Investigation of associations between retinal microvascular parameters and albuminuria in UK Biobank: a cross-sectional case-control study
Euan Paterson, Chris C. Cardwell, Tom MacGillivray, Emanuele Trucco, Alex S. F. Doney, Paul J. Foster, Alexander P. Maxwell, Gareth J. McKay, Tariq Aslam, Sarah Barman, Jenny Barrett, Paul Bishop, Peter Blows, Catey Bunce, Roxana O. Carare, Usha Chakravarthy, Michelle Chan, Antonietta Chianca, Valentina Cipriani, David P. Crabb, Philippa Cumberland, Alexander Day, Parul Desai, Bal Dhillon, Andrew D. Dick, Cathy Egan, Sarah Ennis, Paul J. Foster, Marcus Fruttiger, John Gallacher, David F. Garway‐Heath, Jane Whitney Gibson, Dan Gore, Jeremy A. Guggenheim, Christopher J. Hammond, Alison J. Hardcastle, Simon Harding, Ruth Hogg, Pirro G. Hysi, Pearse A. Keane, Peng T. Khaw, Anthony P. Khawaja, Gerassimos Lascaratos, Andrew Lotery, Philip J. Luthert, Tom MacGillivray, Sarah Mackie, Keith R. Martin, Bernadette McGuinness, Gareth J. McKay, Martin McKibbin, Danny Mitry, Tony Moore, James W. Morgan, Zaynah Muthy, Eoin O’Sullivan, Christopher G. Owen, Praveen J. Patel, Euan Paterson, Tünde Pető, Axel Petzold, Jugnoo S. Rahi, Alicja R. Rudnicka, Jay Self, Sobha Sivaprasad, David Steel, Irene Stratton, Nicholas G. Strouthidis, Cathie Sudlow, Caroline Thaung, Dhanes Thomas, Emanuele Trucco, Adnan Tufail, Marta Ugarte, Véronique Vitart, Stephen T. Vernon, Ananth C. Viswanathan, Cathy Williams, Katie Williams, Jayne V. Woodside, Max Yates, Jennifer Yip, Yalin Zheng, Haogang Zhu, Robyn J. Tapp, Denize Atan, Alex S. F. Doney
Abstract
BACKGROUND: Associations between microvascular variation and chronic kidney disease (CKD) have been reported previously. Non-invasive retinal fundus imaging enables evaluation of the microvascular network and may offer insight to systemic risk associated with CKD. METHODS: Retinal microvascular parameters (fractal dimension [FD] - a measure of the complexity of the vascular network, tortuosity, and retinal arteriolar and venular calibre) were quantified from macula-centred fundus images using the Vessel Assessment and Measurement Platform for Images of the REtina (VAMPIRE) version 3.1 (VAMPIRE group, Universities of Dundee and Edinburgh, Scotland) and assessed for associations with renal damage in a case-control study nested within the multi-centre UK Biobank cohort study. Participants were designated cases or controls based on urinary albumin to creatinine ratio (ACR) thresholds. Participants with ACR ≥ 3 mg/mmol (ACR stages A2-A3) were characterised as cases, and those with an ACR < 3 mg/mmol (ACR stage A1) were categorised as controls. Participants were matched on age, sex and ethnic background. RESULTS: Lower FD (less extensive microvascular branching) was associated with a small increase in odds of albuminuria independent of blood pressure, diabetes and other potential confounding variables (odds ratio [OR] 1.18, 95% confidence interval [CI] 1.03-1.34 for arterioles and OR 1.24, CI 1.05-1.47 for venules). Measures of tortuosity or retinal arteriolar and venular calibre were not significantly associated with ACR. CONCLUSIONS: This study supports previously reported associations between retinal microvascular FD and other metabolic disturbances affecting the systemic vasculature. The association between retinal microvascular FD and albuminuria, independent of diabetes and blood pressure, may represent a useful indicator of systemic vascular damage associated with albuminuria.