Moamer Soraya, Baghestani Ahmadreza, Pourhoseingholi Mohamad Amin, Hajizadeh Nastaran, Ahmadi Farzaneh, Norouzinia Mohsen
Department of Biostatistics, Faculty of Paramedical Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
Physiotherapy Research Centre, Department of Biostatistics, Faculty of Paramedical Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
Gastroenterol Hepatol Bed Bench. 2017 Winter;10(1):54-59.
The aim of this study was to assess the association between survival of patients with colorectal cancer and prognostic factors in a competing risk parametric model using Weibull distribution.
The prognosis of colorectal cancer is relatively good in terms of survival time. In many prognostic studies, patients may be exposed to several types of competing events. These different causes of death are called competing risks.
Data was recorded from 372 patients with colorectal cancer who registered in the Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences (Tehran, Iran) from 2004 to 2015 in a retrospective study. Analysis was performed using competing risks model and Weibull distribution. Software used for data analysis was R, and significance level was regarded as 0.05.
The result indicated that, at the end of follow-up, 111 (29.8%) deaths were from colorectal cancer and 14 (3.8%) deaths were due to other diseases. The average body mass index (BMI) was 24.61(SD 3.98). The mean survival time for a patient in 372 was 62.05(SD 48.78) month with median equals to 48 months. According to competing-risks method, only stageIII (HR, 1.69; 95% CI, 1.246-2.315 ), stageIV( HR, 4.51; 95% CI,2.91-6.99 ) and BMI( HR, 0.96; 95% CI, 0.96-0.975) have a significant effect on patient's survival time.
This study indicated pathologic stage (III,IV) and BMI as the prognosis, using a Weibull model with competing risks analysis, while other models without the competing events lead to significant predictors which may be due to over-estimation.
本研究旨在使用威布尔分布，在竞争风险参数模型中评估结直肠癌患者生存率与预后因素之间的关联。
就生存时间而言，结直肠癌的预后相对较好。在许多预后研究中，患者可能会面临几种类型的竞争事件。这些不同的死亡原因被称为竞争风险。
在一项回顾性研究中，记录了2004年至2015年在伊朗德黑兰沙希德·贝赫什提医科大学胃肠病与肝病研究所登记的372例结直肠癌患者的数据。使用竞争风险模型和威布尔分布进行分析。用于数据分析的软件是R，显著性水平设定为0.05。
结果表明，随访结束时，111例（29.8%）死亡是由结直肠癌引起的，14例（3.8%）死亡是由其他疾病导致的。平均体重指数（BMI）为24.61（标准差3.98）。372例患者的平均生存时间为62.05（标准差48.78）个月，中位数为48个月。根据竞争风险法，只有III期（风险比，1.69；95%置信区间，1.246 - 2.315）、IV期（风险比，4.51；95%置信区间，2.91 - 6.99）和BMI（风险比，0.96；95%置信区间，0.96 - 0.975）对患者的生存时间有显著影响。
本研究表明，使用具有竞争风险分析的威布尔模型时，病理分期（III、IV期）和BMI可作为预后指标，而其他不考虑竞争事件的模型会导致显著的预测因素，这可能是由于高估所致。
