Study Population
During the study period, 500 patients aged 70 or more were referred for elective surgery in the three participating hospitals. 143 of these patients were initially recruited for the study, but 6 of them were excluded from the analysis because they withdraw the informed consent, or the data was incomplete.
Finally, 137 patients were included in the study and 109 of them completed the 6-month follow-up period. 12 patients (8.8%) died within the study period, and 16 patients were lost during follow-up(figure 1 ).