Online Appendix

Table 5. Studies that tested the association between gender and bloodstream infection

Authors, publication year / Study population / Sample size / Covariates / Findings
Studies that reported significantly increased risk of infection for males vs. femalesa
Kritchevsky, et al., 200823 / Patients with CVCs in ICUs of 50 hospitals in 14 countries / 2,970 patients / Central line days; age; CVC insertion urgency (emergency, urgent, elective); multiple CVCs; CVC used for TPN; dialysis; cancer; AIDS; transplantation; surgery; albumin; neutropenia; insertion location (ICU, ER, operating room); CVC inserter’s profession and experience; insertion site (jugular, subclavian, femoral, antecubital), catheter type (tunneled, nontunneled, PICC); number lumens; CVC coating (antimicrobial vs. not); use of sterile gown, mask, drape; dressing type; >1 attempt at insertion site; >1 insertion site attempted; time from initial stick to CVC placement; availability of necessary supplies; unusual occurrence during CVC placement / Females at significantly lower risk for catheter-associated BSIs
OR=0.58 (95% CI: 0.43-0.80)
Uslan, et al., 200724 / Residents of Olmsted County, Minnesota / 124,277 residents / Age / Age-adjusted incidence rate of BSI significantly higher for males than females (237 vs. 156 per 100,000 person-years; p<0.001)
Zingg, et al., 200925 / Adults with at least one CVC in ICUs of a 960-bed tertiary care referral center, Switzerland / 999 patients (13,479 catheter days) / Stay in medical ICU; diabetes; severity of illness; cardiosurgery, intubation, CVC insertion ward (ER vs. ICU) / Males at significantly greater risk for catheter-associated BSI
HR=2.54 (95% CI: 1.05-6.18)
Studies that reported no significant association between gender and infectiona
Al-Hasan, et al., 201126 / Residents of Olmsted County, Minnesota / 124,277 residents / Age / No significant difference in age-adjusted incidence rates of Enterobacter species BSI
3.9 (95% CI: 2.0-5.8) vs. 3.2 (95% CI: 1.8-4.6) per 100,000 person-years for males and females, respectively
Al-Hasan, et al., 201027 / Residents of Olmsted County, Minnesota / 124,277 residents / Age / No significant difference in age-adjusted incidence rate of Klebsiella species BSI
15.4 (95% CI: 11.6-19.2) vs. 9.4 (95% CI: 7.0-11.8) per 100,000 person-years for males and females, respectively
Jensen, et al., 199928 / Patients in four community hospitals, Denmark / 62 BSI cases and 85 uninfected controls / Primary diagnosis (matched) / No significant association between gender and Staphylococcus aureus BSI
OR=0.9 (95% CI: 0.5-1.6; reference=women)
Luft, et al., 201029 / Hematology patients with CVCs in a 1,500-bed tertiary care facility, Germany and a 1000-bed tertiary care facility, Switzerland / 219 patients (5,501 catheter days) / Study center; age; transplantation and type of transplantation (unrelated-allogeneic, related-allogeneic, autologous); LOS prior to CVC placement; CVC coating (chlorhexidine and silver sulfadiazine coating vs. no antimicrobial coating); CVC days (≤21 days vs. >21 days); antibiotics received via CVC; blood products received via CVC; neutropenia; baseline skin colonization; subsequent skin colonization / No association between gender and catheter-associated BSI
OR=2.31 (95% CI: 0.88-6.10; reference=women)
Michalia, et al., 200930 / Patients in ICU of a tertiary hospital for >48 hours, excluding burn patients / 343 patients / Age; severity of illness; reason for admission (medical, elective surgery, emergency surgery, trauma); diabetes / No association between gender and BSI
HR=0.99 (95% CI: 0.64-1.53; reference=female)
Yoshida, et al., 201031 / Patients with central lines in a 430-bed acute care hospital, Japan / 927 patients (22,723 central line days) / Age; institutional MRSA cases and census during hospitalization; central line days; service (surgery vs. other); barrier precautions (maximal vs. standard) / No association between gender and central line-associated BSI
OR=0.83 (95% CI: 0.80-1.29 in univariate analysis; reference=female; NS in multivariable model)

aNo studies reported significantly increased risk of infection for females vs. males.

