RESUMEN
Background: Clinical practice guidelines (CPGs) promote better quality and equity in health care and potentially they could improve patients' outcomes. However, their implementation is hindered by a number of factors including some related to health care professionals. Aim: To assess the perceptions and attitudes of primary care physicians regarding CPGs developed by the Chilean Ministry of Health in the context of the Health Sector Reform. Material and Methods: An adaptation of the survey "Knowledge, perceptions and attitudes towards Clinical Practice Guidelines" was sent to 1,264 primary care physicians in Chile and answered completely by 354. The analysis assessed the attitudes towards CPG, their use in primary care and their relationship with socio demographic features of respondents. Results: Eighty two percent of respondents reviewed the flowcharts of the guidelines, 85% consulted their online version. The classification of evidence levels and the strength of recommendations generated a high level of confidence with the guidelines in 70 and 64% of respondents. Eighty five percent considered that CPG could help to standardize clinical practice. The most relevant barrier hindering CPG use was the lack of a brief, simple and easy to access format in 63% of respondents. The three dimensions of the theory of planned behavior (attitude toward behavior, subjective norms, and perceived behavioral control) were associated with a greater frequency of guideline use. A higher age and not being Chilean were associated with a lower frequency of use. Conclusions: The identified factors associated with CPG use should be considered in future guideline design.