Proteinuria Associated with Elevated Risk of AMD

Kidney complications such as proteinuria (usually diagnosed via dipstick test, shown here) are likely to increase the risk of AMD. However, chronic kidney disease as a whole was not associated with higher AMD risk in this study. Photo: ValueMed. Click image to enlarge.  The glomerulus is a vascular system found in the kidneys that bears some structural similarities to the choroid. This connection has led researchers to realize that there’s a relationship between renal and ocular diseases. In fact, conditions such as von Hippel–Lindau syndrome and Alport syndrome affect both kidney function and vision. It’s been well documented that the eyes and kidneys are somewhat associated, but there is more to be discovered.Researchers in South Korea conducted a study to explore the association between kidney complications and age-related macular degeneration (AMD). Using the Korea National Health Insurance database, they collected data from a national health screening program conducted in 2009. Insured patients who followed up with the screening process in 2019 were analyzed in this study. A total of 4,005,946 individuals were selected and assessed for chronic kidney disease (CKD), proteinuria (excessive protein in the urine, a sign of kidney damage) and AMD.Associations between CKD and the risk of AMD and between proteinuria and the risk of AMD were estimated using the Cox regression hazards model. Data showed that 10% of subjects were diagnosed with CKD and 5.8% had some level of proteinuria, ranging from trace amounts (10mg/dL) to a urinary protein level rated 4+ (1,000 mg/dL) on the “dipstick test.” AMD was diagnosed in 11.7% of patients in the sample as a whole but just 1.3% of patients with CKD, which did not represent a significant risk of AMD. However, the hazard ratios for the risk of AMD in proteinuria cases significantly rose as the urinary protein levels became more severe.Older, female patients were more likely to develop chronic kidney disease; however, AMD development was associated with the opposite traits: AMD developed more in younger patients (<65 years) and in men, which also reflects the traits of subjects more likely to develop level 4+ proteinuria.“A previous study demonstrated that the relationship between proteinuria and AMD was prominent only in men but was limited by measurement errors in women,” explained the authors in their paper for Scientific Reports. “Furthermore, several studies have suggested that AMD progression might follow different processes in women than men due to the protective effect of estrogen, which may lead to favorable alterations in serum lipid levels and may exert antioxidant properties.” The researchers argue for future investigations to elaborate on these results, especially due to the various factors that limited the study’s findings, including selection bias, undefined diagnostic codes, duration of the study, unpredictable proteinuria tests, impact of ocular comorbidities, impact of renal disease medications and the observational nature of this study.“The present study findings enhance our understanding of the relationship between the eyes and kidneys,” concluded the authors. “In young, male patients with persistent high-grade proteinuria, an ophthalmic examination could be helpful.” Click here for the journal source. Park J, Han K, Kim B, et al. Risk of age-related macular degeneration according to the chronic kidney disease and proteinuria in Korea: A 10-year nationwide cohort study. Sci Rep 2025;15:1.  This article was developed by the editorial staff in conjunction with experts in the field. In the process, AI may have been among the editorial tools used to meet the goals of human editors, who approved all content.