https://www.selleckchem.com/products/nik-smi1.html Background Chronic pain is the third main problem of global health and the most common cause of long-term disabilities. The duration that patients suffer from chronic pain is directly proportional to the extent of the suffering and to the amount of health care resources allocated to this problem. There is no research that has studied the risk factors associated with the long pain duration in chronic pain patients. Methods We investigated the potential risk factors associated with long pain duration in a population with diverse pain conditions in a cross-sectional study. We used a questionnaire that included a number of potential risk factors including sex, age, marital status, household condition, number of children, employment, education, body mass index (BMI), pain intensity, and the level of anxiety/depression. The data were analyzed by univariable and multivariable linear regression models. Results We recruited 780 patients. The analyses showed that age and abnormal BMI had a positive correlation with pain duration. Conclusions The risk factors that might be associated with longer pain duration include older age and abnormal BMI. Copyright © 2020, Author(s).Background Spinal anesthesia is the most common technique used for cesarean delivery due to some advantages compared to regional anesthesia. It is easily performed and provides a rapid onset of block. Though bupivacaine is a generally used long-acting amide type local anesthetic drug for spinal anesthesia, ropivacaine may sometimes be selected. Objectives This prospective, randomized, double-blinded study was aimed at comparing clinical efficacy and safety between ropivacaine and bupivacaine during cesarean section. Methods After getting ethical committee approval and written informed consent, 65 women who referred to Imam Khomeini Hospital of Ahvaz, Iran in 2018 were chosen for elective cesarean delivery under spinal anesthesia. They were randomly allocated