Chronic oral bisphosphonate use linked to wet AMD

A team of Canadian researchers using multiple study designs have shown that patients on long-term oral bisphophonate therapy may be at higher risk of wet AMD.

In an effort to mitigate an indiscriminate finding, the researchers used 3 study designs. First, a disproportionality analysis showed that AMD incidence was higher among those who regularly used the osteoporosis drug, with alendronate associated with a nearly 4 times higher risk, followed by risedronate (OR 2.87) and bandronate (OR 2.4).

A case-control analysis showed the risk of wet AMD increased over time, with the odds increasing from 1.24 after 1 year of regular use to 1.59 after 3 or more years of regular use. Lastly, a self-controlled case series showed that the odds of developing AMD increased from 1.22 after 1 year of use to 1.87 after 5 years.

The findings of this study are somewhat unexpected, given that a previous in vitro study showed that human retinal pigment epithelial cells display concurrent proinflammatory and antiangiogenic properties in response to bisphosphonates. The authors believe the pro-inflammatory properties of oral bisphosphonates may overcome their antiangiogenic effects when used over a longer period of time.

While additional studies are clearly needed to confirm this study's findings, it raises an important potential risk for our elderly patients.