Best Albuminuria Measurement to Predict Cardiovascular and Renal Events

Abstract

Background: Kidney Disease Improving Global Outcomes (KDIGO) guidelines encourage clinicians to estimate 24-hour albuminuria as albumin to creatinine ratio (ACR) from spot urine samples. However, ACR underestimates 24-hour albumin excretion in muscular individuals. Equations that adjust ACR for surrogates of muscle mass to yield an estimated albumin excretion rate (eAER) were developed. We hypothesised that eAER is a better predictor of cardiovascular and renal outcomes than ACR. Methods: We determined ACR and eAER among 443 patients with chronic kidney disease G2-G4 recruited into the CARE FOR HOMe study. Patients were classified into KDIGO albuminuria categories, and followed for cardiovascular and renal events. The primary analysis was the net reclassification improvement (NRI) for those with and without events within 3 years of follow-up. Results: Eighty five patients experienced cardiovascular events during 3 years of follow-up, 13 of whom were reclassified to a more advanced albuminuria category, and 1 patient to a less advanced category by eAER compared to ACR (NRI_event: 14.1% (95% CI 5.8-22.4)). Among 358 patients without a cardiovascular event, 17 patients were reclassified to a more advanced albuminuria category, and 2 patients to a less advanced category by eAER (NRI_{no event}: -4.2%, 95% CI -8.5 to -1.8). Sixty patients went through renal events, and 383 patients had event-free 3-year follow-up. NRI_event was 6.7% (95% CI -1.2 to 14.5), and NRI_{no event} was -6.0% (95% CI -10.6 to 3.4) for renal events. Conclusion: Compared to ACR albuminuria categories, eAER categories are better associated with future cardiovascular events, but not with renal events.

Performance of 24-hour urinary creatinine excretion-estimating equations in relation to measured 24-hour urinary creatinine excretion in hospitalized hypertensive patients

“…We did not control for various factors potentially affecting creatinine generation/urinary excretion, such as diet and physical activity, but these factors may be expected to have the same effect on all formulas, and their variability is reduced in hospital settings. We did not include formulas without any anthropometric variables reflecting body size 40,41 , and formulas that include parameters that are often not routinely available, such as serum phosphorus 20 and estimates of muscle mass 21,36 . Reference 24 hrUCr measurements were performed in a single 24-hour urine collection.…”

The application of new complex indicators in the detection of urine

“…From our study results, 24-h urinary protein quantification displayed significant distribution discrepancies in the two pathological types and was more related to Type I. Clinical practice guidelines recommend screening for and monitoring albuminuria and incorporating increased albuminuria into the definition and staging of CKD [ 26 ]. The 24-h urinary protein quantification known as the “gold standard”[ 27 ] method for evaluating proteinuria is an ideal target to be adjusted, as it avoids protein fluctuations during the day and can indirectly reflect patients’ kidney functions.…”

Utilizing Estimated Creatinine Excretion to Improve the Performance of Spot Urine Samples for the Determination of Proteinuria in Kidney Transplant Recipients

“…The studies that have examined the use of the eCER in proteinuria determination were performed in non-transplant recipients[9, 20–22]. Fotheringham showed improved bias and accuracy of the eAER calculated by the eCER using the Fotheringham formula[9] (bias 0.8 mg/24 h) as compared to the standard ACR (bias -3.8 mg/24 h).…”

“…More recently, Hong et al[20] published better correlation of eAER and ePER with 24 hour urine albumin and protein excretion. Finally, Bauer et al[22] revealed better association of eAER compared to ACR in predicting cardiovascular outcomes. In our study comprising only of transplant recipients, we found bias by eAER calculated by Fotheringham CER to be better than ACR and similar to eAER calculated by CKD-EPI formulae CER.…”