Methods to estimate proportion and number of nonexposed cases in a population

National mortality statistics commonly provide disease-specific absolute and relative frequencies of death by sex and age, but not by exposure status. However, it is often of interest to know how many of the diseased individuals, that is the cases, were exposed or not exposed to a specific risk factor. We present two methods to estimate the proportion and the number of exposed and nonexposed cases, both of which require an estimate of the exposure prevalence in the nondiseased population. Method I additionally requires an estimate of the relative effect of exposure, that is a relative risk function if the exposure has a continuous distribution, or a relative risk estimate for each category if the exposure is categorical. Method II additionally requires an estimate of the disease rate among the nonexposed. We provide theoretical justifications, discuss practical limitations, and provide an R script to calculate the probability for nonexposure among the diseased, and compare the approaches. Both methods are subsequently applied to the estimation of the number of never smokers among lung cancer deaths. The two suggested methods rely on the availability of specific data sources and might therefore be applicable in different research settings. Both methods yield unbiased estimates of the number of nonexposed cases, given that the respective underlying assumptions are fulfilled

Spatio‐temporal trends in caries: A study on children in Berlin‐Mitte

Background: Significant inequalities in caries distribution among children in Germany have been reported, but small-scale areas remain understudied. Aim: To examine spatio-temporal trends in children's dental caries at the small-area level in Berlin-Mitte. Design: Routinely collected data from Berlin's annual Health Examination Surveys were used, which also include information on age, sex, country of origin, and residential area. The study population consists of 14,866 children aged 5 to 7 between 2006 and 2014 in the district of Berlin-Mitte. Outcome variables are the dmft (decayed, missing, and filled teeth), the presence of any caries experience, untreated caries, and caries risk. The outcomes are summarized descriptively and graphically presented for 10 quarters and 41 communities within Berlin-Mitte. Results: Relevant gaps in children's dental caries were discovered between the quarters of Mitte. Three quarters in the northeast part of Mitte have consistently indicated the lowest oral health status in all four outcomes, and children having high caries risk have been increasingly concentrating in this area over time. Despite the continuous improvements in the southern part, the averages in total of Mitte for all outcomes have risen. Conclusion: Our findings confirm the spatiotemporally mounting disparities in children's oral health between the quarters in Berlin-Mitte and that particular quarters need urgent attention. The small-area approach made it easier and more effective to reveal the spatial distribution of children's dental caries at the local level. The small-area analysis should be strongly encouraged in future caries research to narrow the inequalities in children's oral health

HIT-6 and EQ-5D-5L in patients with migraine: assessment of common latent constructs and development of a mapping algorithm

Objective: The aims of this study were to assess whether there is a conceptual overlap between the questionnaires HIT-6 and EQ-5D and to develop a mapping algorithm allowing the conversion of HIT-6 to EQ-5D utility scores for Germany. Methods: This study used data from an ongoing randomised controlled trial for patients suffering from migraine. We assessed the conceptual overlap between the two instruments with correlation matrices and exploratory factor analysis. Linear regression, tobit, mixture, and two-part models were used for mapping, accounting for repeated measurements, tenfold cross-validation was conducted to validate the models. Results: We included 1010 observations from 410 patients. The EQ-5D showed a substantial ceiling effect (47.3% had the highest score) but no floor effect, while the HIT-6 showed a very small ceiling effect (0.5%). The correlation between the instruments' total scores was moderate (- 0.30), and low to moderate among each domain (0.021-0.227). The exploratory factor analysis showed insufficient conceptual overlap between the instruments, as they load on different factors. Thus, there is reason to believe that the instruments' domains do not capture the same latent constructs. To facilitate future mapping, we provide coefficients and a variance-covariance matrix for the preferred model, a two-part model with the total HIT-6 score as the explanatory variable. Conclusion: This study showed that the German EQ-5D and the HIT-6 lack the conceptual overlap needed for appropriate mapping. Thus, the estimated mapping algorithms should only be used as a last resort for estimating utilities to be employed in economic evaluations

25 years of experience with transjugular intrahepatic portosystemic shunt (TIPS): changes in patient selection and procedural aspects

Background: TIPS is an established treatment for portal hypertension. The aim was to analyze how patient selection for TIPS implantation and procedural aspects have changed over 25 years. Routinely collected demographic, clinical, laboratory, and procedural data of 835 patients treated with TIPS in a single center were used. Time trends over the observational period from 1993 to 2018 were retrospectively analyzed. Descriptive statistical analysis was performed. Results: The most common indication for TIPS implantation has changed significantly from secondary prevention of variceal hemorrhage in the early years to treatment of recurrent ascites. During the observation period, increasingly more severely ill patients became TIPS candidates. There was little change in MELD scores over this period (in total median 13.00; IQR 10.00-18.00). The proportion of patients with Child-Pugh C cirrhosis increased. The most frequent underlying diseases in total were alcohol-related liver disease (66.5%) and viral hepatitis (11.9%). However, shares of cryptogenic liver cirrhosis, autoimmune hepatitis, and NASH increased over time. The proportion of patients post liver transplant also increased. While bare metal stents were standard in the past, use of covered stents increased. The success rate of TIPS (defined by successful implantation and a decrease in the portosystemic pressure gradient <= 12 mmHg) increased significantly over time. The total success rate according to this definition was 84.9%. Conclusion: The results of our analysis reflect technical developments in TIPS, especially in terms of stent material and gains in clinical experience, particularly regarding indications and patient selection for TIPS implantation

