Evidence indicates that age-related macular degeneration (AMD) is associated with the prior presence of allergic diseases; however, large-scale studies in the literature are limited. A case-control study was conducted to describe the relationship between premorbid allergic diseases and AMD using Taiwan\'s National Health Insurance database. Eligibility criteria for inclusion of new adult AMD cases from 2000 to 2013 were set up. We defined the year of diagnosis as the index year. Age-, gender-, index year- matched controls who were drawn from the same database. The case control ratio was 1:4. For all participants, all premorbid conditions staring 1996 to index year were documented. Binary logistic regression was used to describe factors related to AMD occurrence. The AMD group consisted of 10,911 patients, and the comparison group consisted of 43,644 individuals. Patients with AMD showed significant associations with premorbid allergic diseases (aOR 1.54, 95% CI 1.47-1.61), specifically with allergic conjunctivitis (aOR 2.07, 95% CI 1.94-2.20), allergic rhinitis (aOR 1.32, 95% CI 1.25-1.39), asthma (aOR 0.99, 95% CI 0.93-1.06), and atopic dermatitis (aOR 1.04, 95% CI 0.94-1.17). Further analyses indicated that patients with more concurrent allergic diseases have higher associations with AMD than those with fewer concurrent diseases. Patients with more annual medical visits for their allergic diseases also showed higher associations with AMD than those with fewer visits. AMD is significantly associated with premorbid allergic diseases. The underlying mechanisms must be further investigated.

Population-based surveys are possible sources from which to draw representative control data for case-control studies. However, these surveys involve complex sampling that could lead to biased estimates of measures of association if not properly accounted for in analyses. Approaches to incorporating complex-sampled controls in density-sampled case-control designs have not been examined.
We used a simulation study to evaluate the performance of different approaches to estimating incidence density ratios (IDR) from case-control studies with controls drawn from complex survey data using risk-set sampling. In simulated population data, we applied four survey sampling approaches, with varying survey sizes, and assessed the performance of four analysis methods for incorporating survey-based controls.
Estimates of the IDR were unbiased for methods that conducted risk-set sampling with probability of selection proportional to survey weights. Estimates of the IDR were biased when sampling weights were not incorporated, or only included in regression modeling. The unbiased analysis methods performed comparably and produced estimates with variance comparable to biased methods. Variance increased and confidence interval coverage decreased as survey size decreased.
Unbiased estimates are obtainable in risk-set sampled case-control studies using controls drawn from complex survey data when weights are properly incorporated.

In extensive cohort studies, the ascertainment of covariate information on all individuals can be challenging. In hospital epidemiology, an additional issue is often the time-dependency of the exposure of interest. We revisit and compare two sampling designs constructed for rare time-dependent exposures and possibly common outcomes - the nested exposure case-control design and exposure density sampling. Both designs enable efficient hazard ratio estimation by sampling all exposed individuals but only a small fraction of the unexposed ones. Moreover, they account for time-dependent exposure to avoid immortal time bias. We evaluate and compare their performance using data of patients hospitalised in the neuro-intensive care unit at the Burdenko Neurosurgery Institute in Moscow, Russia. Three different types of hospital-acquired infections with different prevalence are considered. Additionally, inflation factors, a primary performance measure, are discussed. We enhance both designs to allow for a competitive analysis of combined and competing endpoints compared to the full cohort approach while substantially reducing the amount of necessary information. Nonetheless, exposure density sampling outperforms the nested exposure case-control design concerning efficiency and accuracy in most considered settings.

