Postoperative Wound Infection, Surgical Wound Infection
Conditions
Keywords
Surgical Wound Infection, Surgical Site Infection, Abdominal Surgery
Brief summary
This is an observational study to evaluate the relative importance of the known risk factors for severe surgical site infections (SSIs) on the development of the more severe SSI cases, and to describe the demographic, clinical features, etiology and the management and outcome of patients suffering from severe SSIs in Spain.
Detailed description
Case and Control study.
Interventions
PROCEDUREElective or emergency abdominal surgery
Clinical record review.
Sponsors
Pfizer
Study design
Observational model
CASE_CONTROL
Time perspective
PROSPECTIVE
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
No
Inclusion criteria
* Age of or above 18 years. * Admitted to a General Surgery Ward for elective or emergency abdominal surgery. * Contaminated or dirty-infected surgical procedures. * Only for cases, they will have to present symptoms and signs of a surgical site infection (SSI) (within 0-30 days) after abdominal surgery. * Only for controls, patients must be free of SSI after 30 days from surgery, regardless of whether they are still in the hospital or being observed as an outpatient in the external clinic.
Exclusion criteria
* Age under 18 years. * American Society of Anesthesiologist (ASA) score of 5 or above. * Surgical implant in place. * Clean or clean-contaminated surgical procedures.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Percentage of Participants With Post-surgical Drainage | Day 0 (day of surgery) up to 30 days post surgery | — |
| Percentage of Participants Who Underwent Emergency Surgery or Scheduled Surgery | Day 0 (day of surgery) | — |
| Percentage of Participants With Classification of Risk of Surgical Infection of Clean-contaminated, Contaminated or Dirty | Day 0 (day of surgery) | Surgical infection risk class: Clean-contaminated: controlled entry in normally colonized body cavities/no unusual contamination/minimum fluid discharge/minimal sterile technique violation/re-surgery on clean surgical incision within 7 days/negative surgical exploration through intact skin. Contaminated: no acute inflammation/purulent discharge/significant fluid/material violation of sterile technique/penetrating trauma less than 4 hours old/graft in chronic skin wounds. Dirty: pus-abscess drainage/ preoperatively colonized body cavity perforated/penetrating trauma more than 4 hours old. |
| Type of Surgeon | Day 0 (day of surgery) | Surgical speciality of physician who performed surgery. |
| Percentage of Participants With Infection | Day 0 (day of surgery) up to 30 days post surgery | Microorganism infection by bacterial type. |
| Percentage of Participants Who Showed Clinical Improvement of SSI | Day 0 (day of surgery) up to 30 days post surgery | Clinical improvement of SSI was defined as healed (signs and symptoms of initial infection resolved) or improved (initial signs and symptoms significantly diminished without the appearance of new signs). |
| Percentage of Participants With Pre-surgical Morbidities | Baseline (Pre-surgical) | Morbidities (risk factors) included: neoplasm, tobacco use, body mass index (weight in kilograms divided by height in meters squared \[BMI kg/m2\]) greater than (\>) 30, diabetes mellitus (DM), immunosuppression/ corticosteroids, anemia (hemoglobin \[Hb\] less than (\>) 9 grams per deciliter \[gr/dL\]) or malnutrition (hypoalbuminemia). |
| Percentage of Participants Who Received Pre-surgical Antibiotic Prophylaxis | Baseline (Pre-surgical) | — |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Percentage of Participants Whose National Nosocomial Infection Surveillance System (NNISS) Scores of Preoperative Risk of Infection Were Greater Than >0 | Baseline (pre-surgical) | Percentage of participants with NNISS score for increased preoperative risk of infection. |
| ASEPSIS Classification in Participants With Serious SSI | Up to 30 days post surgery | Additional treatment, Serous discharge, Erythema, Purulent exudate, Separation of deep tissue, Isolation of bacteria, Stay in hospital prolonged over 14 days (ASEPSIS). ASEPSIS classification is a numerical indication of wound healing progress: satisfactory healing (0-10), disturbance of healing (11-20), minor wound infection (20-30), moderate wound infection (30-40), and severe wound infection (over 40). |
| Classification of SSI Infection | Day 0 (day of surgery) up to 30 days post surgery | Participants with organ-space or deep incisional SSI. |
| Number of Participants With Antimicrobial Resistance | Day 0 (day of surgery) up to 30 days post surgery | Microbiological resistance reported for microorganisms that were found at a frequency greater (\>) than 5 percent (%). |
| Percentage of Participants Who Had Microbiologic Resolution of SSI (Sensitivity of Microorganisms to Antibiotics) | Day 0 (day of surgery) up to 30 days post surgery | Resolution of SSI ranged from eradication (infection cured) to persistence (infection continued). |
Participant flow
Pre-assignment details
289 participants were screened and 109 were excluded from analysis due to: no matching control, not meeting inclusion/exclusion criteria or did not meet matching criteria.