ICU, intensive care unit; CVC, central venous catheter; BSI, bloodstream infection; ER, emergency room; MRSA, methicillin-resistant Staphylococcus aureus; HR, hazard ratio; CI, confidence interval; OR, odds ratio; LOS, length of stay; TPN, total parenteral nutrition; PICC, peripherally inserted central catheter

Table 6. Studies that tested the association between gender and surgical site infection

Authors, publication year / Study population / Sample size / Covariates / Findings
Studies that reported significantly increased risk of infection for males vs. females
Akiyoshi, et al., 201032 / Patients with rectal tumors undergoing loop ileostomy closure at a cancer hospital, Japan / 125 patients / Age, BMI, smoking, weight loss, diabetes, hemoglobin, ASA score, tumor type, surgery type, preoperative chemoradiotherapy, intraoperative hypothermia, time from primary surgery, SSI after primary surgery, adjuvant chemotherapy, duration of surgery, anastomotic technique, training of surgeon / OR=5.3 (95% CI: 1.14-24.8)
Biscione, et al., 200733 / Patients undergoing diagnostic exploration of abdominal cavity at 5 hospitals, Brazil / 6,761 patients / Age, surgical approach (open vs. laparoscopic), duration of surgery, ASA score, wound class, type of surgery (emergency, elective, trauma), hospital, surgeon, year, phone contact after surgery / RR=1.8 (95% CI: 1.3-2.4) in univariate analysis; Not significant in multivariate analysis (data not presented)
Brandt, et al., 200834 / Patients undergoing hip prosthesis in 55 hospitals, Germany / 28,623 patients / Operating room ventilation type, number of beds in hospital, frequency with which procedure is performed in hospital, academic status of hospital, hospital participation in national surveillance system, ASA score, contaminated wound, operation duration, endoscopic operation, age / OR=1.3 (95% CI: 1.04-1.6)
Jamsen, et al., 201035 / Patients undergoing joint replacement for primary or secondary osteoarthritis, Finland / 1,565 patients / None / OR=5.1 (p=0.002)**
Jeong, et al., 201236 / Patients undergoing gastric surgery at a 13 hospitals, Korea / 121 SSI cases and 242 uninfected controls / Age, BMI, ASA score, reason for surgery, duration of prophylactic antibiotics, surgery, and drainage / OR=1.77 (95% CI: 1.01-3.11)
Kalmeijer, et al., 200037 / Patients undergoing knee, hip, or back prosthesis implantation or revision surgery in one hospital, The Netherlands / 272 / None / OR=4.1 (95% CI: 1.5-10.9)
Korinek, et al., 200538 / Patients undergoing craniotomy in a university hospital, location NA / 4,578 patients / Surgeon, use of prophylactic antibiotics, early reoperation, cerebrospinal fluid leakage, surgical diagnosis / OR-1.6 (95% CI: 1.2-2.1)
Luksamijarulkul, et al., 200639 / Patients undergoing surgery in one hospital, Taiwan / 268 patients / Age, ward, comorbidities, ASA score, smoking, prophylactic antibiotics, length of hospital stay, general anesthesia, wound dressing, shaving before surgery / OR=2.2 (95% CI: 1.1-4.4) in univariate analysis; Not significant in multivariate analysis (data not presented)
Rao, et al., 201140 / Patients undergoing spinal fusion surgery at an 800-bed academic level I trauma center, Philadelphia, PA / 57 SSI cases and 181 uninfected controls / Age, BMI, diabetes, coronary artery disease, hypertension, COPD, malignancy, smoking status, ASA score, type of surgery, surgical service, appropriateness of prophylactic antibiotics, blood loss, interoperative blood transfusion, interoperative temperature, fasting glucose, length of stay / OR=2.7 (95% CI: 1.4-5.6)
Rogues, et al., 200741 / Patients undergoing dermatological surgery at private offices and hospitals, France / 3,491 patients / Immunosuppressive treatment, hemorrhagic complication, use of sterile gloves / OR=5.5 (95% CI: 1.1-26.5)
Tang, et al., 200142 / Patients undergoing colorectal laparotomy in one hospital, Taiwan / 3,100 patients / ASA score, ostomy creation, wound class, use of drains, blood transfusion / OR=1.5 (95% CI: 1.0-2.2)
