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Absolute risk reductions, relative risks, relative risk reductions, and numbers needed to treat can be obtained from a logistic regression model.

https://arctichealth.org/en/permalink/ahliterature152508
Source
J Clin Epidemiol. 2010 Jan;63(1):2-6
Publication Type
Article
Date
Jan-2010
Author
Peter C Austin
Author Affiliation
Institute for Clinical Evaluative Sciences, Toronto, Ontario M4N 3M5, Canada. peter.austin@ices.on.ca
Source
J Clin Epidemiol. 2010 Jan;63(1):2-6
Date
Jan-2010
Language
English
Publication Type
Article
Keywords
Data Interpretation, Statistical
Humans
Hydroxymethylglutaryl-CoA Reductase Inhibitors - therapeutic use
Logistic Models
Myocardial Infarction - drug therapy - mortality
Ontario - epidemiology
Risk Reduction Behavior
Treatment Outcome
Abstract
Logistic regression models are frequently used in cohort studies to determine the association between treatment and dichotomous outcomes in the presence of confounding variables. In a logistic regression model, the association between exposure and outcome is measured using the odds ratio (OR). The OR can be difficult to interpret and only approximates the relative risk (RR) in certain restrictive settings. Several authors have suggested that for dichotomous outcomes, RRs, RR reductions, absolute risk reductions, and the number needed to treat (NNT) are more clinically meaningful measures of treatment effect.
We describe a method for deriving clinically meaningful measures of treatment effect from a logistic regression model. This method involves determining the probability of the outcome if each subject in the cohort was treated and if each subject was untreated. These probabilities are then averaged across the study cohort to determine the average probability of the outcome in the population if all subjects were treated and if they were untreated.
Risk differences, RRs, and NNTs were derived using a logistic regression model.
Clinically meaningful measures of effect can be derived from a logistic regression model in a cohort study. These methods can also be used in randomized controlled trials when logistic regression is used to adjust for possible imbalance in prognostically important baseline covariates.
Notes
Comment In: J Clin Epidemiol. 2010 Jan;63(1):7-819762212
PubMed ID
19230611 View in PubMed
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Accelerated failure time models with covariates subject to measurement error.

https://arctichealth.org/en/permalink/ahliterature164143
Source
Stat Med. 2007 Nov 20;26(26):4817-32
Publication Type
Article
Date
Nov-20-2007
Author
Wenqing He
Grace Y Yi
Juan Xiong
Author Affiliation
Department of Statistical and Actuarial Sciences, University of Western Ontario, 1151 Richmond Street North, London, Ont., Canada N6A 5B7. whe@stats.uwo.ca
Source
Stat Med. 2007 Nov 20;26(26):4817-32
Date
Nov-20-2007
Language
English
Publication Type
Article
Keywords
Bias (epidemiology)
Data Interpretation, Statistical
Humans
Models, Statistical
Ontario
Proportional Hazards Models
Survival Analysis
Abstract
It has been well known that ignoring measurement error may result in substantially biased estimates in many contexts including linear and nonlinear regressions. For survival data with measurement error in covariates there has been extensive discussion in the literature with the focus being on the Cox proportional hazards models. However, the impact of measurement error on accelerated failure time (AFT) models has received little attention, though AFT models are very useful in survival data analysis. In this paper, we discuss AFT models with error-prone covariates and study the bias induced by the naive approach of ignoring measurement error in covariates. To adjust for such a bias, we describe a simulation and extrapolation method. This method is appealing because it is simple to implement and it does not require modelling the true but error-prone covariate process that is often not observable. Asymptotic normality for the resulting estimators is established. Simulation studies are carried out to evaluate the performance of the proposed method as well as the impact of ignoring measurement error in covariates. The proposed method is applied to analyse a data set arising from the Busselton Health study (Australian J. Public Health 1994; 18:129-135).
PubMed ID
17436310 View in PubMed
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Access to health services by Canadians who are chronically ill.