Participants by arm
| Arm | Count |
|---|---|
| Case Cases were defined as participants with severe surgical site infection (SSI) (deep incisional or organ space type; see Center for Disease Control \[CDC\] criteria for definition in the Appendix) in participants who underwent elective or emergency abdominal surgery in the previous 30 days. | 90 |
| Control Participants who were free of surgical site infection (SSI) within 30 days following surgeon matched elective or emergency abdominal surgery. | 90 |
| Total | 180 |
Baseline characteristics
| Characteristic | Case | Control | Total |
|---|---|---|---|
| Age Continuous | 62.49 years STANDARD_DEVIATION 16.11 | 58.46 years STANDARD_DEVIATION 20.4 | 60.47 years STANDARD_DEVIATION 18.44 |
| Sex: Female, Male Female | 27 Participants | 39 Participants | 66 Participants |
| Sex: Female, Male Male | 63 Participants | 51 Participants | 114 Participants |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk |
|---|---|---|
| deaths Total, all-cause mortality | — / — | — / — |
| other Total, other adverse events | 0 / 0 | 0 / 0 |
| serious Total, serious adverse events | 0 / 0 | 0 / 0 |
Outcome results
Primary
Percentage of Participants Who Received Pre-surgical Antibiotic Prophylaxis
Time frame: Baseline (Pre-surgical)
Population: Study Population
| Arm | Measure | Value (NUMBER) |
|---|---|---|
| Case | Percentage of Participants Who Received Pre-surgical Antibiotic Prophylaxis | 95.5 Percentage of participants |
| Control | Percentage of Participants Who Received Pre-surgical Antibiotic Prophylaxis | 96.7 Percentage of participants |
p-value: 1Chi-squared
Primary
Percentage of Participants Who Showed Clinical Improvement of SSI
Clinical improvement of SSI was defined as healed (signs and symptoms of initial infection resolved) or improved (initial signs and symptoms significantly diminished without the appearance of new signs).
Time frame: Day 0 (day of surgery) up to 30 days post surgery
Population: Subset of study population with infection; N=number of participants with evaluable data
| Arm | Measure | Group | Value (NUMBER) |
|---|---|---|---|
| Case | Percentage of Participants Who Showed Clinical Improvement of SSI | healed | 70.8 Percentage of participants |
| Case | Percentage of Participants Who Showed Clinical Improvement of SSI | Improvement | 27.0 Percentage of participants |
Primary
Percentage of Participants Who Underwent Emergency Surgery or Scheduled Surgery
Time frame: Day 0 (day of surgery)
Population: Study Population
| Arm | Measure | Group | Value (NUMBER) |
|---|---|---|---|
| Case | Percentage of Participants Who Underwent Emergency Surgery or Scheduled Surgery | Emergency surgery | 32.2 Percentage of participants |
| Case | Percentage of Participants Who Underwent Emergency Surgery or Scheduled Surgery | Scheduled surgery | 67.8 Percentage of participants |
| Control | Percentage of Participants Who Underwent Emergency Surgery or Scheduled Surgery | Emergency surgery | 31.1 Percentage of participants |
| Control | Percentage of Participants Who Underwent Emergency Surgery or Scheduled Surgery | Scheduled surgery | 68.9 Percentage of participants |
p-value: 0.873Chi-squared
Primary
Percentage of Participants With Classification of Risk of Surgical Infection of Clean-contaminated, Contaminated or Dirty
Surgical infection risk class: Clean-contaminated: controlled entry in normally colonized body cavities/no unusual contamination/minimum fluid discharge/minimal sterile technique violation/re-surgery on clean surgical incision within 7 days/negative surgical exploration through intact skin. Contaminated: no acute inflammation/purulent discharge/significant fluid/material violation of sterile technique/penetrating trauma less than 4 hours old/graft in chronic skin wounds. Dirty: pus-abscess drainage/ preoperatively colonized body cavity perforated/penetrating trauma more than 4 hours old.
