MATERIALS AND METHODS: This is a cross-sectional study of patients referred for 99mTc-DTPA scan at the Nuclear Medicine Centre of International Islamic University Malaysia. The record was taken from patients visiting the centre from January 2016 to December 2019.
RESULTS: The mean measured GFR by 99mTc-DTPA scan was 42.2 ± 20.38 ml/min. These were lower than that estimated by CG, MDRD, and CKD-EPI equations. CKD-EPI had the highest correlation of 0.72, least bias (mean bias of 11.08 ± 23.08) and was more precise (r2 = 0.4) as compared to MDRD and CG. In patients < 65 years old, CKD-EPI had the highest correlation; however, MDRD had the least bias and highest accuracy. In terms of BMI, CKD-EPI had the least bias and highest accuracy for BMI >30 and with the highest correlation for all classes of BMI.
CONCLUSION: CKD-EPI has the best estimation of GFR taking into account the effect of BMI and age. A further study can be done to determine the correlation of estimated GFR equations with different ethnicity in Malaysia.
Objectives: We developed a new equation based on the gold standard of 99mTc-DTPA imaging measured GFR. We then performed an internal validation by comparing the bias, precision, and accuracy of the new equation and the other equations with the gold standard of 99mTc-DTPA imaging measured GFR.
Methods: This was a cross-sectional study using the existing record of patients who were referred for 99mTc-DTPA imaging at the Nuclear Medicine Centre, International Islamic University Malaysia. As this is a retrospective study utilising routinely collected data from the existing pool of data, the ethical committee has waived the need for informed consent.
Results: Data of 187 patients were analysed from January 2016 to March 2021. Of these, 94 were randomised to the development cohort and 93 to the validation cohort. A new equation of eGFR was determined as 16.637 ∗ 0.9935Age ∗ (SCr/23.473)-0.45159. In the validation cohort, both CKD-EPI and the new equation had the highest correlation to 99mTc-DTPA with a correlation coefficient of 0.81 (p < 0.0001). However, the new equation had the least bias and was the most precise (mean bias of -3.58 ± 12.01) and accurate (P30 of 64.5% and P50 of 84.9%) compared to the other equations.
Conclusion: The new equation which was developed specifically using our local data population was the most accurate and precise, with less bias compared to the other equations. Further study validating this equation in the perioperative and intensive care patients is needed.