Elaboration and validation of a measure to evaluate the knowledge of primary care physicians in Brazil about nutritional recommendation for hypertension control

Abstract Background Primary health care physicians play a leading role in nutritional counseling to reduce hypertension related to morbidity and mortality. The literature is scarce on instruments validated for Brazil that evaluate the evidence based on knowledge of these professionals. Objective To elaborate a measure to evaluate the level of knowledge about nutritional recommendation for the control of hypertension for primary care physicians in Brazil. Method A validated instrument for the English language was used as the basis for the questionnaire elaboration, which was tested according to the fundamentals of the Item Response Theory. The dimensionality of the questionnaire was performed on the polychoric correlation matrix. For the estimation of the parameters of the items, the two Parameters Logistic Model (discrimination and difficulty) was used. Results Most of the items were considered easy, the discriminative power varied between high, moderate and low values. The absence of difficult items contributed to the imprecision of the measure among those with higher levels of knowledge. Conclusion The results show a measure that accurately measures physicians with a low level of knowledge, being a useful tool to identify professionals who need to improve their nutritional knowledge.