Development and measurement properties of the self assessment version of the INTERMED for the elderly to assess case complexity.

OBJECTIVES The INTERMED for the Elderly Self Assessment (IM-E-SA) was developed to support health care professionals in providing demand driven elderly care. It assesses case complexity and health care needs as perceived by older adults themselves. By applying this instrument tailored care can be provided as it supports professionals in their allocation decisions. The aim was to evaluate the measurement properties of the IM-E-SA. METHODS In this cross-sectional study 338 elderly people completed a postal questionnaire and participated in an interview. Feasibility of the IM-E-SA was assessed by determining the percentages of missing values per item. Reliability of the IM-E-SA was expressed as Cronbach's alpha. Intraclass correlation coefficients (ICCs) were calculated between the IM-E-SA and IM-E. Nonparametric tests were applied to assess if the IM-E-SA could distinguish between subgroups of elderly adults who differed on demographic characteristics and the prevalence of diseases/disorders. Convergent validity and discriminant validity were assessed using Spearman rank correlations between the IM-E-SA and IM-E, life satisfaction (Cantril's Ladder of Life), activities of daily living (Katz extended), quality of life (EQ-5D), mental health (SF-36) and prevalence of diseases/disorders. RESULTS Percentages of missing values per IM-E-SA item ranged from 0 to 5%. Cronbach's alpha was .78. The ICC between the total scores of the IM-E-SA and the IM-E was .68. The IM-E-SA yielded statistically significant differences between subgroups (known-group validity). Correlations evaluating the convergent validity were moderate to strong (.50-.70). Those correlations assessing the discriminant validity were moderate (.38-.53). CONCLUSION This study supports the feasibility, reliability and validity of the IM-E-SA.