The quality of denominator data in surgical site infection surveillance versus administrative data in Norway 2005-2010

Risk factors for surgical site infection following cesarean delivery: A hospital-based case-control study

INTRODUCTION

Cesarean section is the single most important risk factor for postpartum infection. Where the rest of the world shows increasing trends, the cesarean section rates are low in Norway and risk factors for infection after cesarean section may differ in high and low cesarean section settings. The goal of this study was to examine independent risk factors for surgical site infection after cesarean delivery in a setting of low cesarean section rates.

MATERIAL AND METHODS

We conducted a hospital-based case-control study at Haukeland University Hospital. We included women who presented to our hospital with surgical site infection after cesarean section during the years 2014-2016 (n = 75). Controls were selected at a ratio of 2:1 (n = 148). Cases and controls were compared with respect to maternal and pregnancy characteristics using uni- and multivariable logistic regression models. Main outcome measures were anticipated risk factors for surgical site infection.

RESULTS

The occurrence of surgical site infection was 0.4% and 5.4% after elective and emergency cesarean section, respectively. Compared to women without surgical site infection, women with surgical site infection were almost thrice more obese before pregnancy (OR 2.8, 95% CI 1.2-7.0), four times more likely to have preexisting psychiatric conditions (OR 4.4, 95% CI 1.1-17.6), and five times more likely to receive blood transfusion (OR 5.1, 95% CI 1.4-18.8). Signs of infection during labor was a marginally significant risk factor for surgical site infection (OR 2.0, 95% CI 1.0-5.4).

CONCLUSIONS

Emergency cesarean section was a significant risk factor for surgical site infection. Pregestational obesity, preexisting psychiatric conditions, and blood transfusion during or following delivery, were independent risk factors for surgical site infection. Signs of infection during labor was a marginally significant risk factor. Women with either of these risk factors should be carefully monitored and evaluated for signs of infection in the postpartum period.

Accuracy of hospital-based surveillance systems for surgical site infection after adult spine surgery: A Bayesian latent class analysis

BACKGROUND

Surgical site infections (SSIs) of the spine are morbid and costly complications. An accurate surveillance system is required to properly describe the disease burden and the impact of interventions that mitigate SSI risk. Unfortunately, uniform approaches to conducting SSI surveillance are lacking because of varying SSI case definitions, the lack of a perfect reference case definition and heterogeneous data sources.

AIM

We assessed the accuracy of 4 independent data sources that capture SSIs after spine surgery, with estimation of a measurement error-adjusted SSI incidence.

METHODS

A Bayesian latent class model assessed the sensitivity/specificity of each data source to identify SSI and to estimate a measurement-error adjusted incidence. The four data sources used were: the discharge abstract database (DAD), the National Surgical Quality Improvement Program (NSQIP) database, the Infection Prevention and Control Canada (IPAC) database, and the Spine Adverse Events Severity database.

FINDINGS

A total of 904 patients underwent spine surgery in 2017. The most sensitive data source was DAD (0.799, 95% CrI 0.597, 0.943), while the least sensitive was NSQIP (0.497, 95% CrI 0.308, 0.694). The most specific data source was IPAC (0.997, 95% CrI 0.993, 1.000) and the least specific was DAD (0.969, 95% CrI 0.956, 0.981). The measurement error-adjusted SSI incidence was 0.030 (95% CrI 0.019, 0.045). The crude incidence using the DAD over-estimated the incidence, and the 3 other data sources under-estimated it.

CONCLUSION

SSI surveillance in the spine surgery population is feasible using several data sources, provided that measurement error is considered.

Measuring the impact of varying denominator definitions on standardized antibiotic consumption rates: implications for antimicrobial stewardship programmes

Objectives

To quantify the impact of varying the at-risk days definition on the overall report of at-risk days and on the calculated standardized consumption rates (SCRs) for piperacillin/tazobactam, amikacin, daptomycin and vancomycin.

Methods

Data were evaluated for two system hospitals, an 894 bed academic centre and a 114 bed community hospital. Aggregate inpatient antibiotic administration and occupancy data were extracted from electronic databases at the facility-wide level. Occupancy data were reported from admission-discharge-transfer systems. At-risk days were defined as hospital days present (DP), patient days (PD), persons present (PP) and billing days (BD). Inpatient antimicrobial days of therapy (DOT) across four major antimicrobial agents were used to calculate facility-wide SCRs using each denominator and were evaluated by least-squares regression and R2 values.

