Effect of Potentially Inappropriate Use of Antimuscarinic Medications on Healthcare Use and Cost in Individuals with Overactive Bladder.

Objectives: To examine potentially inappropriate medication (PIM) use in older adults initiating an antimuscarinic medication for the treatment of overactive bladder (OAB).

Design: Retrospective database analysis.

Setting: Medical and pharmacy claims data.

Participants: Medicare Advantage Prescription Drug Plan members aged 65 and older newly initiated on an antimuscarinic OAB treatment were identified and assigned to PIM and non-PIM comparison groups based on 2012 American Geriatrics Society Beers Criteria and/or the presence of an anticholinergic medication interaction at the time of initiation of treatment (N = 66,275).

Measurements: Healthcare costs and OAB medication use.

Results: Of members initiated on an antimuscarinic OAB medication, 31.1% had a drug-drug or drug-disease or syndrome interaction. Dementia was the most common disease or syndrome interaction (11.3%), followed by constipation (8.6%) and delirium (2.9%). Paroxetine (2.6%), amitriptyline (2.2%), cyclobenzaprine (1.7%), and meclizine (1.6%) were the most common interacting medications. Subjects in the PIM group had greater healthcare costs over 12 months of follow-up ($12,001) than those in the non-PIM group ($9,373) after controlling for baseline characteristics (P < .001). There was no difference between the PIM and the non-PIM groups in odds of discontinuing OAB treatment at 12 months after controlling for baseline characteristics (odds ratio = 0.98, 95% confidence interval = 0.89-1.07, P = .63).

Conclusion: Potentially inappropriate medication use was highly prevalent and was associated with greater total healthcare costs. Providers should carefully consider medical history and concurrent medication use when initiating antimuscarinic medication for the treatment of OAB. Development of interventions to reduce potentially inappropriate use of antimuscarinics in individuals with OAB is warranted.