Time frame: Day 0 (day of surgery)
Population: Study population
| Arm | Measure | Group | Value (NUMBER) |
|---|---|---|---|
| Case | Percentage of Participants With Classification of Risk of Surgical Infection of Clean-contaminated, Contaminated or Dirty | Clean-contaminated | 60.0 Percentage of participants |
| Case | Percentage of Participants With Classification of Risk of Surgical Infection of Clean-contaminated, Contaminated or Dirty | Contaminated | 30.0 Percentage of participants |
| Case | Percentage of Participants With Classification of Risk of Surgical Infection of Clean-contaminated, Contaminated or Dirty | Dirty | 10.0 Percentage of participants |
| Control | Percentage of Participants With Classification of Risk of Surgical Infection of Clean-contaminated, Contaminated or Dirty | Clean-contaminated | 60.0 Percentage of participants |
| Control | Percentage of Participants With Classification of Risk of Surgical Infection of Clean-contaminated, Contaminated or Dirty | Contaminated | 30.0 Percentage of participants |
| Control | Percentage of Participants With Classification of Risk of Surgical Infection of Clean-contaminated, Contaminated or Dirty | Dirty | 10.0 Percentage of participants |
Primary
Percentage of Participants With Infection
Microorganism infection by bacterial type.
Time frame: Day 0 (day of surgery) up to 30 days post surgery
Population: Subset of study population with infection; N=number of participants with evaluable data
| Arm | Measure | Group | Value (NUMBER) |
|---|---|---|---|
| Case | Percentage of Participants With Infection | Escherichia coli (E. coli) | 55.8 Percentage of participants |
| Case | Percentage of Participants With Infection | Staphylococcus aureus | 3.5 Percentage of participants |
| Case | Percentage of Participants With Infection | Extended-spectrum β-lactamase producing E.coli | 3.5 Percentage of participants |
| Case | Percentage of Participants With Infection | Bacteroides fragilis group (gr.) | 14.0 Percentage of participants |
| Case | Percentage of Participants With Infection | Enterococcus faecium | 12.8 Percentage of participants |
| Case | Percentage of Participants With Infection | Enterococcus faecalis | 12.8 Percentage of participants |
| Case | Percentage of Participants With Infection | Pseudomonas aeruginosa | 8.1 Percentage of participants |
| Case | Percentage of Participants With Infection | Staphylococcus epidermidis | 7.0 Percentage of participants |
| Case | Percentage of Participants With Infection | Candida albicans | 5.8 Percentage of participants |
| Case | Percentage of Participants With Infection | Staphylococcus species (spp) | 5.8 Percentage of participants |
| Case | Percentage of Participants With Infection | Morganella morganni | 5.8 Percentage of participants |
| Case | Percentage of Participants With Infection | Klebsiella oxytoca | 5.8 Percentage of participants |
| Case | Percentage of Participants With Infection | Klebsiella pneumoniae | 4.7 Percentage of participants |
| Case | Percentage of Participants With Infection | Streptococcus spp | 3.5 Percentage of participants |
| Case | Percentage of Participants With Infection | Streptococcus other | 3.5 Percentage of participants |
| Case | Percentage of Participants With Infection | Streptococcus anginosus | 3.5 Percentage of participants |
| Case | Percentage of Participants With Infection | Enterobacter cloacae | 3.5 Percentage of participants |
| Case | Percentage of Participants With Infection | Streptococcus viridians gr. | 2.3 Percentage of participants |
| Case | Percentage of Participants With Infection | Streptococcus agalactiae | 2.3 Percentage of participants |
| Case | Percentage of Participants With Infection | Coagulase-negative staphylococci | 2.3 Percentage of participants |
| Case | Percentage of Participants With Infection | Serratia marcescens | 2.3 Percentage of participants |
| Case | Percentage of Participants With Infection | Prevotella spp | 2.3 Percentage of participants |
| Case | Percentage of Participants With Infection | Enterococcus spp | 2.3 Percentage of participants |
| Case | Percentage of Participants With Infection | Enterococcus durans | 2.3 Percentage of participants |
| Case | Percentage of Participants With Infection | Bacteroides vulgates bacteroides (B) fragilis gr. | 2.3 Percentage of participants |
| Case | Percentage of Participants With Infection | Candida glabrata | 1.2 Percentage of participants |
| Case | Percentage of Participants With Infection | Stenothropomonas maltophilia | 1.2 Percentage of participants |
| Case | Percentage of Participants With Infection | Methicillin-resistant Staphylococcus aureus | 1.2 Percentage of participants |
| Case | Percentage of Participants With Infection | Serratia spp | 1.2 Percentage of participants |
