Existing data sources for clinical epidemiology: The North Denmark Bacteremia Research Database

Bacteremia is associated with high morbidity and mortality. Improving prevention and treatment requires better knowledge of the disease and its prognosis. However, in order to study the entire spectrum of bacteremia patients, we need valid sources of information, prospective data collection, and complete follow-up. In North Denmark Region, all patients diagnosed with bacteremia have been registered in a population-based database since 1981. The information has been recorded prospectively since 1992 and the main variables are: the patient’s unique civil registration number, date of sampling the first positive blood culture, date of admission, clinical department, date of notification of growth, place of acquisition, focus of infection, microbiological species, antibiogram, and empirical antimicrobial treatment. During the time from 1981 to 2008, information on 22,556 cases of bacteremia has been recorded. The civil registration number makes it possible to link the database to other medical databases and thereby build large cohorts with detailed longitudinal data that include hospital histories since 1977, comorbidity data, and complete follow-up of survival. The database is suited for epidemiological research and, presently, approximately 60 studies have been published. Other Danish departments of clinical microbiology have recently started to record the same information and a population base of 2.3 million will be available for future studies

Nationwide trends in pneumonia hospitalization rates and mortality, Denmark 1997–2011

SummaryObjectiveTo provide up-to-date population-based data on nationwide trends in pneumonia hospitalization rates and associated 30-day mortality.MethodsUsing medical databases we identified all in-hospital episodes of pneumonia between 1997 and 2011. We computed age- and sex-standardized hospitalization rates of total and first-time pneumonia-related hospitalization and adjusted 30-day mortality rates by calendar year.ResultsAmong 552,528 pneumonia-related hospitalizations in Denmark between 1997 and 2011, 385,985 (69.9%) were first-time events. Total pneumonia hospitalizations increased by 63%, from 4.96 per 1000 population in 1997 to 8.09 in 2011. Rates of first-time pneumonia per 1000 population increased by 33%, from 3.99 in 1997 to 5.31 in 2011. Pneumonia rates stabilized in the mid-00s but primary pneumonia rates increased 16% from 2008 to 2011, most notably among children and young adults. In patients aged ≥80 years the rate of hospitalizations with secondary pneumonia more than doubled during the study period. Average 30-day mortality remained stable at 13%, but increased slightly over time in patients aged ≥80 years.ConclusionsIn an era of smoking cessation and vaccination efforts, pneumonia hospitalization rates are continuously increasing, largely driven by secondary diagnoses and recurrent pneumonia episodes in elderly patients. Thirty-day mortality remains persistently high

Design of a tablet computer app for facilitation of a molecular blood culture test in clinical microbiology and preliminary usability evaluation

BACKGROUND: User mobility is an important aspect of the development of clinical information systems for health care professionals. Mobile phones and tablet computers have obtained widespread use by health care professionals, offering an opportunity for supporting the access to patient information through specialized applications (apps) while supporting the mobility of the users. The use of apps for mobile phones and tablet computers may support workflow of complex tasks, for example, molecular-based diagnostic tests in clinical microbiology. Multiplex Blood Culture Test (MuxBCT) is a molecular-based diagnostic test used for rapid identification of pathogens in positive blood cultures. To facilitate the workflow of the MuxBCT, a specialized tablet computer app was developed as an accessory to the diagnostic test. The app aims to reduce the complexity of the test by step-by-step guidance of microscopy and to assist users in reaching an exact bacterial or fungal diagnosis based on blood specimen observations and controls. Additionally, the app allows for entry of test results, and communication thereof to the laboratory information system (LIS). OBJECTIVE: The objective of the study was to describe the design considerations of the MuxBCT app and the results of a preliminary usability evaluation. METHODS: The MuxBCT tablet app was developed and set up for use in a clinical microbiology laboratory. A near-live simulation study was conducted in the clinical microbiology laboratory to evaluate the usability of the MuxBCT app. The study was designed to achieve a high degree of realism as participants carried out a scenario representing the context of use for the MuxBCT app. As the MuxBCT was under development, the scenario involved the use of molecular blood culture tests similar to the MuxBCT for identification of microorganisms from positive blood culture samples. The study participants were observed, and their interactions with the app were recorded. After the study, the participants were debriefed to clarify observations. RESULTS: Four medical laboratory technicians, for example, representative of end users of the app, participated in the clinical simulation study. Using the MuxBCT app, the study participants successfully identified and reported all microorganisms from the positive blood cultures examined. Three of the four participants reported that they found the app useful, while one study participant reported that she would prefer to make notes on paper and later enter them into the LIS. CONCLUSIONS: The preliminary usability evaluation results indicate that use of the MuxBCT tablet app can facilitate the workflow of the MuxBCT diagnostic test

