The relationship of the ratio of platelet distribution width to serum albumin with kidney disease progression in patients with hypertension

Abstract

Platelet distribution width (PDW), which represents the heterogeneity of platelet size, can predict a poor prognosis in various populations. However, the PDW-to-serum albumin ratio (PAR) has not been evaluated in any disease population, and whether the PAR could be a prognostic marker in hypertension remains unknown. The relationship between the PAR and adverse outcomes was examined retrospectively using longitudinal data of 1,578 patients with hypertension from the Fukushima Cohort Study. Participants were categorized into tertiles by baseline PAR. The primary endpoint of the present study was a kidney event, defined as a combination of a 50% decline in eGFR from baseline and end-stage kidney disease requiring kidney replacement therapy. During the median follow-up period of 5.4 years, 146 patients had kidney events. The higher PAR group (tertile 3) showed an increased incidence of kidney events on Kaplan-Meier curve analysis. Compared with the lowest PAR tertile, the highest PAR tertile (tertile 3) showed a significantly higher risk of kidney events (adjusted hazard ratio 3.74, 95% confidence interval (CI) 1.65-8.48). Similar relationships were observed for risks of all-cause death and cardiovascular events. The predictive value of the PAR for kidney events was superior to that of PDW alone. The areas under the curves for PDW and the PAR were 0.61 (95% CI 0.56-0.66) and 0.77 (95% CI 0.74-0.81), respectively (P < 0.001). The PAR could be a useful predictive marker of adverse outcomes in this population.

Keywords: Hypertension; Kidney; Observational study; Platelet distribution width; Prognosis.

Fig. 1

Flow of participants through the present study. eGFR, estimated glomerular filtration rate; PDW, platelet distribution width.

Fig. 2

Kaplan-Meier curves for the incidence of kidney events by PDW (a) and PAR (b) tertiles at baseline in patients with hypertension. PDW, platelet distribution width; PAR, PDW-to-albumin ratio.

Fig. 3

Distributions and model-adjusted restricted cubic splines assessing the relationship of PDW (a) and PAR (b) to kidney events. The solid lines represent adjusted hazard ratio estimates, and the dashed lines represent 95% confidence intervals, respectively. Model adjusted for age, sex, smoking history, history of cardiovascular disease, diabetes mellitus, body mass index, systolic blood pressure, diastolic blood pressure, eGFR, hemoglobin, platelet, LDL-cholesterol, proteinuria, use of ACE inhibitor or ARB, and use of antiplatelet agent. PDW, platelet distribution width; PAR, PDW-to-albumin ratio; eGFR, estimated glomerular filtration rate; LDL, low-density lipoprotein; ACE, angiotensin-converting enzyme; ARB, angiotensin II receptor blocker.

Fig. 4

Comparison of the ROC curves of PDW and PAR for predicting kidney events in patients with hypertension. The AUC for PAR was significantly higher than the AUC for PDW (P < 0.001). PDW, platelet distribution width; PAR, PDW-to-albumin ratio; AUC, area under the curve; CI, confidence interval; ROC, receiver-operating characteristic.