Outcomes of SARS-CoV-2 Omicron Variant Infections Compared With Seasonal Influenza and Respiratory Syncytial Virus Infections in Adults Attending the Emergency Department: A Multicenter Cohort Study

BACKGROUND

There is a controversy over the impact of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections in an era of less virulent variants and an increasing population immunity. We compared outcomes in adults attending the emergency department (ED) with an Omicron, influenza, or respiratory syncytial virus (RSV) infection.

METHODS

Retrospective multicenter cohort study including adults attending the ED in 6 acute care hospitals in Stockholm County, Sweden, with an Omicron, influenza, or RSV infection during 2021-2022 and 2015-2019. During 2021-2022, patients were tested for all 3 viruses by multiplex polymerase chain reaction (PCR) testing. The primary outcome was 30-day all-cause mortality. Secondary outcomes were 90-day all-cause mortality, hospitalization, and intensive care unit (ICU) admission.

RESULTS

A total of 6385 patients from 2021-2022 were included in the main analyses: 4833 Omicron, 1099 influenza, and 453 RSV. The 30-day mortality was 7.9% (n = 381) in the Omicron, 2.5% (n = 28) in the influenza, and 6.0% (n = 27) in the RSV cohort. Patients with Omicron had an adjusted 30-day mortality odds ratio (OR) of 2.36 (95% confidence interval [CI] 1.60-3.62) compared with influenza and 1.42 (95% CI .94-2.21) compared with RSV. Among unvaccinated Omicron patients, stronger associations were observed compared with both influenza (OR 5.51 [95% CI 3.41-9.18]) and RSV (OR 3.29 [95% CI 2.01-5.56]). Similar trends were observed for secondary outcomes. Findings were consistent in comparisons with 5709 pre-pandemic influenza 995 RSV patients.

CONCLUSIONS

In patients attending the ED, infections with Omicron were both more common and associated with more severe outcomes compared with influenza and RSV, in particular among unvaccinated patients.

In-hospital mortality during the wild-type, alpha, delta, and omicron SARS-CoV-2 waves: a multinational cohort study in the EuCARE project

Background

Investigating outcomes of hospitalised COVID-19 patients throughout the pandemic is crucial to understand the impact of different SARS-CoV-2 variants. We compared 28-day in-hospital mortality of Wild-type, Alpha, Delta, and Omicron variant infections. Whether the difference in risk by variant varied by age was also evaluated.

Methods

We conducted a cohort study including patients ≥18 years, hospitalised between 2020 and 02-01 and 2022-10-15 with a SARS-CoV-2 positive test, from nine countries. Variant was classified based on sequenced viruses or from national public metadata. Mortality was compared using the cumulative incidence function and subdistribution hazard ratios (SHR) adjusted for age, sex, calendar time, and comorbidities. Results were shown age-stratified due to effect measure modification (P < 0.0001 for interaction between age and variant).

Findings

We included 38,585 participants: 19,763 Wild-type, 6387 Alpha, 3640 Delta, and 8795 Omicron. The cumulative incidence of mortality decreased throughout the study period. Among participants ≥70 years, the adjusted SHR (95% confidence interval) for Delta vs. Omicron was 1.66 (1.29-2.13). This estimate was 1.66 (1.17-2.36) for Alpha vs. Omicron, and 1.34 (0.92-1.95) for Wild-type vs. Omicron. These were 1.21 (0.81-1.82), 1.21 (0.68-2.17), and 0.98 (0.53-1.82) among unvaccinated participants. When comparing Omicron sublineages, the aSHR for BA.1 was 1.92 (1.43-2.58) compared to BA.2 and 1.52 (1.11-2.08) compared to BA.5.

Interpretation

The herein observed decrease in in-hospital mortality seems to reflect a combined effect of immunity from vaccinations and previous infections, although differences in virulence between SARS-CoV-2 variants may also have contributed.

Funding

European Union's Horizon Europe Research and Innovation Programme.

Outcomes of Pediatric SARS-CoV-2 Omicron Infection vs Influenza and Respiratory Syncytial Virus Infections

This cohort study compares outcomes of SARS-CoV-2 Omicron infection with those of influenza or respiratory syncytial virus infection in pediatric patients attending the emergency department.

Post-COVID-19 Condition After SARS-CoV-2 Infections During the Omicron Surge vs the Delta, Alpha, and Wild Type Periods in Stockholm, Sweden

Little is known about the post-COVID-19 condition (PCC) after infections with different SARS-CoV-2 variants. We investigated the risk of PCC diagnosis after primary omicron infections as compared with preceding variants in population-based cohorts in Stockholm, Sweden. When compared with omicron (n = 215 279, 0.2% receiving a PCC diagnosis), the adjusted hazard ratio (95% CI) was 3.26 (2.80-3.80) for delta (n = 52 182, 0.5% PCC diagnosis), 5.33 (4.73-5.99) for alpha (n = 97 978, 1.0% PCC diagnosis), and 6.31 (5.64-7.06) for the wild type (n = 107 920, 1.3% PCC diagnosis). These findings were consistent across all subgroup analyses except among those treated in the intensive care unit.

Multimodal fine-tuning of clinical language models for predicting COVID-19 outcomes

Clinical prediction models tend only to incorporate structured healthcare data, ignoring information recorded in other data modalities, including free-text clinical notes. Here, we demonstrate how multimodal models that effectively leverage both structured and unstructured data can be developed for predicting COVID-19 outcomes. The models are trained end-to-end using a technique we refer to as multimodal fine-tuning, whereby a pre-trained language model is updated based on both structured and unstructured data. The multimodal models are trained and evaluated using a multicenter cohort of COVID-19 patients encompassing all encounters at the emergency department of six hospitals. Experimental results show that multimodal models, leveraging the notion of multimodal fine-tuning and trained to predict (i) 30-day mortality, (ii) safe discharge and (iii) readmission, outperform unimodal models trained using only structured or unstructured healthcare data on all three outcomes. Sensitivity analyses are performed to better understand how well the multimodal models perform on different patient groups, while an ablation study is conducted to investigate the impact of different types of clinical notes on model performance. We argue that multimodal models that make effective use of routinely collected healthcare data to predict COVID-19 outcomes may facilitate patient management and contribute to the effective use of limited healthcare resources.

Clinical outcomes during and beyond different COVID-19 critical illness variant periods compared with other lower respiratory tract infections

BACKGROUND

It is yet to be better understood how outcomes during and after the critical illness potentially differ between severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants from other lower respiratory tract infections (LRTIs). We aimed to compare outcomes in adults admitted to an intensive care unit (ICU) with coronavirus disease 2019 (COVID-19) during the Wild-type, Alpha, Delta, and Omicron periods with individuals admitted with other LRTI.

METHODS

Population-based cohort study in Stockholm, Sweden, using health registries with high coverage, including ICU-admitted adults from 1 January 2016 to 15 September 2022. Outcomes were in-hospital mortality, 180-day post-discharge mortality, 180-day hospital readmission, 180-day days alive and at home (DAAH), and incident diagnoses registered during follow-up.

RESULTS

The number of ICU admitted individuals were 1421 Wild-type, 551 Alpha, 190 Delta, 223 Omicron, and 2380 LRTI. In-hospital mortality ranged from 28% (n = 665) in the LRTI cohort to 35% (n = 77) in the Delta cohort. The adjusted cause-specific hazard ratio (CSHR) compared with the LRTI cohort was 1.33 (95% confidence interval [CI] 1.16-1.53) in the Wild-type cohort, 1.53 (1.28-1.82) in the Alpha cohort, 1.70 (1.30-2.24) in the Delta cohort, and 1.59 (1.24-2.02) in the Omicron cohort. Among patients discharged alive from their COVID-19 hospitalization, the post-discharge mortality rates were lower (1-3%) compared with the LRTI cohort (9%), and the risk of hospital readmission was lower (CSHRs ranging from 0.42 to 0.68). Moreover, all COVID-19 cohorts had compared with the LRTI cohort more DAAH after compared with before the critical illness.

CONCLUSION

Overall, COVID-19 critical was associated with an increased hazard of in-hospital mortality, but among those discharged alive from the hospital, less severe long-term outcomes were observed compared with other LRTIs.

Sociodemographic disparities affect COVID-19 vaccine uptake in non-elderly adults with increased risk of severe COVID-19

BACKGROUND

There is limited information about sociodemographic disparities in COVID-19 vaccine uptake among non-elderly adults with an increased risk of severe COVID-19. We investigated the COVID-19 vaccine uptake in individuals aged 18-64 years with an increased risk of severe COVID-19 (non-elderly risk group) in Stockholm County, Sweden.