‘All in a box’ a concept for optimizing microbiological diagnostic sampling in prosthetic joint infections

BACKGROUND: Accurate microbial diagnosis is crucial for effective management of prosthetic joint infections. Culturing of multiple intraoperative tissue samples has increased diagnostic accuracy, but new preparatory techniques and molecular methods hold promise of further improvement. The increased complexity of sampling is, however, a tough challenge for surgeons and assistants in the operation theatre, and therefore we devised and tested a new concept of pre-packed boxes with a complete assortment of swabs, vials and additional tools needed in the operating theatre for non-standard samples during a clinical study of prosthetic joint infections. FINDINGS: The protocol for the clinical study required triplicate samples of joint fluid, periprosthetic tissue, bone tissue, and swabs from the surface of the prosthesis. Separate boxes were prepared for percutaneous joint puncture and surgical revision; the latter included containers for prosthetic components or the entire prosthesis. During a 2-year project period 164 boxes were used by the surgeons, 98 of which contained a complete set of samples. In all, 1508 (89%) of 1685 scheduled samples were received. CONCLUSION: With this concept a high level of completeness of sample sets was achieved and thus secured a valid basis for evaluation of new diagnostics. Although enthusiasm for the project may have been a contributing factor, the extended project period suggests that the ‘All in a box’ concept is equally applicable in routine clinical settings with standardized but complex diagnostic sampling

Classification of positive blood cultures:computer algorithms versus physicians' assessment - development of tools for surveillance of bloodstream infection prognosis using population-based laboratory databases

BACKGROUND: Information from blood cultures is utilized for infection control, public health surveillance, and clinical outcome research. This information can be enriched by physicians’ assessments of positive blood cultures, which are, however, often available from selected patient groups or pathogens only. The aim of this work was to determine whether patients with positive blood cultures can be classified effectively for outcome research in epidemiological studies by the use of administrative data and computer algorithms, taking physicians’ assessments as reference. METHODS: Physicians’ assessments of positive blood cultures were routinely recorded at two Danish hospitals from 2006 through 2008. The physicians’ assessments classified positive blood cultures as: a) contamination or bloodstream infection; b) bloodstream infection as mono- or polymicrobial; c) bloodstream infection as community- or hospital-onset; d) community-onset bloodstream infection as healthcare-associated or not. We applied the computer algorithms to data from laboratory databases and the Danish National Patient Registry to classify the same groups and compared these with the physicians’ assessments as reference episodes. For each classification, we tabulated episodes derived by the physicians’ assessment and the computer algorithm and compared 30-day mortality between concordant and discrepant groups with adjustment for age, gender, and comorbidity. RESULTS: Physicians derived 9,482 reference episodes from 21,705 positive blood cultures. The agreement between computer algorithms and physicians’ assessments was high for contamination vs. bloodstream infection (8,966/9,482 reference episodes [96.6%], Kappa = 0.83) and mono- vs. polymicrobial bloodstream infection (6,932/7,288 reference episodes [95.2%], Kappa = 0.76), but lower for community- vs. hospital-onset bloodstream infection (6,056/7,288 reference episodes [83.1%], Kappa = 0.57) and healthcare-association (3,032/4,740 reference episodes [64.0%], Kappa = 0.15). The 30-day mortality in the discrepant groups differed from the concordant groups as regards community- vs. hospital-onset, whereas there were no material differences within the other comparison groups. CONCLUSIONS: Using data from health administrative registries, we found high agreement between the computer algorithms and the physicians’ assessments as regards contamination vs. bloodstream infection and monomicrobial vs. polymicrobial bloodstream infection, whereas there was only moderate agreement between the computer algorithms and the physicians’ assessments concerning the place of onset. These results provide new information on the utility of computer algorithms derived from health administrative registries

Utility of (11)C-methionine and (11)C-donepezil for imaging of Staphylococcus aureus induced osteomyelitis in a juvenile porcine model:comparison to autologous (111)In-labelled leukocytes, (99m) Tc-DPD, and (18)F-FDG