https://arctichealth.org/en/permalink/ahliterature174970
Source
West J Nurs Res. 2005 Jun;27(4):465-86
Publication Type
Article
Date
Jun-2005
Author
Shannon M Spenceley
Author Affiliation
University of Alberta, Canada.
Source
West J Nurs Res. 2005 Jun;27(4):465-86
Date
Jun-2005
Language
English
Publication Type
Article
Keywords
Attitude to Health
Canada - epidemiology
Chronic Disease - epidemiology - psychology - therapy
Data Collection - standards
Data Interpretation, Statistical
Health Care Reform - organization & administration
Health Services Accessibility - organization & administration
Health Services Research - organization & administration
Humans
National health programs - organization & administration
Needs Assessment - organization & administration
Research Design - standards
Abstract
Access to health care services in Canada has been identified as an urgent priority, and chronic disease has been suggested as the most pressing health concern facing Canadians. Access to services for Canadians living with chronic disease, however, has received little emphasis in the research literature or in health policy reform documents. A systematic review of research into factors impeding or facilitating access to formal health services for people in Canada living with chronic illness is presented. The review includes 31 studies of Canadian populations published between 1990 and 2002; main results were analyzed for facilitators and barriers to access for people experiencing chronic disease. An underlying organizing construct of symmetry between consumers, providers, and the larger Canadian system is suggested as a relevant lens from which to view the findings. Finally, a discussion of the relationship between identified factors and the principles of primary health care is offered.
PubMed ID
15870244 View in PubMed
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Accommodation of additional non-randomly sampled cases in a study of Helicobacter pylori infection in families.

https://arctichealth.org/en/permalink/ahliterature29334
Source
Stat Med. 2005 Dec 30;24(24):4045-54
Publication Type
Article
Date
Dec-30-2005
Author
Mårten Kivi
Anna L V Johansson
Agus Salim
Ylva Tindberg
Marie Reilly
Author Affiliation
Department of Medical Epidemiology and Biostatistics (MEB), Karolinska Institutet, Stockholm, Sweden.
Source
Stat Med. 2005 Dec 30;24(24):4045-54
Date
Dec-30-2005
Language
English
Publication Type
Article
Keywords
Child
Cross-Sectional Studies
Data Interpretation, Statistical
Epidemiologic Studies
Family
Helicobacter Infections - epidemiology
Helicobacter pylori - pathogenicity
Humans
Logistic Models
Patient Selection
Research Support, Non-U.S. Gov't
Sweden - epidemiology
Abstract
Epidemiological studies with two-stage designs typically gather information about some covariates from all study subjects in the first sampling stage, while additional data from only a subset of the subjects are collected in the second sampling stage. Appropriate analysis of two-stage studies maintains validity and can also improve precision. We describe an application of a weighted likelihood method, mean-score logistic regression, to accommodate data from a cross-sectional study of Helicobacter pylori infection in children, where the study sample was enriched with additional non-randomly sampled cases. The present work exemplifies how careful analysis of epidemiological data from complex sampling schemes can adjust for potential selection bias, improve precision and enable a more complete investigation of factors of interest. Our results highlight the importance of H. pylori infected mothers and siblings as risk factors for the infection in children in Sweden.
PubMed ID
16320286 View in PubMed
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Accumulation and depuration of the synthetic antioxidant ethoxyquin in the muscle of Atlantic salmon (Salmo salar L.).

https://arctichealth.org/en/permalink/ahliterature86374
Source
Food Chem Toxicol. 2008 May;46(5):1834-43
Publication Type
Article
Date
May-2008
Author
Bohne Victoria J Berdikova
Lundebye Anne-Katrine
Hamre Kristin
Author Affiliation
National Institute of Nutrition and Seafood Research (NIFES), Nordnes, Bergen, Norway. victoria.bohne@nifes.no
Source
Food Chem Toxicol. 2008 May;46(5):1834-43
Date
May-2008
Language
English
Publication Type
Article
Keywords
Agriculture
Algorithms
Animal Feed - analysis
Animals
Antioxidants - metabolism
Body Weight - drug effects
Data Interpretation, Statistical
Diet
Dose-Response Relationship, Drug
Ethoxyquin - metabolism
Growth - drug effects
Humans
Lipids - analysis
Mice
Muscle, Skeletal - chemistry - metabolism
Norway
Salmo salar - metabolism
Abstract
The biological fate of the fish feed additive, ethoxyquin (EQ) was examined in the muscle of Atlantic salmon during 12 weeks of feeding followed by a 2 weeks depuration period. Parent EQ (1,2-dihydro-6-ethoxy-2,2,4-trimethylquinoline), quinone imine (2,6-dihydro-2,2,4-trimethyl-6-quinolone), de-ethylated EQ (6-hydroxy-2,2,4-trimethyl-1,2-dihydroquinoline) and EQDM (EQ dimer or 1,8'-di(1,2-dihydro-6-ethoxy-2,2,4-trimethyl-quinoline) were found to be the ubiquitous metabolites of dietary EQ, with EQDM as a main metabolite. A rapid decrease in the level of EQ (2.4 days of half-life) was balanced by an increase in EQDM, giving an unchanged net sum following 2 weeks of depuration. The mandatory 14 days depuration period prior to slaughtering of farmed salmon in Norway was not sufficient for complete elimination of EQ-derived residuals. Post depuration, EQDM accounted for 99% of sum of the two compounds in all treatment groups; possible toxicological effects of EQDM are not known. The individual concentrations of EQ and EQDM and their sum are dependent on EQ level in the feed, consequently, their residual concentrations may be controlled. The theoretical amount of EQ and EQDM consumed in one meal of farmed salmon would be under the recommended ADI, provided that the fish were raised on feed with no more than 150 mg EQ/kg feed, which is the EU maximum limit for EQ in fish feed.
PubMed ID
18329775 View in PubMed
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Accurately describing changes in disease activity in Systemic Lupus Erythematosus.

