Letter to the Editor

PEDIATRICS ◽  
1990 ◽  
Vol 86 (3) ◽  
pp. 490-491
Author(s):  
Neal Halsey ◽  
Elizabeth Holt
Keyword(s):  
Multivariate Analysis ◽  
Observational Studies ◽  
Confounding Factors ◽  
Letter To The Editor ◽  
Confounding Variables ◽  
Final Sentence ◽  
The Relationship ◽  
Extensive List

Dr Brunskill's primary point appears to be in the final sentence of his letter. As noted in our discussion, we are well aware of the potential for hidden confounding factors in retrospective observational studies... We attempted to minimize this possibility by obtaining information on an extensive list of factors that might have confounded the relationship between vaccination and mortality and by controlling for these factors through multivariate analysis.1 Despite our rigor, we could have failed to measure all possible confounding variables.

scholarly journals Does deprivation affect the demand for NHS Direct? Observational study of routine data from Wales

BMJ Open ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. e029203
Author(s):  
Julie Peconi ◽  
Steven Macey ◽  
Sarah E Rodgers ◽  
Ian T Russell ◽  
Helen Snooks ◽  
...  
Keyword(s):  
National Health Service ◽  
Routine Data ◽  
Confounding Factors ◽  
Policy Makers ◽  
On Demand ◽  
Confounding Variables ◽  
Day Of The Week ◽  
Nhs Direct ◽  
The Relationship ◽  
Index Of Multiple Deprivation

ObjectiveTo estimate the effect of deprivation on the demand for calls to National Health Service Direct Wales (NHSDW) controlling for confounding factors.DesignStudy of routine data on over 400 000 calls to NHSDW using multiple regression to analyse the logarithms of ward-specific call rates across Wales by characteristics of call, patient and ward, notably the Welsh Index of Multiple Deprivation.Setting810 electoral wards with average population of 3300, defined by 1998 administrative boundaries.PopulationAll calls to NHSDW between January 2002 and June 2004.Main outcome measuresWe used ward populations as denominators to calculate the rates of three categories of calls: calls seeking advice, calls seeking information and all calls combined.ResultsConfounding variables explained 31% of variation in advice call rates, but only 14% of variation in information call rates and in all call rates (all significant at 0.1% level). However, deprivation was only a statistically significant predictor of information call rates. The proportion of the ward population categorised as ‘white’ was a highly significant predictor of all three call rates. For advice calls and combined calls, rates decreased highly significantly with the proportion of those who called the service for themselves. Information call rates were higher on weekdays and highest on Mondays, while advice call rates were highest on Sundays.ConclusionsDeprivation had no consistent effect on demand for the service and the relationship needs further exploration. While our data may have underestimated the ‘need’ of deprived patients, they yield no evidence that policy-makers should seek to improve demand from those patients. However, we found differences in the way callers use advice and information calls. Previously unexplored variables that help to predict ward-specific call rates include: ethnicity, day of the week and whether patients made the calls themselves.

scholarly journals Relationship between initial peritoneal dialysis modality and risk of peritonitis

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Maiko Kokubu ◽  
Masaru Matsui ◽  
Takayuki Uemura ◽  
Katsuhiko Morimoto ◽  
Masahiro Eriguchi ◽  
...  
Keyword(s):  
Peritoneal Dialysis ◽  
Lower Risk ◽  
Observational Studies ◽  
Primary Outcome ◽  
Propensity Scores ◽  
First Episode ◽  
Connection Type ◽  
Adjusted Model ◽  
The Relationship ◽  
Nara Prefecture

Abstract Peritonitis is a critical complication of peritoneal dialysis (PD). Investigators have reported the risk of peritonitis in patients on continuous ambulatory peritoneal dialysis (CAPD) versus automated peritoneal dialysis (APD), but the available evidence is predominantly based on observational studies which failed to report on the connection type. Our understanding of the relationship between peritonitis risk and PD modality thus remained insufficient. We studied 285 participants who began PD treatment between 1997 and 2014 at three hospitals in Nara Prefecture in Japan. We matched 106 APD patients with 106 CAPD patients based on their propensity scores. The primary outcome was time to first episode of peritonitis within 3 years after PD commencement. In total, PD peritonitis occurred in 64 patients during the study period. Patients initiated on APD had a lower risk of peritonitis than did those initiated on CAPD in both the unadjusted and adjusted models. The hazard ratio (HR) and 95% confidence interval (CI) for the primary endpoint were 0.30 (0.17–0.53) in the fully adjusted model including connection type. In the matched cohort, APD patients had a significantly lower risk of peritonitis than did CAPD patients (log-rank: p < 0.001, HR 0.32, 95% CI 0.16–0.59). The weighting-adjusted analysis of the inverse probability of treatment yielded a similar result (HR 0.35, 95% CI 0.18–0.67). In conclusion, patients initiated on APD at PD commencement had a reduced risk of peritonitis compared with those initiated on CAPD, suggesting APD may be preferable for prevention of peritonitis among PD patients.

