.73 m2 could not be improved further without decreasing accuracy and classification ability at lower GFR-levels. Adding LBM to the equations had no strong effect on accuracy. Conclusion. Comparisons with the CKD-EPI and MDRD equations suggest that the LM equations are superior for the present Swedish population, due to markedly higher accuracy of the LM equations at measured GFR <30 mL/min/1.73 m2. However, the LM equations cannot be recommended for use in general clinical practice until validated in other populations.
Acknowledgement
We thank librarian Elisabeth Sassersson for her excellent service regarding literature references.
Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.