Beyond the operating room: do hospital characteristics have an impact on surgical site infections after colorectal surgery? A systematic review

Background

Hospital characteristics have been recognized as potential risk factors for surgical site infection for over 20 years. However, most research has focused on patient and procedural risk factors. Understanding how structural and process variables influence infection is vital to identify targets for effective interventions and to optimize healthcare services. The aim of this study was to systematically review the association between hospital characteristics and surgical site infection in colorectal surgery.

Main body

A systematic literature search was conducted using PubMed, Scopus and Web of Science databases until the 31st of May, 2021. The search strategy followed the Participants, Exposure/Intervention, Comparison, Outcomes and Study design. The primary outcome of interest was surgical site infection rate after colorectal surgery. Studies were grouped into nine risk factor typologies: hospital size, ownership affiliation, being an oncological hospital, safety-net burden, hospital volume, surgeon caseload, discharge destination and time since implementation of surveillance. The STROBE statement was used for evaluating the methodological quality.

A total of 4703 records were identified, of which 172 were reviewed and 16 were included. Studies were published between 2008 and 2021, and referred to data collected between 1996 and 2016. Surgical site infection incidence ranged from 3.2 to 27.6%. Two out of five studies evaluating hospital size adjusted the analysis to patient and procedure-related risk factors, and showed that larger hospitals were either positively associated or had no association with SSI. Public hospitals did not present significantly different infection rates than private or non-profit ones. Medical school affiliation and higher safety-net burden were associated with higher surgical site infection (crude estimates), while oncological hospitals were associated with higher incidence independently of other variables. Hospital caseload showed mixed results, while surgeon caseload and surveillance time since implementation appear to be associated with fewer infections.

Conclusions

Although there are few studies addressing hospital-level factors on surgical site infection, surgeon experience and the implementation of a surveillance system appear to be associated with better outcomes. For hospitals and services to be efficiently optimized, more studies addressing these variables are needed that take into account the confounding effect of patient case mix.

A computerized indicator for surgical site infection (SSI) assessment after total hip or total knee replacement: The French ISO-ORTHO indicator

OBJECTIVE

The French National Authority for Health (HAS), with a multidisciplinary working group, developed an indicator 'ISO-ORTHO' to assess surgical site infections (SSIs) after total hip arthroplasty or total knee arthroplasty (THA/TKA) based on the hospital discharge database. We present the ISO-ORTHO indicator designed for SSI automated detection and its relevance for quality improvement and hospital benchmarks.

METHODS

The algorithm is based on a combination of International Statistical Classification of Diseases, Tenth Revision (ICD-10) and procedure codes of the hospital stay. The target population was selected among adult patients who had a THA or TKA between January 1, 2017, and September 30, 2017. Patients at very high risk of SSI and/or with SSI not related to hospital care were excluded. We searched databases for SSIs up to 3 months after THA/TKA. The standardized infection ratio (SIR) of observed versus expected SSIs was calculated (logistic regression) and displayed as funnel plot with 2 and 3 standard deviations (SD) after adjustment for 13 factors known to increase SSI risk.

RESULTS

In total, 790 hospitals and 139,926 THA/TKA stays were assessed; 1,253 SSI were detected in the 473 included hospitals (incidence, 0.9%: 1.0% for THA, 0.80% for TKA). The SSI rate was significantly higher in males (1.2%), in patients with previous osteo-articular infection (4.4%), and those with cancer (2.3%), obesity, or diabetes. Most hospitals (89.9%) were within 2 SD; however, 12 hospitals were classified as outliers at more than +3 SD (1.6% of facilities), and 59 hospitals (7.9%) were outliers between +2 SD and +3 SD.

CONCLUSION

ISO-ORTHO is a relevant indicator for automated surveillance; it can provide hospitals a metric for SSI assessment that may contribute to improving patient outcomes.

Prolonged antibiotic prophylaxis use in elective orthopaedic surgery - a cross-sectional analysis

Purpose

Surgical antibiotic prophylaxis (SAP) prevents surgical site infections (SSI). In orthopaedic surgery, the use of prolonged SAP (PSAP) has been reported in daily routine, despite guidelines advising against it. Therefore, we asked: What is the proportion of PSAP use, defined as administration of SAP ≥24 h after elective orthopaedic surgery? Are there patient- and surgery-related predictors of PSAP use?

Methods

This cross-sectional analysis investigated 1292 patients who underwent elective orthopaedic surgery including total joint arthroplasties at one Swiss centre between 2015 and 2017. Patient comorbidities, surgical characteristics and occurrence of SSI at 90 days in PSAP group were compared to the SAP group (< 24 h post-operative).

Results

PSAP use was 12% (155 of 1292). Patient-related factors associated with PSAP compared to the SAP group included older age (63 vs. 58y; p < 0.001), higher BMI (29 vs. 27 kg/m²; p < 0.001), ASA classification ≥3 (31% vs. 17%; p < 0.001) and lung disease (17% vs. 9%; p = 0.002). Surgery-related factors associated with PSAP were use of prosthetics (62% vs. 45%; p < 0.001), surgery of the knee (65% vs. 25%; p < 0.001), longer surgery duration (87 vs. 68 min; p < 0.001) and presence of drains (90% vs. 65%; p < 0.001). All four SSI occurred in the SAP group (0 vs. 4; p = 1.0). Surgeons administered PSAP with varying frequencies; proportions ranged from 0 to 33%.

