Background::Previous studies have reported associations of specific maternal and paternal lifestyle factors with offspring’s cognitive development during early childhood. This study aimed to investigate the prospective associations between overall parental lifestyle and offspring’s cognitive performance during adolescence and young adulthood in China.Methods::We included 2531 adolescents aged 10-15 years at baseline in 2010 from the China Family Panel Studies. A healthy parental lifestyle score (ranged 0-5) was constructed based on the following five modifiable lifestyle factors: Smoking, drinking, exercise, sleep, and diet. Generalized estimating equation models were used to examine the association between baseline parental healthy lifestyle scores and offspring’s fluid and crystallized intelligence in subsequent years (2012, 2014, 2016, and 2018).Results::Offspring in the top tertile of parental healthy lifestyle scores performed better in overall fluid intelligence (multivariable-adjusted β = 0.53, 95% confidence interval [CI]: 0.29-0.77) and overall crystallized intelligence (multivariable-adjusted β = 0.35, 95% CI: 0.16-0.54) than those in the bottom tertile of parental healthy lifestyle scores. The results were similar after further adjustment for the offspring’s healthy lifestyle scores and persisted across the subgroups of parental socioeconomic status. Additionally, maternal and paternal healthy lifestyle scores were independently associated with better offspring’s cognitive performance, with significant contribution observed for paternal never-smoking, weekly exercise, and diversified diet. When both parents and offspring adhered to a healthier lifestyle, we observed the highest level of the offspring’s overall crystallized intelligence. Conclusions::Our study indicates that parental adherence to a healthier lifestyle is associated with significantly better offspring’s cognitive performance during adolescence and early adulthood, regardless of socioeconomic status. These findings highlight the potential cognitive benefits of promoting healthy lifestyles among parents of adolescents.

Objective:We investigated the incidence of surgical site infection (SSI) following emergency abdominal surgery (EAS) in China and further explored its risk factors, providing a reference for preventing and controlling SSI after EAS.Methods:This was an observational study. Data of patients who had undergone EAS and been enrolled in the Chinese SSI Surveillance Program during 2018–2021were retrospectively analyzed. All included patients had been followed up for 30 days after surgery. The analyzed data consisted of relevant patient characteristics and perioperative clinical data, including preoperative hemoglobin, albumin, and blood glucose concentrations, American Society of Anesthesiologists (ASA) score, grade of surgical incision, intestinal preparation, skin preparation, location of surgical site, approach, and duration. The primary outcome was the incidence of SSI occurring within 30 days following EAS. SSI was defined as both superficial and deep incisional infections and organ/space infections, diagnoses being supported by results of microbiological culture of secretions and pus. Secondary outcomes included 30-day postoperative mortality rates, length of stay in the intensive care unit (ICU), duration of postoperative hospitalization, and associated costs. The patients were classified into two groups, SSI and non-SSI, based on whether an infection had been diagnosed. Univariate and multivariate logistic regression analyses were performed to identify risk factors associated with SSI following EAS.Results:The study cohort comprised 5491 patients who had undergone