| Case | Percentage of Participants With Infection | Pseudomonas stutzeri | 1.2 Percentage of participants |
| Case | Percentage of Participants With Infection | Proteus vulgaris | 1.2 Percentage of participants |
| Case | Percentage of Participants With Infection | Lactobacillus spp | 1.2 Percentage of participants |
| Case | Percentage of Participants With Infection | Haemophilus parainfluenzae | 1.2 Percentage of participants |
| Case | Percentage of Participants With Infection | Gemella spp | 1.2 Percentage of participants |
| Case | Percentage of Participants With Infection | Eubacterium gr. | 1.2 Percentage of participants |
| Case | Percentage of Participants With Infection | Enterococcus avium | 1.2 Percentage of participants |
| Case | Percentage of Participants With Infection | Enterobacter agglomerans | 1.2 Percentage of participants |
| Case | Percentage of Participants With Infection | Citrobacter freundii | 1.2 Percentage of participants |
| Case | Percentage of Participants With Infection | Bacteroides no fragilis gr. | 1.2 Percentage of participants |
| Case | Percentage of Participants With Infection | Bacteroides thetaiotaomicrom B. fragilis gr. | 1.2 Percentage of participants |
| Case | Percentage of Participants With Infection | Bacteroides ovatus B. fragilis gr. | 1.2 Percentage of participants |
| Case | Percentage of Participants With Infection | Bacteroides distasonis B. fragilis gr. | 1.2 Percentage of participants |
| Case | Percentage of Participants With Infection | Non-fermenting gram negative bacilli | 1.2 Percentage of participants |
Primary
Percentage of Participants With Post-surgical Drainage
Time frame: Day 0 (day of surgery) up to 30 days post surgery
Population: Study Population
| Arm | Measure | Value (NUMBER) |
|---|---|---|
| Case | Percentage of Participants With Post-surgical Drainage | 71.1 Percentage of participants |
| Control | Percentage of Participants With Post-surgical Drainage | 61.1 Percentage of participants |
p-value: 0.156Chi-squared
Primary
Percentage of Participants With Pre-surgical Morbidities
Morbidities (risk factors) included: neoplasm, tobacco use, body mass index (weight in kilograms divided by height in meters squared \[BMI kg/m2\]) greater than (\>) 30, diabetes mellitus (DM), immunosuppression/ corticosteroids, anemia (hemoglobin \[Hb\] less than (\>) 9 grams per deciliter \[gr/dL\]) or malnutrition (hypoalbuminemia).
Time frame: Baseline (Pre-surgical)
Population: Study population: participants with or without SSI after surgery, treated in major hospitals with general surgical units located in Spain
| Arm | Measure | Group | Value (NUMBER) |
|---|---|---|---|
| Case | Percentage of Participants With Pre-surgical Morbidities | BMI kg/mˆ2>30 | 23.3 percentage of participants |
| Case | Percentage of Participants With Pre-surgical Morbidities | Immunosuppression/corticosteroids | 7.8 percentage of participants |
| Case | Percentage of Participants With Pre-surgical Morbidities | Tobacco use | 26.7 percentage of participants |
| Case | Percentage of Participants With Pre-surgical Morbidities | Anemia (Hb<9 gr/dL) | 7.8 percentage of participants |
| Case | Percentage of Participants With Pre-surgical Morbidities | Neoplasm | 47.8 percentage of participants |
| Case | Percentage of Participants With Pre-surgical Morbidities | Malnutrition (hypoalbuminemia) | 4.4 percentage of participants |
| Case | Percentage of Participants With Pre-surgical Morbidities | Diabetes mellitus | 17.8 percentage of participants |
| Control | Percentage of Participants With Pre-surgical Morbidities | Malnutrition (hypoalbuminemia) | 2.2 percentage of participants |
| Control | Percentage of Participants With Pre-surgical Morbidities | Neoplasm | 48.9 percentage of participants |
| Control | Percentage of Participants With Pre-surgical Morbidities | BMI kg/mˆ2>30 | 12.2 percentage of participants |
| Control | Percentage of Participants With Pre-surgical Morbidities | Diabetes mellitus | 11.1 percentage of participants |
| Control | Percentage of Participants With Pre-surgical Morbidities | Immunosuppression/corticosteroids | 7.8 percentage of participants |
| Control | Percentage of Participants With Pre-surgical Morbidities | Anemia (Hb<9 gr/dL) | 2.2 percentage of participants |
| Control | Percentage of Participants With Pre-surgical Morbidities | Tobacco use | 23.3 percentage of participants |
Comparison: Neoplasmp-value: 0.881Chi-squared
Comparison: Tobacco usep-value: 0.517Chi-squared
Comparison: BMI(kg/mˆ2)\>30p-value: 0.053Chi-squared
Comparison: Diabetes mellitusp-value: 0.289Chi-squared
Comparison: Immunosuppression/Corticosteroidsp-value: 1Chi-squared
Comparison: Anemia (Hb\<9gr/dL)p-value: 0.169Chi-squared
Comparison: Malnutrition (hypoalbuminemia)p-value: 0.637Chi-squared
Primary
Type of Surgeon
Surgical speciality of physician who performed surgery.
