Stig Lønberg Nielsen

Decreasing incidence rates of bacteremia: A 9-year population-based study

BACKGROUND Numerous studies have shown that the incidence rate of bacteremia has been increasing over time. However, few studies have distinguished between community-acquired, healthcare-associated and nosocomial bacteremia. METHODS We conducted a population-based study among adults with first-time bacteremia in Funen County, Denmark, during 2000-2008 (N = 7786). We reported mean and annual incidence rates (per 100,000 person-years), overall and by place of acquisition. Trends were estimated using a Poisson regression model. RESULTS The overall incidence rate was 215.7, including 99.0 for community-acquired, 50.0 for healthcare-associated and 66.7 for nosocomial bacteremia. During 2000-2008, the overall incidence rate decreased by 23.3% from 254.1 to 198.8 (3.3% annually, p < .001), the incidence rate of community-acquired bacteremia decreased by 25.6% from 119.0 to 93.8 (3.7% annually, p < .001) and the incidence rate of nosocomial bacteremia decreased by 28.9% from 82.2 to 56.0 (4.2% annually, p < .001). The incidence rate of healthcare-associated bacteremia remained stable. The most common microorganisms were Escherichia coli (28.3%), Staphylococcus aureus (12.3%), coagulase-negative staphylococci (10.0%) and Streptococcus pneumoniae (9.1%). Regardless of place of acquisition, the proportion of bacteremias caused by enterococci increased (p < .05) and the proportion caused by coagulase-negative staphylococci decreased (p < .05). CONCLUSIONS The incidence rates of community-acquired and nosocomial bacteremia decreased substantially over time.

How Well Do Discharge Diagnoses Identify Hospitalised Patients with Community-Acquired Infections? – A Validation Study

Background Credible measures of disease incidence, trends and mortality can be obtained through surveillance using manual chart review, but this is both time-consuming and expensive. ICD-10 discharge diagnoses are used as surrogate markers of infection, but knowledge on the validity of infections in general is sparse. The aim of the study was to determine how well ICD-10 discharge diagnoses identify patients with community-acquired infections in a medical emergency department (ED), overall and related to sites of infection and patient characteristics. Methods We manually reviewed 5977 patients admitted to a medical ED in a one-year period (September 2010-August 2011), to establish if they were hospitalised with community-acquired infection. Using the manual review as gold standard, we calculated the sensitivity, specificity, predictive values, and likelihood ratios of discharge diagnoses indicating infection. Results Two thousand five hundred eleven patients were identified with community-acquired infection according to chart review (42.0%, 95% confidence interval [95%CI]: 40.8–43.3%) compared to 2550 patients identified by ICD-10 diagnoses (42.8%, 95%CI: 41.6–44.1%). Sensitivity of the ICD-10 diagnoses was 79.9% (95%CI: 78.1–81.3%), specificity 83.9% (95%CI: 82.6–85.1%), positive likelihood ratio 4.95 (95%CI: 4.58–5.36) and negative likelihood ratio 0.24 (95%CI: 0.22–0.26). The two most common sites of infection, the lower respiratory tract and urinary tract, had positive likelihood ratios of 8.3 (95%CI: 7.5–9.2) and 11.3 (95%CI: 10.2–12.9) respectively. We identified significant variation in diagnostic validity related to age, comorbidity and disease severity. Conclusion ICD-10 discharge diagnoses identify specific sites of infection with a high degree of validity, but only a moderate degree when identifying infections in general.

Characteristics and Clinical Outcome of Bone and Joint Tuberculosis From 1994 to 2011: A Retrospective Register-based Study in Denmark