EAS, comprising 3169 male and 2322 female patients. SSIs were diagnosed in 168 (3.1%) patients after EAS (SSI group); thus, the non-SSI group consisted of 5323 patients. The SSIs comprised superficial incision infections in 69 (41.1%), deep incision infections in 51 (30.4%), and organ or space infections in 48 (28.6%). Cultures of secretions and pus were positive in 115 (68.5%) cases. The most frequently detected organism was Escherichia coli (47/115; 40.9%). There were no significant differences in sex or body mass index between the SSI and non-SSI groups (both P>0.05). However, the proportion of individuals aged 60 years or older was significantly greater in the SSI than in the non-SSI group (49.4% [83/168] vs. 27.5% [1464/5323), χ 2=38.604, P<0.001). Compared with the non-SSI group, the SSI group had greater proportions of patients with diabetes (11.9% [20/168] vs. 4.8% [258/5323], χ 2=16.878, P<0.001), hypertension (25.6% [43/168] vs. 12.2% [649/5323], χ 2=26.562, P<0.001); hemoglobin <110 g/L (27.4% [46/168] vs. 13.1% [697/5323], χ 2=28.411, P<0.001), and albuminemia <30 g/L (24.4% [41/168] vs. 5.9% [316/5323], χ 2=91.352, P<0.001), and a reduced rate of preoperative skin preparation (66.7% [112/168] vs. 75.9% [4039/5323], χ 2=7.491, P=0.006). Furthermore, fewer patients in the SSI group had preoperative ASA scores of between one and two (56.0% [94/168] vs. 88.7% [4724/5323], χ 2=162.869, P<0.001) in the non-SSI group. The incidences of contaminated and infected incisions were greater in the SSI group (63.1% [106/168] vs. 38.6% [2056/5323], χ 2=40.854, P<0.001). There was a significant difference in surgical site distribution between the SSI and non-SSI groups (small intestine 29.8% [50/168] vs. 10.6% [565/5323], colorectal 26.2% [44/168] vs. 5.6% [298/5 323], and appendix 24.4% [41/168] vs. 65.1% [3465/5323]) χ 2=167.897, P<0.001), respectively. There was a significantly lower proportion of laparoscope or robotic surgery in the non-SSI group (24.4 % [41/168] vs. 74.2% [3949/5323], χ 2=203.199, P<0.001); the percentage of operations of duration less than 2 hours was significantly lower in the SSI than non-SSI group (35.7% [60/168] vs. 77.4% [4119/5323], χ 2=155.487, P<0.001). As to clinical outcomes, there was a higher 30-day postoperative mortality rate (3.0%[5/168] vs. 0.2%[10/5323], χ 2=36.807, P<0.001) and higher postoperative ICU occupancy rate (41.7% [70/168] vs. 19.7% [1046/5323], χ 2=48.748, P<0.001) in the SSI group. The median length of stay in the ICU (0[2] vs. 0[0] days, U=328597.000, P<0.001), median total length of stay after surgery (16[13] vs. 6[5] days, U=128146.000, P<0.001), and median hospitalization cost (ten thousand yuan, 4.7[4.4] vs. 1.7[1.8], U=175965.000, P<0.001) were all significantly greater in the SSI group. Multivariate logistic regression analysis revealed that the absence of skin preparation before surgery (OR=2.435,95%CI: 1.690–3.508, P<0.001), preoperative albuminemia <30 g/L (OR=1.680, 95%CI: 1.081–2.610, P=0.021), contaminated or infected incisions (OR=3.031, 95%CI: 2.151–4.271, P<0.001), and laparotomy (OR=3.436, 95% CI: 2.123–5.564, P<0.001) were independent risk factors of SSI. Operative duration less than 2 hours (OR=0.465, 95%CI: 0.312–0.695, P<0.001) and ASA score of 1–2 (OR=0.416, 95% CI: 0.289–0.601, P<0.001) were identified as independent protective factors for SSI. Conclusions:It is important to consider the nutritional status in the perioperative period of patients undergoing EAS. Preoperative skin preparation should be conducted and, whenever possible, laparoscope or robot-assisted surgery. Duration of surgery should be as short as possible while maintaining surgery quality and improving patient care.