METHOD

We used population-based health and sociodemographic registries with high coverage to perform a cohort study of COVID-19 vaccine uptake of one to four doses up until 21 November 2022. The vaccine uptake in the non-elderly risk group was compared with non-risk groups aged 18-64 years (non-elderly non-risk group) and individuals aged ≥65 years (elderly).

RESULTS

The uptake of ≥3 vaccine doses was 55%, 64% and 87% in the non-elderly non-risk group (n = 1,005,182), non-elderly risk group (n = 308,904) and elderly (n = 422,604), respectively. Among non-elderly risk group conditions, Down syndrome showed the strongest positive association with receiving three doses (adjusted risk ratio [aRR] 1.62, 95% confidence interval [CI] 1.54-1.71), whereas chronic liver disease showed the strongest negative association (aRR 0.90, 95% CI 0.88-0.92). Higher vaccine uptake among the non-elderly risk group was associated with increasing age, being born in Sweden, higher education, higher income and living in a household where other adults had been vaccinated. Similar trends were observed for the first, second, third and fourth doses.

CONCLUSION

These results call for measures to tackle sociodemographic disparities in vaccination programmes during and beyond the COVID-19 pandemic.

Nosocomial SARS-CoV-2 Infections and Mortality During Unique COVID-19 Epidemic Waves

Importance

Quantifying the burden of nosocomial SARS-CoV-2 infections and associated mortality is necessary to assess the need for infection prevention and control measures.

Objective

To investigate the occurrence of nosocomial SARS-CoV-2 infections and associated 30-day mortality among patients admitted to hospitals in Region Stockholm, Sweden.

Design, Setting, and Participants

A retrospective, matched cohort study divided the period from March 1, 2020, until September 15, 2022, into a prevaccination period, early vaccination and pre-Omicron (period 1), and late vaccination and Omicron (period 2). From among 303 898 patients 18 years or older living in Region Stockholm, 538 951 hospital admissions across all hospitals were included. Hospitalized admissions with nosocomial SARS-CoV-2 infections were matched to as many as 5 hospitalized admissions without nosocomial SARS-CoV-2 by age, sex, length of stay, admission time, and hospital unit.

Exposure

Nosocomial SARS-CoV-2 infection defined as the first positive polymerase chain reaction test result at least 8 days after hospital admission or within 2 days after discharge.

Main Outcomes and Measures

Primary outcome of 30-day mortality was analyzed using time-to-event analyses with a Cox proportional hazards regression model adjusted for age, sex, educational level, and comorbidities.

Results

Among 2193 patients with SARS-CoV-2 infections or reinfections (1107 women [50.5%]; median age, 80 [IQR, 71-87] years), 2203 nosocomial SARS-CoV-2 infections were identified. The incidence rate of nosocomial SARS-CoV-2 infections was 1.57 (95% CI, 1.51-1.64) per 1000 patient-days. In the matched cohort, 1487 hospital admissions with nosocomial SARS-CoV-2 infections were matched to 5044 hospital admissions without nosocomial SARS-CoV-2 infections. Thirty-day mortality was higher in the prevaccination period (adjusted hazard ratio [AHR], 2.97 [95% CI, 2.50-3.53]) compared with period 1 (AHR, 2.08 [95% CI, 1.50-2.88]) or period 2 (AHR, 1.22 [95% CI, 0.92-1.60]). Among patients with nosocomial SARS-CoV-2 infections, 30-day AHR comparing those with 2 or more doses of SARS-CoV-2 vaccination and those with less than 2 doses was 0.64 (95% CI, 0.46-0.88).

Conclusions and Relevance

In this matched cohort study, nosocomial SARS-CoV-2 infections were associated with higher 30-day mortality during the early phases of the pandemic and lower mortality during the Omicron variant wave and after the introduction of vaccinations. Mitigation of excess mortality risk from nosocomial transmission should be a strong focus when population immunity is low through implementation of adequate infection prevention and control measures.

EuCARE-hospitalised study protocol: a cohort study of patients hospitalised with COVID-19 in the EuCARE project

BACKGROUND

Severe acute respiratory syndrome coronavirus 2 (SARS CoV-2), the virus responsible for coronavirus disease 2019 (COVID-19), can lead to hospitalisation, particularly in elderly, immunocompromised, and non-vaccinated or partially vaccinated individuals. Although vaccination provides protection, the duration of this protection wanes over time. Additional doses can restore immunity, but the influence of viral variants, specific sequences, and vaccine-induced immune responses on disease severity remains unclear. Moreover, the efficacy of therapeutic interventions during hospitalisation requires further investigation. The study aims to analyse the clinical course of COVID-19 in hospitalised patients, taking into account SARS-CoV-2 variants, viral sequences, and the impact of different vaccines. The primary outcome is all-cause in-hospital mortality, while secondary outcomes include admission to intensive care unit and length of stay, duration of hospitalisation, and the level of respiratory support required.

METHODS

This ongoing multicentre study observes hospitalised adult patients with confirmed SARS-CoV-2 infection, utilising a combination of retrospective and prospective data collection. It aims to gather clinical and laboratory variables from around 35,000 patients, with potential for a larger sample size. Data analysis will involve biostatistical and machine-learning techniques. Selected patients will provide biological material. The study started on October 14, 2021 and is scheduled to end on October 13, 2026.

DISCUSSION

The analysis of a large sample of retrospective and prospective data about the acute phase of SARS CoV-2 infection in hospitalised patients, viral variants and vaccination in several European and non-European countries will help us to better understand risk factors for disease severity and the interplay between SARS CoV-2 variants, immune responses and vaccine efficacy. The main strengths of this study are the large sample size, the long study duration covering different waves of COVID-19 and the collection of biological samples that allows future research.

TRIAL REGISTRATION

The trial has been registered on ClinicalTrials.gov. The unique identifier assigned to this trial is NCT05463380.

Post COVID-19 condition diagnosis: A population-based cohort study of occurrence, associated factors, and healthcare use by severity of acute infection

BACKGROUND

The occurrence and healthcare use trajectory of post COVID-19 condition (PCC) is poorly understood. Our aim was to investigate these aspects in SARS-CoV-2-positive individuals with and without a PCC diagnosis.

METHODS

We conducted a population-based cohort study of adults in Stockholm, Sweden, with a verified infection from 1 March 2020 to 31 July 2021, stratified by the severity of the acute infection. The outcome was a PCC diagnosis registered any time 90-360 days after a positive test. We performed Cox regression models to assess baseline characteristics associated with the PCC diagnosis. Individuals diagnosed with PCC were then propensity-score matched to individuals without a diagnosis to assess healthcare use beyond the acute infection.

RESULTS

Among 204,805 SARS-CoV-2-positive individuals, the proportion receiving a PCC diagnosis was 1% among individuals not hospitalized for their COVID-19 infection, 6% among hospitalized, and 32% among intensive care unit (ICU)-treated individuals. The most common new-onset symptom diagnosis codes among individuals with a PCC diagnosis were fatigue (29%) among nonhospitalized and dyspnea among both hospitalized (25%) and ICU-treated (41%) individuals. Female sex was associated with a PCC diagnosis among nonhospitalized and hospitalized individuals, with interactions between age and sex. Previous mental health disorders and asthma were associated with a PCC diagnosis among nonhospitalized and hospitalized individuals. Among individuals with a PCC diagnosis, the monthly proportion with outpatient care was substantially elevated up to 1 year after acute infection compared to before, with substantial proportions of this care attributed to PCC-related care.

CONCLUSION

The differential association of age, sex, comorbidities, and healthcare use with the severity of the acute infection indicates different trajectories and phenotypes of PCC, with incomplete resolution 1 year after infection.

The association between pre-exposure to glucocorticoids and other immunosuppressant drugs with severe COVID-19 outcomes

OBJECTIVES

Whether preinfection use of immunosuppressant drugs is associated with COVID-19 severity remains unclear. The study was aimed to determine the association between preinfection use of immunosuppressant drugs with COVID-19 outcomes within 1 month after COVID-19 diagnosis.