Population-representative household survey methods require up-to-date sampling frames and sample designs that minimize time and cost of fieldwork especially in low- and middle-income countries. Traditional methods such as multi-stage cluster sampling, random-walk, or spatial sampling can be cumbersome, costly or inaccurate, leading to well-known biases. However, a new tool, Epicentre\'s Geo-Sampler program, allows simple random sampling of structures, which can eliminate some of these biases. We describe the study design process, experiences and lessons learned using Geo-Sampler for selection of a population representative sample for a kidney disease survey in two sites in Guatemala.
We successfully used Epicentre\'s Geo-sampler tool to sample 650 structures in two semi-urban Guatemalan communities. Overall, 82% of sampled structures were residential and could be approached for recruitment. Sample selection could be conducted by one person after 30 min of training. The process from sample selection to creating field maps took approximately 40 h.
In combination with our design protocols, the Epicentre Geo-Sampler tool provided a feasible, rapid and lower-cost alternative to select a representative population sample for a prevalence survey in our semi-urban Guatemalan setting. The tool may work less well in settings with heavy arboreal cover or densely populated urban settings with multiple living units per structure. Similarly, while the method is an efficient step forward for including non-traditional living arrangements (people residing permanently or temporarily in businesses, religious institutions or other structures), it does not account for some of the most marginalized and vulnerable people in a population-the unhoused, street dwellers or people living in vehicles.

Infection with SARS-CoV-2 represents a great source of concern and a new threat for immunocompromised patients. Limited studies are available on COVID-19 in immunocompromised children. This case series aimed to evaluate the clinical and laboratory characteristics, management and outcomes of COVID-19 in five children immunocompromised due to different underlying conditions. All had mild symptoms or were asymptomatic at presentation. All had a benign course of illness. No changes or delays in their treatment regimens occurred, and none experienced a relapse of the original disease, developed severe COVID-19 or died. However, these cases showed a prolonged duration of virus shedding. This report suggests that immunocompromised paediatric patients may not be at a higher risk of developing severe COVID-19. However, further studies are required to elaborate on the pathogenesis of COVID-19 in this vulnerable group.

Coronavirus Disease 2019 (COVID-19) is a pandemic disease that increased the burden on health-care system. In the Kingdom of Saudi Arabia, 74,795 cases have been reported until 26 May 2020 and the number of cases is rapidly increasing. The mortality rate of COVID-19 worldwide is 6.37%. Here we report three cases of acute kidney injury (AKI) secondary to pneumonia of severe COVID-19; they were treated with automated peritoneal dialysis (PD) with full recovery. To the best of our knowledge, few reports in the literature have discussed the use of PD in AKI secondary to COVID-19.

Pneumomediastinum is a rare clinical finding, but one which can be the source of significant concern for clinicians. By presenting 3 such cases, we highlight that pneumomediastinum can complicate the course of a severe coronavirus disease 2019 infection but emphasize that conservative management is the first-line method of treatment, with gradual resorption of the air from the tissues. It is important to be alert to the development of pneumothorax, which will require drainage.

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Several studies suggested that the acute phase of SARS-CoV-2 infection may be associated with a hypercoagulable state and increased risk for venous thromboembolism but the incidence of thrombotic complications in the late phase of the disease is currently unknown. The present article describes three cases of patients with SARS-CoV-2 pneumonia and late occurrence of pulmonary embolism. Case 1: a 57-year-old man diagnosed with pulmonary embolism and type B aortic dissection after 12 days from SARS-CoV-2 pneumonia. Laboratory panel at the time of pulmonary embolism showed no signs of ongoing inflammation but only an elevated D-dimer. Case 2: a 76-year-old man with a diagnosis of SARS-CoV-2 pneumonia followed by pulmonary embolism 20 days later, high-resolution computed tomography on that time showed a partial resolution of crazy paving consolidation. Case 3: a 77-year-old man with SARS-CoV-2 pneumonia who developed a venous thromboembolic event despite thromboprophylaxis with low molecular weight heparin. Also in this patients no markers of inflammation were present at the time of complication.The present cases raise the possibility that in SARS-CoV-2 infection the hypercoagulable state may persist over the active inflammation phase and cytokine storm. These findings suggest a role for medium-long term therapeutic anticoagulation started at the time of SARS-CoV-2 pneumonia diagnosis.

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