Objective:To investigate the risk factors of surgical site infection (SSI) after colorectal surgery, and to establish and validate a risk prediction model nomogram.Methods:An observational study was conducted to retrospectively collect data of 6527 patients aged ≥16 years who underwent colorectal surgery in 56 domestic hospitals from March 1, 2021 to February 28, 2022 from the national Surgical Site Infection Surveillance network. The incidence of SSI after surgery was 2.3% (149/6527). According to the ratio of 7:3, 6527 patients were randomly divided into the modeling cohort (4568 cases) and the validation cohort (1959 cases), and there was no statistically significant difference between the two datasets ( P>0.05). Univariate analysis was performed using t test /Mann-Whitney U test /χ 2 test. Multivariate analysis was performed using binary logistic regression to establish a preliminary model and select variables using Lasso analysis to establish an optimized model nomogram. The discrimination and calibration of the model were evaluated by ROC curve, calibration curve, and Hosmer-Lemeshow test. AUC value>0.7 is considered a good discrimination of the model. The Bootstrap method (repeated self-sampling 1000 times) was used to verify the constructed model internally and externally to evaluate the accuracy of the constructed model. Results:Multivariate analysis showed that history of chronic liver disease (OR=3.626, 95%CI: 1.297-10.137, P<0.001) and kidney disease (OR=1.567,95%CI:1.042-2.357, P=0.038), surgical antibiotic prophylaxis (OR=1.564, 95%CI:1.038-2.357, P=0.035), and emergency surgery (OR=1.432,95%CI: 1.089-1.885, P=0.021), open surgery (OR=1.418, 95%CI:1.045-1.924, P=0.042), preoperative stoma (OR=3.310, 95%CI:1.542-7.105, P<0.001), postoperative stoma (OR=2.323,95%CI: 1.537-8.134, P<0.001), surgical incision type above grade II (OR=1.619,95%CI:1.097-2.375, P=0.014), and each unit increase in total bilirubin (OR=1.003,95%CI:-0.994-1.012, P=0.238), alanine aminotransferase (OR=1.006, 95%CI:1.001-1.011, P=0.032), blood urea nitrogen (OR=1.003,95%CI:0.995-1.011, P=0.310), blood glucose (OR=1.024, 95%CI:1.005-1.043, P=0.027), C-reactive protein (OR=1.007, 95%CI:1.003-1.011, P<0.001), length of incision (OR=1.042, 95%CI:1.002-1.087, P=0.031), surgical duration (OR=1.003,95%CI:1.001-1.005, P=0.017), and surgical blood loss (OR=1.001,95%CI: 1.000-1.002, P=0.045) were risk factors for SSI after colorectal surgery. Each unit increase in albumin level (OR=0.969,95%CI:0.941-0.998, P=0.036) was an independent protective factor for SSI after colorectal surgery. The area under the curve of the optimized model obtained by internal and external validation were 0.768 (95%CI: 0.723-0.813) and 0.753 (95%CI: 0.680-0.832), respectively. The predicted value of the calibration curve was basically consistent with the actual value. Conclusions:The risk prediction model for SSI after colorectal surgery constructed in this study has good discrimination and calibration. The nomogram created in this model can provide an evaluation basis for the observed rate and expected event rate of SSI after clinical colorectal surgery.

Objective:We investigated the incidence of surgical site infection (SSI) following emergency abdominal surgery (EAS) in China and further explored its risk factors, providing a reference for preventing and controlling SSI after EAS.Methods:This was an observational study. Data of patients who had undergone EAS and been enrolled in the Chinese SSI Surveillance Program during 2018–2021were retrospectively analyzed. All included patients had been followed up for 30 days after surgery. The analyzed data consisted of relevant patient characteristics and perioperative clinical data, including preoperative hemoglobin, albumin, and blood glucose concentrations, American Society of Anesthesiologists (ASA) score, grade of surgical incision, intestinal preparation, skin preparation, location of surgical site, approach, and duration. The primary outcome was the incidence of SSI occurring within 30 days following EAS. SSI was defined as both superficial and deep incisional infections and organ/space infections, diagnoses being supported by results of microbiological culture