Conclusion

PSAP use and SSI proportions were lower than reported in the literature. Several patient- and surgery-related factors associated with PSAP use were identified and some were potentially modifiable. Also, experienced surgeons seemed to implement differing approaches regarding the duration of SAP administration.

Increasing but levelling out risk of revision due to infection after total hip arthroplasty: a study on 108,854 primary THAs in the Norwegian Arthroplasty Register from 2005 to 2019

Background and purpose - Focus on prevention, surveillance, and treatment of infection after total hip arthroplasty (THA) in the last decade has resulted in new knowledge and guidelines. Previous publications have suggested an increased incidence of surgical revisions due to infection after THA. We assessed whether there have been changes in the risk of revision due to deep infection after primary THAs reported to the Norwegian Arthroplasty Register (NAR) over the period 2005-2019.Patients and methods - Primary THAs reported to the NAR from January 1, 2005 to December 31, 2019 were included. Adjusted Cox regression analyses with the first revision due to deep infection after primary THA were performed. We investigated changes in the risk of revision as a function of time of primary THA. Time was stratified into 5-year periods. We studied the whole population of THAs, and the subgroups: all-cemented, all-uncemented, reverse hybrid (cemented cup), and hybrid THAs (cemented stem). In addition, we investigated factors that were associated with the risk of revision, and changes in the time span from primary THA to revision.Results - Of the 108,854 primary THAs that met the inclusion criteria, 1,365 (1.3%) were revised due to deep infection. The risk of revision due to infection, at any time after primary surgery, increased through the period studied. Compared with THAs implanted in 2005-2009, the relative risk of revision due to infection was 1.4 (95% CI 1.2-1.7) for 2010-2014, and 1.6 (1.1-1.9) for 2015-2019. We found an increased risk for all types of implant fixation. Compared to 2005-2009, for all THAs, the risk of revision due to infection 0-30 days postoperatively was 2.2 (1.8-2.8) for 2010-2014 and 2.3 (1.8-2.9) for 2015-2019, 31-90 days postoperatively 1.0 (0.7-1.6) for 2010-2014 and 1.6 (1.0-2.5) for 2015-2019, and finally 91 days-1 year postoperatively 1.1 (0.7-1.8) for 2010-2014 and 1.6 (1.0-2.6) for 2015-2019. From 1 to 5 years postoperatively, the risk of revision due to infection was similar to 2005-2009 for both the subsequent time periodsInterpretation - The risk of revision due to deep infection after THA increased throughout the period 2005-2019, but appears to have levelled out after 2010. The increase was mainly due to an increased risk of early revisions, and may partly have been caused by a change of practice rather than a change in the incidence of infection.

Have We Actually Reduced Our 30-Day Short-Term Surgical Site Infection Rates in Primary Total Hip Arthroplasty in the United States?

BACKGROUND

The purpose of this study is to track the 30-day postoperative annual rates and trends of (1) overall, (2) deep, and (3) superficial surgical site infections (SSIs) following total hip arthroplasty (THA) using a large nationwide database.

METHODS

The National Surgical Quality Improvement Program database was queried for all THA cases performed between 2012 and 2016. After an overall 5-year correlation and trends analysis, univariate analysis was performed to compare the most recent year, 2016, with the preceding 4 years. Correlation coefficients and chi-squared tests were used to determine correlation and statistical significance.

RESULTS

The lowest incidence of SSIs was in the most recent year, 2016 (0.81%), while the greatest incidence was in the earliest year, 2012 (1.12%), marking a 31% decrease (P < .01). The lowest rate was in the most recent year, 2016 (0.23%), marking a 26% decrease from 2012. The lowest superficial SSI incidence occurred in the most recent year, 2016 (0.58%), while greatest incidence was in 2012 (0.83%), marking a 31% decrease over time (P < .05). There was an inverse correlation among overall, deep, and superficial SSI rates with operative year.

CONCLUSION

The findings from this study suggest a decreasing trend in SSIs within 30 days following THA. Furthermore, deep SSIs, which can pose substantial threats to implant survivorship, have also decreased throughout the years. These results highlight that potentially through improved medical and surgical techniques, we are winning the fight against short-term infections, but that more can still be done.

Impact of participation in a surgical site infection surveillance network: results from a large international cohort study

BACKGROUND

Surveillance of surgical site infections (SSIs) is a core component of effective infection control practices, though its impact has not been quantified on a large scale.

AIM

To determine the time-trend of SSI rates in surveillance networks.

METHODS

SSI surveillance networks provided procedure-specific data on numbers of SSIs and operations, stratified by hospitals' year of participation in the surveillance, to capture length of participation as an exposure. Pooled and procedure-specific random-effects Poisson regression was performed to obtain yearly rate ratios (RRs) with 95% confidence intervals (CIs), and including surveillance network as random intercept.

