The Role of Personality in Treatment-Related Outcome Preferences Among Pharmacy Students

Ernest H. Law, PharmD, PhD; Ruixuan Jiang, PharmD; Anika Kaczynski, MS; Axel Mühlbacher, PhD; A. Simon Pickard, PhD

Disclosures

Am J Pharm Educ. 2019;83(7) 

In This Article

Methods

A brief 10-item questionnaire, known as the Ten-Item Personality Inventory (TIPI),[13] was used to measure the level of each of the Big Five personality traits. The TIPI has been validated across multiple demographic groups in the US general population.[13–15] The TIPI measures responses on a 7-point scale ranging from 1 (disagree strongly) to 7 (agree strongly) with two items for each of the Big Five personality traits. Items were reverse scored where appropriate, summed, and the individual mean personality trait score for each respondent was calculated, where higher values correspond to more of that trait. Individual respondent mean scores for each dimension could range from 1 to 7. Respondent mean scores for each personality trait were then categorized into "low," "moderate," or "high" tertiles.

This study was approved by the the University of Illinois at Chicago (UIC) Institutional Review Board. All participants provided informed consent. Doctor of Pharmacy (PharmD) students from the University of Illinois at Chicago College of Pharmacy in Chicago were recruited to participate in the study. An email was sent directly or forwarded to second-year students via UIC list servers. The email included information about the study and a link to the online questionnaire; the respondents were instructed to follow the link if they agreed to participate in the study.

The online questionnaire was developed using Qualtrics (Provo, Utah). The questionnaire included several sections presented in the same sequence for all respondents. In the first section, respondents were asked to fill out the Ten-Item Personality Inventory (TIPI)[13] to measure their level of each of the Big Five personality traits. The TIPI has been validated across multiple demographic groups in the US general population.[13–15] The TIPI measures responses on a seven-point scale ranging from 1=disagree strongly to 7=agree strongly, with two items included to measure each of the Big Five personality traits. Items on the TIPI were reverse scored where appropriate, summed, and the individual mean personality trait score for each respondent was calculated, where higher values correspond to having more of that trait. Respondent mean scores for each personality trait were then categorized into low, moderate, or high tertiles.

In the second section of the questionnaire, the students were asked to complete the EQ-5D-Y, which was used to describe treatment-related outcomes (Appendix 1).[16] The EQ-5D-Y is comprised of five dimensions of health: self-care, defined as having mobility, able to look after myself; usual activities, defined as able to do my usual activities; pain/discomfort, defined as having pain or discomfort; and anxiety/depression defined as feeling worried, sad, or unhappy.[17] On the EQ-5D-Y, each of the five dimensions of health is assessed based on three severity levels: no problem (level 1), some or a bit of a problem (level 2), and very or a lot of problems (level 3).[18] Each unique health state described by the EQ-5D-Y system is represented by a five-digit descriptor that ranges from 11111 (perfect health; no problems in any dimension) to 33333 (worst possible state; a lot of problems in every dimension of health). In the five-digit EQ-5D-Y descriptor, each digit represents one dimension of health; thus, the descriptive system defines 243 (3[5]) health states. The dimensions (attributes) and levels of the EQ-5D-Y were explained in the questionnaire, and the respondents were asked to complete the EQ-5D-Y measure based on their own health as a warm-up exercise.

To address the first aim of the study, in the third section of the questionnaire, respondents were presented with 15 profile-based, best-worst scaling choices comprised of health states based on the EQ-5D-Y descriptive system (Appendix 2). Health states included in the best-worst scaling items were selected by employing a simple, orthogonal main-effects plan (OMEP) using statistical software (Sawtooth Software, Sequim, WA).[10] The OMEP is a balanced design which ensures that all attributes and all attribute levels are presented with a balanced frequency to responders (Appendix 3). For each best-worst scaling task, the same hypothetical scenario was presented in which the respondent is asked to assume the role of a clinical pharmacist on a multidisciplinary oncology team that makes decisions for patients with cancer (Appendix 2). Respondents were asked to assess a list of five attribute levels (each level is a combination of one health dimension and a corresponding severity level) for each task and choose which attribute levels they considered to be the best and worst treatment-related outcomes.

To examine the second study aim, respondents were asked to choose between death and moderate ("22222") or severe ("33333") health states in two additional scenarios. This task was presented as it was suspected that perceptions surrounding this choice might differ by respondent personality traits. Also, considerations for quality (eg, health outcomes) and quantity (eg, survival) of life are important factors in medical decision-making, particularly in many oncology settings. Further, the place of states worse than "dead" on the health state utility scale (ie, values < 0) is a major issue in health state valuation.

In the final section of the questionnaire, respondents were asked demographic questions about age, gender, race/ethnicity, and prior education. The full survey was piloted with three graduate students (some of whom were recent PharmD graduates) to ensure questions were understood as intended and precisely worded. Differences in characteristics between the low, moderate, and high conscientiousness groups were compared using independent t tests for continuous variables and chi-square or Fisher exact test for categorical variables. Separate count analyses were used to determine preference weights for each of the conscientiousness and agreeableness tertiles, which included counting the individual selection frequencies,[19] calculation of best-worst score, and calculating the maximum difference between the individual scores.[20,21] Best-worst scores were also standardized to allow comparisons across groups.[21] Attributes were ranked on the basis of average best-worst scores. Differences in average best-worst scores were examined using analysis of variance (ANOVA) across conscientiousness and agreeableness tertiles when appropriate.

Logistic regression models evaluated the association between higher levels of conscientiousness and agreeableness and choosing death over a moderate health state (22222) or the worst health state (33333); with odds ratios (ORs) and 95% confidence intervals (CIs) reported. Unadjusted models were favored for statistical efficiency as there were no differences in baseline characteristics seen between conscientiousness or between agreeableness tertiles (data not reported).

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