Millions of adults take medications to help relieve symptoms of overactive bladder and reduce episodes of urinary incontinence.
But research linking some of those medications called anticholinergic drugs, such as oxybutynin, to memory loss drove recommendations to treat urinary incontinence with beta-3 agonists, drugs that offer the same benefit but without the risk of cognitive decline.
A new study in JAMA Network Open led by Northwestern Medicine and Duke University School of Medicine shows Black patients are less likely to fill prescriptions for newer, safer urinary incontinence drugs compared to white patients, potentially raising their risk for dementia.
“There’s no difference in prevalence of overactive bladder based on racial differences and no biological differences that would explain the observed inequalities that we saw in the study,” said lead study author Douglas Luchristt, MD, MPH, an assistant professor at Northwestern Medicine and former fellow in the female pelvic medicine and reconstructive surgery fellowship program at Duke school of medicine.
An estimated 3 million adults filled a prescription to treat overactive bladder in 2019, according to the study that analyzed the 2019 Medical Expenditure Panel Survey of households in the United States. However, Black patients were 54% less likely than white individuals to fill a prescription for the newer class of drugs to treat overactive bladder.
The stark racial differences suggest a pattern of prescribing that may result in Black patients lacking access to the highest quality treatment to manage an overactive bladder, authors say.
Even when comparing individuals with the same income and insurance status, Black women had the lowest odds of getting the recommended beta-3 agonist medications, according to the study.
“The anticholinergics are the older class of medicines and were the only drugs on the market until the beta-3 agonists emerged,” said senior study author Oluwateniola Brown, MD, assistant professor of female pelvic medicine and reconstructive surgery at Northwestern Medicine.
“But over the past five to seven years we’ve seen a ton of data about the association between anticholinergics and dementia,” said Brown, the director of diversity, equity, and inclusion for the Department of Obstetrics and Gynecology. “We wanted to know who is getting the recommended therapy.”
Medication is a mainstay in the treatment of overactive bladder and is recommended for those who do not get results from behavioral interventions like pelvic floor exercises to strengthen muscles that support the bladder.
Epidemiology surveys show up to 27% of men and 43% of women report bothersome symptoms of overactive bladder.
Medication side effects include dry mouth and constipation, but concerns were raised about long-term risks after a 2019 study in British Medical Journal showed those who took an anticholinergic drug for a year or more had a 30% increased risk for dementia down the road.
The American Family Physicians cautions against using anticholinergics in older adults, and the American Urological Association recommends oral beta-3 agonists when prescribing medicine to treat overactive bladder.
In 2020, the American Urogynecologic Society explicitly recommended avoiding anticholinergic medications to treat OAB in those over age 70, although studies have shown increased dementia risk in patients younger than 70.
Still anticholinergic medications are the predominant prescription medication for overactive bladder, according to the new analysis. Seventy-five percent of OAB prescriptions were for an anticholinergic medication.
The most common prescription was for oxybutynin, followed by the beta-3 agonist drug mirabegron.
Filling a prescription for the newer urinary incontinence drugs can cost patients more. Beta-3 agonists, which are still under patent after gaining FDA approval in 2008, have an average out-of-pocket cost of $45. That’s compared to an out-of-pocket cost of $9.78 for generic versions of anticholinergics.
Authors note that the findings were based on filled prescriptions. Meaning it’s possible for an individual to go home with a medication that’s different from what their doctor prescribed due to pharmacy inventory, co-pay amount, or insurance formulary -- the list of generic and brand name medications covered by their insurance.
“While cost may be a factor that is playing a part in driving these observed differences, the important takeaway for us is who is being exposed to this higher risk medication,” Luchristt said.
Additional authors include Emi Bretschneider, MD; Kimberly Kenton, MD, MS; and Melissa Simon, MD, MPH at Northwestern University Feinberg School of Medicine.
The research was supported in part through grants U01DK126045 and R01DK129849 from the National Institute of Diabetes and Digestive and Kidney Diseases.