Time frame: Day 0 (day of surgery)
Population: No data collected
Secondary
ASEPSIS Classification in Participants With Serious SSI
Additional treatment, Serous discharge, Erythema, Purulent exudate, Separation of deep tissue, Isolation of bacteria, Stay in hospital prolonged over 14 days (ASEPSIS). ASEPSIS classification is a numerical indication of wound healing progress: satisfactory healing (0-10), disturbance of healing (11-20), minor wound infection (20-30), moderate wound infection (30-40), and severe wound infection (over 40).
Time frame: Up to 30 days post surgery
Population: Subset of study population with infection
| Arm | Measure | Group | Value (NUMBER) |
|---|---|---|---|
| Case | ASEPSIS Classification in Participants With Serious SSI | Satisfactory healing | 1 participants |
| Case | ASEPSIS Classification in Participants With Serious SSI | Disturbance of healing | 12 participants |
| Case | ASEPSIS Classification in Participants With Serious SSI | Minor wound infection | 58 participants |
| Case | ASEPSIS Classification in Participants With Serious SSI | Moderate wound infection | 15 participants |
| Case | ASEPSIS Classification in Participants With Serious SSI | Severe wound infection | 4 participants |
Secondary
Classification of SSI Infection
Participants with organ-space or deep incisional SSI.
Time frame: Day 0 (day of surgery) up to 30 days post surgery
Population: Subset of study population with infection; N=number of participants with evaluable data
| Arm | Measure | Group | Value (NUMBER) |
|---|---|---|---|
| Case | Classification of SSI Infection | Organ-space infection | 60 participants |
| Case | Classification of SSI Infection | Deep incisional infection | 29 participants |
Secondary
Number of Participants With Antimicrobial Resistance
Microbiological resistance reported for microorganisms that were found at a frequency greater (\>) than 5 percent (%).
Time frame: Day 0 (day of surgery) up to 30 days post surgery
Population: Subset of study population with infection; N=number of participants with evaluable data
| Arm | Measure | Group | Value (NUMBER) |
|---|---|---|---|
| Case | Number of Participants With Antimicrobial Resistance | Morganella morganni (Cef-3) | 2 Number of participants |
| Case | Number of Participants With Antimicrobial Resistance | Morganella morganni (Carb) | 0 Number of participants |
| Case | Number of Participants With Antimicrobial Resistance | E. coli-cephalosporins 3rd generation (Cef-3) | 1 Number of participants |
| Case | Number of Participants With Antimicrobial Resistance | Escherichia coli-carbapenems (Carb) | 0 Number of participants |
| Case | Number of Participants With Antimicrobial Resistance | Escherichia coli-fluoroquinolones (FQ) | 7 Number of participants |
| Case | Number of Participants With Antimicrobial Resistance | Bacteroides fragilis gr. (Cef-3) | 0 Number of participants |
| Case | Number of Participants With Antimicrobial Resistance | Bacteroides fragilis gr. (Carb) | 1 Number of participants |
| Case | Number of Participants With Antimicrobial Resistance | Bacteroides fragilis gr. (FQ) | 4 Number of participants |
| Case | Number of Participants With Antimicrobial Resistance | Enterococcus faecium (Cef-3) | 0 Number of participants |
| Case | Number of Participants With Antimicrobial Resistance | Enterococcus faecium (Carb) | 1 Number of participants |
| Case | Number of Participants With Antimicrobial Resistance | Enterococcus faecium (FQ) | 0 Number of participants |
| Case | Number of Participants With Antimicrobial Resistance | Enterococcus faecalis (FQ) | 2 Number of participants |
| Case | Number of Participants With Antimicrobial Resistance | Pseudomonas aeruginosa (Cef-3) | 1 Number of participants |
| Case | Number of Participants With Antimicrobial Resistance | Pseudomonas aeruginosa (Carb) | 1 Number of participants |
| Case | Number of Participants With Antimicrobial Resistance | Morganella morganni (FQ) | 0 Number of participants |
| Case | Number of Participants With Antimicrobial Resistance | Pseudomonas aeruginosa (FQ) | 1 Number of participants |
| Case | Number of Participants With Antimicrobial Resistance | Staphylococus epidermis (FQ) | 4 Number of participants |
| Case | Number of Participants With Antimicrobial Resistance | Staphylococus spp (FQ) | 4 Number of participants |
| Case | Number of Participants With Antimicrobial Resistance | Enterococcus faecium (enterococcus vancomycin[EV]) | 0 Number of participants |
| Case | Number of Participants With Antimicrobial Resistance | Enterococcus faecalis (EV) | 0 Number of participants |
Secondary
Percentage of Participants Who Had Microbiologic Resolution of SSI (Sensitivity of Microorganisms to Antibiotics)
Resolution of SSI ranged from eradication (infection cured) to persistence (infection continued).