METHODS

This cohort study included individuals aged ≥18 years with underlying conditions associated with an immunocompromised state and diagnosed with COVID-19 between February 2020 and January 2021 at Karolinska University Hospital, Stockholm. Exposure to immunosuppressant drugs was defined based on dose and duration of drugs (glucocorticoids and drugs included in L01 or L04 chapter of Anatomical Therapeutic Chemical classification) before COVID-19 diagnosis. Outcomes included hospital admission, ICU admission, mechanical ventilation, mortality, renal failure, stroke, pulmonary embolism, and cardiac event. ORs were calculated using logistic regression and baseline covariate adjustment for confounding with inverse probability of treatment weights.

RESULTS

Of 1067 included individuals, 444 were pre-exposed to immunosuppressive treatments before COVID-19 diagnosis (72 high-dose glucocorticoids, 255 L01 drugs (antineoplastics), 198 L04 (other immunosuppressants) and 78 to multiple drugs). There was no association between pre-exposure and hospital admission (OR 0.83, 95% CI 0.64 to 1.09) because of COVID-19. Pre-exposure to L01 or L04 drugs were not associated with hospital admission (adjusted ORs (aORs): 1.23, 0.86 to 1.76 and 1.31, 0.77 to 2.21) or other outcomes. High-dose glucocorticoids (≥20 mg/day prednisolone equivalent) were associated with hospital admission (aOR 2.50, 1.26 to 4.96), cardiac events (aOR 1.93, 1.08 to 3.46), pulmonary embolism (aOR 2.78, 1.08 to 7.15), and mortality (aOR 3.48, 1.77 to 6.86) due to COVID-19.

DISCUSSION

Antineoplastic and other immunosuppressants drugs were not associated with COVID-19 severity whereas high-dose glucocorticoids were associated. Further studies should evaluate the effect of pre-exposure of different dose of glucocorticoids on COVID-19 prognosis.

Association Between Time to Appropriate Antimicrobial Treatment and 30-day Mortality in Patients With Bloodstream Infections: A Retrospective Cohort Study

BACKGROUND

Effective antimicrobial treatment is key for survival in bloodstream infection (BSI), but the impact of timing of treatment remains unclear. Our aim was to assess the association between time to appropriate antimicrobial treatment and 30-day mortality in BSI patients.

METHODS

This was a retrospective cohort study using electronic health record data from a large academic center in Sweden. Adult patients admitted between the years 2012 and 2019, with onset of BSI at the emergency department or general wards, were included. Pathogen-antimicrobial drug combinations were classified as appropriate or inappropriate based on reported in vitro susceptibilities. To avoid immortal time bias, the association between appropriate therapy and mortality was assessed with multivariable logistic regression analysis at pre-specified landmark times.

RESULTS

We included 10 628 BSI-episodes, occurring in 9192 unique patients. The overall 30-day mortality was 11.8%. No association in favor of a protective effect between appropriate therapy and mortality was found at the 1, 3 and 6 hours landmark after blood culture collection. At 12 hours, the risk of death increased with inappropriate treatment (adjusted odds ratio 1.17 [95% confidence interval {CI}, 1.01-1.37]) and continued to increase gradually at 24, 48, and 72 hours. Stratifying by high or low SOFA score generated similar odds ratios, with wider confidence intervals.

CONCLUSIONS

Delays in appropriate antimicrobial treatment were associated with increased 30-day mortality after 12 hours from blood culture collection, but not at 1, 3, and 6 hours, in BSI. These results indicate a benchmark for providing rapid microbiological diagnostics of blood cultures.

Clinical prediction models for mortality in patients with covid-19: external validation and individual participant data meta-analysis

OBJECTIVE

To externally validate various prognostic models and scoring rules for predicting short term mortality in patients admitted to hospital for covid-19.

DESIGN

Two stage individual participant data meta-analysis.

SETTING

Secondary and tertiary care.

PARTICIPANTS

46 914 patients across 18 countries, admitted to a hospital with polymerase chain reaction confirmed covid-19 from November 2019 to April 2021.

DATA SOURCES

Multiple (clustered) cohorts in Brazil, Belgium, China, Czech Republic, Egypt, France, Iran, Israel, Italy, Mexico, Netherlands, Portugal, Russia, Saudi Arabia, Spain, Sweden, United Kingdom, and United States previously identified by a living systematic review of covid-19 prediction models published in The BMJ, and through PROSPERO, reference checking, and expert knowledge.

MODEL SELECTION AND ELIGIBILITY CRITERIA

Prognostic models identified by the living systematic review and through contacting experts. A priori models were excluded that had a high risk of bias in the participant domain of PROBAST (prediction model study risk of bias assessment tool) or for which the applicability was deemed poor.

METHODS

Eight prognostic models with diverse predictors were identified and validated. A two stage individual participant data meta-analysis was performed of the estimated model concordance (C) statistic, calibration slope, calibration-in-the-large, and observed to expected ratio (O:E) across the included clusters.

MAIN OUTCOME MEASURES

30 day mortality or in-hospital mortality.

RESULTS

Datasets included 27 clusters from 18 different countries and contained data on 46 914patients. The pooled estimates ranged from 0.67 to 0.80 (C statistic), 0.22 to 1.22 (calibration slope), and 0.18 to 2.59 (O:E ratio) and were prone to substantial between study heterogeneity. The 4C Mortality Score by Knight et al (pooled C statistic 0.80, 95% confidence interval 0.75 to 0.84, 95% prediction interval 0.72 to 0.86) and clinical model by Wang et al (0.77, 0.73 to 0.80, 0.63 to 0.87) had the highest discriminative ability. On average, 29% fewer deaths were observed than predicted by the 4C Mortality Score (pooled O:E 0.71, 95% confidence interval 0.45 to 1.11, 95% prediction interval 0.21 to 2.39), 35% fewer than predicted by the Wang clinical model (0.65, 0.52 to 0.82, 0.23 to 1.89), and 4% fewer than predicted by Xie et al's model (0.96, 0.59 to 1.55, 0.21 to 4.28).

CONCLUSION

The prognostic value of the included models varied greatly between the data sources. Although the Knight 4C Mortality Score and Wang clinical model appeared most promising, recalibration (intercept and slope updates) is needed before implementation in routine care.

Influence of perioperative SARS-CoV-2 infection on mortality in orthopaedic inpatients with surgically treated traumatic fractures

BACKGROUND

SARS-CoV-2 has had an extensive influence on orthopaedic surgery practice and has been associated with an increased risk of mortality. There is limited evidence of how this pertains to acute orthopaedic surgery with inpatient care.

METHODS

A retrospective cohort study on traumatic fracture patients requiring inpatient care between February 25, 2020 and March 25, 2021 was conducted. Patients were grouped by perioperative SARS-CoV-2 infection, defined as a positive SARS-CoV-2 test from 7 days before to 7 days after orthopaedic surgery, and compared using linear regression and Cox proportional hazards model for primary outcome 30-day mortality and secondary outcome hospital length of stay.

RESULTS

In total, 5174 adults with a length of stay ≥ 48 h and an orthopaedic procedure due to a registered traumatic fracture were admitted from February 25, 2020 and discharged before March 26, 2021. Among the 5174 patients, 65% (3340/5174) were female, 22% (1146/5174) were 60-74 years and 56% (2897/5174) were 75 years or older. In total, 144 (3%) had a perioperative SARS-CoV-2 infection. Perioperative SARS-CoV-2 infection was associated with an increased 30-day mortality (aOR 4.19 [95% CI 2.67-6.43], p < 0.001). The median (IQR) length of stay after surgery was 13 days (IQR 6-21) for patients with, and 7 days (IQR 2-13) for patients without, perioperative SARS-CoV-2 infection.

CONCLUSIONS

Perioperative SARS-CoV-2 infection increased 30-day mortality risk and hospital length of stay for traumatic fracture patients requiring inpatient surgical care. Pre- and postoperative infection were both associated with similar increases in mortality risk.

SARS-CoV-2 testing in patients with low COVID-19 suspicion at admission to a tertiary care hospital, Stockholm, Sweden, March to September 2020

Background

Universal SARS-CoV-2 testing at hospital admission has been proposed to prevent nosocomial transmission.

Aim

To investigate SARS-CoV-2 positivity in patients tested with low clinical COVID-19 suspicion at hospital admission.

Methods

We characterised a retrospective cohort of patients admitted to Karolinska University Hospital tested for SARS-CoV-2 by PCR from March to September 2020, supplemented with an in-depth chart review (16 March–12 April). We compared positivity rates in patients with and without clinical COVID-19 suspicion with Spearman’s rank correlation coefficient. We used multivariable logistic regression to identify factors associated with test positivity.

