Economic impact of extended-release tolterodine versus immediate- and extended-release oxybutynin among commercially insured persons with overactive bladder.
OBJECTIVE
To examine levels of persistence and compliance as well as the economic impact of extended-release tolterodine (tolterodine ER) versus immediate- and extended-release oxybutynin (oxybutynin IR or oxybutynin ER) among commercially-insured patients with overactive bladder (OAB).


METHODS
Patients with OAB who initiated tolterodine ER, oxybutynin IR, or oxybutynin ER between January 2001 and December 2002 were identified from the PharMetrics Patient-Centric database; the first medication used in this timeframe was used for treatment group assignment (ie, patients were only in 1 group). Exploratory assessment of persistency and compliance was conducted among all treated patients: subjects were matched 1:1 based on the estimated propensity score for tolterodine ER in remaining analyses. Measures included patient characteristics as well as levels of medication, outpatient and inpatient resource utilization, and costs. Primary comparisons were made descriptively; costs were evaluated using generalized linear models with a gamma distribution and log-link function.


RESULTS
Compliance did not differ between tolterodine ER (77.4%) and oxybutynin ER (74.3%), but was lower for oxybutynin IR (60.9%). Mean (+/- standard deviation) duration of therapy was higher for tolterodine ER (139 +/- 132 days) versus oxybutynin ER (115 +/- 122) and oxybutynin IR (60 +/- 85). Totals of 7257 and 5936 matched pairs were available for tolterodine ER versus oxybutynin ER and oxybutynin IR comparisons, respectively. The mean age was 54 years in all groups; the majority was women. Utilization of outpatient and inpatient medical services was consistently lower among tolterodine ER patients in both comparisons. Total costs were slightly lower for tolterodine ER versus oxybutynin ER (dollar 8303 +/- dollar 18 802 vs dollar 8862 +/- dollar 18 684) and oxybutynin IR (dollar 9975 +/- dollar 24860 vs dollar 10521 +/- dollar 22 602); differences were significant after multivariate adjustment.


CONCLUSIONS
Use of tolterodine ER results in comparable compliance to oxybutynin ER and longer duration of use relative to either form of oxybutynin. In addition, tolterodine ER may be cost-effective relative to oxybutynin IR or oxybutynin ER among commercially-insured persons with OAB.
Varadharajan
Sujata
S
Pfizer Inc, New York, New York, USA.
Jumadilova
Zhanna
Z
Girase
Prafulla
P
Ollendorf
Daniel A
DA
D000368:Aged; D001559:Benzhydryl Compounds / Q000008:administration & dosage / Q000191:economics* / Q000627:therapeutic use; D003408:Cresols / Q000008:administration & dosage / Q000191:economics* / Q000627:therapeutic use; D003692:Delayed-Action Preparations; D005260:Female; D006801:Humans; D019458:Insurance Coverage; D008297:Male; D008333:Mandelic Acids / Q000008:administration & dosage / Q000191:economics* / Q000627:therapeutic use; D018727:Muscarinic Antagonists / Q000008:administration & dosage / Q000191:economics* / Q000627:therapeutic use; D010665:Phenylpropanolamine / Q000008:administration & dosage / Q000191:economics* / Q000627:therapeutic use; D000068737:Tolterodine Tartrate; D014481:United States; D014549:Urinary Incontinence / Q000188:drug therapy* / Q000191:economics
D001559:Benzhydryl Compounds; D003408:Cresols; D003692:Delayed-Action Preparations; D008333:Mandelic Acids; D018727:Muscarinic Antagonists; D010665:Phenylpropanolamine; D000068737:Tolterodine Tartrate; C005419:oxybutynin