FINDINGS

Of 36 invited networks, 17 networks from 15 high-income countries across Asia, Australia and Europe participated in the study. Aggregated data on 17 surgical procedures (cardiovascular, digestive, gynaecological-obstetrical, neurosurgical, and orthopaedic) were collected, resulting in data concerning 5,831,737 operations and 113,166 SSIs. There was a significant decrease in overall SSI rates over surveillance time, resulting in a 35% reduction at the ninth (final) included year of surveillance (RR: 0.65; 95% CI: 0.63-0.67). There were large variations across procedure-specific trends, but strong consistent decreases were observed for colorectal surgery, herniorrhaphy, caesarean section, hip prosthesis, and knee prosthesis.

CONCLUSION

In this large, international cohort study, pooled SSI rates were associated with a stable and sustainable decrease after joining an SSI surveillance network; a causal relationship is possible, although unproven. There was heterogeneity in procedure-specific trends. These findings support the pivotal role of surveillance in reducing infection rates and call for widespread implementation of hospital-based SSI surveillance in high-income countries.

Decreased rate of surgical site infection after spinal surgery with instrumentation using bundled approach including surveillance and intrawound vancomycin application

Surgical site infections (SSIs) increase the risk of mortality, postsurgery, extend hospital stay, and increase the costs of healthcare. Our aim in this study was to evaluate the effectiveness of a multidisciplinary, evidence-based, surveillance program combined with intrawound application of vancomycin in lowering the incidence rate of SSI after spinal surgery with instrumentation.We conducted a retrospective analysis of 637 patients who underwent spinal fusion with instrumentation in our institution at 3 different time periods: prior to our surveillance program (control group), surveillance only (surveillance group 1), and surveillance combined with intrawound vancomycin application (surveillance group 2). The following covariates were considered in the evaluation of between-group differences in SSI rate: sex, age, surgical site, National Nosocomial Infection Surveillance (NNIS) risk index, American Society of Anesthesiologists (ASA) physical status classification, and other health comorbidities. The causative organism in cases of SSI was confirmed in all cases.The rate of SSI was significantly lower in the surveillance group 2 (1.4%) than in the control group (4.6%; P = .04). On multivariate logistic regression analysis, steroid use (adjusted odd's ratio (OR), 6.06; 95% confidence interval (CI), 1.45-23.6) and operative time (adjusted OR.1.01; 95% CI, 1.00-1.01) were identified as independent risk factors of SSI. Staphylococcus species and Propionibacterium acnes were the principal causative organisms.A bundled approach that includes surveillance and intrawound application of vancomycin is an effective strategy to lower the risk of SSI after spinal fusion with instrumentation. The use of steroid and longer operative time are risk factors of SSI.Our findings support the implementation of a program of surveillance, combined with intrawound vancomycin application, to reduce the incidence rate of SSIs in spinal surgery.

Key features of bone and joint infections following the implementation of reference centers in France

OBJECTIVES

French reference centers for bone and joint infections (BJI) were implemented from 2009 onwards to improve the management of complex BJIs. This study compared BJI burden before and after the implementation of these reference centers.

PATIENTS AND METHODS

BJI hospital stays were selected from the 2008 and 2013 national hospital discharge database using a validated algorithm, adding the new complex BJI code created in 2011. Epidemiology and economic burden were assessed.

RESULTS

BJI prevalence increased in 2013 (70 vs. 54/100,000 in 2008). Characteristics of BJI remained similar between 2008 and 2013: septic arthritis (50%), increasing prevalence with age and sex, case fatality 5%, mean length of stay 17.5 days, rehospitalization 20%. However, device-associated BJIs increased (34 vs. 26%) as well as costs (€421 million vs. €259 in 2008). Similar device-associated BJI characteristics between 2008 and 2013 were: septic arthritis (70%), case fatality (3%), but with more hospitalizations in reference centers (34 vs. 30%) and a higher cost per stay. Among the 7% of coded complex BJIs, the mean length of stay was 22.2 days and mean cost was €11,960.

CONCLUSIONS

BJI prevalence highly increased in France. Complex BJI prevalence assessment is complicated by the absence of clinical consensus and probable undercoding. A validation of clinical case definition of complex BJI is required.

Prevention of hospital infections by intervention and training (PROHIBIT): results of a pan-European cluster-randomized multicentre study to reduce central venous catheter-related bloodstream infections

PURPOSE

To test the effectiveness of a central venous catheter (CVC) insertion strategy and a hand hygiene (HH) improvement strategy to prevent central venous catheter-related bloodstream infections (CRBSI) in European intensive care units (ICUs), measuring both process and outcome indicators.

METHODS

Adult ICUs from 14 hospitals in 11 European countries participated in this stepped-wedge cluster randomised controlled multicentre intervention study. After a 6 month baseline, three hospitals were randomised to one of three interventions every quarter: (1) CVC insertion strategy (CVCi); (2) HH promotion strategy (HHi); and (3) both interventions combined (COMBi). Primary outcome was prospective CRBSI incidence density. Secondary outcomes were a CVC insertion score and HH compliance.