Results

From March to September 2020, 66.9% (24,245/36,249) admitted patient episodes were tested; of those, 61.2% (14,830/24,245) showed no clinical COVID-19 suspicion, and the positivity rate was 3.2% (469/14,830). There was a strong correlation of SARS-CoV-2 positivity in patients with low vs high COVID-19 suspicion (rho = 0.92; p < 0.001).

From 16 March to 12 April, the positivity rate was 3.9% (58/1,482) in individuals with low COVID-19 suspicion, and 3.1% (35/1,114) in asymptomatic patients. Rates were higher in women (5.0%; 45/893) vs men (2.0%; 12/589; p = 0.003), but not significantly different if pregnant women were excluded (3.7% (21/566) vs 2.2% (12/589); p = 0.09). Factors associated with SARS-CoV-2 positivity were testing of pregnant women before delivery (odds ratio (OR): 2.6; 95% confidence interval (CI): 1.3–5.4) and isolated symptoms in adults (OR: 3.3; 95% CI: 1.8–6.3).

Conclusions

This study shows a relatively high SARS-CoV-2 positivity rate in patients with low COVID-19 suspicion upon hospital admission. Universal SARS-CoV-2 testing of pregnant women before delivery should be considered.

Bacterial co-infections in community-acquired pneumonia caused by SARS-CoV-2, influenza virus and respiratory syncytial virus

Background

A mismatch between a widespread use of broad-spectrum antibiotic agents and a low prevalence of reported bacterial co-infections in patients with SARS-CoV-2 infections has been observed. Herein, we sought to characterize and compare bacterial co-infections at admission in hospitalized patients with SARS-CoV-2, influenza or respiratory syncytial virus (RSV) positive community-acquired pneumonia (CAP).

Methods

A retrospective cohort study of bacterial co-infections at admission in SARS-CoV-2, influenza or RSV-positive adult patients with CAP admitted to Karolinska University Hospital in Stockholm, Sweden, from year 2011 to 2020. The prevalence of bacterial co-infections was investigated and compared between the three virus groups. In each virus group, length of stay, ICU-admission and 30-day mortality was compared in patients with and without bacterial co-infection, adjusting for age, sex and co-morbidities. In the SARS-CoV-2 group, risk factors for bacterial co-infection, were assessed using logistic regression models and creation of two scoring systems based on disease severity, age, co-morbidities and inflammatory markers with assessment of concordance statistics.

Results

Compared to influenza and RSV, the bacterial co-infection testing frequency in SARS-CoV-2 was lower for all included test modalities. Four percent [46/1243 (95% CI 3–5)] of all SARS-CoV-2 patients had a bacterial co-infection at admission, whereas the proportion was 27% [209/775 (95% CI 24–30)] and 29% [69/242 (95% CI 23–35)] in influenza and RSV, respectively. S. pneumoniae and S. aureus constituted the most common bacterial findings for all three virus groups. Comparing SARS-CoV-2 positive patients with and without bacterial co-infection at admission, a relevant association could not be demonstrated nor excluded with regards to risk of ICU-admission (aHR 1.53, 95% CI 0.87–2.69) or 30-day mortality (aHR 1.28, 95% CI 0.66–2.46) in adjusted analyses. Bacterial co-infection was associated with increased inflammatory markers, but the diagnostic accuracy was not substantially different in a scoring system based on disease severity, age, co-morbidities and inflammatory parameters [C statistic 0.66 (95% CI 0.59–0.74)], compared to using disease severity, age and co-morbidities only [C statistic 0.63 (95% CI 0.56–0.70)].

Conclusions

The prevalence of bacterial co-infections was significantly lower in patients with community-acquired SARS-CoV-2 positive pneumonia as compared to influenza and RSV positive pneumonia.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-022-07089-9.

Impact of the COVID-19 pandemic on the incidence and mortality of hospital-onset bloodstream infection: a cohort study

The COVID-19 pandemic burdens hospitals, but consequences for quality of care outcomes such as healthcare-associated infections are largely unknown. This cohort included all adult hospital episodes (n=186 945) at an academic centre between January 2018 and January 2021. Data were collected from the hospitals’ electronic health record data repository. Hospital-onset bloodstream infection (HOB) was defined as any positive blood culture obtained ≥48 hours after admission classified based on microbiological and hospital administrative data. Subgroup analyses were performed with exclusion of potential contaminant bacteria. The cohort was divided into three groups: controls (prepandemic period), non-COVID-19 (pandemic period) and COVID-19 (pandemic period) based on either PCR-confirmed SARS-CoV-2 infections from respiratory samples or International Classification of Diseases 10th Revision diagnoses U071 and U72 at discharge. Adjusted incidence rate ratios (aIRR) and risk of death in patients with HOB were compared between the prepandemic and pandemic periods using Poisson and logistic regression. The incidence of HOB was increased for the COVID-19 group compared with the prepandemic period (aIRR 3.34, 95% CI 2.97 to 3.75). In the non-COVID-19 group, the incidence was slightly increased compared with prepandemic levels (aIRR 1.20, 95% CI 1.08 to 1.32), but the difference decreased when excluding potential contaminant bacteria (aIRR 1.15, 95% CI 1.00 to 1.31, p=0.04). The risk of dying increased for both the COVID-19 group (adjusted odds ratio (aOR) 2.44, 95% CI 1.75 to 3.38) and the non-COVID-19 group (aOR 1.63, 95% CI 1.22 to 2.16) compared with the prepandemic controls. These findings were consistent also when excluding potential contaminants. In summary, we observed a higher incidence of HOB during the COVID-19 pandemic, and the mortality risk associated with HOB was greater, compared with the prepandemic period. Results call for specific attention to quality of care during the pandemic.

Red blood cell blood group A antigen level affects the ability of heparin and PfEMP1 antibodies to disrupt Plasmodium falciparum rosettes

Background

The histo-blood group ABO system has been associated with adverse outcomes in COVID-19, thromboembolic diseases and Plasmodium falciparum malaria. An integral part of the severe malaria pathogenesis is rosetting, the adherence of parasite infected red blood cells (RBCs) to uninfected RBCs. Rosetting is influenced by the host’s ABO blood group (Bg) and rosettes formed in BgA have previously been shown to be more resilient to disruption by heparin and shield the parasite derived surface antigens from antibodies. However, data on rosetting in weak BgA subgroups is scarce and based on investigations of relatively few donors.

Methods

An improved high-throughput flow cytometric assay was employed to investigate rosetting characteristics in an extensive panel of RBC donor samples of all four major ABO Bgs, as well as low BgA expressing samples.

Results

All non-O Bgs shield the parasite surface antigens from strain-specific antibodies towards P. falciparum erythrocyte membrane protein 1 (PfEMP1). A positive correlation between A-antigen levels on RBCs and rosette tightness was observed, protecting the rosettes from heparin- and antibody-mediated disruption.

Conclusions

These results provide new insights into how the ABO Bg system affects the disease outcome and cautions against interpreting the results from the heterogeneous BgA phenotype as a single group in epidemiological and experimental studies.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s12936-021-03975-w.

Clinical phenotypes and outcomes of SARS-CoV-2, influenza, RSV and seven other respiratory viruses: a retrospective study using complete hospital data

Background

An understanding of differences in clinical phenotypes and outcomes COVID-19 compared with other respiratory viral infections is important to optimise the management of patients and plan healthcare. Herein we sought to investigate such differences in patients positive for SARS-CoV-2 compared with influenza, respiratory syncytial virus (RSV) and other respiratory viruses.

Methods

We performed a retrospective cohort study of hospitalised adults and children (≤15 years) who tested positive for SARS-CoV-2, influenza virus A/B, RSV, rhinovirus, enterovirus, parainfluenza viruses, metapneumovirus, seasonal coronaviruses, adenovirus or bocavirus in a respiratory sample at admission between 2011 and 2020.

Results

A total of 6321 adult (1721 SARS-CoV-2) and 6379 paediatric (101 SARS-CoV-2) healthcare episodes were included in the study. In adults, SARS-CoV-2 positivity was independently associated with younger age, male sex, overweight/obesity, diabetes and hypertension, tachypnoea as well as better haemodynamic measurements, white cell count, platelet count and creatinine values. Furthermore, SARS-CoV-2 was associated with higher 30-day mortality as compared with influenza (adjusted HR (aHR) 4.43, 95% CI 3.51 to 5.59), RSV (aHR 3.81, 95% CI 2.72 to 5.34) and other respiratory viruses (aHR 3.46, 95% CI 2.61 to 4.60), as well as higher 90-day mortality, ICU admission, ICU mortality and pulmonary embolism in adults. In children, patients with SARS-CoV-2 were older and had lower prevalence of chronic cardiac and respiratory diseases compared with other viruses.

