Patterns of use of antimuscarinic drugs to treat overactive bladder in Denmark, Sweden, and the United Kingdom

Abstract

PurposeTo describe the use of antimuscarinic drugs to treat overactive bladder (OAB) in Denmark, Sweden, and the United Kingdom (UK).MethodsWe identified new users of darifenacin, fesoterodine, oxybutynin, solifenacin, tolterodine, and trospium aged 18 years or older from the Danish National Registers (2004–2012), the Swedish National Registers (2006–2012), and UK Clinical Practice Research Datalink (2004–2012). Users were followed until disenrollment, cancer diagnosis, death, or study end. Treatment episodes, identified by linking consecutive prescriptions, were described with respect to duration, drug switch, and drug add-on.ResultsMean age of OAB drug users was 66 years in Denmark (n = 72,917) and Sweden (n = 130,944), and 62 years in the UK (n = 119,912); 60% of Danish and Swedish patients and 70% of UK patients were female. In Denmark, of 224,680 treatment episodes, 39% were with solifenacin, and 35% with tolterodine; 2% were with oxybutynin. In Sweden, of 240,141 therapy episodes, 37% were with tolterodine and 35% with solifenacin; 5% were with oxybutynin. In the UK, of 245,800 treatment episodes, 28% were with oxybutynin, 27% with solifenacin, and 26% with tolterodine. In the three countries, 49%-52% of treatment episodes comprised one prescription and over 80% of episodes ended because of no refill; less than 20% ended because of a switch to another antimuscarinic. During the study years, we observed a change in OAB treatment preference from tolterodine to solifenacin.ConclusionsIn these cohorts, persistence with antimuscarinic drugs was low. By 2012, the preferred drug was solifenacin; oxybutynin use was marginal in Nordic countries compared with the UK.

Variation in Cardiovascular Risk Related to Individual Antimuscarinic Drugs Used to Treat Overactive Bladder: A UK Cohort Study

“…Lower IRRs for CV end points for solifenacin in comparison with tolterodine were also observed in a Swedish cohort study with the same design as this one, but not in a similar study conducted in Denmark, where the risk of the targeted CV end points was similar across individual OAB drugs and did not indicate a consistently increased risk for any individual OAB drug . In the Nordic countries, use of oxybutynin is minimal and insufficient to study its effects on CV end points . The fact that results are not consistent across these populations in observational studies, together with unclear safety results from in vitro studies and randomized clinical trials, precludes us from making recommendations to modify clinical practice.…”

“…Duration of use was estimated using the waiting‐time distribution method in Denmark, the dispensed number of daily defined doses in Sweden, and the recorded days’ supply in the CPRD. Despite these differences, patterns of drug utilization were similar in the three populations . In the Danish and Swedish studies, data sources included outpatient visits to hospitals and hospitalizations, whereas in the present study, data sources also include primary care, and hospitalization data are available for a part of the population.…”

“…Exposure information, including drug‐use and treatment patterns, was derived from prescriptions issued that the patient might not have filled and followed. Therapy episodes of current use after prescriptions of OABs were based on published information on OAB use, but we may not have captured the reality of drug treatments . Prescriptions in electronic medical records (just like filled or reimbursed prescriptions in other sources of data used in observational studies) do not provide information on whether a drug was discontinued before the end of the days’ supply or continued after the end of the days’ supply.…”

“…Therapy episodes of current use after prescriptions of OABs were based on published information on OAB use, but we may not have captured the reality of drug treatments. 29 Prescriptions in electronic medical records (just like filled or reimbursed prescriptions in other sources of data used in observational studies) do not provide information on whether a drug was discontinued before the end of the days' supply or continued after the end of the days' supply. Thus we rely on assumptions and indirect methods to obtain this information, such as incorporating a 7-day extension of current use or requiring gaps longer than 60 days to consider a therapy discontinued.…”

“…15 In the Nordic countries, use of oxybutynin is minimal and insufficient to study its effects on CV end points. 15,29,38 The fact that results are not consistent across these populations in observational studies, together with unclear safety results from in vitro studies and randomized clinical trials, 9,10 precludes us from making recommendations to modify clinical practice.…”