The association of skin autofluorescence with cardiovascular events and all-cause mortality in persons with chronic kidney disease stage 3: A prospective cohort study

PLoS Med. 2020 Jul 13;17(7):e1003163. doi: 10.1371/journal.pmed.1003163. eCollection 2020 Jul.

Abstract

Background: Tissue advanced glycation end product (AGE) accumulation has been proposed as a marker of cumulative metabolic stress that can be assessed noninvasively by measurement of skin autofluorescence (SAF). In persons on haemodialysis, SAF is an independent risk factor for cardiovascular events (CVEs) and all-cause mortality (ACM), but data at earlier stages of chronic kidney disease (CKD) are inconclusive. We investigated SAF as a risk factor for CVEs and ACM in a prospective study of persons with CKD stage 3.

Methods and findings: Participants with estimated glomerular filtration rate (eGFR) 59 to 30 mL/min/1.73 m2 on two consecutive previous blood tests were recruited from 32 primary care practices across Derbyshire, United Kingdom between 2008 and 2010. SAF was measured in participants with CKD stage 3 at baseline, 1, and 5 years using an AGE reader (DiagnOptics). Data on hospital admissions with CVEs (based on international classification of diseases [ICD]-10 coding) and deaths were obtained from NHS Digital. Cox proportional hazards models were used to investigate baseline variables associated with CVEs and ACM. A total of 1,707 of 1,741 participants with SAF readings at baseline were included in this analysis: The mean (± SD) age was 72.9 ± 9.0 years; 1,036 (60.7%) were female, 1,681 (98.5%) were of white ethnicity, and mean (±SD) eGFR was 53.5 ± 11.9 mL/min/1.73 m2. We observed 319 deaths and 590 CVEs during a mean of 6.0 ± 1.5 and 5.1 ± 2.2 years of observation, respectively. Higher baseline SAF was an independent risk factor for CVEs (hazard ratio [HR] 1.12 per SD, 95% CI 1.03-1.22, p = 0.01) and ACM (HR 1.16, 95% CI 1.03-1.30, p = 0.01). Additionally, increase in SAF over 1 year was independently associated with subsequent CVEs (HR 1.11 per SD, 95% CI 1.00-1.22; p = 0.04) and ACM (HR 1.24, 95% CI 1.09-1.41, p = 0.001). We relied on ICD-10 codes to identify hospital admissions with CVEs, and there may therefore have been some misclassification.

Conclusions: We have identified SAF as an independent risk factor for CVE and ACM in persons with early CKD. These findings suggest that interventions to reduce AGE accumulation, such as dietary AGE restriction, may reduce cardiovascular risk in CKD, but this requires testing in prospective randomised trials. Our findings may not be applicable to more ethnically diverse or younger populations.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Aged, 80 and over
  • Cardiovascular Diseases / physiopathology*
  • Female
  • Fluorescence
  • Glomerular Filtration Rate
  • Glycation End Products, Advanced / metabolism*
  • Humans
  • Kaplan-Meier Estimate
  • Male
  • Proportional Hazards Models
  • Prospective Studies
  • Renal Insufficiency, Chronic / complications
  • Renal Insufficiency, Chronic / mortality*
  • Risk Factors
  • Skin / chemistry*

Substances

  • Glycation End Products, Advanced

Grant support

The RRID study was funded by a Research Project Grant (R302/0713) from the Dunhill Medical Trust (https://dunhillmedical.org.uk) awarded to MWT. Previous study funding includes a joint British Renal Society (https://britishrenal.org) and Kidney Research UK (https://kidneyresearchuk.org) fellowship, awarded to NJM, and an unrestricted educational grant from Roche Products Ltd (https://www.roche.co.uk) awarded to MWT. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.