OBJECTIVES: The INTERMED Self-Assessment questionnaire (IMSA) was developed as an alternative to the observer-rated INTERMED (IM) to assess biopsychosocial complexity and health care needs. We studied feasibility, reliability and validity of the IMSA within a large and heterogeneous international sample of adult hospital in- and outpatients, and its predictive value for health care utilization (HCU) and quality of life (QoL).

METHODS: 850 participants aged 17 to 90 from 5 countries completed the IMSA and were evaluated with the IM. The following measurement properties were determined: feasibility by percentages of missing values; reliability by Cronbach's alpha; interrater agreement by intraclass correlation coefficients (ICCs); convergent validity of IMSA scores with mental health (SF-36 emotional well-being subscale and HADS), medical health (CIRS) and QoL (EQ-5D) by Spearmans rank correlations; predictive validity of IMSA scores with HCU and QoL by (generalized) linear mixed models.

RESULTS: Feasibility, face validity and reliability (Cronbach's alpha 0.80) were satisfactory. ICC between IMSA and IM total scores was .78 (95% CI .75-.81). Correlations of the IMSA with the SF-36, HADS, CIRS and EQ-5D (convergent validity) were -.65, .15, .28 and -.59, respectively. The IMSA significantly predicted QoL and also HCU (emergency room visits, hospitalization, outpatient visits, and diagnostic exams) after 3 and 6 months follow-up. Results were comparable between hospital sites, in- and outpatients, and age groups.

CONCLUSION: The IMSA is a generic and time-efficient method to assess biopsychosocial complexity and to provide guidance for multidisciplinary care trajectories in adult patients, with good reliability and validity across different cultures.