BACKGROUND Most information on bone-joint (BJ)-tuberculosis is based on data from high-incidence areas. We conducted a nationwide register-based analysis of BJ-tuberculosis in Denmark from 1994 to 2011. METHODS We linked data from the national tuberculosis surveillance system on BJ-tuberculosis, hospital records, the Danish Hospital and Civil Registration System. RESULTS We identified 282 patients with BJ-tuberculosis, 3.6% of all tuberculosis cases (n = 7936). Spinal tuberculosis was found in 153 of 282 patients (54.3%); 83.3% of all cases were immigrants. Danes were older and had higher Charlson comorbidity index scores than immigrants (P < .01). C-reactive protein and erythrocyte sedimentation rates were elevated in most cases. Median time to diagnosis after first hospital contact was 19.5 days for spinal tuberculosis and 28 days for other forms of BJ-tuberculosis (P = .01). Of patients with spinal tuberculosis, 54/133 (40.6%) had neurologic deficits at admission and 17.3% presented with cauda equina. Diagnosis was culture verified in 87%. (Resistance to any drug was found in 10.2%). Median time on antituberculous treatment for patients with spinal and other forms of BJ-tuberculosis was 9 months and 7 months, respectively (P < .01). Surgery was required in 44.4% patients with spinal tuberculosis and in 32.6% patients with other forms of BJ-tuberculosis (P = .04). Sequelae were reported in 57.5% of patients with spinal tuberculosis and 29.1% of patient with other forms of BJ-tuberculosis (P < .01). One-year mortality was 25.5% among Danes compared with 1.3% among immigrants (P < .01). CONCLUSIONS BJ-tuberculosis was rare and seen mainly in younger immigrants in Denmark. More than half of cases were spinal tuberculosis, presenting with more severe symptoms and worse outcome, compared with other forms of BJ-tuberculosis.

No Specific Time Window Distinguishes between Community-, Healthcare-, and Hospital-Acquired Bacteremia, but They Are Prognostically Robust

OBJECTIVE We examined whether specific time windows after hospital admission reflected a sharp transition between community and hospital acquisition of bacteremia. We further examined whether different time windows to distinguish between community acquisition, healthcare association (HCA), and hospital acquisition influenced the results of prognostic models. DESIGN Population-based cohort study. SETTING Hospitals in 3 areas of Denmark (2.3 million inhabitants) during 2000-2011. METHODS We computed graphs depicting proportions of males, absence of comorbidity, microorganisms, and 30-day mortality pertaining to bacteremia 0, 1, 2, …, 30, and 31 days and later after admission. Next, we assessed whether different admission (0-1, 0-2, 0-3, 0-7 days) and HCA (30, 90 days) time windows were associated with changes in odds ratio (OR) and area under the receiver operating characteristic (ROC) curve for 30-day mortality, adjusting for sex, age, comorbidity, and microorganisms. RESULTS For 56,606 bacteremic episodes, no sharp transitions were detected on a specific day after admission. Among the 8 combined time windows, ORs for 30-day mortality varied from 1.30 (95% confidence interval [CI], 1.23-1.37) to 1.99 (95% CI, 1.48-2.67) for HCA and from 1.36 (95% CI, 1.24-1.50) to 2.53 (95% CI, 2.01-3.20) for hospital acquisition compared with community acquisition. Area under the ROC curve changed marginally from 0.684 (95% CI, 0.679-0.689) to 0.700 (95% CI, 0.695-0.705). CONCLUSIONS No time transitions unanimously distinguished between community and hospital acquisition with regard to sex, comorbidity, or microorganisms, and no difference in 30-day mortality was seen for HCA patients in relation to a 30- or 90-day time window. ORs decreased consistently in the order of hospital acquisition, HCA, and community acquisition, regardless of time window combination, and differences in area under the ROC curve were immaterial.

Seasonal Variation of Escherichia coli , Staphylococcus aureus , and Streptococcus pneumoniae Bacteremia According to Acquisition and Patient Characteristics: A Population-Based Study

OBJECTIVE Seasonal variation is a characteristic of many infectious diseases, but relatively little is known about determinants thereof. We studied the impact of place of acquisition and patient characteristics on seasonal variation of bacteremia caused by the 3 most common pathogens. DESIGN Seasonal variation analysis. METHODS In 3 Danish health regions (2.3 million total inhabitants), patients with bacteremia were identified from 2000 through 2011 using information from laboratory information systems. Analyses were confined to Escherichia coli, Staphylococcus aureus, and Streptococcus pneumoniae. Additional data were obtained from the Danish National Hospital Registry for the construction of admission histories and calculation of the Charlson comorbidity index (CCI). Bacteremias were categorized as community acquired, healthcare associated (HCA), and hospital acquired. We defined multiple subgroups by combining the following characteristics: species, acquisition, age group, gender, CCI level, and location of infection. Assuming a sinusoidal model, seasonal variation was assessed by the peak-to-trough (PTT) ratio with a 95% confidence interval (CI). RESULTS In total, we included 16,006 E. coli, 6,924 S. aureus, and 4,884 S. pneumoniae bacteremia cases. For E. coli, the seasonal variation was highest for community-acquired cases (PTT ratio, 1.24; 95% CI, 1.17-1.32), was diminished for HCA (PTT ratio, 1.14; 95% CI, 1.04-1.25), and was missing for hospital-acquired cases. No seasonal variation was observed for S. aureus. S. pneumoniae showed high seasonal variation, which did not differ according to acquisition (overall PTT ratio, 3.42; 95% CI, 3.10-3.83). CONCLUSIONS Seasonal variation was mainly related to the species although the place of acquisition was important for E. coli. Infect Control Hosp Epidemiol 2016;37:946-953.

