Patient-related risk factors for recurrence after inguinal hernia repair: A systematic review and meta-analysis of observational studies

Background. Several factors influence the risk of recurrence after inguinal hernia surgery; however, a systematic review and meta-analysis of patient-related risk factors for recurrence after inguinal hernia surgery has not been performed earlier. Methods. MEDLINE, Embase, and Cochrane databases were searched in June 2013 for studies evaluating patient-related risk factors for recurrence after inguinal hernia operation. Observational studies evaluating nontechnical patient-related risk factors for recurrence after inguinal hernia surgery were included. Outcome variables were grouped under patient demographics, hernia characteristics, connective tissue composition and degradation, habits and social relations, and conditions related to inguinal hernia recurrence. Results. From a total of 5061 records screened, we included 40 observational studies enrolling 720 651 inguinal hernia procedures in 714 917 patients in the systematic review. Of the 40 studies, 14 studies were included in 8 meta-analyses evaluating sex, hernia type, hernia size, re-recurrence, bilaterality, mode of admission, age, and smoking as risk factors for recurrence after inguinal hernia surgery in a total of 378 824 procedures in 375 620 patients. Conclusions. We found that female sex, direct inguinal hernias at the primary procedure, operation for a recurrent inguinal hernia, and smoking were significant risk factors for recurrence after inguinal hernia surgery. This knowledge of patient-related risk factors for recurrence after inguinal hernia surgery could be implemented in clinical practice.