Identifying Patient-relevant Endpoints Among Individuals with Schizophrenia: an Application of Patient-centered Health Technology Assessment

Objectives: Schizophrenia imposes a great burden on society, and while evaluation should play an important role in informing society's efforts to alleviate these burdens, it is unclear what "endpoints" should be chosen as the objective of such analyses. The objectives of the study were to elicit endpoints directly from patients with schizophrenia, to ascertain whether patients are sufficiently cognoscente to express what endpoints are and are not important to them and to rank the relevant endpoints.

Methods: We applied principles of patient-centered health technology assessment to identify and value endpoints from the patient's perspective. Focus groups were conducted to elicit endpoints, using interpretive phenomalogical analysis (IPA) to guide the collection, analysis and interpretation of data. Patient interviews were subsequently used to elicit patient preference over endpoints. Respondents were presented with cards outlining the endpoints and asked to remove irrelevant cards. They where then asked to identify and rank their five most relevant endpoints in order of importance. Interviews were recorded for the purposed of triangulation, and data was analyzed using descriptive statistics. Patients were recruited from five geographically diverse cities in Germany. Eligibility required a diagnosis of schizophrenia by a physician and treatment with an antipsychotic medication for at least one year. Respondents were excluded if they were experiencing an acute episode.

Results: Thirteen endpoints emerged as important from the focus groups spanning side-effects, functional status, processes of care and clinical outcomes. Respondents could clearly identify relevant and irrelevant endpoints, and rank which factors were important to them. Triangulation between field notes of the ranking exercise and recordings confirmed that rankings were not arbitrary, but justified from the respondents' point of view.

Conclusions: Patients with schizophrenia can express preferences over endpoints. Our results show that qualitative methods such as IPA can be used to identify factors, but ranking exercises provide a more robust method for ranking the importance of endpoints. Future research involving patients with schizophrenia ranking outcomes is needed to identify variations across patients and methods such as conjoint analysis could prove beneficial in identifying acceptable tradeoffs across endpoints.