Hege Line Løwer

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.

National surveillance of surgical site infections after coronary artery bypass grafting in Norway: incidence and risk factors

OBJECTIVE A mandatory national surveillance system for surgical site infections (SSIs) following certain surgical procedures, including coronary artery bypass grafting (CABG), was introduced in Norway in 2005. The objectives of this study were to measure national baseline incidence rates of SSIs after CABG, describe the characteristics of the patients and procedures, and identify possible risk factors for infection. METHODS In 2005-2009, all hospitals that performed CABG were invited to assess all patients undergoing CABG surgery in 3-month periods for SSIs. The hospitals evaluated infection status at discharge and 30 days after surgery by sending post-discharge questionnaires to all patients. We calculated incidence proportions and risk ratios for different risk factors. We applied the National Nosocomial Infection Surveillance (NNIS) risk index to the data. RESULTS In total, 2440 patients were included. Altogether, 124 sternal and 217 harvest site infections were registered, giving incidence proportions of 5.1% and 8.9%, respectively. Over 95% of infections occurred post-discharge from the hospital. No risk factors were identified. Incidence did not significantly increase with higher NNIS risk index; however, 93% of the patients fell into the same risk category. CONCLUSIONS We have provided a baseline rate for SSIs after CABG procedures in Norway. The results show the importance of post-hospital discharge follow-up. The NNIS risk index did not adequately stratify CABG patients. We recommend that more potential risk variables should be included in the surveillance, such as the European System for Cardiac Operative Risk Evaluation (EuroSCORE), height, weight, and diabetes.

Infections after caesarean sections

BACKGROUND All hospitals in Norway are required to participate in the Norwegian Surveillance System for Hospital-Acquired Infections (NOIS). Hospitals can choose to have from one to five given surgical procedures under surveillance, caesarean section being one of them. This article describes the incidence of surgical site infections after caesarean sections and identifies causes for such infections. MATERIAL AND METHODS A national protocol, was developed in accordance with the European protocol (HELICS). Patients undergoing a caesarean section (1 September - 30 November in 2005, 2006 or 2007) in the participating hospitals were included and followed-up for 30 days. Cases were identified in accordance to standardised case definitions. Potential risk factors as well as demographic and clinical data were recorded. RESULTS 3900 women were included. 290 infections were diagnosed (incidence 8.3 %) among the 3491 women who were followed up after discharge. Only 14 % of the infections were diagnosed during the hospital stay. Age higher than 29 years and contaminated wound class 3 were significantly associated with infection. Among the 54 women with an organ/space or deep infection, 20 were readmitted to the hospital and 11 were reoperated. INTERPRETATION One of 12 women who undergo a caesarean section develops a surgical site infection. The incidence of infections in Norway is lower than in many other European countries. We recommend hospitals to evaluate the preventive measures implemented at their institution.

Response to letter to the editor regarding: "Surgical site infections after hip arthroplasty in Norway, 2005-2011: Influence of duration and intensity of postdischarge surveillance".

replacement and prosthetic joint infection diagnosis was 284 days (95% CI, 281-286 days) and the median time was 91 days (0-1,631 days). We found that SSI occurred during the first 30 days after the replacement in 30.3% of patients; 40.1% of patients were infected between 1 month and 1 year. Moreover, this hospital discharge cohort model allowed detecting SSI occurring >1 year after joint replacement (29.4%) (unpublished data). The findings reported by Lower et al,1 when compounded with our French results, demonstrate the potential use of passive postdischarge surveillance in SSI after arthroplasty. The hospital information systems covering the entire population allows data analysis and productions of indicators and then benchmarking,7,8 and could be promoted as a cost-effective method for routine infection control surveillance.