Acknowledgements
This research has been financially supported by Tehran University of Medical Sciences & health services grant [grant number: 99-1-101-47279]. The supporting institution had no involvement in study design; in the collection, analysis and interpretation of data; in the writing of the report; and in the decision to submit the article for publication. Authors also would like to appreciate the support and constructive comments of the methodologist(s) research development office, Imam khomeini Hospital complex. We would like to thank our patients for their time and cooperation, and also the medical staff of the Imam Khomeini Hospital Complex who helped facilitated the process of our research.
Conflict of Interest: none