Background: The caliber of the retinal vessels has been linked to chronic kidney disease (CKD) but studies have not shown consistent results. We conducted meta-analyses using 1) individual participant data (IPD-MA, flexible and more powerful) and 2) aggregate data (AD-MA, based on summary estimates) to evaluate the cross-sectional association between retinal vessel calibers and CKD.
Methods: We performed a systematic review on Medline for articles published up to October 2017. For IPD-MA, we used one-stage approach combining raw data from 10 studies (5 from Asia, 3 from USA, 2 from Australia, n=35,090) and for the AD-MA we used two-stage approach combining summary estimates from 14 studies (including the above 10 studies+ 3 USA and 1 European study, n=47,589). CKD was defined as an estimated glomerular filtration rate (eGFR) <60 mL/min/1.73m2. Retinal arteriolar and venular calibers (central retinal arteriolar equivalent [CRAE] and central retinal venular equivalent [CRVE]) were assessed from retinal photographs using computer-assisted methods. We used logistic regression models to estimate pooled odds ratios (OR) of CKD associated with 1 standard deviation (SD, 20-µm) increase in CRAE and CRVE measurements.
Results: Prevalence of CKD was 11.7% (n=4100) and 12% (n=5694) in the IPD-MA and AD-MA respectively. After adjustment for age, sex, ethnicity, education, current smoking, diabetes, hypertension, body mass index, total cholesterol, and fellow vessel caliber, in IPD-MA, both CRAE and CRVE were significantly associated with CKD (pooled OR 1.12 [95% confidence interval (CI):1.07, 1.17] per SD increase in CRAE and 1.27 [1.22,1.32] for CRVE). However, in the AD-MA (14 cohorts), neither CRAE nor CRVE were significantly associated with CKD (0.94 [0.86,1.03] for CRAE and 0.99 [0.94, 1.04] for CRVE. Similar non-significant associations were observed in AD-MA including summary estimates from the 10 IPD-MA cohorts.
Conclusion: Wider retinal arterioles and wider retinal venules were associated with CKD in IPD-MA but not in AD-MA. IPD-MA from longitudinal data may clarify the association.