Conclusions

SARS-CoV-2 is associated with more severe outcomes compared with other respiratory viruses, and although associated with specific patient and clinical characteristics at admission, a substantial overlap precludes discrimination based on these characteristics.

P5537Biomarkers in addition to clinical characteristics for prediction of peripheral artery disease in patients with recent myocardial infarction

Background

Peripheral artery disease (PAD) is associated with increased risk of cardiovascular events and mortality. PAD is underdiagnosed in patients admitted for myocardial infarction (MI).

Purpose

To evaluate whether biomarkers in addition to clinical characteristics could improve the identification of PAD in MI patients.

Methods

Two prospectively observational studies including unselected patients with recent ST-elevation or non-ST elevation MI were used for the analyses. PAD was defined as abnormal ankle brachial indexes (ABI) score (<0.9 or >1.4) on at least one side. The Proximity Extension Assay (PEA) technique was used to simultaneously analyze 92 biomarkers with association to cardiovascular disease (CVD I and III, Olink Proteomics) in samples early after the acute MI. Random forest was used to identify the biomarkers with higher association to PAD. The discriminating accuracy of adding biomarkers to clinical characteristics including age, sex, diabetes mellitus, hypertension and smoking were analyzed by the c-statistic.

Results

In the REBUS cohort (n=420) the mean age was 67 years, 22.1% were women, 26.4% were smoking, 16.2% had diabetes and 53.3% hypertension. In the VAMIS cohort (n=998) the mean age was 71 years, 33.5% were women, 19.9% were smoking, 18.1% and 49.9% had diabetes and hypertension, respectively. PAD was found in 20.0% and 22.8% of the patients in the REBUS and VAMIS cohort, respectively. Six biomarkers associated with PAD (Tnfrsf 14, tnf r2, tnf r1, GDF-15, IL-6 ra, ctsd) were identified in the REBUS cohort and validated in the VAMIS cohort.

Additional predictive value of the biomarkers compared to the performance of the model with clinical characteristics, as measured by the c-statistic Clinical characteristics (CC) CC + Tnfrsf14 CC + Tnf r2 CC + Tnf r1 CC + GDF-15 CC + IL-6 ra CC + ctsd REBUS (n=420) 0.683 (0.610,0.756) 0.702 (0.632, 0.772) 0.703 (0.633, 0.773) 0.709 (0.640, 0.779) 0.710 (0.640, 0.781) 0.682 (0.608, 0.775) 0.683 (0.610, 0.757) VaMIS (n=998) 0.729 (0.687, 0.770) 0.732 (0.691, 0.733) 0.745 (0.704, 0.785) 0.746 (0.706, 0.787) 0.752 (0.711, 0.792) 0.729 (0.688, 0.770) 0.736 (0.695, 0.777) Tnfrsf 14 = tumor necrosis factor receptor superfamily member 14; Tnf r2 = tumor necrosis factor receptor 2; Tnf r1 = tumor necrosis factor receptor 1; GDF-15 = growth differentiation factor 15; IL-6 ra = interleukin-6 receptor subunit alpha; ctsd = Cathepsin D.

Conclusion

Out of a large panel of biomarkers, tumor necrosis factor and its receptors and GDF-15 were identified associated with PAD in MI patients.

In this underdiagnosed manifestation of atherosclerosis in MI patients, clinical characteristics are strong predictors of PAD, but the cytokines may have an additional value. Further studies focusing on more widespread atherosclerosis in acute coronary syndrome might identify a patient group with benefit of treatment targeting inflammation.

Acknowledgement/Funding

None

High plasma leptin levels are associated with impaired diastolic function in patients with coronary artery disease

BACKGROUND AND AIMS

Obese subjects have elevated leptin levels, which have been associated with increased risk of cardiovascular events. Because leptin has direct cellular effects on various tissues, we tested the hypothesis that leptin levels are associated with cardiac structure or function in patients with coronary artery disease (CAD).

METHODS AND RESULTS

The study population consisted of 1 601 CAD patients, of whom 42% had type 2 diabetes mellitus. Plasma leptin was measured in fasted state and an echocardiography performed. Leptin levels were not related to LV dimensions or LV ejection fraction (NS for all), but higher leptin levels were associated with elevated E/E' (9.43 vs. 11.94 in the lowest and the highest leptin quartile, respectively; p=0.018 for trend). Correspondingly, a decreasing trend was observed in E/A (1.15 vs. 1.06; p=0.037). These associations were independent of obesity and other relevant confounding variables.

CONCLUSION

We conclude that elevated plasma leptin levels are associated with impaired left ventricular diastolic function in patients with CAD independently of obesity and other confounding variables. Leptin may be one of the mechanistic links explaining the development of congestive heart failure in obese subjects.

Survival after in-hospital cardiac arrest is highly associated with the Age-combined Charlson Co-morbidity Index in a cohort study from a two-site Swedish University hospital

BACKGROUND

In-hospital cardiac arrest (IHCA) has a poor prognosis and clinicians often write "Do-Not-Attempt-Resuscitation" (DNAR) orders based on co-morbidities.

AIM

To assess the impact of the Age-combined Charlson Co-morbidity Index (ACCI) on 30-days survival after IHCA.

MATERIAL AND METHODS

All patients suffering IHCA at Karolinska University Hospital between 1st January and 31st December 2014 were included. Data regarding patient characteristics, co-morbidities and survival were drawn from the electronic patient records. Co-morbidities were assessed prior to the IHCA as ICD-10 codes according to the ACCI. Differences in survival were assessed with adjusted logistic regression models and presented as Odds Ratios with 95% Confidence Intervals (OR, 95% CI) between patients with an ACCI of 0-4 points versus those with 5-7 points, as well as those with ≥8 points. Adjustments included hospital site, heart rhythm, ECG surveillance, witnessed status and place of IHCA.

RESULTS

In all, 174 patients suffered IHCA, of whom 41 (24%) survived at least 30 days. Patients with an ACCI of 5-7 points had a minor chance and those with an ACCI of ≥8 points had a minimal chance of surviving IHCA compared to those with an ACCI of 0-4 points (adjusted OR 0.10, 95% CI 0.04-0.26 and OR 0.04, 95% CI 0.03-0.42, respectively).

CONCLUSION

Patients with a moderate or severe burden of ACCI have a minor chance of surviving an IHCA. This information could be used as part of the decision tools during ongoing CPR, and could be an aid for clinicians in planning care and discussing DNAR orders.

Serum 25-hydroxyvitamin D is associated with major cardiovascular risk factors and cardiac structure and function in patients with coronary artery disease

BACKGROUND AND AIMS

Vitamin D deficiency has been associated with increased risk for cardiovascular (CV) disease, but the possible effects of Vitamin D on cardiac structure and function are not well characterized.

METHODS AND RESULTS

The correlation between 25-hydroxyvitamin D levels and metabolic and cardiac echocardiographic parameters was studied in ARTEMIS study population including 831diabetic and 659 non-diabetic patients with stable coronary artery disease (CAD). Low levels of Vitamin D were associated with high BMI (p < 0.001), high total and LDL cholesterol and triglyceride levels (p < 0.001 for all) in both diabetics and non-diabetics. Among non-diabetic patients, low Vitamin D was also associated independently with elevated systolic and diastolic blood pressure (p < 0.005). Low Vitamin D levels were independently associated with reduced left ventricular (LV) ejection fraction (p < 0.005) and increased left atrial diameter (p < 0.03) measured by cardiac ultrasound by 2-dimensional echo. In the non-diabetic group, low Vitamin D levels were associated with impaired LV filling (high E/E') (p < 0.03) and low E/A mitral flow pattern measured by Doppler echocardiography (p < 0.05). Among diabetics, low Vitamin D levels were also related to increased LV end-systolic diameter (p < 0.05) and right ventricular diameter (p < 0.005). The association between LV diastolic filling (E/E') and Vitamin D levels was significant (p < 0.01) after adjustment for the commonly recognized risk factors of diastolic dysfunction in linear regression analysis.

CONCLUSIONS

Low Vitamin D is associated with several major cardiovascular risk factors and cardiac structural changes including impaired systolic and diastolic function, which together may explain the association of low Vitamin D to worse cardiovascular outcome.

