investigation factors affecting the first recurrence of coronary artery disease in patients undergone angioplasty using cox survival model

background: the incidence of restenosis in patients suffering from coronary artery disease after undergoing angioplasty is of paramount importance. accordingly, this study aimed to investigate factors affecting the time of the first incidence of restenosis in patients undergone angioplasty in the city of zanjan, iran.   methods: this retrospective cohort study was conducted on 421 patients who referred to ayatollah musavi hospital in zanjan for angioplasty during 2009 to 2012.  the time of the incidence of restenosis after angioplasty constituted the dependent variable of the study. independent variables of the study included signs of diabetes, hypertension, hyperlipidemia, kidney disease, carotid stenosis, lung disease, anemia, angina history, and mi. the cox regression model with the significance level of 0.05 was deployed for the statistical analysis.   results: according to the cox regression model, hazard ratio of the first incidence of restenosis in patients with hypertension and angina was 22.8% and 29.5% less than other patients, respectively. however, hazard ratio of the first incidence of restenosis was 7.4 times more in patients suffering from carotid stenosis than other patients (p< 0.05).   conclusion: the results of this study revealed that as time goes on, the risk of the incidence of restenosis in angioplasty patients increases such that patients' survival decreases dramatically after a year. to determine the role of effective factors on the incidence of restenosis, conducting a prospective interventional study is highly recommended.