CT-Based Risk Stratification for Intensive Care Need and Survival in COVID-19 Patients—A Simple Solution

We evaluated a simple semi-quantitative (SSQ) method for determining pulmonary involvement in computed tomography (CT) scans of COVID-19 patients. The extent of lung involvement in the first available CT was assessed with the SSQ method and subjectively. We identified risk factors for the need of invasive ventilation, intensive care unit (ICU) admission and for time to death after infection. Additionally, the diagnostic performance of both methods was evaluated. With the SSQ method, a 10% increase in the affected lung area was found to significantly increase the risk for need of ICU treatment with an odds ratio (OR) of 1.68 and for invasive ventilation with an OR of 1.35. Male sex, age, and pre-existing chronic lung disease were also associated with higher risks. A larger affected lung area was associated with a higher instantaneous risk of dying (hazard ratio (HR) of 1.11) independently of other risk factors. SSQ measurement was slightly superior to the subjective approach with an AUC of 73.5% for need of ICU treatment and 72.7% for invasive ventilation. SSQ assessment of the affected lung in the first available CT scans of COVID-19 patients may support early identification of those with higher risks for need of ICU treatment, invasive ventilation, or death

Diagnostic Value of Initial Chest CT Findings for the Need of ICU Treatment/Intubation in Patients with COVID-19

Computed tomography (CT) plays an important role in the diagnosis of COVID-19. The aim of this study was to evaluate a simple, semi-quantitative method that can be used for identifying patients in need of subsequent intensive care unit (ICU) treatment and intubation. We retrospectively analyzed the initial CT scans of 28 patients who tested positive for SARS-CoV-2 at our Level-I center. The extent of lung involvement on CT was classified both subjectively and with a simple semi-quantitative method measuring the affected area at three lung levels. Competing risks Cox regression was used to identify factors associated with the time to ICU admission and intubation. Their potential diagnostic ability was assessed with receiver operating characteristic (ROC)/area under the ROC curves (AUC) analysis. A 10% increase in the affected lung parenchyma area increased the instantaneous risk of intubation (hazard ratio (HR) = 2.00) and the instantaneous risk of ICU admission (HR 1.73). The semi-quantitative measurement outperformed the subjective assessment diagnostic ability (AUC = 85.6% for ICU treatment, 71.9% for intubation). This simple measurement of the involved lung area in initial CT scans of COVID-19 patients may allow early identification of patients in need of ICU treatment/intubation and thus help make optimal use of limited ICU/ventilation resources in hospitals

Changes of radiological examination volumes over the course of the COVID-19 pandemic: a comprehensive analysis of the different waves of infection

Objectives: Data from radiological departments provide important information on overall quantities of medical care provided. With this study we used a comprehensive analysis of radiological examinations as a surrogate marker to quantify the effect of the different COVID-19 waves on medical care provided. Methods: Radiological examination volumes during the different waves of infection were compared among each other as well as to time-matched control periods from pre-pandemic years using a locally weighted scatterplot smoothing as well as negative binominal regression models. Results: A total of 1,321,119 radiological examinations were analyzed. Examination volumes were reduced by about 10% over the whole study period (IRR = 0.90; 95% CI 0.89-0.92), with a focus on acute medical care (0.84; 0.83-0.85) and outpatients (0.93: 0.90-0.97). When compared to wave 1, examination volumes were about 17% higher during wave 2 (1.17; 1.10-1.25), and 33% higher in wave 3 of the pandemic (1.33; 1.24-1.42). Conclusions: This study shows the severe effect of COVID-19 pandemic and related shutdown measures on overall provided medical care as measured by radiological examinations. When compared, the decrease of medical care was more pronounced in the earlier waves of the pandemic

