Boeri M, Saure D, Schacht A, Riedl E, Hauber B. Modeling heterogeneity in patients' preferences for psoriasis treatments in a multicountry study: a comparison between random-parameters logit and latent class approaches. Pharmacoeconomics. 2020 Jun;38(6):593-606. doi: 10.1007/s40273-020-00894-7.


BACKGROUND: Either a random-parameters logit (RPL) or a latent class (LC) model can be used to account for unobserved preference heterogeneity in discrete-choice experiment (DCE) data. The former assumes continuous distribution of preferences across the sample, while the latter assumes a discrete distribution. This study aimed to compare RPL and LC models to explore preference heterogeneity when analyzing patient preferences for psoriasis treatments.

METHODS:
Using DCE data collected from respondents with moderate-to-severe plaque psoriasis, we calculated and compared preference weights derived from RPL and LC models. We then compared how RPL and LC explain preference heterogeneity by exploring differences across subgroups defined by observed characteristics (i.e., country, age, gender, marital status, and psoriasis severity).

RESULTS:
While RPL and LC models resulted in the same mean preference weights, different preference-heterogeneity patterns emerged from the two approaches. In both models, country of residence and self-reported disease severity explained systematic differences in preferences. The RPL also identified gender and marital status, but not age, as sources of heterogeneity; the LC membership probability model indicated that age was a significant factor, but not gender or marital status.

CONCLUSIONS:
There are two options to explicitly model preference heterogeneity across well-defined subgroups: subgroup analysis in the RPL model and including the subgroup characteristics in the class membership probability function of the LC model. The two models may imply different results. Researchers should model data using the most adaptable approach to respond to the initial study question.

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