RESULTS

Overall 25,348 patients with 35,831 CVCs were included. CRBSI incidence density decreased from 2.4/1000 CVC-days at baseline to 0.9/1000 (p < 0.0001). When adjusted for patient and CVC characteristics all three interventions significantly reduced CRBSI incidence density. When additionally adjusted for the baseline decreasing trend, the HHi and COMBi arms were still effective. CVC insertion scores and HH compliance increased significantly with all three interventions.

CONCLUSIONS

This study demonstrates that multimodal prevention strategies aiming at improving CVC insertion practice and HH reduce CRBSI in diverse European ICUs. Compliance explained CRBSI reduction and future quality improvement studies should encourage measuring process indicators.

Temporal trends and epidemiology of Staphylococcus aureus surgical site infection in the Swiss surveillance network: a cohort study

BACKGROUND

Staphylococcus aureus is the leading pathogen in surgical site infections (SSI).

AIM

To explore trends and risk factors associated with S. aureus SSI.

METHODS

Risk factors for monomicrobial S. aureus SSI were identified from the Swiss multi-centre SSI surveillance system using multi-variate logistic regression. Both in-hospital and postdischarge SSI were identified using standardized definitions.

FINDINGS

Over a six-year period, data were collected on 229,765 surgical patients, of whom 499 (0.22%) developed monomicrobial S. aureus SSI; 459 (92.0%) and 40 (8.0%) were due to meticillin-susceptible S. aureus (MSSA) and meticillin-resistant S. aureus (MRSA), respectively. There was a significant decrease in the rate of MSSA SSI (P = 0.007), but not in the rate of MRSA SSI (P = 0.70). Independent protective factors for S. aureus SSI were older age [≥75 years vs <50 years: odds ratio (OR) 0.60, 95% confidence interval (CI) 0.44-0.83], laparoscopy/minimally invasive surgery (OR 0.68, 95% CI 0.50-0.92), non-clean surgery [OR 0.78 (per increase in wound contamination class), 95% CI 0.64-0.94] and correct timing of pre-operative antibiotic prophylaxis (OR 0.80, 95% CI 0.65-0.98). Independent risk factors were male sex (OR 1.38, 95% CI 1.14-1.66), higher American Society of Anesthesiologists' score (per one-point increment: OR 1.30, 95% CI 1.13-1.51), re-operation for non-infectious reasons (OR 4.59, 95% CI 3.59-5.87) and procedure type: cardiac surgery, laminectomy, and hip or knee arthroplasty had two-to nine-fold increased odds of S. aureus SSI compared with other procedures.

CONCLUSIONS

SSI due to S. aureus are decreasing and becoming rare events in Switzerland. High-risk procedures that may benefit from specific preventive measures were identified. Unfortunately, many of the independent risk factors are not easily modifiable.

First Results of the Swiss National Surgical Site Infection Surveillance Program: Who Seeks Shall Find

OBJECTIVES

To report on the results of the Swiss national surgical site infection (SSI) surveillance program, including temporal trends, and to describe methodological characteristics that may influence SSI rates

DESIGN

Countrywide survey of SSI over a 4-year period. Analysis of prospectively collected data including patient and procedure characteristics as well as aggregated SSI rates stratified by risk categories, type of SSI, and time of diagnosis. Temporal trends were analyzed using stepwise multivariate logistic regression models with adjustment of the effect of the duration of participation in the surveillance program for confounding factors.

SETTING

The study included 164 Swiss public and private hospitals with surgical activities.

RESULTS

From October 2011 to September 2015, a total of 187,501 operations performed in this setting were included. Cumulative SSI rates varied from 0.9% for knee arthroplasty to 14.4% for colon surgery. Postdischarge follow-up was completed in &gt;90% of patients at 1 month for surgeries without an implant and in &gt;80% of patients at 12 months for surgeries with an implant. High rates of SSIs were detected postdischarge, from 20.7% in colon surgeries to 93.3% in knee arthroplasties. Overall, the impact of the duration of surveillance was significantly and independently associated with a decrease in SSI rates in herniorraphies and C-sections but not for the other procedures. Nevertheless, some hospitals observed significant decreases in their rates for various procedures.

CONCLUSIONS

Intensive post-discharge surveillance may explain high SSI rates and cause artificial differences between programs. Surveillance per se, without structured and mandatory quality improvement efforts, may not produce the expected decrease in SSI rates.