Association between infectious burden, socioeconomic status, and ischemic stroke

Background and aims: Infectious diseases contribute to stroke risk, and are associated with socioeconomic status (SES). We tested the hypotheses that the aggregate burden of infections increases the risk of ischemic stroke (IS) and partly explains the association between low SES and ischemic stroke. Methods: In a case-control study with 470 ischemic stroke patients and 809 age- and sex-matched controls, randomly selected from the population, antibodies against the periodontal microbial agents Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis, against Chlamydia pneumonia, Mycoplasma pneumoniae (IgA and IgG), and CagA-positive Helicobacter pylori (IgG) were assessed. Results: IgA seropositivity to two microbial agents was significantly associated with IS after adjustment for SES (OR 1.45 95% CI 1.01-2.08), but not in the fully adjusted model (OR 1.32 95% CI 0.86-2.02). By trend, cumulative IgA seropositivity was associated with stroke due to large vessel disease (LVD) after full adjustment (OR 1.88, 95% CI 0.96e3.69). Disadvantageous childhood SES was associated with higher cumulative seropositivity in univariable analyses, however, its strong impact on stroke risk was not influenced by seroepidemiological data in the multivariable model. The strong association between adulthood SES and stroke was rendered nonsignificant when factors of dental care were adjusted for. Conclusions: Infectious burden assessed with five microbial agents did not independently contribute to ischemic stroke consistently, but may contribute to stroke due to LVD. High infectious burden may not explain the association between childhood SES and stroke risk. Lifestyle factors that include dental negligence may contribute to the association between disadvantageous adulthood SES and stroke. (C) 2016 Elsevier Ireland Ltd. All rights reserved.Peer reviewe

Socioeconomic decline and advancement within and between generations and the risk of stroke - a case-control study

Background: Disadvantageous socioeconomic conditions (SEC) in both childhood and adulthood increase the risk of stroke. We investigated whether intergenerational and lifetime social advancement decreases and/or social descent increases stroke risk. Methods: In a case-control study with 466 patients with first-ever ischemic stroke and 807 controls randomly selected from the general population, we compared paternal profession to subjects’ professional education in adolescence and their last profession in adulthood. Furthermore, we constructed a socioeconomic risk score for childhood (based on paternal and maternal profession and occupation, familial, living and material conditions), adolescence (based on highest school degree and professional education), and adulthood (based on last profession, periods of unemployment, and marital status), and compared subjects´ positions at different life stages. Odds ratios were derived based on conditional logistic regression conditioning on age and sex only, after adjustment for medical and lifestyle risk factors, and after additional adjustment for socioeconomic risk score values. Results: Intergenerational upward mobility between paternal profession and subject’s professional education was associated with lower ischemic stroke risk independent of medical and lifestyle risk factors (odds ratio (OR) 0.58; 95% confidence interval (CI) 0.41–0.81) and after additional adjustment for socioeconomic conditions in all three life stages (OR 0.67; 95% CI 0.45–0.99). Advancement between fathers´ profession and subject’s last profession was associated with reduced odds of stroke after adjustment for risk factors (OR 0.65; 95% CI 0.47–0.89), but not significantly after additional adjustment for SEC (OR 0.77; 95% CI 0.52–1.13). Social descent between adolescence and adulthood indicated by the transition into a more disadvantageous tertile of socioeconomic risk score was associated with increased odds of stroke after adjustment for all risk factor (OR 2.93; 95% CI 1.21–7.13). Analyses by sex revealed mostly similar results in men and women with only few potential differences. Conclusions: Our study results indicate that aspects of social downward mobility during adulthood may be associated with increased risk of stroke, whereas intergenerational upward mobility may be linked to a lower stroke risk. If confirmed by future studies, such results may help to focus stroke prevention measures at high risk populations

Identifying patients at risk for myasthenic crisis with hemogram and inflammation-related laboratory parameters – a pilot study

Background: Myasthenia gravis (MG) is a rare autoimmune disease characterized by fatigable weakness of the voluntary muscles and can exacerbate to life-threatening myasthenic crisis (MC), requiring intensive care treatment. Routine laboratory parameters are a cost-effective and widely available method for estimating the clinical outcomes of several diseases, but so far, such parameters have not been established to detect disease progression in MG. Methods: We conducted a retrospective analysis of selected laboratory parameters related to inflammation and hemogram for MG patients with MC compared to MG patients without MC. To identify potential risk factors for MC, we applied time-varying Cox regression for time to MC and, as a sensitivity analysis, generalized estimating equations logistic regression for the occurrence of MC at the next patient visit. Results: 15 of the 58 examined MG patients suffered at least one MC. There was no notable difference in the occurrence of MC by antibody status or sex. Both regression models showed that higher counts of basophils (per 0.01 unit increase: HR = 1.32, 95% CI = 1.02–1.70), neutrophils (per 1 unit increase: HR = 1.40, 95% CI = 1.14–1.72), potentially leukocytes (per 1 unit increase: HR = 1.15, 95% CI = 0.99–1.34), and platelets (per 100 units increase: HR = 1.54, 95% CI = 0.99–2.38) may indicate increased risk for a myasthenic crisis. Conclusion: This pilot study provides proof of the concept that increased counts of basophils, neutrophils, leukocytes, and platelets may be associated with a higher risk of developing MC in patients with MG