The aim of this study was to compare (11)C-methionine and (11)C-donepezil positron emission tomography (PET) with (111)In-labeled leukocyte and (99m)Tc-DPD (Tc-99m 3,3-diphosphono-1,2-propanedicarboxylic acid) single-photon emission computed tomography (SPECT), and (18)F-fluorodeoxyglucose ((18)F-FDG) PET to improve detection of osteomyelitis. The tracers’ diagnostic utility where tested in a juvenile porcine hematogenously induced osteomyelitis model comparable to osteomyelitis in children. Five 8-9 weeks old female domestic pigs were scanned seven days after intra-arterial inoculation in the right femoral artery with a porcine strain of Staphylococcus aureus. The sequential scan protocol included Computed Tomography, (11)C-methionine and (11)C-donepezil PET, (99m)Tc-DPD and (111)In-labelled leukocytes scintigraphy, and (18)F-FDG PET. This was followed by necropsy of the pigs and gross pathology, histopathology, and microbial examination. The pigs developed a total of 24 osteomyelitic lesions, 4 lesions characterized as contiguous abscesses and pulmonary abscesses (in two pigs). By comparing the 24 osteomyelitic lesions, (18)F-FDG accumulated in 100%, (111)In-leukocytes in 79%, (11)C-methionine in 79%, (11)C-donepezil in 58%, and (99m)Tc-DPD in none. Overall, (18)F-FDG PET was superior to (111)In-leukocyte SPECT and (11)C-methionine in marking infectious lesions

Partner Bereavement and Risk of Herpes Zoster: Results from Two Population-Based Case-Control Studies in Denmark and the United Kingdom.

Background: Psychological stress is commonly thought to increase the risk of herpes zoster by causing immunosuppression. However, epidemiological studies on the topic are sparse and inconsistent. We conducted 2 parallel case-control studies of the association between partner bereavement and risk of zoster using electronic healthcare data covering the entire Danish population and general practices in the UK Clinical Practice Research Datalink. Methods: We included patients with a zoster diagnosis from the primary care or hospital-based setting in 1997-2013 in Denmark (n = 190671) and 2000-2013 in the United Kingdom (n = 150207). We matched up to 4 controls to each case patient by age, sex, and general practice (United Kingdom only) using risk-set sampling. The date of diagnosis was the index date for case patients and their controls. We computed adjusted odds ratios with 99% confidence intervals for previous bereavement among case patients versus controls using conditional logistic regression with results from the 2 settings pooled using random-effects meta-analysis. Results: Overall, the adjusted odds ratios for the association between partner bereavement and zoster were 1.05 (99% confidence interval, 1.03-1.07) in Denmark and 1.01 (.98-1.05) in the United Kingdom. The pooled estimates were 0.72, 0.90, 1.10, 1.08, 1.02, 1.04, and 1.03 for bereavement within 0-7, 8-14, 15-30, 31-90, 91-365, 366-1095, and >1095 days before the index date, respectively. Conclusions: We found no consistent evidence of an increased risk of zoster after partner death. Initial fluctuations in estimates may be explained by delayed healthcare contact due to the loss

Salmonella enterica bacteraemia: a multi-national population-based cohort study

<p>Abstract</p> <p>Background</p> <p><it>Salmonella enterica </it>is an important emerging cause of invasive infections worldwide. However, population-based data are limited. The objective of this study was to define the occurrence of <it>S. enterica </it>bacteremia in a large international population and to evaluate temporal and regional differences.</p> <p>Methods</p> <p>We conducted population-based laboratory surveillance for all salmonella bacteremias in six regions (annual population at risk 7.7 million residents) in Finland, Australia, Denmark, and Canada during 2000-2007.</p> <p>Results</p> <p>A total of 622 cases were identified for an annual incidence of 1.02 per 100,000 population. The incidence of typhoidal (serotypes Typhi and Paratyphi) and non-typhoidal (other serotypes) disease was 0.21 and 0.81 per 100,000/year. There was major regional and moderate seasonal and year to year variability with an increased incidence observed in the latter years of the study related principally to increasing rates of non-typhoidal salmonella bacteremias. Advancing age and male gender were significant risk factors for acquiring non-typhoidal salmonella bacteremia. In contrast, typhoidal salmonella bacteremia showed a decreasing incidence with advancing age and no gender-related excess risk.</p> <p>Conclusions</p> <p><it>Salmonella enterica </it>is an important emerging pathogen and regional determinants of risk merits further investigation.</p