Infect Control Hosp Epidemiol 2017;38:697–704

Incidence of surgical site infections cannot be derived reliably from point prevalence survey data in Dutch hospitals

Thorough studies on whether point prevalence surveys of healthcare-associated infections (HAIs) can be used to reliably estimate incidence of surgical site infections (SSIs) are scarce. We examined this topic using surveillance data of 58 hospitals that participated in two Dutch national surveillances; HAI prevalence and SSI incidence surveillance, respectively. First, we simulated daily prevalences of SSIs from incidence data. Subsequently, Rhame & Sudderth's formula was used to estimate SSI incidence from prevalence. Finally, we developed random-effects models to predict SSI incidence from prevalence and other relevant variables. The prevalences simulated from incidence data indicated that daily prevalence varied greatly. Incidences calculated with Rhame & Sudderth's formula often had values below zero, due to the large number of SSIs occurring post-discharge. Excluding these SSIs, still resulted in poor correlation between calculated and observed incidence. The two models best predicting total incidence and incidence during initial hospital stay both performed poorly (proportion of explained variance of 0·25 and 0·10, respectively). In conclusion, incidence of SSIs cannot be reliably estimated from point prevalence data in Dutch hospitals by any of the applied methods. We therefore conclude that prevalence surveys are not a useful measure to give reliable insight into incidence of SSIs.

Quality Assessment of Hospital Discharge Database for Routine Surveillance of Hip and Knee Arthroplasty–Related Infections

Objective.

Surgical site infection (SSI) surveillance represents a key method of nosocomial infection control programs worldwide. However, most SSI surveillance systems are considered to be poorly cost effective regarding human and economic resources required for data collection and patient follow up. This study aims to assess the efficacy of using hospital discharge databases (HDDs) as a routine surveillance system for detecting hip or knee arthroplasty–related infections (HKAIs).

Methods.

A case-control study was conducted among patients hospitalized in the Centre region of France between 2008 and 2010. HKAI cases were extracted from the HDD with various algorithms based on the International Classification of Diseases, Tenth Revision, and procedure codes. The control subjects were patients with hip or knee arthroplasty (HKA) without infection selected at random from the HDD during the study period. The gold standard was medical chart review. Sensitivity (Se), specificity (Spe), positive predictive value (PPV), and negative predictive value (NPV) were calculated to evaluate the efficacy of the surveillance system.

Results.

Among 18,265 hospital stays for HKA, corresponding to 17,388 patients, medical reports were checked for 1,010 hospital stays (989 patients). We identified 530 cases in total (incidence rate, 1% [95% confidence interval (CI), 0.4%–1.6%), and 333 cases were detected by routine surveillance. As compared with 480 controls, Se was 98%, Spe was 71%, PPV was 63%, and NPV was 99%. Using a more specific case definition, based on a sample of 681 hospital stays, Se was 97%, Spe was 95%, PPV was 87%, and NPV was 98%.

Conclusions.

This study demonstrates the potential of HDD as a tool for routine SSI surveillance after low-risk surgery, under conditions of having an appropriate algorithm for selecting infections.

Infect Control Hosp Epidemiol 2014;35(6):646–651

Improving Surveillance for Surgical Site Infections Following Total Hip and Knee Arthroplasty Using Diagnosis and Procedure Codes in a Provincial Surveillance Network

OBJECTIVE

To evaluate hospital administrative data to identify potential surgical site infections (SSIs) following primary elective total hip or knee arthroplasty.

DESIGN

Retrospective cohort study.

SETTING

All acute care facilities in Alberta, Canada.

METHODS

Diagnosis and procedure codes for 6 months following total hip or knee arthroplasty were used to identify potential SSI cases. Medical charts of patients with potential SSIs were reviewed by an infection control professional at the acute care facility where the patient was identified with a diagnosis or procedure code. For SSI decision, infection control professionals used the National Healthcare Safety Network SSI definition. The performance of traditional surveillance methods and administrative data–triggered medical chart review was assessed.

RESULTS

Of the 162 patients identified by diagnosis or procedure code, 46 (28%) were confirmed as an SSI by an infection control professional. More SSIs were identified following total hip vs total knee arthroplasty (42% vs16%). Of 46 confirmed SSI cases, 20 (43%) were identified at an acute care facility different than their procedure facility. Administrative data–triggered medical chart review with infection control professional confirmation resulted in a 1.1- to 1.7-fold increase in SSI rate compared with traditional surveillance. SSIs identified by administrative data resulted in sensitivity of 90% and specificity of 99%.

CONCLUSION

Medical chart review for cases identified through administrative data is an efficient supplemental SSI surveillance strategy. It improves case-finding by increasing SSI identification and making identification consistent across facilities, and in a provincial surveillance network it identifies SSIs presenting at nonprocedure facilities.

Infect Control Hosp Epidemiol 2016;37:699–703

Five-year decreased incidence of surgical site infections following gastrectomy and prosthetic joint replacement surgery through active surveillance by the Korean Nosocomial Infection Surveillance System

BACKGROUND

Surveillance of healthcare-associated infection has been associated with a reduction in surgical site infection (SSI).

AIM

To evaluate the Korean Nosocomial Infection Surveillance System (KONIS) in order to assess its effects on SSI since it was introduced.

METHODS

SSI data after gastrectomy, total hip arthroplasty (THA), and total knee arthroplasty (TKA) between 2008 and 2012 were analysed. The pooled incidence of SSI was calculated for each year; the same analyses were also conducted from hospitals that had participated in KONIS for at least three consecutive years. Standardized SSI rates for each year were calculated by adjusting for SSI risk factors. SSI trends were analysed using the Cochran-Armitage test.

