Association between alkaline phosphatase/albumin ratio and the prognosis in patients with chronic kidney disease stages 1–4: results from a C-STRIDE prospective cohort study

BACKGROUND: The alkaline phosphatase-to-albumin ratio (APAR) has been demonstrated to be a promising non-invasive biomarker for predicting prognosis in certain diseases. However, the relationship between APAR and prognosis in non-dialysis chronic kidney disease (CKD) patients remains unclear. This study aims to identify the association between APAR and prognosis among CKD stages 1–4 in China. METHODS: Patients with CKD stages 1–4 were consecutively recruited from 39 clinical centers in China from 2011 to 2016. New occurrences of end-stage kidney disease (ESKD), major adverse cardiovascular and cerebrovascular events, and all-cause deaths were the outcome events of this study. Subdistribution hazard competing risk and Cox proportional hazards regression models were adopted. RESULTS: A total of 2,180 participants with baseline APAR values were included in the analysis. In the primary adjusted analyses, higher APAR level [per 1-standard deviation (SD) increase in natural logarithm transformed (ln-transformed) APAR] was associated with 33.5% higher risk for all-cause deaths [adjusted hazard ratio (HR) 1.335, 95% confidence interval (CI) 1.068–1.670]. In addition, there was evidence for effect modification of the association between APAR and ESKD by baseline estimated glomerular filtration rate (eGFR) (P interaction < 0.001). A higher APAR level (per 1-SD increase in ln-transformed APAR) was associated with a greater risk of ESKD among participants with eGFR ≥ 60 ml/min/1.73 m(2) (adjusted SHR 1.880, 95% CI 1.260–2.810) but not in eGFR < 60 ml/min/1.73 m(2). CONCLUSION: Higher APAR levels in patients with CKD stages 1–4 seemed to be associated with an increased risk of all-cause death. Thus, APAR appears to be used in risk assessment for all-cause death among patients with CKD stages 1–4.