Abstract
Objective
To explore and quantify men’s preferences and willingness to pay (WTP) for attributes of medications for lower urinary tract symptoms associated with benign prostatic hyperplasia using a discrete choice experiment.
Subjects and methods
Men in the UK aged ≥45 years with moderate-to-severe lower urinary tract symptoms/benign prostatic hyperplasia (based on self-reported International Prostate Symptom Score ≥8) were recruited. An online discrete choice experiment survey was administered. Eligible men were asked to consider different medication scenarios and select their preferred medication according to seven attributes: daytime and nighttime (nocturia) urinary frequency, urinary urgency, sexual and nonsexual side effects, number of tablets/day, and cost/month. A mixed-logit model was used to estimate preferences and WTP for medication attributes.
Results
In all, 247 men completed the survey. Men were willing to trade-off symptom improvements and treatment side effects. Men preferred medications that reduced urinary urgency and reduced day- and nighttime urinary frequency. Men preferred medications without side effects (base-case level), but did not care about the number of tablets per day. WTP for symptomatic improvement was £25.33/month for reduced urgency (urge incontinence to mild urgency), and £6.65/month and £1.39/month for each unit reduction in night- and daytime urination frequency, respectively. The sexual and nonsexual side effects reduced WTP by up to £30.07/month. There was significant heterogeneity in preferences for most attributes, except for reduced urinary urgency from urge incontinence to mild urgency and no fluid during ejaculation (dry orgasm).
Conclusion
To compensate for side effects, a medicine for lower urinary tract symptoms/benign prostatic hyperplasia must provide a combination of benefits, such as reduced urgency of urination plus reduced nighttime and/or reduced daytime urination.
Supplementary material
Description of mixed-logit model used to analyze discrete choice experiment responses
This approach allows preferences for attributes to vary across individuals and requires the specification of a distribution for each coefficient hypothesized to vary across participants. The distribution of the coefficients of the day- and nighttime frequency attributes was assumed to be log normal, given that all respondents ought to prefer reductions in the frequency of urination.Citation1,Citation2 All other coefficients were assumed to have a normal distribution, allowing for both positive and negative effects on utility. The estimation was based on 3,000 Halton draws using Stata version 13 (StataCorp LP, College Station, TX, USA).Citation3 A fixed parameter was assumed for the cost attribute, thus assuming all individuals had the same negative preference, and allowing easier estimation of willingness to pay for all other attributes.Citation4
References
- HensherDRoseJGreeneWApplied Choice Analysis: A PrimerCambridge, UKCambridge University Press2007
- TrainKDiscrete Choice Methods with SimulationNew YorkCambridge University Press2002
- HoleARFitting mixed logit models by using maximum simulated likelihoodStata J200773388401
- DalyAHessSTrainKAssuring finite moments for willingness to pay in random coefficient modelsTransportation20123911931
Acknowledgments
HERU is supported by the Chief Scientist Office at the Scottish Government Health and Social Care Directorate. Sebastian Heidenreich acknowledges financial support from the Institute of Applied Health Science, University of Aberdeen. Medical writing support was provided by Tyrone Daniel from Bioscript Medical and was funded by Astellas Pharma Europe Ltd. Presented in part as a poster at the ISPOR 17th Annual European Congress, November 8–12, 2014, Amsterdam, the Netherlands. The poster’s abstract was published in Value in Health. 2014;17(7):A472.
Author contributions
All authors contributed toward data analysis, drafting and critically revising the paper and agree to be accountable for all aspects of the work.
Disclosure
DI, SH, MR, and VW are employed by the University of Aberdeen and performed the research which was funded by Astellas; CM, CN and JN are employees of Astellas.