Propiedades psicométricas del índice de impacto de la enfermedad en la productividad laboral (Índice IMPALA) en una población laboral

Abstract

OBJECTIVE: To adapt into Spanish and validate the Spanish version of the IMPALA Index for measuting the looses of work productivity health related. METHODS: Observational, cross sectional study, performed in the occupational medicine setting, with subjects 18 years older, full-time employees for at least 3 months by an Spanish Pharmaceutical Company (Pfizer España). FINDINGS: Among 399 valuable subjects the IMPALA Index showed: A) adequate feasibility, with a 20.6% of patients without response or wrong/not applicable response; B) adequate reliability (Alpha of Cronbach coefficient = 0.93 and 0.86 and Guttman coefficient = 0.92 and 0.86 in subjects with and without history of illnesses); C) adequate convergent/divergent validity, obtaining moderate to high correlation with work days with symptoms, performance percent and lost working days equivalents (LWDE) (r=-0.60, 0.64 and -0.67, respectively), and a moderate correlation with all domains and Summary Scores of Physical and Mental Health of the questionnaire of Quality of Life SF-36 (r=0.30-0.63), up to Emotional Role (r<0.30); O) adequate discriminant validity, finding higher work productivity among men, subjects with lower LWDE, higher Quality of Life and being healthy (without history of illnessess in general, without migraine and without treatment); E) acceptable construct validity, obtaining from the exploratory factorial analysis performed a single factor and a 72.0% of variability explained for. CONCLUSION: The IMPALA Index showed adequate feasibility, reliability and validity for use in research in clinical practice and occupational medicine.