Time frame: Day 0 (day of surgery) up to 30 days post surgery
Population: Subset of study population with infection; N=number of participants with evaluable data
| Arm | Measure | Group | Value (NUMBER) |
|---|---|---|---|
| Case | Percentage of Participants Who Had Microbiologic Resolution of SSI (Sensitivity of Microorganisms to Antibiotics) | Erradication | 29.2 Percentage of participants |
| Case | Percentage of Participants Who Had Microbiologic Resolution of SSI (Sensitivity of Microorganisms to Antibiotics) | Presumed erradication | 57.3 Percentage of participants |
| Case | Percentage of Participants Who Had Microbiologic Resolution of SSI (Sensitivity of Microorganisms to Antibiotics) | Persistance | 4.5 Percentage of participants |
| Case | Percentage of Participants Who Had Microbiologic Resolution of SSI (Sensitivity of Microorganisms to Antibiotics) | Unknown | 9.0 Percentage of participants |
Secondary
Percentage of Participants Whose National Nosocomial Infection Surveillance System (NNISS) Scores of Preoperative Risk of Infection Were Greater Than >0
Percentage of participants with NNISS score for increased preoperative risk of infection.
Time frame: Baseline (pre-surgical)
Population: Study population
| Arm | Measure | Group | Value (NUMBER) |
|---|---|---|---|
| Case | Percentage of Participants Whose National Nosocomial Infection Surveillance System (NNISS) Scores of Preoperative Risk of Infection Were Greater Than >0 | 1.5 % increased risk | 23.3 Percentage of participants |
| Case | Percentage of Participants Whose National Nosocomial Infection Surveillance System (NNISS) Scores of Preoperative Risk of Infection Were Greater Than >0 | 2.9% increased risk | 50.0 Percentage of participants |
| Case | Percentage of Participants Whose National Nosocomial Infection Surveillance System (NNISS) Scores of Preoperative Risk of Infection Were Greater Than >0 | 6.8% increased risk | 23.3 Percentage of participants |
| Case | Percentage of Participants Whose National Nosocomial Infection Surveillance System (NNISS) Scores of Preoperative Risk of Infection Were Greater Than >0 | 13.0% increased risk | 3.3 Percentage of participants |
| Control | Percentage of Participants Whose National Nosocomial Infection Surveillance System (NNISS) Scores of Preoperative Risk of Infection Were Greater Than >0 | 13.0% increased risk | 2.2 Percentage of participants |
| Control | Percentage of Participants Whose National Nosocomial Infection Surveillance System (NNISS) Scores of Preoperative Risk of Infection Were Greater Than >0 | 1.5 % increased risk | 26.7 Percentage of participants |
| Control | Percentage of Participants Whose National Nosocomial Infection Surveillance System (NNISS) Scores of Preoperative Risk of Infection Were Greater Than >0 | 6.8% increased risk | 14.4 Percentage of participants |
| Control | Percentage of Participants Whose National Nosocomial Infection Surveillance System (NNISS) Scores of Preoperative Risk of Infection Were Greater Than >0 | 2.9% increased risk | 56.7 Percentage of participants |
p-value: 0.444Fisher Exact