scholarly journals A Student’s Guide to the Classification and Operationalization of Variables in the Conceptualization and Design of a Clinical Study: Part 1

2021 ◽  
Vol 43 (2) ◽  
pp. 177-179 ◽  
Author(s):  
Chittaranjan Andrade
Keyword(s):  
Clinical Study ◽  
Significant Relationship ◽  
Research Experience ◽  
Process Variables ◽  
Know How ◽  
Independent Variables ◽  
Cause And Effect ◽  
Confounding Variables ◽  
Dependent Variables ◽  
The Relationship

Students without prior research experience may not know how to conceptualize and design a study. This article explains how an understanding of the classification and operationalization of variables is the key to the process. Variables describe aspects of the sample that is under study; they are so called because they vary in value from subject to subject in the sample. Variables may be independent or dependent. Independent variables influence the value of other variables; dependent variables are influenced in value by other variables. A hypothesis states an expected relationship between variables. A significant relationship between an independent and dependent variable does not prove cause and effect; the relationship may partly or wholly be explained by one or more confounding variables. Variables need to be operationalized; that is, defined in a way that permits their accurate measurement. These and other concepts are explained with the help of clinically relevant examples.

scholarly journals Blood pressure level and laboratory indicators of disease severity in patients with arterial hypertension and COVID-19

2021 ◽  
Vol 28 (Supplement_1) ◽  
Author(s):  
K Popov ◽  
A Novitskiy ◽  
Y Shvarts
Keyword(s):  
Blood Pressure ◽  
Multivariate Analysis ◽  
Arterial Hypertension ◽  
Negative Correlation ◽  
Diastolic Pressure ◽  
Negative Relationship ◽  
Laboratory Parameters ◽  
Acute Period ◽  
Nonparametric Correlation ◽  
The Relationship

Abstract Funding Acknowledgements Type of funding sources: None. Background. Many patients with COVID-19 suffer from arterial hypertension and have marked variations in blood pressure (BP) during the acute period of infection. The reasons for such changes are poorly understood. Purpose. To assess the relationship between the level of BP and the severity of changes in the main clinical and laboratory parameters in patients with arterial hypertension and with a moderate course of COVID-19 at the stage of the height of the disease. Materials and methods. The study included 86 hospitalized patients with verified coronavirus disease of moderate severity: 46 of them were male, the median age was 65 years. Patients received adequate hypertension therapy for a long time. After hospitalization, treatment was adjusted if necessary. The level of laboratory parameters in the acute period of the disease was determined, including the electrolytes, C-reactive protein (CRP), albumin, ferritin, general blood test, etc. BP measured daily. The relationship between laboratory parameters and BP level was evaluated by nonparametric correlation using the Spearman coefficient and multivariate analysis based on the "generalized nonlinear model". Results. In 67.44% of patients with hypertension, an elevated BP level (&gt;140/90) was observed against the background of moderate COVID-19. There was a significant negative correlation between the levels of CRP and BP throughout the stay in the hospital, the most significant is the 5th day of hospitalization. At the same time, a slightly stronger relationship is observed with diastolic BP (r = -0.4425) than with systolic BP (r = -0.3525). A similar trend is observed in all BP measurements. Besides, a negative correlation was found between potassium levels and BP values. The strongest association of potassium levels is with systolic BP on the day of hospitalization (r = -0.4850) and diastolic pressure on the 1st day of hospitalization (r = -0.3561). Multivariate analysis confirmed independent and reliable "influence" of CRP (p = 0.00018) and potassium (p = 0.03921) as independent predictors of diastolic pressure. Conclusions. Most patients with hypertension and moderate COVID-19 have elevated BP levels. There is a statistically significant negative relationship between the values of BP and levels of CRP and potassium. The obtained data may correspond to the existing hypothesis about the significant role of the kinin–kallikrein system in the pathogenesis of COVID-19.

scholarly journals Association of body condition with lameness in dairy cattle: a single-farm longitudinal study

2021 ◽  
pp. 1-4
Author(s):  
Michaela Kranepuhl ◽  
Detlef May ◽  
Edna Hillmann ◽  
Lorenz Gygax
Keyword(s):  
Body Condition ◽  
Body Condition Score ◽  
Mixed Effects ◽  
Mixed Effects Models ◽  
Linear Mixed Effects Models ◽  
Linear Mixed Effects ◽  
Confounding Variables ◽  
Condition Score ◽  
The Impact ◽  
The Relationship

