Psychometric performance and WHOQOL-BREF reference intervals in a healthy population of Medellín-Colombia.

Abstract

Introduction: The Quality of Life Instrument of the World Health Organization is widely used in healthy and sick people; however, few Colombian studies have analyzed its dimensions in a healthy population.

Objective: To evaluate the psychometric properties of the WHOQOL-BREF in a healthy population of Medellín, and to estimate the reference intervals for its four dimensions.

Methods: Cross-sectional study and psychometric evaluation in 1938 people. Reliability was evaluated with Cronbach's α, internal consistency and discriminant power with Spearman's Rho, content validity with λ coefficients and variance explained by exploratory factor analysis with extraction by principal components. The outliers values were eliminated using the Grubbs statistic, the global reference intervals were estimated for each dimension of the WHOQOL-BREF and the specific ones, according to demographic and socioeconomic variables, using 95% confidence intervals for the mean, and comparisons by T-Student and Anova. The analyzes were performed in SPPS 27.0®.

Results: Excellent reliability, internal consistency, discriminant power, and content validity were found in the four dimensions of the instrument in a healthy population. The reference values were 64.3-65.6 in physical health, 70.8-72.0 in psychological health, 64.3-65.9 in social health and 60.5-61.6 in environmental health, with statistically significant differences according to demographic and socioeconomic characteristics

Conclusion: The excellent psychometric performance of the scale in healthy population allowed the estimation of the reference intervals for the four dimensions, as well as the values for subgroups formed by demographic and socioeconomic variables, which is decisive for including the outcomes centered on people in medical and public health programs, as well as suitable indicators for the sick population.