of secretions and pus. Secondary outcomes included 30-day postoperative mortality rates, length of stay in the intensive care unit (ICU), duration of postoperative hospitalization, and associated costs. The patients were classified into two groups, SSI and non-SSI, based on whether an infection had been diagnosed. Univariate and multivariate logistic regression analyses were performed to identify risk factors associated with SSI following EAS.Results:The study cohort comprised 5491 patients who had undergone EAS, comprising 3169 male and 2322 female patients. SSIs were diagnosed in 168 (3.1%) patients after EAS (SSI group); thus, the non-SSI group consisted of 5323 patients. The SSIs comprised superficial incision infections in 69 (41.1%), deep incision infections in 51 (30.4%), and organ or space infections in 48 (28.6%). Cultures of secretions and pus were positive in 115 (68.5%) cases. The most frequently detected organism was Escherichia coli (47/115; 40.9%). There were no significant differences in sex or body mass index between the SSI and non-SSI groups (both P>0.05). However, the proportion of individuals aged 60 years or older was significantly greater in the SSI than in the non-SSI group (49.4% [83/168] vs. 27.5% [1464/5323), χ 2=38.604, P<0.001). Compared with the non-SSI group, the SSI group had greater proportions of patients with diabetes (11.9% [20/168] vs. 4.8% [258/5323], χ 2=16.878, P<0.001), hypertension (25.6% [43/168] vs. 12.2% [649/5323], χ 2=26.562, P<0.001); hemoglobin <110 g/L (27.4% [46/168] vs. 13.1% [697/5323], χ 2=28.411, P<0.001), and albuminemia <30 g/L (24.4% [41/168] vs. 5.9% [316/5323], χ 2=91.352, P<0.001), and a reduced rate of preoperative skin preparation (66.7% [112/168] vs. 75.9% [4039/5323], χ 2=7.491, P=0.006). Furthermore, fewer patients in the SSI group had preoperative ASA scores of between one and two (56.0% [94/168] vs. 88.7% [4724/5323], χ 2=162.869, P<0.001) in the non-SSI group. The incidences of contaminated and infected incisions were greater in the SSI group (63.1% [106/168] vs. 38.6% [2056/5323], χ 2=40.854, P<0.001). There was a significant difference in surgical site distribution between the SSI and non-SSI groups (small intestine 29.8% [50/168] vs. 10.6% [565/5323], colorectal 26.2% [44/168] vs. 5.6% [298/5 323], and appendix 24.4% [41/168] vs. 65.1% [3465/5323]) χ 2=167.897, P<0.001), respectively. There was a significantly lower proportion of laparoscope or robotic surgery in the non-SSI group (24.4 % [41/168] vs. 74.2% [3949/5323], χ 2=203.199, P<0.001); the percentage of operations of duration less than 2 hours was significantly lower in the SSI than non-SSI group (35.7% [60/168] vs. 77.4% [4119/5323], χ 2=155.487, P<0.001). As to clinical outcomes, there was a higher 30-day postoperative mortality rate (3.0%[5/168] vs. 0.2%[10/5323], χ 2=36.807, P<0.001) and higher postoperative ICU occupancy rate (41.7% [70/168] vs. 19.7% [1046/5323], χ 2=48.748, P<0.001) in the SSI group. The median length of stay in the ICU (0[2] vs. 0[0] days, U=328597.000, P<0.001), median total length of stay after surgery (16[13] vs. 6[5] days, U=128146.000, P<0.001), and median hospitalization cost (ten thousand yuan, 4.7[4.4] vs. 1.7[1.8], U=175965.000, P<0.001) were all significantly greater in the SSI group. Multivariate logistic regression analysis revealed that the absence of skin preparation before surgery (OR=2.435,95%CI: 1.690–3.508, P<0.001), preoperative albuminemia <30 g/L (OR=1.680, 95%CI: 1.081–2.610, P=0.021), contaminated or infected incisions (OR=3.031, 95%CI: 2.151–4.271, P<0.001), and laparotomy (OR=3.436, 95% CI: 2.123–5.564, P<0.001) were independent risk factors of SSI. Operative duration less than 2 hours (OR=0.465, 95%CI: 0.312–0.695, P<0.001) and ASA score of 1–2 (OR=0.416, 95% CI: 0.289–0.601, P<0.001) were identified as independent protective factors for SSI. Conclusions:It is important to consider the nutritional status in the perioperative period of patients undergoing EAS. Preoperative skin preparation should be conducted and, whenever possible, laparoscope or robot-assisted surgery. Duration of surgery should be as short as possible while maintaining surgery quality and improving patient care.