Abstract This research communication describes the relationship between the occurrence of lameness and body condition score (BCS) in a sample of 288 cows from a single farm that were repeatedly scored in the course of 9 months while controlling for confounding variables. The relationship between BCS and lameness was evaluated using generalised linear mixed-effects models. It was found that the proportion of lame cows was higher with decreasing but also with increasing BCS, increased with lactation number and decreased with time since the last claw trimming. This is likely to reflect the importance of sufficient body condition in the prevention of lameness but also raises the question of the impact of overcondition on lameness and the influence of claw trimming events on the assessment of lameness. A stronger focus on BCS might allow improved management of lameness that is still one of the major problems in housed cows.

scholarly journals Calcium Channel Autoantibodies Predicted Sudden Cardiac Death and All-Cause Mortality in Patients with Ischemic and Nonischemic Chronic Heart Failure

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Haiyun Yu ◽  
Juanhui Pei ◽  
Xiaoyan Liu ◽  
Jingzhou Chen ◽  
Xian Li ◽  
...  
Keyword(s):  
Heart Failure ◽  
Multivariate Analysis ◽  
Sudden Cardiac Death ◽  
Chronic Heart Failure ◽  
Cardiac Death ◽  
Independent Predictor ◽  
All Cause Mortality ◽  
Patient Prognosis ◽  
The Relationship

The purpose of this study was to evaluate whether CC-AAbs levels could predict prognosis in CHF patients. A total of 2096 patients with CHF (841 DCM patients and 1255 ICM patients) and 834 control subjects were recruited. CC-AAbs were detected and the relationship between CC-AAbs and patient prognosis was analyzed. During a median follow-up time of 52 months, there were 578 deaths. Of these, sudden cardiac death (SCD) occurred in 102 cases of DCM and 121 cases of ICM. The presence of CC-AAbs in patients was significantly higher than that of controls (bothP<0.001). Multivariate analysis revealed that positive CC-AAbs could predict SCD (HR 3.191, 95% CI 1.598–6.369 for DCM; HR 2.805, 95% CI 1.488–5.288 for ICM) and all-cause mortality (HR 1.733, 95% CI 1.042–2.883 for DCM; HR 2.219, 95% CI 1.461–3.371 for ICM) in CHF patients. A significant association between CC-AAbs and non-SCD (NSCD) was found in ICM patients (HR = 1.887, 95% CI 1.081–3.293). Our results demonstrated that the presence of CC-AAbs was higher in CHF patients versus controls and corresponds to a higher incidence of all-cause death and SCD. Positive CC-AAbs may serve as an independent predictor for SCD and all-cause death in these patients.

Social support and delusional-like experiences: a nationwide population-based study

2012 ◽  
Vol 21 (2) ◽  
pp. 203-212 ◽  
Author(s):  
S. Saha ◽  
J. Scott ◽  
D. Varghese ◽  
J. McGrath
Keyword(s):  
Social Support ◽  
General Population ◽  
Community Sample ◽  
Composite International Diagnostic Interview ◽  
Population Based ◽  
Diagnostic Interview ◽  
Confounding Factors ◽  
Poor Social Support ◽  
Physical Disorders ◽  
The Relationship

Background.Population-based studies have identified that delusional-like experiences (DLEs) are common in the general population. While there is a large literature exploring the relationship between poor social support and risk of mental illness, there is a lack of empirical data examining the association of poor social support and DLEs. The aim of the study was to explore the association between social support and DLEs using a large, nationally representative community sample.Methods.Subjects were drawn from a national multistage probability survey of 8841 adults aged between 16 and 85 years. The Composite International Diagnostic Interview was used to identify DLEs, common psychiatric disorders and physical disorders. Eight questions assessed various aspects of social support with spouse/partners and other family and friends. We examined the relationship between DLEs and social support using logistic regression, adjusting for potential confounding factors.Results.Of the sample, 8.4% (n = 776) positively endorsed one or more DLEs. Individuals who (a) had the least contact with friends, or (b) could not rely on or confide in spouse/partner, family or friends were significantly more likely to endorse DLEs. The associations remained significant after adjusting for a range of potential confounding factors.Conclusions.DLEs are associated with impoverished social support in the general population. While we cannot exclude the possibility that the presence of isolated DLEs results in a reduction of social support, we speculate that poor social support may contribute in a causal fashion to the risk of DLEs.

