The Relationships among the Cardio-Ankle Vascular Index Values, Proteinuria, and Estimated Glomerular Filtration Rate in Diabetic and Non-Diabetic Patients (the Coupling Registry).

INTRODUCTION

Chronic kidney disease (CKD) raises cardiovascular risk, but its link with the cardio-ankle vascular index (CAVI) in diabetic and non-diabetic patients remains unclear. The aim of this study was to clarify the relationships between CAVI values and an aspect of renal function.

METHODS

We investigated the relationships among CAVI values, proteinuria, and the estimated glomerular filtration rate (eGFR) in 4,682 patients enrolled in a multicenter prospective coupling study (patients aged ≥30 years with at least one cardiovascular risk factor) and both eGFR and proteinuria data available. Based on vascular insufficiency guidelines, we classified the patients as having low (<8) or high (≥8) CAVI values.

RESULTS

The proteinuria positivity rate differed significantly between the low- and high-CAVI groups, and the difference was significant even after adjusting for age, gender, and other factors. Although direct comparisons showed a higher proportion of CKD (eGFR <60 mL/min/1.73 m2) in the high-CAVI group, this difference disappeared after adjustment. We further divided the low- and high-CAVI groups into diabetes mellitus (DM) and no diabetes mellitus (non-DM) subgroups to examine the rate of proteinuria positivity and the percentage of patients with eGFRs <60 mL/min/1.73 m2. After the multivariate analysis adjustment, the odds ratios for positive proteinuria the high-CAVI group were 1.69 (confidence interval [CI]: 1.08-2.63, p = 0.021) for the non-DM subgroup and 0.91 (95% CI: 0.56-1.47, p = 0.705) for the DM subgroup. The percentage of patients with eGFRs <60 mL/min/1.73 m2 was not significantly different between the low- and high-CAVI groups in both the DM and non-DM subgroups after the multivariate analysis adjustment (p = 0.088 for non-DM and p = 0.135 for DM).

CONCLUSIONS

Proteinuria was associated with a CAVI ≥8 in patients without DM. High arterial stiffness may serve as a surrogate marker for renal damage in non-diabetic patients.