Low Completeness of Bacteraemia Registration in the Danish National Patient Registry

Bacteraemia is associated with significant morbidity and mortality and timely access to relia-ble information is essential for health care administrators. Therefore, we investigated the complete-ness of bacteraemia registration in the Danish National Patient Registry (DNPR) containing hospital discharge diagnoses and surgical procedures for all non-psychiatric patients. As gold standard we identified bacteraemia patients in three defined areas of Denmark (~2.3 million inhabitants) from 2000 through 2011 by use of blood culture data retrieved from electronic microbiology databases. Diagnoses coded according to the International Classification of Diseases, version 10, and surgical procedure codes were retrieved from the DNPR. The codes were categorized into seven groups, ranked a priori according to the likelihood of bacteraemia. Completeness was analysed by contin-gency tables, for all patients and subgroups. We identified 58,139 bacteraemic episodes in 48,450 patients; 37,740 episodes (64.9%) were covered by one or more discharge diagnoses within the sev-en diagnosis/surgery groups and 18,786 episodes (32.3%) had a code within the highest priority group. Completeness varied substantially according to speciality (from 17.9% for surgical to 36.4% for medical), place of acquisition (from 26.0% for nosocomial to 36.2% for community), and mi-croorganism (from 19.5% for anaerobic Gram-negative bacteria to 36.8% for haemolytic strepto-cocci). The completeness increased from 25.1% in 2000 to 35.1% in 2011. In conclusion, one third of the bacteraemic episodes did not have a relevant diagnosis in the Danish administrative registry recording all non-psychiatric contacts. This source of information should be used cautiously to iden-tify patients with bacteraemia.

Mortality and prognostic factors of patients who have blood cultures performed in the emergency department: a cohort study.

Background Early identification and treatment of patients with severe infection improve their prognosis. The aims of this study were to describe the 30-day mortality and to identify prognostic factors among blood-cultured patients in a medical emergency department (MED). Patients and methods This was a hospital-based cohort study including all adult (≥15 years old) blood-cultured patients at the MED at Odense University Hospital between 1 August 2009 and 31 August 2011. Results During the study period, 5499/11 988 (45.9%) patients had blood cultures performed within 72 h of arrival and were included in the study. Of those included, 2631 (47.8%) were men, median age 69 years (range 15–103), and 418 (7.6%) were diagnosed with bacteraemia. The overall 30-day mortality among blood-cultured patients was 11.0% (10.2–11.9). In a multivariate Cox regression model, age of more than 80 years [hazard ratio (HR) 4.6 (95% CI 3.6–6.0)], at least two organ failure [HR 3.6 (2.9–4.5)], bacteraemia [HR 1.4 (1.1–1.8)], Charlson Comorbidity Index of at least 2 h [HR 1.7 (1.3–2.0)], SIRS [HR 1.5 (1.2–1.7)], a history of alcohol dependency [HR 1.7 (1.3–2.3)] and late drawing of blood cultures 24–48 h after arrival [HR 1.7 (1.3–2.2)] were found to be prognostic factors of mortality among blood-cultured patients in the MED. Conclusion Among blood-cultured patients in the MED, we found an 11.0% overall 30-day mortality. Factors associated with 30-day mortality were age more than 80 years, at least two organ failure, bacteraemia, Charlson Comorbidity Index of at least 2, SIRS, a history of alcohol dependency and late drawing of blood cultures.

Bacteremic patients in the Emergency Department – how do they present and what is the diagnostic validity of temperature, CRP and SIRS?

Background It might be a clinical challenge to identify patients with bacteremia. Blood cultures are often ordered based on the symptoms of fever and chills. Detailed knowledge of the clinical presentation of acute medical patients will improve the identification of bacteremic patients. The aim of this study was to evaluate the diagnostic value of temperature (°C), C-reactive-protein (CRP), and Systemic Inflammatory Response Syndrome (SIRS) in bacteremic patients admitted to the Medical Emergency Department (ED).