Objective:To investigate the risk factors of surgical site infection (SSI) after colorectal surgery, and to establish and validate a risk prediction model nomogram.Methods:An observational study was conducted to retrospectively collect data of 6527 patients aged ≥16 years who underwent colorectal surgery in 56 domestic hospitals from March 1, 2021 to February 28, 2022 from the national Surgical Site Infection Surveillance network. The incidence of SSI after surgery was 2.3% (149/6527). According to the ratio of 7:3, 6527 patients were randomly divided into the modeling cohort (4568 cases) and the validation cohort (1959 cases), and there was no statistically significant difference between the two datasets ( P>0.05). Univariate analysis was performed using t test /Mann-Whitney U test /χ 2 test. Multivariate analysis was performed using binary logistic regression to establish a preliminary model and select variables using Lasso analysis to establish an optimized model nomogram. The discrimination and calibration of the model were evaluated by ROC curve, calibration curve, and Hosmer-Lemeshow test. AUC value>0.7 is considered a good discrimination of the model. The Bootstrap method (repeated self-sampling 1000 times) was used to verify the constructed model internally and externally to evaluate the accuracy of the constructed model. Results:Multivariate analysis showed that history of chronic liver disease (OR=3.626, 95%CI: 1.297-10.137, P<0.001) and kidney disease (OR=1.567,95%CI:1.042-2.357, P=0.038), surgical antibiotic prophylaxis (OR=1.564, 95%CI:1.038-2.357, P=0.035), and emergency surgery (OR=1.432,95%CI: 1.089-1.885, P=0.021), open surgery (OR=1.418, 95%CI:1.045-1.924, P=0.042), preoperative stoma (OR=3.310, 95%CI:1.542-7.105, P<0.001), postoperative stoma (OR=2.323,95%CI: 1.537-8.134, P<0.001), surgical incision type above grade II (OR=1.619,95%CI:1.097-2.375, P=0.014), and each unit increase in total bilirubin (OR=1.003,95%CI:-0.994-1.012, P=0.238), alanine aminotransferase (OR=1.006, 95%CI:1.001-1.011, P=0.032), blood urea nitrogen (OR=1.003,95%CI:0.995-1.011, P=0.310), blood glucose (OR=1.024, 95%CI:1.005-1.043, P=0.027), C-reactive protein (OR=1.007, 95%CI:1.003-1.011, P<0.001), length of incision (OR=1.042, 95%CI:1.002-1.087, P=0.031), surgical duration (OR=1.003,95%CI:1.001-1.005, P=0.017), and surgical blood loss (OR=1.001,95%CI: 1.000-1.002, P=0.045) were risk factors for SSI after colorectal surgery. Each unit increase in albumin level (OR=0.969,95%CI:0.941-0.998, P=0.036) was an independent protective factor for SSI after colorectal surgery. The area under the curve of the optimized model obtained by internal and external validation were 0.768 (95%CI: 0.723-0.813) and 0.753 (95%CI: 0.680-0.832), respectively. The predicted value of the calibration curve was basically consistent with the actual value. Conclusions:The risk prediction model for SSI after colorectal surgery constructed in this study has good discrimination and calibration. The nomogram created in this model can provide an evaluation basis for the observed rate and expected event rate of SSI after clinical colorectal surgery.

Tetanus consists of neonatal tetanus and non-neonatal tetanus. Non-neonatal tetanus remains a serious public health problem, although neonatal tetanus has been eliminated in China since 2012. Non-neonatal tetanus is a potential fatal disease. In the absence of medical intervention, the mortality rate of severe cases is almost 100%. Even with vigorous treatment, the mortality rate remains 30%-50% globally. These specifications aim to regulate non-neonatal tetanus diagnosis and treatment in China, in order to improve medical quality and safety. These specifications introduce the etiology, epidemiology, pathogenesis, clinical manifestations and laboratory tests, diagnosis, differential diagnosis, grading and treatment of non-neonatal tetanus.

