anvar esmaili department of health management and economics, school of public health, tehran university of medical sciences, tehran, ir iran hesam seyedin health management and economics research centre, school of health management and information sciences, iran university of medical sciences, tehran, ir iran; health management and economics research centre, school of health management and information sciences, iran university of medical sciences, tehran, ir iran. tel: +98-214422236591, fax: +98-2188883334 obeidollah faraji department of health management and economics, school of public health, tehran university of medical sciences, tehran, ir iran jalal arabloo department of health management and economics, school of public health, tehran university of medical sciences, tehran, ir iran yaghoub qahraman bamdady mahabad imam khomeini hospital, urmia university of medical sciences, urmia, ir iran shahin shojaee mahabad imam khomeini hospital, urmia university of medical sciences, urmia, ir iran