Abstract
BACKGROUND: The Multidimensional Prognostic Index (MPI) is a comprehensive geriatric assessment (CGA)-based tool that has shown excellent accuracy in predicting negative health outcomes in older people. Recently, the self-administered version of MPI (SELFY-MPI) has been validated in a community-dwelling sample, revealing excellent agreement with the original MPI. In the SELFY-MPI, Gijon's social-familial evaluation scale (SFES) was used to assess socio-relational and economic aspects. Completion of the SELFY-MPI, however, requires a significant amount of time in people aged over 60 years, particularly to fill in the SFES scale. The aim of this study was to validate, in a sample of community-dwelling older people, a short-form version of the SELFY-MPI (SELFY-MPI-SF), in which the SFES scale was replaced by the "co-habitation status" domain, as in the original version of the MPI. METHODS: All participants included in the study completed both versions of the self-administered MPI, which share the following seven domains: 1) basic and 2) instrumental activities of daily living, 3) mobility, 4) cognition, 5) nutrition, 6) comorbidity, and 7) number of medications. Moreover, in the SELFY-MPI-SF, the 8th domain "co-habitation status" (ie living alone, with family or in a residential facility) replaced the SFES scale. The Bland-Altman methodology was applied in order to measure the agreement between the two instruments. Finally, the time to complete the SFES scale and the question on co-habitation was measured. RESULTS: The final study sample was composed of 129 participants (mean age=76.8 years, range=65-93 years, 64.3% women) were enrolled. The mean SELFY-MPI and SELFY-MPI-SF values were 0.221±0.196 and 0.246± 0.188, respectively. The mean difference was clinically irrelevant (-0.025±0.058). None of the 129 observations showed values outside the established 5% limits of agreement. The agreement between SELFY-MPI and SELFY-MPI-SF was excellent (k=0.762; rho=0.924, p<0.0001 for both). Stratified analyses of agreement among subgroups of participants of different ages did not show any significant differences between the two versions. Completion of the SFES required about 7 mins, on average, while the question on habitation status required about 10 s. CONCLUSION: The SELFY-MPI-SF showed strong agreement and precision when compared with the standard SELFY-MPI in people aged 65 and older and can therefore be successfully used as a quicker self-administered frailty instrument in community-dwelling older people.