Search results for "Confounding"
showing 10 items of 385 documents
Randomized Controlled Trials and real life studies. Approaches and methodologies: a clinical point of view.
2014
Randomized Controlled Trials (RCTs) are the "gold standard" for evaluating treatment outcomes providing information on treatments "efficacy". They are designed to test a therapeutic hypothesis under optimal setting in the absence of confounding factors. For this reason they have high internal validity. The strict and controlled conditions in which they are conducted, leads to low generalizability because they are performed in conditions very different from real life usual care. Conversely, real life studies inform on the "effectiveness" of a treatment, that is, the measure of the extent to which an intervention does what is intended to do in routine circumstances. At variance to RCTs, real …
Analysis of the effects of microbiome-related confounding factors on the reproducibility of the volatolomic test.
2016
Volatile organic compound (VOC) testing in breath has potential in gastric cancer (GC) detection. Our objective was to assess the reproducibility of VOCs in GC, and the effects of conditions modifying gut microbiome on the test results. Ten patients with GC were sampled for VOC over three consecutive days; 17 patients were sampled before and after H. pylori eradication therapy combined with a yeast probiotic; 61 patients were sampled before and after bowel cleansing (interventions affecting the microbiome). The samples were analyzed by: (1) gas chromatography linked to mass spectrometry (GC-MS), applying the non-parametric Wilcoxon test (level of significance p 0.05); (2) by cross-reacti…
Eligibility of real-life patients with copd for inclusion in rcts: A commentary
2017
Randomized clinical trials (RCTs) are performed to provide evidence to support treatment decisions. Based on the nature of those studies and the need to avoid confounding factors, it has been argued that the population selected in RCTs only partially represents the real-life population. This assumption casts doubts on the applicability of the results provided by RCTs in the management of individuals with an established diagnosis of COPD, and advocates the need for complementary studies with a pragmatic design. Herein, we comment on the recent article published by Halpin and colleagues on the Journal [Halpin et al, Respir Res 17:120, 2016], in which higher rates of inclusions in RCTs for COP…
The value of FeNO measurement in childhood asthma: uncertainties and perspectives
2013
Asthma is considered an heterogeneous disease, requiring multiple biomarkers for diagnosis and management. Fractional exhaled nitric oxide in exhaled breath (FeNO) was the first useful non-invasive marker of airway inflammation in asthma and still is the most widely used. The non-invasive nature and the relatively easy use of FeNO technique make it an interesting tool to monitor airway inflammation and rationalize corticosteroid therapy in asthmatic patients, together with the traditional clinical tools (history, physical examination and lung function tests), even if some controversies have been published regarding the use of FeNO to support the management of asthma in children. The problem…
Visit-to-visit blood pressure variability and renal outcomes: results from ONTARGET and TRANSCEND trials.
2020
AIMS There is conflicting evidence on whether in treated hypertensive patients the risk of renal outcomes is associated with visit-to-visit SBP variability. Furthermore, limited evidence is available on how important is SBP variability for prediction of renal outcomes compared with on-treatment mean SBP. We addressed these issues in 28 790 participants of the Ongoing Treatment Alone and in combination with Ramipril Global End point Trial and Telmisartan Randomized Assessment Study in ace iNtolerant Subjects with Cardiovascular Disease trials. METHODS AND RESULTS SBP variability was expressed as the coefficient of variation of the mean with which it showed no relationship. SBP variability an…
Contribution of 30 biomarkers to 10-year cardiovascular risk estimation in 2 population cohorts: the MONICA, risk, genetics, archiving, and monograph…
2010
Background— Cardiovascular risk estimation by novel biomarkers needs assessment in disease-free population cohorts, followed up for incident cardiovascular events, assaying the serum and plasma archived at baseline. We report results from 2 cohorts in such a continuing study. Methods and Results— Thirty novel biomarkers from different pathophysiological pathways were evaluated in 7915 men and women of the FINRISK97 population cohort with 538 incident cardiovascular events at 10 years (fatal or nonfatal coronary or stroke events), from which a biomarker score was developed and then validated in the 2551 men of the Belfast Prospective Epidemiological Study of Myocardial Infarction (PRIME) co…
Occupational exposure to extremely low frequency electric and magnetic fields and Alzheimer disease: a meta-analysis
2008
Background Among potential environmental risk factors for Alzheimer disease (AD), occupational exposures have received some attention, including extremely low frequency electromagnetic fields (ELF-EMF). A systematic review and meta-analysis of published epidemiological studies on this subject was carried out. Methods The search was concluded in April 2006. Bibliographic databases consulted included PubMed, EMBASE, Cochrane Library and NIOSHTIC2. Pooled estimates were obtained using random-effects meta-analysis. Sources of heterogeneity between studies were explored, as was publication bias. Results Fourteen different studies (nine case-control and five cohort studies) accomplished inclusion…
Occupational Exposure to Extremely Low-Frequency Magnetic Fields and Risk of Amyotrophic Lateral Sclerosis : Results of a Feasibility Study for a Poo…
2021
Bioelectromagnetics 42(4), 271-283 (2021). doi:10.1002/bem.22335
Mitochondrial genetic haplogroups and incident obesity: a longitudinal cohort study.
2018
Background/Objectives: A small number of case-control studies have suggested that mitochondrial haplogroups could be associated with obesity. We examined whether obesity risk was influenced by mitochondrial haplogroup in a large North American cohort across an 8-year period. We conducted a longitudinal cohort study including individuals from the Osteoarthritis Initiative. Subjects/Methods: Mitochondrial haplogroups were determined by sequencing and PCR-RFLP techniques using this nomenclature: HV, JT, KU, IWX, and super HV/others. The strength of the association between mitochondrial haplogroups and incident obesity was quantified with hazard ratios (HRs), adjusted for potential confounders …
Early infancy BMI trajectories and lung function and asthma during childhood
2019
Previous studies assessing the association of birthweight and infant weight gain with lung function and asthma have focused on the difference between two time points or on growth patterns. Body mass index (BMI) trajectories, which integrate information on multiple aspects of growth, may allow a more accurate identification of children at higher risk of future respiratory diseases. We assessed the associations of BMI trajectories from birth to 4 years with lung function and current asthma at 7 years. We included 1399 participants from the population-based INMA birth cohort study. Five BMI trajectories were previously identified: ‘average birth size-slower BMI gain’, ‘higher birth size-accele…