FINDINGS

The SSI rate following gastrectomy was 3.12% (522/16,918). There was a significant trend of decreased crude SSI rates over five years. This trend was also evident in analysis of hospitals that had participated for more than three years. The SSI rate for THA was 2.05% (157/7656), which decreased significantly from 2008 to 2012. The risk factors for SSI after THA included the National Nosocomial Infections Surveillance risk index, trauma, reoperation, and age (60-69 years). The SSI rate for TKA was 1.90% (152/7648), which also decreased significantly during a period of five years. However, the risk-adjusted analysis of SSI did not show a significant decrease for all surgical procedures.

CONCLUSION

The SSI incidence of gastrectomy and prosthetic joint replacement declined over five years as a result of active surveillance by KONIS.

Obstructive Sleep Apnea: A Risk Factor for Surgical Site Infection following Colectomy

BACKGROUND

Obstructive sleep apnea (OSA) is associated with increased systemic oxidative stress, endothelial dysfunction, and activation of pro-inflammatory cascades, which increase host susceptibility to infection. OSA has not been evaluated as a risk factor for surgical site infection (SSI) following colectomy. We hypothesized that OSA increases the risk for SSI after colectomy.

METHODS

We performed a retrospective review of 507 colectomies that took place between August 2011 and September 2013. Forty-two patients carried the diagnosis of OSA prior to surgery. These 42 patients were matched to 68 patients with no OSA for age, body mass index (BMI), diabetes mellitus (DM), reason for surgery and surgical approach.

RESULTS

The rate of SSI was 28.6% (12 of 42) in the patients with and 10.3% (7 of 68) in the patients without OSA (p=0.03). Using logistic regression, the predictors of SSI following colectomy were found to be OSA (odds ratio [OR] of 3.98, 95% confidence interval [CI]=1.29-12.27), and DM (OR of 7.16, 95% CI=2.36-21.96). The average hospital stay after colectomy for patients with OSA complicated with SSI was 16.7 d whereas patients with OSA without SSI stayed 7.4 d (p<0.001). The rate of organ space infections was 9.5% (4 of 42) in the patients with OSA compared with 0 (p=0.02) in patients without OSA.

CONCLUSIONS

OSA is an independent risk factor for SSI following colectomy. Patients with OSA have substantially greater rates of organ space SSI and longer hospital stay.

Hip and knee arthroplasty: quo vadis?

Despite of the steady decrease of surgical site infection (SSI) over the last two decades, the incidence of SSI after hip and knee arthroplasty has recently surged. This may be explained by technical changes that may result in an increased risk of SSI, such as the broad implementation of fast track programs, and/or early interventions on suspected SSI. By definition, early intervention may lead to a higher SSI score, even in the absence of a true SSI. In any case, the reverse trend of SSI warrants further investigations.

Surgical attire, practices and their perception in the prevention of surgical site infection

INTRODUCTION

Clean surgical scrubs, surgical gowns and headgear are worn by operative teams to decrease bacterial contamination and lower surgical site infection (SSI) rates.

METHODS

A detailed review was undertaken of peer-reviewed publications and other sources of material in the English language over the last 50 years included.

RESULTS

Surgical scrubs should be clean and made of tightly woven material. Studies investigating single-use gowns and drapes versus reusable gowns report conflicting evidence. Double gloving may reduce SSI rates in procedures where no antibiotic prophylaxis was administered. Bacterial contamination of the operative field has been shown to be decreased by the wearing of surgical headgear by the operating team.

CONCLUSIONS

Further consideration and better trials are required to determine the impact of different theatre clothing on SSI rates.

Use of surgical-site infection rates to rank hospital performance across several types of surgery

BACKGROUND

Comparing and ranking hospitals based on health outcomes is becoming increasingly popular, although case-mix differences between hospitals and random variation are known to distort interpretation. The aim of this study was to explore whether surgical-site infection (SSI) rates are suitable for comparing hospitals, taking into account case-mix differences and random variation.

METHODS

Data from the national surveillance network in the Netherlands, on the eight most frequently registered types of surgery for the year 2009, were used to calculate SSI rates. The variation in SSI rate between hospitals was estimated with multivariable fixed- and random-effects logistic regression models to account for random variation and case mix. 'Rankability' (as the reliability of ranking) of the SSI rates was calculated by relating within-hospital variation to between-hospital variation.

RESULTS

Thirty-four hospitals reported on 13 629 patients, with overall SSI rates per surgical procedure varying between 0 and 15·1 per cent. Statistically significant differences in SSI rate between hospitals were found for colonic resection, caesarean section and for all operations combined. Rankability was 80 per cent for colonic resection but 0 per cent for caesarean section. Rankability was 8 per cent in all operations combined, as the differences in SSI rates were explained mainly by case mix.

CONCLUSION

When comparing SSI rates in all operations, differences between hospitals were explained by case mix. For individual types of surgery, case mix varied less between hospitals, and differences were explained largely by random variation. Although SSI rates may be used for monitoring quality improvement within hospitals, they should not be used for ranking hospitals.

Decreasing time trend in SSI incidence for orthopaedic procedures: surveillance matters!

