[Convergent and discriminative validity of the Frail-VIG index with the Pfeiffer test in people cared for in home care]

Abstract

Introduction: The Frail-VIG index-and the Pfeiffer test are measurements used in Primary Care for assessment frailty and the cognitive impairment screening. The Frail-VIG index is a multidimensional instrument that allows a rapid assessment of the degree of frailty in the context of clinical practice.

Objective: Our aim was to investigate the convergent and discriminative validity of the Frail-VIG index with regard to Pfeiffer test value.

Design: A cross-sectional study. SITE: Two urban Primary Health Care centres of the Catalan Institute of Health, Barcelona (Spain).

Participants: All people included under a home care programme during the year 2018. No exclusion criteria were applied.

Main measurements: We used the Frail-VIG index to measure frailty and the Pfeiffer test to cognitive impairment screening. Trained nurses administered both instruments during face-to-face assessments in a participant's home during usual care. The relationships between both instruments were examined using Pearson's correlation coefficient.

Results: A total of 412 participants were included. Frail-VIG score and Pfeiffer test value were moderately correlated (r=0.564; P<0.001). Non-frail people had a lower risk of developing cognitive impairment than moderate to severe frail people. The value of the Pfeiffer test increased significantly as the Frail-VIG index score also increased.

Conclusions: Frail-VIG index demonstrated a convergent validity with the Pfeiffer test. Its discriminative validity was optimal, as their scores showed an excellent capacity to differentiate between people with a higher and lower risk of developing cognitive impairment. These findings provide additional pieces of evidence for construct validity of the Frail-VIG index.

Keywords: Atención Primaria de Salud; Estudios de validación; Fragilidad; Frailty; Frailty index; Primary Health Care; Psicometría; Psychometrics; Validation studies; Índice de fragilidad.