BACKGROUND: Oral antipsychotic treatments are often prescribed to manage schizophrenia (SZ). While effective in treating SZ symptoms, oral antipsychotics are associated with various side effects, including weight gain and sexual dysfunction. The goal of this study was to assess patients’ preferences for characteristics of oral antipsychotics. Further, this study explored tradeoffs that patients may make between treatment efficacy and tolerability.
METHODS: A cross-sectional online survey was designed to collect patient preference data using a discrete choice experiment (DCE). The DCE consisted of a series of choice questions between pairs of hypothetical oral antipsychotics characterized across five attributes: efficacy (i.e., improvement in symptom severity), weight gain over six months, sexual dysfunction, risk of sedation, and akathisia. The survey was pretested among fifteen people with SZ to ensure comprehension and understanding of the DCE and other survey questions. The final survey was administered to US adults with a self-reported physician diagnosis of SZ. A random parameters logit model was used to estimate preference weights and to explore patients' acceptability of treatment tradeoffs.
RESULTS: A total of 144 respondents with SZ completed the survey (mean age of 41 years, 50% female, 69% White). Approximately 44% of respondents were diagnosed with SZ within five years of survey participation. When asked about SZ symptoms at their worst in the past week, 27% reported their symptoms to be severe, 45% reported moderate symptoms, and 28% reported mild to no symptoms. Most respondents experienced side effects assessed in the DCE with a previous treatment, including weight gain (85%), sexual dysfunction (75%), sedation (82%), and akathisia (71%).
Symptom improvement was the most important attribute across those included in the DCE (relative importance=31%). Sexual dysfunction (23%) and weight gain (21%) were the two most important side effects respondents wanted to avoid, followed by sedation (16%). Akathisia was considered the least important attribute to avoid (8%) among those included in the DCE. Respondents preferred treatments associated with 0, 4, or 7 pounds of weight gain significantly more than treatments associated with 11 pounds of weight gain over six months of treatment. Respondents were willing to accept an increase in weight of 9 to 10 pounds over six months for the smallest improvement in symptom control as assessed in this study (one incremental step of improvement of disease severity). For the largest improvement in symptom control (two incremental steps of improvement in disease severity), respondents were willing to accept an increase in weight of more than 11 pounds over 6 months (the maximum weight gain included in the DCE). In addition, respondents were willing to accept higher than a 25% risk of sedation for any incremental improvement in symptoms assessed in the DCE.
DISCUSSION: In this survey, treatment efficacy was the most important attribute of oral antipsychotics endorsed by respondents with SZ; sexual dysfunction and weight gain were endorsed as the two side effects patients most wanted to avoid. Respondents were willing to accept some weight gain as a side effect for better efficacy (greater improvement in symptoms). As oral antipsychotics have different efficacy and tolerability profiles, it is important to understand what patients value in a treatment and how they balance the benefits and risks of different treatments. Patient preference research may be a valuable tool to incorporate patient voice and inform treatment decision making.