BACKGROUND

Infection is the most common reason for early revision after hip and knee arthroplasty, and the revision rate is increasing. Surgical site infection (SSI) surveillance data are important to assess the true infection rate. There is little information regarding the potential time trend in SSI incidence following orthopaedic surgery.

AIM

To evaluate whether a time trend exists in SSI incidence due to surveillance following orthopaedic surgery.

METHODS

The SSI rates after hip and knee replacements and osteosynthesis of trochanteric femoral fractures and ankle fractures were recorded prospectively from May 1998 to October 2008 according to the criteria of the US Centers for Disease Control and Prevention. In total, 4177 procedures were analysed, 65.8% of which were performed on female patients. Linear regression was used to analyse trends in SSI rates.

FINDINGS

SSI incidence decreased significantly from 7% in the first year to 3% in the last year; a 57% relative reduction. The duration of surgery was the only significant predictor for infection (P < 0.001) in a logistic regression model that also included age, American Society of Anesthesiologists' score and level of emergency.

CONCLUSION

Surveillance following orthopaedic procedures showed a significant decrease in SSI incidence over the 11-year surveillance period. The causality between surveillance and SSI incidence is difficult to prove, but surveillance with feedback probably influences several procedures that affect the quality of health care, even if duration of surgery is the only significant predictor of this effect.

Increasing risk of prosthetic joint infection after total hip arthroplasty

BACKGROUND AND PURPOSE

The risk of revision due to infection after primary total hip arthroplasty (THA) has been reported to be increasing in Norway. We investigated whether this increase is a common feature in the Nordic countries (Denmark, Finland, Norway, and Sweden).

MATERIALS AND METHODS

The study was based on the Nordic Arthroplasty Register Association (NARA) dataset. 432,168 primary THAs from 1995 to 2009 were included (Denmark: 83,853, Finland 78,106, Norway 88,455, and Sweden 181,754). Adjusted survival analyses were performed using Cox regression models with revision due to infection as the endpoint. The effect of risk factors such as the year of surgery, age, sex, diagnosis, type of prosthesis, and fixation were assessed.

RESULTS

2,778 (0.6%) of the primary THAs were revised due to infection. Compared to the period 1995-1999, the relative risk (with 95% CI) of revision due to infection was 1.1 (1.0-1.2) in 2000-2004 and 1.6 (1.4-1.7) in 2005-2009. Adjusted cumulative 5-year revision rates due to infection were 0.46% (0.42-0.50) in 1995-1999, 0.54% (0.50-0.58) in 2000-2004, and 0.71% (0.66-0.76) in 2005-2009. The entire increase in risk of revision due to infection was within 1 year of primary surgery, and most notably in the first 3 months. The risk of revision due to infection increased in all 4 countries. Risk factors for revision due to infection were male sex, hybrid fixation, cement without antibiotics, and THA performed due to inflammatory disease, hip fracture, or femoral head necrosis. None of these risk factors increased in incidence during the study period.

INTERPRETATION

We found increased relative risk of revision and increased cumulative 5-year revision rates due to infection after primary THA during the period 1995-2009. No change in risk factors in the NARA dataset could explain this increase. We believe that there has been an actual increase in the incidence of prosthetic joint infections after THA.

Infection after primary hip arthroplasty: a comparison of 3 Norwegian health registers

BACKGROUND AND PURPOSE

The aim of the present study was to assess incidence of and risk factors for infection after hip arthroplasty in data from 3 national health registries. We investigated differences in risk patterns between surgical site infection (SSI) and revision due to infection after primary total hip arthroplasty (THA) and hemiarthroplasty (HA).

MATERIALS AND METHODS

This observational study was based on prospective data from 2005-2009 on primary THAs and HAs from the Norwegian Arthroplasty Register (NAR), the Norwegian Hip Fracture Register (NHFR), and the Norwegian Surveillance System for Healthcare-Associated Infections (NOIS). The Norwegian Patient Register (NPR) was used for evaluation of case reporting. Cox regression analyses were performed with revision due to infection as endpoint for data from the NAR and the NHFR, and with SSI as the endpoint for data from the NOIS.

RESULTS

The 1-year incidence of SSI in the NOIS was 3.0% after THA (167/5,540) and 7.3% after HA (103/1,416). The 1-year incidence of revision due to infection was 0.7% for THAs in the NAR (182/24,512) and 1.5% for HAs in the NHFR (128/8,262). Risk factors for SSI after THA were advanced age, ASA class higher than 2, and short duration of surgery. For THA, the risk factors for revision due to infection were male sex, advanced age, ASA class higher than 1, emergency surgery, uncemented fixation, and a National Nosocomial Infection Surveillance (NNIS) risk index of 2 or more. For HAs inserted after fracture, age less than 60 and short duration of surgery were risk factors of revision due to infection.

INTERPRETATION

The incidences of SSI and revision due to infection after primary hip replacements in Norway are similar to those in other countries. There may be differences in risk pattern between SSI and revision due to infection after arthroplasty. The risk patterns for revision due to infection appear to be different for HA and THA.