White blood cell counts associate more strongly to the metabolic syndrome in 75-year-old women than in men: a population based study

BACKGROUND

A positive relation between the metabolic syndrome (MetS) and inflammatory activity has been reported. The purpose of this investigation was to study the relationships between 1) white blood cell (WBC) count and MetS, 2) WBC count and the individual components of MetS and 3) WBC count and insulin sensitivity in 75-year-old women and men from the general population.

METHODS

The study included 200 women and 196 men comprising 64% of the 75-year old people from the city of Västerås in Sweden. MetS was defined according to the National Cholesterol Education Program (NCEP).

RESULTS

WBC count (10(9)/L; median and interquartile range) was 5.7 (4.9-6.8) for women and 6.3 (5.4-7.2) for men, P < .001 for gender difference. For women with and without MetS, WBC count was 6.3 (5.3-7.3) and 5.4(4.7-6.3), respectively. For men the corresponding figures were 6.7 (5.9-7.6) and 6.1 (5.4-7.1).The difference in WBC count between individuals with and without MetS was significant (P < .001 for women; P = .014 for men). All individual components of MetS (with exception of blood pressure) were more strongly associated with WBC count for women than for men. Insulin sensitivity, measured as HOMA-IR (HOmeostasis Model Assessment-Insulin Resistance) index, was significantly associated with WBC count in women but not in men.

CONCLUSIONS

In this elderly population, individuals with MetS had a higher WBC count than those without. Women had a lower WBC count and stronger relationship between WBC count and insulin sensitivity than did men.

Oral, transdermal and vaginal combined contraceptives induce an increase in markers of chronic inflammation and impair insulin sensitivity in young healthy normal-weight women: a randomized study

STUDY QUESTION

What is the effect of alternative administration routes of combined contraceptives (CCs) on androgen secretion, chronic inflammation, glucose tolerance and lipid profile?

SUMMARY ANSWER

The use of oral, transdermal and vaginal CCs impairs glucose tolerance and induces chronic inflammation.

WHAT IS KNOWN AND WHAT THIS PAPER ADDS

Oral CCs worsen insulin sensitivity and are associated with increased levels of circulating inflammatory markers, whereas the metabolic effects of transdermal and vaginal CCs have been reported to be minimal. This is the first study comparing three different administration routes of CCs on metabolic variables.

STUDY DESIGN, SIZE AND DURATION

This randomized (computer-generated) open-label 9-week follow-up study was conducted at the Oulu University Hospital, Finland. Fasting blood samples were collected at baseline and thereafter at 5 and 9 weeks of treatment, and serum levels of 17-hydroxyprogesterone, androstenedione, testosterone, C-reactive protein (CRP), sex hormone-binding globulin (SHBG), glucose, insulin, C-peptide, total, low-density lipoprotein and high-density lipoprotein cholesterol and triglycerides were measured. Oral glucose tolerance tests were performed and plasma levels of pentraxin 3 (PTX-3) were measured at 0 and 9 weeks. The randomization list, with an allocation ratio of 1:1:1 and block size of six, was computer generated and constructed by a pharmacist at the Oulu University Hospital. The research nurse controlled the randomization list and assigned participants to their groups at the first visit.

PARTICIPANTS AND SETTING

Forty-two of 54 healthy women who entered the study used oral contraceptive pills (n = 13), transdermal contraceptive patches (n = 15) or contraceptive vaginal rings (n = 14) continuously for 9 weeks. Inclusion criteria were regular menstrual cycles, at least a 2-month washout as regards hormonal contraceptives and no medication.

MAIN RESULTS AND THE ROLE OF CHANCE

Serum levels of SHBG increased and consequently the free androgen index (FAI) decreased in all study groups from baseline to 9 weeks of treatment [FAI, oral: 1.3 (95% confidence interval, CI: 0.94; 1.62) to 0.40 (0.25; 0.54); transdermal: 1.2 (0.96; 1.4) to 0.36 (0.30; 0.43); vaginal: 1.6 (1.1; 2.1) to 0.43 (0.29; 0.58), P < 0.001 in all groups]. Insulin sensitivity was reduced at 9 weeks in all three groups according to the Matsuda index [oral: 7.3 (5.5; 9.0) to 5.6 (3.9; 7.3); transdermal: 9.1 (6.7; 11.4) to 6.6 (4.5; 8.8); vaginal: 7.7 (5.9; 9.5) to 5.4 (3.9; 7.0), P= 0.004-0.024]. Levels of HDL cholesterol, triglycerides and CRP rose in all three groups [CRP, oral: 0.70 (0.38; 1.0) to 5.4 (1.0; 9.9) mg/l; transdermal: 0.77 (0.45; 1.1) to 2.9 (1.4;4.4) mg/l; vaginal: 0.98 (0.52; 1.4) to 3.7 (-0.25; 7.7, a negative value due to skewed distribution to right) mg/l, P≤ 0.002 in all groups] and PTX-3 levels increased in the oral and transdermal study groups (P = 0.007 and P = 0.002).

WIDER IMPLICATIONS OF THE FINDINGS

Although the long-term consequences of the present results remain undetermined, these findings emphasize the importance of monitoring glucose metabolism during the use of CCs, especially in women with known risks of type 2 diabetes or cardiovascular diseases. BIAS, LIMITATIONS, GENERALIZABILITY: The number of subjects was relatively low. Moreover, the 9-week exposure to CCs is too short to draw conclusions about the long-term health consequences. However, as the subjects were healthy, normal-weight young women, the possible alterations in the glucose and inflammatory profiles among women with known metabolic risks might be even greater.

STUDY FUNDING/COMPETING INTERESTS

This work was supported by grants from the Academy of Finland, the Sigrid Jusélius Foundation, the Finnish Medical Foundation, the Research Foundation of Obstetrics and Gynecology, Oulu University Scholarship Foundation, the North Ostrobothnia Regional Fund of the Finnish Cultural Foundation, the Tyyni Tani Foundation of the University of Oulu and the Finnish-Norwegian Medical Foundation. No competing interests.

TRIAL REGISTRATION NUMBER

NCT01087879.

Cardiac troponin-I as a screening tool for myocarditis in children hospitalized for viral infection

AIM

The incidence of myocarditis in children is uncertain because patients with minor symptoms can remain undiagnosed. We hypothesized that screening all children who are hospitalized for an acute infection with troponin-I (TnI) would reveal myocarditis cases and performed a prospective screening study.

METHODS

Between October 2005 and July 2008, a blood sample for TnI measurement was taken every time a sample for C-reactive protein measurement was drawn. If TnI value was above the screening limit (0.06 microg/L), electrocardiogram (ECG) and cardiac ultrasound were performed. TnI measurements were repeated until at normal level.

RESULTS

Altogether, 1009 children were screened during the 33 months. TnI was above the screening limit (0.06 microg/L) in six children. None of them had any signs of myocarditis in ECG or cardiac ultrasound. Five of those six children were younger than 30 days. All had a respiratory infection as a cause for hospitalization, three of which was caused by RSV. In four children, all younger than 30 days, TnI levels remained high (>0.37 microg/L) for two months, but decreased after that to normal levels.

CONCLUSION

The incidence of myocarditis during viral infections is low and a routine TnI screening for asymptomatic myocarditis is not useful.

Performance evaluation of Abbott CELL-DYN Ruby for routine use

CELL-DYN Ruby is a new automated hematology analyzer suitable for routine use in small laboratories and as a back-up or emergency analyzer in medium- to high-volume laboratories. The analyzer was evaluated by comparing the results from the CELL-DYN((R)) Ruby with the results obtained from CELL-DYN Sapphire . Precision, linearity, and carryover between patient samples were also assessed. Precision was good at all levels for the routine cell blood count (CBC) parameters, CV% being <or=2.6, except for platelet count (PLT) at the low level with CV% of <or=6.9%. The CV% for reticulocyte percentage was highest at the low level (10.4). In a comparative study, the CELL-DYN Ruby results showed a good correlation (R(2) >or= 0.98) with CELL-DYN Sapphire for the CBC parameters. For the absolute reticulocyte count, R(2) was 0.82. In the white blood cell (WBC) differentials, the between-days precision was good for all parameters (CV%: <or=8.0), except basophil percentage and absolute basophil count (CV%: <=or 31.8 and 31.3, respectively). Additionally, in the commercial control sample with the low WBC count (2.5 x 10(9)/l), the precisions in the WBC differentials were <or=16.9%. The cell types that occur in low numbers showed higher CVs, as expected. The methodological comparison of the WBC differential parameters of neutrophils, lymphocytes, and eosinophils showed excellent correlations (R(2) >or= 0.97), and the correlation coefficient for absolute monocyte count and monocyte percentage were 0.91 and 0.87, respectively. For absolute basophil count and basophil percentage the correlations were weaker (R(2) = 0.46 and 0.34, respectively). Carryover was minimal for all the parameters studied. The linearities of WBC, red blood cell, PLTs, and hemoglobin were acceptable within the tested ranges. In conclusion, the results of the evaluation showed the performance of CELL-DYN Ruby to be good.

