Patients with primary open-angle glaucoma (POAG) may be at greater risk of developing chronic kidney disease, a team of South Korean researchers report.

Their population-based study, published in Glaucoma, included information from more than a million subjects listed in the 2002-2013 Korean National Health Insurance database. The researchers identified patients with POAG and used diagnostic codes to evaluate the risk of subsequent chronic kidney disease.

The study also analyzed three models: the first included POAG only; the second included POAG and demographic information; the third included POAG, demographic information, comorbidities and medication use. The fixed cohort represented 478,303 subjects, including 1,749 who had incident POAG and 3,157 who developed chronic kidney disease.

In model one, the researchers reported POAG was associated with an increased risk of chronic kidney disease by more than seven-fold. However, the risk was lower in model two, dropping to more than three-fold. Even with model three, which adjusted for demographic factors, covariates and the use of co-medications, the researchers found a nearly three-fold increased risk of chronic kidney disease for those with POAG. The team found the male sex, older age and low household income were also associated with an increased risk of kidney disease.

Most previous studies note an increased prevalence of POAG in kidney disease patient, not the other way around, the researchers wrote in their paper.

The team also found that all five topical glaucoma drug classes had similar increased risks of kidney disease in the general population. “These results indicate that the use of topical CAIs may not increase the risk of chronic kidney disease development, compared to other topical drugs,” as has been reported in the past, the investigators wrote in their paper.