[Multicentre study of infection incidence in knee prosthesis]

OBJECTIVE

To determine the incidence of surgical site infection in knee prosthesis surgical procedure for a follow-up period of one year in twelve hospitals in Madrid region.

MATERIAL AND METHOD

A prospective study was carried out from January to December 2009 using a national surveillance system called Indicadores Clínicos de Mejora Continua de Calidad. Primary and revision knee joint replacements in patients operated on in the previous year were included. Criteria used to define surgical site infection and patient risk index categories were those established by the Centers for Disease Control and Prevention and National Nosocomial Infections Surveillance. The incidence rates were worked out crude and adjusted by hazard ratio.

RESULTS

2,088 knee prosthesis procedures were analyzed. The overall incidence of surgical site infection was 2.1%. Sixty-five percent of the infections were organ/space. Sixty percent of the infections were identified in the early postoperative period. Of all surgical site infections, 41.9% were microbiologically confirmed. Antibiotic prophylaxis was implemented correctly in 63.3% of the cases. The most important cause of inappropriate prophylaxis was an unsuitable duration in 85.7% of the cases. The presurgical preparation was carried out correctly in 50.3% of surgical operations. The incidence of knee arthroplasty infection was twice as high as in the National Healthcare Safety Network and similar to national rates.

DISCUSSION

In this study, the incidence of infection was within the range of infection rates in other published European studies. Surveillance and control strategies of health care for associated infections allow us to assess trends and the impact of preventive measures.

Preventing surgical site infections

The risk of surgical site infection (SSI) is approximately 1-3% for elective clean surgery. Apart from patient endogenous factors, the role of external risk factors in the pathogenesis of SSI is well recognized. However, among the many measures to prevent SSI, only some are based on strong evidence, for example, adequate perioperative administration of prophylactic antibiotics, and there is insufficient evidence to show whether one method is superior to any other. This highlights the need for a multimodal approach involving active post-discharge surveillance, as well as measures at every step of the care process, ranging from the operating theater to postoperative care. Multicenter or supranational intervention programs based on evidence-based guidelines, 'bundles' or safety checklists are likely to be beneficial on a global scale. Although theoretically reducible to zero, the maximal realistic extent by which SSI can be decreased remains unknown.

Increasing risk of revision due to deep infection after hip arthroplasty

BACKGROUND AND PURPOSE

Over the decades, improvements in surgery and perioperative routines have reduced the incidence of deep infections after total hip arthroplasty (THA). There is, however, some evidence to suggest that the incidence of infection is increasing again. We assessed the risk of revision due to deep infection for primary THAs reported to the Norwegian Arthroplasty Register (NAR) over the period 1987-2007.

METHOD

We included all primary cemented and uncemented THAs reported to the NAR from September 15, 1987 to January 1, 2008 and performed adjusted Cox regression analyses with the first revision due to deep infection as endpoint. Changes in revision rate as a function of the year of operation were investigated.

RESULTS

Of the 97,344 primary THAs that met the inclusion criteria, 614 THAs had been revised due to deep infection (5-year survival 99.46%). Risk of revision due to deep infection increased throughout the period studied. Compared to the THAs implanted in 1987-1992, the risk of revision due to infection was 1.3 times higher (95%CI: 1.0-1.7) for those implanted in 1993-1997, 1.5 times (95% CI: 1.2-2.0) for those implanted in 1998-2002, and 3.0 times (95% CI: 2.2-4.0) for those implanted in 2003-2007. The most pronounced increase in risk of being revised due to deep infection was for the subgroup of uncemented THAs from 2003-2007, which had an increase of 5 times (95% CI: 2.6-11) compared to uncemented THAs from 1987-1992.

INTERPRETATION

The incidence of deep infection after THA increased during the period 1987-2007. Concomitant changes in confounding factors, however, complicate the interpretation of the results.

Reducing surgical site infection incidence through a network: results from the French ISO-RAISIN surveillance system

Surgical-site infections (SSIs) are a key target for nosocomial infection control programmes. We evaluated the impact of an eight-year national SSI surveillance system named ISO-RAISIN (infection du site opératoire - Réseau Alerte Investigation Surveillance des Infections). Consecutive patients undergoing surgery were enrolled during a three-month period each year and surveyed for 30 days following surgery. A standardised form was completed for each patient including SSI diagnosis according to standard criteria, and several risk factors such as wound class, American Society of Anesthesiologists (ASA) score, operation duration, elective/emergency surgery, and type of surgery. From 1999 to 2006, 14,845 SSIs were identified in 964,128 patients (overall crude incidence: 1.54%) operated on in 838 participating hospitals. The crude overall SSI incidence decreased from 2.04% to 1.26% (P<0.001; relative reduction: -38%) and the National Nosocomial Infections Surveillance system (NNIS)-0 adjusted SSI incidence from 1.10% to 0.74% (P<0.001; relative reduction: -33%). The most significant SSI incidence reduction was observed for hernia repair and caesarean section, and to a lesser extent, cholecystectomy, hip prosthesis arthroplasty, and mastectomy. Active surveillance striving for a benchmark throughout a network is an effective strategy to reduce SSI incidence.