QTc interval and survival in 75-year-old men and women from the general population

AIMS

The study concerns the relationship of the corrected QT (QTc) interval to 6.4 years of survival and to measures of cardiac function, such as echocardiographic variables and plasma levels of brain natriuretic peptide (BNP), in 75-year-old people.

METHODS AND RESULTS

QTc was measured in a 12-lead electrocardiogram (ECG) in 210 men and 223 women, comprising a randomly selected sample from the general population (70% participation rate). The Sicard 440/740 computer-analysis program, with Hodges' formula for heart rate-based QT correction, was used. The optimal cut-off point for predicting survival according to the receiver operating characteristic curve was found between 429 and 430 ms. Individuals with a QTc interval of > or =430 ms (n = 115) had decreased survival when compared with those with shorter QTc interval (n = 318); the relative risk was 2.4 (95% confidence interval 1.5-3.7). The predictive ability of QTc reflects an association between QTc and the following variables: BNP, left ventricular mass, and left ventricular ejection fraction (but not diastolic filling patterns). Both Hodges' and Bazett's formulae for heart rate correction of the QT interval were useful for predicting survival. The median QTc was 415 ms using Hodges' formula and 430 ms with Bazett's formula. The QRS component of QTc predicted survival better than the rest of the QTc interval and was approximately as useful as the QTc interval itself.

CONCLUSION

The computer-derived QTc obtained from the ordinary 12-lead ECG identifies high-risk individuals among elderly people from the general population.

Evaluation of innotrac aio! Second-generation cardiac troponin I assay: the main characteristics for routine clinical use

The availability of a simple, sensitive, and rapid test using whole blood to facilitate processing and to reduce the turnaround time could improve the management of patients presenting with chest pain. The aim of this study was an evaluation of the Innotrac Aio! second-generation cardiac troponin I (cTnI) assay. The Innotrac Aio! second-generation cTnI assay was compared with the Abbott AxSYM first-generation cTnI, Beckman Access AccuTnI, and Innotrac Aio! first-generation cTnI assays. We studied serum samples from 15 patients with positive rheumatoid factor but with no indication of myocardial infarction (MI). Additionally, the stability of the sample with different matrices and the influence of hemodialysis on the cTnI concentration were evaluated. Within-assay CVs were 3.2%-10.9%, and between-assay precision ranged from 4.0% to 17.2% for cTnI. The functional sensitivity (CV = 20 %) and the concentration giving CV of 10% were approximated to be 0.02 and 0.04, respectively. The assay was found to be linear within the tested range of 0.063-111.6 mu g/L. The correlations between the second-generation Innotrac Aio!, Access, and AxSYM cTnI assays were good (r coefficients 0.947-0.966), but involved differences in the measured concentrations, and the biases were highest with cTnI at low concentrations. The second-generation Innotrac Aio! cTnI assay was found to be superior to the first-generation assay with regard to precision in the low concentration range. The stability of the cTnI level was best in the serum, lithium-heparin plasma, and lithium-heparin whole blood samples (n = 10 , decrease < 10 % in 24 hours at +20( degrees )C and at +4( degrees )C. There was no remarkable influence of hemodialysis on the cTnI release. False-positive cTnI values occurred in the presence of very high rheumatoid factor values, that is, over 3000 U/L. The 99th percentile of the apparently healthy reference group was </= 0.03 mu g/L. The results demonstrate the very good analytical performance of the second-generation Innotrac Aio! cTnI assay.

Highly sensitive determination of C-reactive protein on the Innotrac Aio! immunoanalyzer

C-reactive protein (CRP) is a widely recognized indicator of inflammation. Prospective studies have shown that CRP can be used to predict the risk of future cardiovascular events in apparently healthy subjects. Clinical and laboratory studies have also shown that inflammation has an important role in the inititation, progression and destabilization of atheromas, which makes high-sensitivity CRP determinations valuable in cardiovascular risk assessment. Innotrac Aio! is a fully automated random-access immunoanalyzer using a unique all-in-one (Aio!) dry reagent concept and time-resolved fluorometric detection. In this study, the analytic performance of the Innotrac Aio! ultrasensitive CRP assay (usCRP) was evaluated. The analytical detection limit was 0.003 mg/L, the limit of quantification was <or= 0.03 mg/L and the carry-over result was within acceptable limits. Within-assay CVs obtained in lithium-heparin plasma at five concentrations ranged within 3.2 and 24.9%. Inter-assay precision using lithium-heparin plasma pools and commercial controls was 6.2-8.6% at concentrations of 0.17-33.3 mg/L. The inter-assay precision at a concentration of 0.04 mg/L using the serum pool was 67%. Regression analysis between Aio! usCRP and Cobas Integra CRP latex (Roche Diagnostics) using lithium-heparin plasma samples yielded the following results: correlation coefficient 0.983, slope 1.17 (< 50 mg/L) and correlation coefficient 0.974, slope 1.137 (< 10 mg/L). The correlation coefficient between Integra and Aio! usCRP assays using serum samples was 0.979 and the slope 1.106. Regresssion analysis between Aio! usCRP and Hitachi CRP (Latex) HS using serum samples revealed the following results: correlation coefficient 0.942, slope 0.879 (< 20 mg/L) and correlation coefficient 0.973, slope 0.983 (< 10 mg/L). EDTA whole blood samples correlated well with the corresponding plasma samples. Innotrac Aio! usCRP assay was found to be linear in the CRP concentration range of 0.09-62 mg/L. In the first quartile (0-25th percentile), 2nd quartile (25th-50th percentile), 3rd quartile (50th-75th percentile) and 4th quartile (75th-100th percentile), the mean CRP values were 0.16 mg/L, 0.52 mg/L, 1.24 mg/L and 4.39 mg/L, respectively.

Left ventricular volumes during exercise in endurance athletes assessed by contrast echocardiography

AIM

The objective was to assess left ventricular (LV) volumes at rest and during upright submaximal exercise in endurance athletes to see whether changes in heart volume could explain the large predicted increase in cardiac output in endurance athletes.

METHOD

Contrast echocardiography was used to assess changes in LV volumes during upright bicycle exercise in 24 healthy male endurance athletes. Maximal oxygen uptake and oxygen pulse were measured by using cardiopulmonary exercise testing.

RESULTS

From rest to exercise at a heart rate of 160 beats min(-1) end-diastolic volume increased by 18% (P < 0.001) and end-systolic volume decreased by 21% (P = 0.002). Stroke volume showed an almost linear increase during exercise (45% increase, P < 0.001). The increase in end-diastolic volume contributed to 73% of the increase in stroke volume. No significant differences were observed between stroke volume calculated from LV volumes with contrast echocardiography and stroke volume calculated from oxygen pulse at heart rates of 130 and 160 beats min(-1). Using the linear regression equation between oxygen uptake and cardiac output assessed by echocardiography during exercise (r=0.87, P=0.002), cardiac output at maximal exercise was estimated at 33 +/- 3 L min(-1), with an estimated increase in stroke volume by 69% from rest to maximal exercise.

CONCLUSION

By using contrast echocardiography, a large increase in stroke volume in endurance athletes could be explained by an almost linear increase in end-diastolic volume and an initial small decrease in end-systolic volume during incremental upright exercise.