Disruptive Vocalization and Depression in Older Nursing Home Residents

2000 ◽  
Vol 12 (4) ◽  
pp. 463-471 ◽  
Author(s):  
Michael Dwyer ◽  
Gerard J. A. Byrne
Keyword(s):  
Nursing Home ◽  
Cognitive Impairment ◽  
Depressive Symptoms ◽  
Mini Mental State Examination ◽  
Mmse Score ◽  
Nursing Home Residents ◽  
Confounding Variables ◽  
The Relationship ◽  
State Examination ◽  
Age And Sex

Screaming and other types of disruptive vocalization are commonly observed among nursing home residents. Depressive symptoms are also frequently seen in this group, although the relationship between disruptive vocalization and depressive symptoms is unclear. Accordingly, we sought to examine this relationship in older nursing home residents. We undertook a controlled comparison of 41 vocally disruptive nursing home residents and 43 non-vocally-disruptive nursing home residents. All participants were selected to have Mini-Mental State Examination (MMSE) scores of at least 10. Participants had a mean age of 81.0 years (range 63-97 years) and had a mean MMSE score of 17.8 (range 10-29). Nurse ratings of disruptive vocalization according to a semioperationalized definition were validated against the noisy behavior subscale of the Cohen-Mansfield Agitation Inventory. Subjects were independently rated for depressive symptoms by a psychiatrist using the Dementia Mood Assessment Scale, the Cornell Scale for Depression in Dementia, and the Depressive Signs Scale. Vocally disruptive nursing home residents scored significantly higher than controls on each of these three depresion-in-dementia scales. These differences remained significant when the effects of possible confounding variables of cognitive impairment, age, and sex were removed. We conclude that depressive symptoms are associated with disruptive vocalization and may have an etiological role in the generation of disruptive vocalization behaviors in elderly nursing home residents.

scholarly journals Family involvement, adolescent self-concept and academic achievement

2015 ◽  
Vol 5 (3) ◽  
pp. 293-311
Author(s):  
Ana Álvarez ◽  
Natalia Suárez ◽  
Ellián Tuero ◽  
José C. Núñez ◽  
Antonio Valle ◽  
...  
Keyword(s):  
Academic Achievement ◽  
Multivariate Analysis ◽  
Parental Involvement ◽  
Family Involvement ◽  
Significant Relationship ◽  
Study Data ◽  
Self Concept ◽  
First Year ◽  
Achievement Scores ◽  
The Relationship

The purpose of this work was to analyze the specific relationship between parental involvement, dimensions of student self-concept and achievement. 503 students of Secondary Education (ESO) and the first year of Baccalaureate course participated in the study. Data were collected using two questionnaires (Family Involvement Questionnaire and Self-Concept Scale for Adolescents) and academic achievement scores. Data were analyzed using multivariate analysis of variance and paths analysis. The results obtained suggest a significant relationship between the dimensions of perceived family involvement and the dimensions of self-concept (except for parents' praise behaviors). What's more, the relationship between perceived family involvement and achievement is partially mediated by the academic self-concept.

Visit-to-Visit Blood Pressure Variability, Neuropathology, and Cognitive Function

Neurology ◽  
2021 ◽  
pp. 10.1212/WNL.0000000000012065
Author(s):  
Yuan Ma ◽  
Deborah Blacker ◽  
Anand Viswanathan ◽  
Susanne J. van Veluw ◽  
Daniel Bos ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Neurofibrillary Tangle ◽  
Vascular Pathology ◽  
Cognitive Deterioration ◽  
Braak Staging ◽  
Confounding Variables ◽  
Tangle Pathology ◽  
The Relationship ◽  
Normal Cognition

ObjectiveLarge systolic blood pressure (SBP) variability has been proposed as a novel risk factor for dementia above and beyond SBP levels, but the underlying neuropathology is largely unknown. We investigated the relationship among visit-to-visit SBP variability, cognitive deterioration and underlying neuropathological changes.MethodsWe used longitudinal data (between 2005 and 2019) from the National Alzheimer’s Coordinating Center. 13,284 dementia-free participants aged≥50 years were followed over a median of 5.0 (interquartile range: 3.1-7.6) years. Neuropathology data were available in 1,400 autopsied participants. Visit-to-visit SBP variability was quantified from repeated annual SBP measurements. Cognitive deterioration was defined as conversion from normal cognition to mild cognitive impairment (MCI) or dementia, or from MCI to dementia.ResultsLarger visit-to-visit SBP variability was associated with cognitive deterioration (adjusted odds ratio comparing extreme quintiles: 2.64; 95%CI:2.29-3.04, P <0.001). It was also associated with a higher burden of vascular pathology (including microinfarcts, white matter lesion, atherosclerosis of the circle of Willis and arteriolosclerosis) and with neurofibrillary tangle pathology assessed by Braak staging (All P < 0.05). The association with cognitive deterioration and vascular pathology appeared stronger among those with normal cognition versus MCI at baseline. These findings were observed after adjusting for age, sex, mean SBP and other confounding variables. Similar results were observed for diastolic BP variability.ConclusionLarger visit-to-visit SBP variability was associated with cognitive deterioration. It was also associated with cerebrovascular pathology and neurofibrillary tangles. These results suggest the intertwined role of vascular and Alzheimer's disease pathology in the etiology of dementia.

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