Results

Within the 894 bed academic hospital, the average monthly facility-wide days were 28 424, 22 198, 15 957 and 14 789 by the DP, PP, PD and BD definitions, respectively. Within the 114 bed community hospital, the average monthly facility-wide days were 5175, 3523 and 2816 by the DP, PP and PD definitions, respectively. Strong concordance was observed between facility-wide SCRs using the DP and PP definitions in both the academic (R2 = 0.99, y = 0.78x - 0.001) and community (R2 = 0.99, y = 0.68x - 0.03) centres across all four inpatient antibiotics evaluated. In an analysis of piperacillin/tazobactam SCRs, rates were over-predicted by 28%-93% at the facility-wide level across centres using alternative denominators.

Conclusions

We found that data source and definitions of at-risk denominator days meaningfully impact antibiotic SCRs. Centres should carefully consider these potential sources of variation when setting consumption benchmarks and internally evaluating use.

Systematic review of electronic surveillance of infectious diseases with emphasis on antimicrobial resistance surveillance in resource-limited settings

BACKGROUND

Electronic surveillance of infectious diseases involves rapidly collecting, collating, and analyzing vast amounts of data from interrelated multiple databases. Although many developed countries have invested in electronic surveillance for infectious diseases, the system still presents a challenge for resource-limited health care settings.

METHODS

We conducted a systematic review by performing a comprehensive literature search on MEDLINE (January 2000-December 2015) to identify studies relevant to electronic surveillance of infectious diseases. Study characteristics and results were extracted and systematically reviewed by 3 infectious disease physicians.

RESULTS

A total of 110 studies were included. Most surveillance systems were developed and implemented in high-income countries; less than one-quarter were conducted in low-or middle-income countries. Information technologies can be used to facilitate the process of obtaining laboratory, clinical, and pharmacologic data for the surveillance of infectious diseases, including antimicrobial resistance (AMR) infections. These novel systems require greater resources; however, we found that using electronic surveillance systems could result in shorter times to detect targeted infectious diseases and improvement of data collection.

CONCLUSIONS

This study highlights a lack of resources in areas where an effective, rapid surveillance system is most needed. The availability of information technology for the electronic surveillance of infectious diseases, including AMR infections, will facilitate the prevention and containment of such emerging infectious diseases.

Is It Valid to Compare Surgical Site Infections Rates Between Countries? Insights From a Study of English and Norwegian Surveillance Systems

OBJECTIVE

To assess whether differences in surveillance methods or underlying populations significantly influence internationally reported national SSI rates by comparing surveillance data from 2 countries.

DESIGN

Retrospective cohort.

SETTING

England and Norway.

METHODS

We assessed the population under surveillance and surveillance methodology to compare SSI rates in 2 countries (September 2012–January 2015) for 4 surgical categories: coronary artery bypass graft (CABG), colon surgery, cholecystectomy, and hip prosthesis (HPRO). We compared the inpatient SSI incidence using logistic regression, adjusting for the following known risk factors: sex, age, ASA score, wound class, postoperative hospital days, and operation duration. Subsequently, we restricted further analyses to the procedures reported by both countries.

RESULTS

There were important differences in case definitions for superficial infection, so we restricted our analyses to deep incisional and organ-space SSIs. For CABG, the crude odds ratio (OR) for England compared to Norway was 2.4 (95% CI, 1.4–4.4), whereas adjusted OR (aOR) lost significance (aOR, 1.1; 95% CI, 0.57–2.0). For colon surgery the decreased odds (OR, 0.68; 95% CI, 0.56–0.81) remained significant after adjustment (aOR, 0.42; 95% CI, 0.34–0.51). We found no associations for cholecystectomy. For HPRO, the crude OR suggested no significant difference (OR, 1.2; 95% CI, 0.72–2.1), whereas the aOR was significantly lower in England (aOR, 0.45; 95% CI, 0.25–0.81). Including only the subset of procedures reported by both countries yielded comparable results.

CONCLUSION

Differences in case definitions and population under surveillance in the English and Norwegian SSI surveillance systems affected SSI estimates, making the comparison of crude rates unreliable. Standardized definitions and adjustment for established risk factors are essential for European comparisons to guide related public health actions.

Infect Control Hosp Epidemiol 2017;38:162–171