Willis-Owens, et al., 201043 / Patients undergoing hip or knee replacement surgery at an orthopedic hospital, Australia / 5,277 patients / Age, surgeon, operating room, time spent in operating room, use of postoperative drains, type of procedure / OR=3.4 (p=0.002)**
Studies that reported no significant association between gender and infection
Brandt, et al., 200834 / Patients undergoing knee prosthesis, appendectomy, cholecystectomy, or colon surgery in 55 hospitals, Germany / 49,737 patients / Operating room ventilation type, number of beds in hospital, frequency with which procedure is performed in hospital, academic status of hospital, hospital participation in national surveillance system, ASA score, contaminated wound, operation duration, endoscopic operation, age / Knee prosthesis OR=1.0 (95% CI: 0.6-1.6); Appendectomy OR=1.4 (95% CI: 0.9-1.9); Cholecystectomy OR=1.1 (95% CI: 0.9-1.4); Colon surgery OR=1.2 (95% CI: 0.96-1.4; reference=female)
Chen, et al., 200944 / Patients undergoing elective posterior instrumented lumbar arthrodesis, location N/A / 244 patients / None / RR=1.3 (95% CI: 0.6-2.8; reference=female)
de Boer, et al., 199945 / Patients undergoing orthopedic surgery in 26 hospitals, The Netherlands / 4,872 patients / Age, number of surgeries, preoperative length of stay / OR=0.8 (95% CI: 0.2-1.4; reference=male)
Dizer, et al., 200946 / Patients undergoing abdominal surgery in a military academy hospital, Turkey / 82 patients / Age, preoperative surgical site shave technique, preoperative chlorhexidine wash / OR=2.38 (95% CI: 0.53-10.67; reference=female)
Gaberel et al., 201147 / Patients undergoing craniotomy in a university hospital, France / 30 SSI cases and 60 uninfected controls / Type of surgery (matched) / OR=1.0 (95% CI: 0.41-2.42; reference =female)
George et al., 201148 / Patients undergoing transperitoneal laproscopic procedures, location N/A / 556 patients / None / OR=1.3 (p=0.645; reference=female)*
Govinda, et al., 201049 / Patients undergoing colorectal surgery at two academic hospitals, US / 116 patients / None / OR=0.52 (p=0.175; reference=female)*
Kaafarani, et al., 201050 / Patients undergoing surgery for ventral incisional hernia at four VA centers, US / 145 patients / None / OR=0.83 (p=0.686; reference=female)*
Kamath, et al., 200551 / Patients undergoing surgery for neck or femur fracture in one hospital, United Kingdom / 100 patients / Age, current smoking status, type of fracture, use of topical antibiotic post-surgery / OR=0.9 (95% CI: 0.2-4.3; reference=female)
Kuhlfelt, et al., 201252 / Patients presenting for follow-up at a university hospital within 30 days of undergoing jaw surgery, Finland / 286 patients / Age, smoking status, surgical site, duration of surgery, implant materials, use of postoperative drains / OR=1.2 (95% CI: 0.5-2.9; reference=male)
Lamloum, et al., 200953 / Patients with diabetes undergoing orthopedic surgery at a 200-bed orthopedic hospital, Kuwait / 318 patients / None / OR=0.97 (p>0.05; reference=female)*
Lark, et al., 200154 / Patients undergoing Freestyle valve implantation at an 800-bed University hospital, Michigan / 64 patients / None / OR=2.0 (95% CI: 0.2-17.7; reference=female)
Martin, et al., 201055 / Patients receiving long-term left ventricular assist devices at a university medical center, Ohio / 145 patients / None / OR=1.3 (p=0.351; reference=female)*
Miki, et al., 200656 / Patients undergoing surgery for colorectal cancer, location N/A / 285 patients / Tumor location, blood transfusion, blood loss, duration of surgery, comorbidities, / OR=0.6 (95% CI: 0.2-2.2; reference=male)
Montgomery, et al., 200557 / Patients undergoing hand assisted laparoscopic surgery, location N/A / 422 patients / None / OR=1.7 (p=0.25; reference=female)*
Ridgeway, et al., 200458 / Patients undergoing hip surgery at 102 hospitals, England / 24,808 patients / Trauma, age, ASA score, duration of surgery / Not significant in multivariate analysis (data not presented)
