The ratio and difference of urine protein-to-creatinine ratio and albumin-to-creatinine ratio facilitate risk prediction of all-cause mortality

Abstract

The role of the difference and ratio of albuminuria (urine albumin-to-creatinine ratio, uACR) and proteinuria (urine protein-to-creatinine ratio, uPCR) has not been systematically evaluated with all-cause mortality. We retrospectively analyzed 2904 patients with concurrently measured uACR and uPCR from the same urine specimen in a tertiary hospital in Taiwan. The urinary albumin-to-protein ratio (uAPR) was derived by dividing uACR by uPCR, whereas urinary non-albumin protein (uNAP) was calculated by subtracting uACR from uPCR. Conventional severity categories of uACR and uPCR were also used to establish a concordance matrix and develop a corresponding risk matrix. The median age at enrollment was 58.6 years (interquartile range 45.4–70.8). During the 12,391 person-years of follow-up, 657 deaths occurred. For each doubling increase in uPCR, uACR, and uNAP, the adjusted hazard ratios (aHRs) of all-cause mortality were 1.29 (95% confidence interval [CI] 1.24–1.35), 1.12 (1.09–1.16), and 1.41 (1.34–1.49), respectively. For each 10% increase in uAPR, it was 1.02 (95% CI 0.98–1.06). The linear dose–response association with all-cause mortality was only observed with uPCR and uNAP. The 3 × 3 risk matrices revealed that patients with severe proteinuria and normal albuminuria had the highest risk of all-cause mortality (aHR 5.25, 95% CI 1.88, 14.63). uNAP significantly improved the discriminative performance compared to that of uPCR (c statistics: 0.834 vs. 0.828, p-value = 0.032). Our study findings advocate for simultaneous measurements of uPCR and uACR in daily practice to derive uAPR and uNAP, which can provide a better mortality prognostic assessment.

Urinary non-albumin protein-creatinine ratio is an independent predictor of mortality in patients with type 2 diabetes: a retrospective cohort study

“…However, the study exploring the prognostic value of non-albumin proteinuria on mortality was limited and the study focusing on patients with type 2 DM was unavailable. Chang et al 25 investigated the predictive values of UACR, UPCR, and UNAPCR on all-cause mortality in a population with 32.1% patients with DM and in the 3 × 3 risk matrices demonstrating HRs for all-cause mortality categorized by UPCR (< 150, ≥ 150 to < 500, and ≥ 500 mg/g) and UACR (< 30, ≥ 30 to < 300, and ≥ 300 mg/g). Interestingly, subjects with UACR < 30 and UPCR ≥ 500 mg/g had the highest risk of mortality among all groups compared to subjects with UACR < 30 and UPCR < 150 mg/g as the reference group in a multivariable model.…”

“…A composite of non-albumin proteinuria and albuminuria may improve the prediction of DKD progression in patients with type 2 DM 24 . In a population consisting of 32.1% patients with DM, UNAPCR had the most linear dose–response relationship with all-cause mortality and significantly improved the risk assessment for mortality compared to UACR and urine protein-to-creatinine ratio (UPCR) 25 .…”

Reduced Systemic Microvascular Function in Patients With Resistant Hypertension and Microalbuminuria: an Observational Study

“…Typical three-drug regimens include a renin-angiotensin system inhibitor, a calcium channel blocker, and a thiazide or thiazide-like diuretic (9). Microalbuminuria (MAU) is de ned as an abnormally increased excretion rate of albumin in the urine in the range of 30-299 mg/g creatinine and is associated with increased mortality independent of the estimated glomerular ltration rate (eGFR) (10,11). MAU is associated with different cardiometabolic conditions, including salt sensitivity and hypertension, obesity, insulin resistance and diabetes, as well as other components of metabolic syndrome, such as dyslipidemia (12).…”

The relationship between urinary albumin to creatinine ratio and all-cause mortality in the elderly population in the Chinese community: a 10-year follow-up study

“…Studies have shown that high levels of urinary albumin excretion are associated with an increase in cardiovascular (CV) mortality, especially in patients with diabetes, and hypertension, as well as those with a history of cardiovascular disease, but there are few studies on the prediction of all-cause mortality in community populations [ 15 – 19 ]. In addition, in healthy people (UACR less than 30 mg/g), the urinary albumin to creatinine ratio as a risk indicator is controversial in predicting all-cause death in healthy people [ 20 ]. Their previous relationship and degree of association have not yet been specifically studied [ 2 , 17 , 21 ].…”