Objective:To explore the correlation between the index of hemodynamics in perinatal period and retinopathy of prematurity(ROP), so as to provide basis for the better prevention and treatment of ROP.Methods:From May 2017 to April 2019, the preterm infants were admitted to the Neonatal Intensive Care Unit of the First Affiliated Hospital of Zhengzhou University at birth and were hospitalized for more than 2 weeks, gestational age ≤ 35 weeks and birth weight ≤ 2 500 g. They were selected as the study objects.The perinatal data including heart rate, blood pressure, patent ductus arteriosus, ventricular septal defect, and NT-proBNP level on the 1 st, 7 th and 14 th day, respectively after birth were collected.They were divided into ROP group and non ROP group according to the results of the retinopathy screening report.The influencing factors of ROP were screened out by univariate analysis and multivariate regression analysis. Results:A total of 1 119 subjects were included, 105 infants with ROP were detected, and the prevalence of ROP was 9.4%.Among them, 12 cases of pre-threshold lesion type 1 and threshold lesions required treatment, accoun-ting for 1.07% of screened preterm infants .Univariate analysis and multivariate regression analysis revealed that gestational age, birth weight, total oxygen therapy time, and intrauterine growth restriction were all factors affecting ROP, and 2 hemodynamic related indicators, such as the level of NT-proBNP in plasma on the 14 th day after birth, and placenta previa or abruption were also related to ROP( OR=0.604, 0.647, 1.276, 2.361, 1.688 and 2.506, respectively, all P<0.05). Conclusion:The hemodynamic changes in perinatal period may be involved in the formation of ROP, and it is necessary to further clarify its mechanism.

Objective:To analyze clinical characteristics of recurrent appendicitis.Methods:A retrospective cohort study was carried out. Clinical data of patients who underwent appendectomy due to acute appendicitis confirmed by pathology in the Affiliated Hospital of Qingdao University from January 2011 to December 2015 were analyzed retrospectively. Exclusion criteria: (1) age of less than 18 years;(2) chronic appendicitis; (3) periappendiceal abscess; (4) appendiceal mucocele or mucinous neoplasms; (5) appendiceal neuroendocrine tumors or cancers; (6) appendicitis during pregnancy; (7) concurrent AIDS, hematological disease, autoimmune disease, inflammatory bowel disease or advanced cancer; (8) other simultaneous surgery. A total of 373 patients were enrolled the study. These patients were divided into the recurrent group (133 cases) and the first episode group (240 cases) according to the previous history of antibiotic therapy for acute appendicitis. The prevalence of recurrent appendicitis was calculated, and the clinical characteristics were analyzed, including gender, age, comorbidities and preoperative CT images.Results:Of 373 patients, 209 were male and 164 were female, with a median age of 42 (18 to 88) years. Median recurrent time of the recurrent group was 4 (1 to 60) months. Compared to the first episode group, the recurrent group had higher proportion of age <50 years [71.4% (95/133) vs. 57.5% (138/240), χ 2=7.081, P=0.008], higher proportion of concurrent diabetes [13.5% (18/133) vs. 5.4% (13/240), χ 2=7.399, P=0.007], shorter onset time [(41.7±13.6) hours vs. (59.4±56.2) hours, t=-3.286, P=0.001], lower proportion of abdominal tension and rebound pain [57.9% (77/133) vs. 66.7% (160/240), χ 2=5.065, P=0.024], lower score of modified Alvarado score [(5.6±1.9) point vs. (6.1±1.9) point, t=-2.417, P=0.016], lower WBC count [(10.5±4.6) ×10 9/L vs. (11.5±4.5)×10 9/L, t=-1.190, P=0.047], higher percentage of lymphocyte [(19.4±14.7)% vs. (16.1±13.3)%, t=2.069, P=0.039]. In the recurrent group, ratio of length of removed appendix ≥7 cm was higher as compared with the first episode group [44.4% (59/133) vs. 32.9% (79/240), χ 2=4.808, P=0.028], while the ratio of complicated appendicitis was significantly lower [8.3% (11/133) vs. 22.9% (55/240), χ 2=10.823, P=0.001]. CT images were available in 129 patients, intraluminal appendicoliths was found in 19 of 50 patients (38%) in the recurrent group, while in 16 of 79 patients (20.3%) in the first episode group, and there was statistically significant difference between the two groups (χ 2=4.880, P=0.027). Conclusions:Clinical characteristics of recurrent acute appendicitis include age less than 50 years, concurrent diabetes, short onset time, less abdominal tension or rebound pain, low modified Alvarado score, low WBC count, high percentage of lymphocyte, appendix length longer than 7 cm, non-complicated appendicitis and intraluminal appendicoliths.

