Healthcare professional preferences for long-acting injectable treatments in schizophrenia: a discrete choice experiment

Background

Medication non-adherence remains a substantial barrier to effective schizophrenia treatment. In patients with schizophrenia, long-acting injectable (LAI) antipsychotics provide improved adherence and clinical outcomes versus oral antipsychotics, yet are underutilised. The aims of this study included assessing healthcare professional (HCP) preferences for key treatment attributes, examining how HCP characteristics impact these preferences, and identifying drivers of HCP prescribing of LAIs. These objectives were part of a larger study that also included patients and caregivers.

Methods

A discrete choice experiment (DCE) was developed via a targeted literature review and study design workshop, as well as input from clinical experts, tested via cognitive pilot interviews and a quantitative pilot. This cross-sectional preference study included HCPs from Canada, Germany, Spain, the United Kingdom, and the United States (US).

Primary treatment-related attributes examined included: (1) frequency and mode of administration (daily oral, monthly subcutaneous injection without loading dose, monthly intramuscular injection without loading dose, monthly intramuscular injection with loading dose); (2) post-injection monitoring (none, 3 hours in clinic); (3) weight gain (0 kg, 5 kg, 10 kg); (4) risk of post-injection delirium/sedation syndrome (PDSS) (none, 2%); (5) severity of hallucinations and delusions (minimal, moderate, severe); (6) severity of hostility and aggression (minimal, moderate, severe); and (7) risk of hospitalisation due to relapse (5%, 10%, 15%).

Results

Among 321 HCP participants (median age 40 years; 51% male; 85% psychiatrists, 15% psychiatric nurses with prescribing authority from the US), most practiced in community/outpatient (42%) or inpatient (35%) settings. Overall, HCPs reported prescribing oral medications for 60% and LAIs for 30% of their adult patients with schizophrenia. HCPs rated medication adherence as having the most influence on LAI prescribing (mean 4.5 of 5.0), followed by symptom severity (4.1), access to/availability of treatments (4.0), and cost (2.9). In the DCE, all 7 attributes significantly impacted HCP treatment choices. When considering patients who were adherent to treatment, HCPs ranked attributes (highest to lowest) as control of positive symptoms (hostility and aggression, hallucinations and delusions), weight gain, reduced hospitalisation risk, mode and frequency of administration, need for post-injection monitoring, and reduced risk of PDSS. For nonadherent patients, HCPs ranked mode and frequency of administration as the most important attribute, with the other attributes following the same pattern as for adherent patients. When considering nonadherent patients, HCPs were willing to accept up to a 32.8% increase in hospitalisation risk to be able to provide patients with monthly subcutaneous injections instead of daily pills. Across all patients, HCPs were willing to accept up to a 15.5% increase in hospitalisation risk for hallucinations to be minimal instead of severe and up to an 18.4% risk for hostility to be minimal instead of severe.

Conclusions

HCP preferences were strongly influenced by perceived patient adherence; for nonadherent patients, mode and frequency of administration was the most influential treatment attribute, with HCPs preferring subcutaneous monthly injections over daily pills. Education should highlight the potential for LAIs to be beneficial to patients with and without perceived adherence challenges.

References

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