Ruolan Huang
Background: Stroke is the second leading cause of death and the primary cause of chronic neurological disability worldwide, and a high prevalence has been reported in China in the past ten years. Similarly, chronic kidney disease (CKD) is a considerable public health challenge worldwide. Growing evidence indicates that the presence of protein in the urine, which represents an early sign of kidney disease, may be related to the risk of stroke. There are different data regarding whether proteinuria, which is often measured via the urine albumin-to-creatinine ratio (UACR), could be a risk factor for stroke and its subtypes. Renal insufficiency could be one considerable risk for worse clinical outcome of cerebral vascular disease. High albumin urea, better interpreted by UACR, predict higher risk of renal insufficiency, latent glomerular damage and systemic change of small arteries. Further studies are needed.
Objective: This study aimed to clarify the association between increased spot urine albumin-to-creatinine ratio (UACR) and the risk of stroke.
Methods: We performed a systematic review and meta-analysis of cohort studies, case-control studies, and ancillary data randomized controlled trials (RCTs), which were treated as cohorts in this study, and estimated the association between albuminuria, as measured with the UACR, and the risk of stroke. We performed a comprehensive search of PubMed, Embase, and the Cochrane Library and conducted a systematic review and cumulative meta-analysis of cohort studies with a cross-sectional with prospective design in which stroke incidence was reported and the baseline UACR was measured. Ancillary data from RCTs were also included as part of the cohort study. We studied the characteristics of the participants, quality scores and risk ratios (RR, with confidence intervals, CI) of stroke associated with normal and high UACRs, and we synthesized the data via a meta-analysis.
Results: Twelve eligible studies including a total of 32,888 participants and 3,944 cases of stroke were identified. A high UACR (>30 mg/mmol) increased the risk of stroke by 1.67 times (RR: 1.67, 95% CI: 1.49-1.86, P<0.001 I2=26%). The results were not different between Asian and non-Asian patients (RR: 1.64, 95% CI: 1.41-1.91, P<0.001, I2=23% compared with RR: 1.67, 95% CI: 1.50-1.85, P<0. 00, I2=39%) or between subgroups classified by old age (RR: 1.61, 95% CI: 1.39-1.88, P<0.001, I2=34% compared with RR: 1.68, 95% CI: 1.52-1.87, P<0.001, I2=13%). A sensitivity analysis did not significantly change the results.
Conclusion: The incidence of stroke increased significantly in the high UACR group compared with the normal UACR group. The UACR could be a clinical addition for the early indication of high-risk stroke patients.