Tetanus consists of neonatal tetanus and non-neonatal tetanus.Non-neonatal tetanus remains a serious public health problem,although neonatal tetanus has been eliminated in China since 2012.Non-neonatal tetanus is a potential fatal disease.In the absence of medical intervention,the mortality rate of severe cases is almost 100％.Even with vigorous treatment,the mortality rate is still 30％-50％ globally.These specifications aim to regulate non-neonatal tetanus diagnosis and treatment in China,in order to improve medical quality and safety.These specifications introduce the etiology,epidemiology,pathogenesis,clinical manifestations and laboratory tests,diagnosis,differential diagnosis,grading and treatment of non-neonatal tetanus.

Objective:To analyze clinical characteristics of recurrent appendicitis.Methods:A retrospective cohort study was carried out. Clinical data of patients who underwent appendectomy due to acute appendicitis confirmed by pathology in the Affiliated Hospital of Qingdao University from January 2011 to December 2015 were analyzed retrospectively. Exclusion criteria: (1) age of less than 18 years;(2) chronic appendicitis; (3) periappendiceal abscess; (4) appendiceal mucocele or mucinous neoplasms; (5) appendiceal neuroendocrine tumors or cancers; (6) appendicitis during pregnancy; (7) concurrent AIDS, hematological disease, autoimmune disease, inflammatory bowel disease or advanced cancer; (8) other simultaneous surgery. A total of 373 patients were enrolled the study. These patients were divided into the recurrent group (133 cases) and the first episode group (240 cases) according to the previous history of antibiotic therapy for acute appendicitis. The prevalence of recurrent appendicitis was calculated, and the clinical characteristics were analyzed, including gender, age, comorbidities and preoperative CT images.Results:Of 373 patients, 209 were male and 164 were female, with a median age of 42 (18 to 88) years. Median recurrent time of the recurrent group was 4 (1 to 60) months. Compared to the first episode group, the recurrent group had higher proportion of age <50 years [71.4% (95/133) vs. 57.5% (138/240), χ 2=7.081, P=0.008], higher proportion of concurrent diabetes [13.5% (18/133) vs. 5.4% (13/240), χ 2=7.399, P=0.007], shorter onset time [(41.7±13.6) hours vs. (59.4±56.2) hours, t=-3.286, P=0.001], lower proportion of abdominal tension and rebound pain [57.9% (77/133) vs. 66.7% (160/240), χ 2=5.065, P=0.024], lower score of modified Alvarado score [(5.6±1.9) point vs. (6.1±1.9) point, t=-2.417, P=0.016], lower WBC count [(10.5±4.6) ×10 9/L vs. (11.5±4.5)×10 9/L, t=-1.190, P=0.047], higher percentage of lymphocyte [(19.4±14.7)% vs. (16.1±13.3)%, t=2.069, P=0.039]. In the recurrent group, ratio of length of removed appendix ≥7 cm was higher as compared with the first episode group [44.4% (59/133) vs. 32.9% (79/240), χ 2=4.808, P=0.028], while the ratio of complicated appendicitis was significantly lower [8.3% (11/133) vs. 22.9% (55/240), χ 2=10.823, P=0.001]. CT images were available in 129 patients, intraluminal appendicoliths was found in 19 of 50 patients (38%) in the recurrent group, while in 16 of 79 patients (20.3%) in the first episode group, and there was statistically significant difference between the two groups (χ 2=4.880, P=0.027). Conclusions:Clinical characteristics of recurrent acute appendicitis include age less than 50 years, concurrent diabetes, short onset time, less abdominal tension or rebound pain, low modified Alvarado score, low WBC count, high percentage of lymphocyte, appendix length longer than 7 cm, non-complicated appendicitis and intraluminal appendicoliths.