Analytical performance of time-resolved fluorometry-based Innotrac Aio! cardiac marker immunoassays

The results of an evaluation of the Innotrac Aio! cardiac markers are presented. This system is based on dry-chemistry, time-resolved fluorometry. All assay-specific reagents are dry-coated into assay-specific cups, and only the generic assay buffer is required. The levels of precision attained with pooled serum samples and control materials were acceptable for cTnI and CK-MB. Myoglobin assay showed higher CV, 5.6-9.5%. The linearity studies were performed in concentration ranges of 0.1-76 microg/L for cTnI, 0.7-450 microg/L for CK-MB and 0.6-1500 microg/L for myoglobin. The markers were found to be linear within the ranges tested. The correlation coefficient between the Aio! and AxSYM cTnI assays was 0.960, and the slope was 0.07. The correlation coefficients between the Aio! and AxSYM CK-MB and myoglobin assays were 0.995 and 0.971, respectively. They involved some differences in the measured concentrations (Aio! CK-MB was about 9% higher than AxSYM CK-MB, and Aio! myoglobin was 19% higher than AxSYM). Comparative studies with all the markers, using EDTA whole blood and lithium heparin plasma specimens and lithium heparin whole blood and plasma, yielded the following results: the slopes were close to 1.0 for all correlations, with the exception of that between CK-MB EDTA whole blood and lithium heparin (0.83). High correlation coefficients were obtained (> or = 0.97). The carryover results for all the cardiac markers were good, 0.0%, 0.0%, and 0.3% for cTnI, CK-MB, and myoglobin, respectively. The analytical detection limits were 0.01 microg/L for cTnI, 0.8 microg/L for CK-MB and 0.5 microg/L for myoglobin. The stability of the analytes in the lithium heparin samples at room temperature was also studied and was found to be decreased by from 10% (myoglobin and CK-MB) to 17% (cTnI) in 8 h. Innotrac Aio! provides a rapid and easy quantitative measurement of cardiac TnI, CK-MB, and myoglobin within < 18 min. This system is therefore suitable for use in emergency departments, coronary care units or central laboratory settings.

Left ventricular systolic dysfunction in 75-year-old men and women; a population-based study

AIMS

To determine the prevalence of left ventricular systolic dysfunction in 75-year-old men and women.

METHODS AND RESULTS

In a population-based random sample of 75-year-old subjects (n=433; response rate 70.1%) the left ventricular systolic function was determined using two echocardiographic methods: (1) wall motion in nine left ventricular segments was visually scored and wall motion index was calculated as the mean value of the nine segments and (2) ejection fraction as measured by the disc summation method. Presence of heart failure was determined by a cardiologist's clinical evaluation. Wall motion index was achievable in 95% of the participants while ejection fraction was measurable in 65%. Normal values were obtained from a healthy subgroup (n=108) and left ventricular systolic dysfunction was defined as the 0.5th percentile of the wall motion index (i.e. <1.7). In participants in whom both ejection fraction and wall motion index were achievable, wall motion index <1.7 predicted ejection fraction <43% with a sensitivity and specificity of 84.0% and 99.6%, respectively. The prevalence of left ventricular systolic dysfunction was 6.8% (95% CI, 5.6--8.0%) and was greater in men than in women (10.2% vs 3.4%, P=0.006). Clinical evidence of heart failure was absent in 46% of the participants with left ventricular systolic dysfunction.

CONCLUSIONS

Left ventricular systolic dysfunction is common among 75-year-olds with a prevalence of 6.8% in our estimate. The condition is more likely to affect men than women. In nearly half of 75-year-olds with left ventricular systolic dysfunction there is no clinical evidence of heart failure.

An echocardiographic study of right and left ventricular adaptation to physical exercise in elite female orienteers

BACKGROUND

A considerable body of echocardiographic studies has described how athletic training induces morphological adaptation of the left ventricle in male endurance athletes, but only a few studies have described left ventricular adaptation in female endurance athletes. In contrast to changes in the left ventricle far less attention has been directed towards right ventricular changes due to extensive physical exercise. The purpose of this study was to obtain normal values and to determine if there are any differences in right and left ventricular cavity and wall dimensions between female orienteers and females with a mainly sedentary lifestyle.

METHODS

Echocardiography was performed in 42 highly trained elite female orienteers and 32 healthy female students with a predominantly sedentary lifestyle. The 74 females had no history of cardiac disease, a normal electrocardiogram and showed no echocardiographic abnormalities. M-mode and two-dimensional measurements of the right and left ventricular cavity and wall were obtained in elite orienteers and sedentary females. For the right ventricle and wall, multiple cross-sections were used and measurements were obtained from the right ventricular inflow and outflow tract.

RESULTS

The left ventricular end-diastolic cavity dimension and the left ventricular wall thickness were significantly greater in the athletes compared with the sedentary controls. The right ventricular inflow tract measurements were all significantly greater in the orienteers compared with the controls but the right ventricular outflow tract measurements were comparable in the study groups. The right ventricular wall thickness, calculated as the mean of three different wall measurements was an average of 13% greater in the athletes compared with the sedentary controls.

CONCLUSION

This study suggests symmetrical cardiac enlargement with a concomitant increase in both the right and left ventricular wall, probably reflecting the increased haemodynamic loading in the female athletes.

An echocardiographic study of right ventricular adaptation to physical exercise in elite male orienteers

Considerably more publications appear on left ventricular morphology than on the right ventricle. The reasons for this imbalance are related to the complex shape of the right ventricular cavity and its position beneath the sternum, making imaging, measurement and functional assessment much more complex than the left ventricular chamber. Little attention has been directed towards right ventricular changes because of training, therefore the present study was designed to assess right ventricular changes due to extensive training by comparing cavity and wall dimensions in 29 sedentary men (mean age 23 years) and 82 elite male orienteers (mean age 22 years). The elite orienteers had on average significantly larger right ventricular outflow (10%) and right ventricular inflow (12%) tract 2 and 3 dimensions. The right ventricular wall measurements were on average 13% larger in the orienteers than the sedentary men. The right ventricular enlargement in endurance athletes probably reflects the increased haemodynamic loading that is caused by prolonged and extensive physical training. The thicker right ventricular wall in endurance athletes increases the contractile reserve and decreases wall stress in the right ventricle.

Steroid-involved transcriptional regulation of human genes encoding prostatic acid phosphatase, prostate-specific antigen, and prostate-specific glandular kallikrein

We have compared the steroid regulation of human genes encoding prostatic acid phosphatase (hPAP), prostate-specific antigen (hPSA), and prostate-specific glandular kallikrein (hK2) at the level of transcription. Reporter constructs of hPAP promoter covering the region -734/+467 were functional in both prostatic (LNCaP and PC-3) and nonprostatic (CV-1) cell lines in transient transfections. hPAP -231/+50 with eight identified transcription factor-binding sites showed the highest, and hPAP -734/+467 showed the lowest transcriptional activity in CV-1 cells. The hPAP promoter could not be induced with androgen, glucocorticoid, or progesterone, contrary to the hPSA (-620/+40) and hK2 (-493/+27) promoters in PC-3 cells cotransfected with the respective steroid receptor expression vector. Therefore, steroids cannot directly regulate hPAP gene expression via receptor binding to steroid response elements at -178 and +336, which have been shown to have androgen receptor-binding ability in vitro. Glucocorticoid was the most powerful activator of the hPSA construct at 10-nM steroid concentrations. On the contrary, glucocorticoid stimulation of the transcriptional activity of the hK2 construct was the weakest among the tested steroids. The results indicate that the steroid response elements in the proximal promoters of hPSA and hK2 genes are not androgen specific, offering the molecular basis for the expression of these genes outside the prostate in tissues containing steroid receptors.

Transfecting well-differentiated prostatic cancer cell line LNCaP

The transfection of well-differentiated sensitive cells requires careful optimization of the conditions used. In addition to the transfection method chosen, the amount of cells plated, and thus the density of the cells, as well as the influence of the serum concentration play a critical role in the case of LNCaP cells. We also found out that the only appropriate control plasmid for the transfection efficiency was pCMV beta-gal driven by the cytomegalovirus promoter.

Structural comparison of human and rat prostate-specific acid phosphatase genes and their promoters: identification of putative androgen response elements

Structural comparison of human and rat prostate-specific acid phosphatase (hPAP and rPAP) genes indicate that the exon number is different between these species. The hPAP gene contains 10 exons, whereas the rPAP gene was 11 exons. However, exons 2-9 of the genes are identical in size. The 5' regions of the two genes show 71% identity in the most homologous region +1 to +340. The 5' untranslated regions of the human and rat genes are 50 and 49 nucleotides long, respectively. An Alu sequence is present upstream from the proximal promoter of the hPAP gene. Five putative androgen response elements altogether were localized in both the human and rat gene, one of which is conserved in location and sequence between the two genes. Two of these elements in both genes, the conserved one in the proximal promoter region and another one in intron 1, were shown to bind androgen receptor efficiently in vitro.