OR=1.3 (95% CI: 1.04-1.6) for primary total hip replacement; OR=0.8 (95% CI: 0.6-1.1) for primary hemiarthroplasties; OR=0.6 (95% CI: 0.4-0.9) for total hip replacement revisions in univariate analysis (reference=male)
Shiba, et al., 200959 / Patients undergoing hepatectomy for hepatocellular carcinoma at a university hospital, Japan / 99 patients / None / Odds of infection in 0:15 in females, 13:71 in males (OR undefined, p=0.102)*
Yokoyama, et al., 200660 / Patients undergoing intramedullary nailing for tibial fractures at a university hospital, Japan / 42 patients / None / OR=1.2 (p=0.85; reference=female)*
Studies that reported significantly increased risk of infection for females vs. males
Brandt, et al., 200834 / Patients undergoing Herniorrhaphy in 55 hospitals, Germany / 20,870 patients / Operating room ventilation type, number of beds in hospital, frequency with which procedure is performed in hospital, academic status of hospital, hospital participation in national surveillance system, ASA score, contaminated wound, operation duration, endoscopic operation, age / OR=0.4 (95% CI: 0.3-0.7)
Bundy, et al., 200661 / Patients undergoing CABG at a cardiac center, Texas / 3,878 patients / Diabetes, BMI, urgency of surgery / OR=1.4 (95% CI: 1.04-1.8)
Giles, et al., 201062 / Patients undergoing lower extremity bypass surgery at ACS-NSQIP hospitals / 7,595 patients / Obesity, diabetes, functional status, lifetime smoking / OR=1.3 (95% CI: 1.1-1.6)
Greenblatt et al., 201163 / Patients undergoing open bypass or thromboendarterectomy for infrainguinal occlusive diasease at ACS-NSQIP hospitals / 12,330 patients / Age; rest pain; gangrene; history of revascularization or amputation; functional status; BMI; diabetes; dyspnea; COPD; coronary artery disease; hypertension; neurologic disease; dialysis; steroid use; wound infection or open wound; sepsis; preoperative sodium, creatinine, and albumin; type of graft; ASA score; blood transfusion; duration of surgery; emergency surgery / OR=1.44 (95% CI: 1.28-1.63)
Ku, et al., 200564 / Patients undergoing cardiac surgery at one hospital, Taiwan / 471 patients / Smoking, diabetes, hypertension, COPD, BMI, previous cardiac surgery, use of steroids or antibiotics, lung function, right and left ejection fraction, albumin concentration, preoperative LOS in ICU, urgency of surgery, operating room, surgical team, surgical procedure, use and duration of intraaortic balloon pump, use of internal mammary artery, total vs. other bypass procedure, use of aortic clamp, blood loss, use of ventricular assist device, blood transfusion and materials, homeostasis, cardiac massage, inotropic support, complications, duration of intermittent positive pressure ventilation / OR=8.1 (95% CI: 2.0-32.5) for sternal infection
(No difference in odds of leg infection; OR=1.2 [95% CI: 0.2-6.5]; reference=male)
Olsen, et al., 200365 / Patients undergoing CABG at one hospital, St. Louis, MO / 1,980 patients / Circulatory arrest during surgery, previous cerebrovascular accident, obesity, age, receipt of red blood cells postoperatively / OR=1.8 (95% CI: 1.1-3.0)
Schnee, et al., 199766 / Patients undergoing iliac crest graft harvest, location N/A / 144 patients / None / OR=9.1 (p>0.001)*
Trussell, et al., 200867 / Patients undergoing CABG, location N/A / 1,482 patients / Diabetes, NNIS wound score / OR=2.8 (95% CI: 1.5-5.7)
Vuorisalo, et al., 199868 / Patients undergoing CABG at a university hospital, Finland / 172 patients / BMI, COPD / OR=1.6 (p=0.23)*

SSI, surgical site infection; BMI, body mass index; ASA, American Society of Anesthesiologists; COPD, chronic obstructive pulmonary disease; ACS-NSQIP, American College of Surgeons National Surgical Quality Improvement Project; N/A, not available; VA, Veteran Affairs; NNIS, National Nosocomial Infection Surveillance System; CABG; coronary artery bypass grafting

*Chi-square

**CI not reported