https://arctichealth.org/en/permalink/ahliterature199452
Source
J Rheumatol. 2000 Feb;27(2):377-9
Publication Type
Article
Date
Feb-2000
Author
D D Gladman
M B Urowitz
A. Kagal
D. Hallett
Author Affiliation
The University of Toronto Lupus Clinic, Centre for Prognosis Studies in the Rheumatic Diseases, University Health Network, Toronto Western Hospital, Ontario, Canada. dafna.gladman@utoronto.ca
Source
J Rheumatol. 2000 Feb;27(2):377-9
Date
Feb-2000
Language
English
Publication Type
Article
Keywords
Adolescent
Adult
Aged
Canada
Child
Data Interpretation, Statistical
Databases, Factual
Female
Humans
Lupus Erythematosus, Systemic - physiopathology
Male
Middle Aged
Severity of Illness Index
Abstract
To determine whether Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) scores correlate with the clinician's impression of level of disease activity.
In total, 230 patients with SLE followed at the University of Toronto Lupus Clinic who had 5 visits 3 months apart in 1992-93 were studied. At each visit a standard protocol was completed. A clinician who did not know the patients or their SLEDAI scores evaluated each patient record and assigned a clinical activity level. "Flare" was defined by new or increased therapy for active disease, an expression of concern, or use of the term "flare" in the physician's notes. The SLEDAI score was calculated from the database.
SLEDAI scores described a range of clinical activity as recognized by the clinician. Median SLEDAI scores ranged from 2 (inactive disease) to 8 (persistently active or flare). When the clinician assessed the patient to be improved, the median SLEDAI score decreased by 2. When the clinician assessed that the patient was experiencing a flare, the SLEDAI score increased by a median of 4.
Based on our data we propose the following outcomes for patients with SLE: flare, an increase in SLEDAI > 3; improvement is a reduction in SLEDAI of > 3; persistently active disease is change in SLEDAI +/- 3; and remission a SLEDAI of 0. These outcomes will allow a more complete description of a patient's response to therapeutic intervention in a responder index.
PubMed ID
10685800 View in PubMed
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ACTION: application and extension of the GENESIS community analysis model.

https://arctichealth.org/en/permalink/ahliterature211809
Source
Public Health Nurs. 1996 Jun;13(3):187-94
Publication Type
Article
Date
Jun-1996
Author
C K Russell
D M Gregory
D. Wotton
E. Mordoch
M M Counts
Author Affiliation
College of Nursing, University of Tennessee, Memphis 38163, USA.
Source
Public Health Nurs. 1996 Jun;13(3):187-94
Date
Jun-1996
Language
English
Publication Type
Article
Keywords
Canada
Community Health Nursing
Cultural Diversity
Data Interpretation, Statistical
Health services needs and demand
Health Status Indicators
Humans
Models, Nursing
Nursing Assessment
Nursing Evaluation Research
United States
Urban health
Abstract
GENESIS (General Ethnographic and Nursing Evaluation Studies In the State) is a tested and proven community analysis strategy that integrates ethnographic and epidemiologic data to arrive at a comprehensive, holistic description of the health of a community and its residents. Communities analyzed in most project GENESIS studies have been rural or semirural. ACTION (Assessing Communities Together in the Identification Of Needs) is an extension of the GENESIS community analysis model that was developed to meet the unique needs of community-level research and analysis in an urban, multicultural setting. Significant differences in the context in which the ACTION projects took place necessitated extensions in specific components of the GENESIS model. Application of the GENESIS model by the ACTION team is described. Based on the experiences with ACTION, recommendations are offered for future urban, multicultural community analysis projects.
PubMed ID
8677234 View in PubMed
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Acute myocardial infarction. A feasibility study using record-linkage of routinely collected health information to create a two-year patient profile. Manitoba, 1984-85 and 1985-86.

https://arctichealth.org/en/permalink/ahliterature103865
Source
Health Rep. 1990;2(4):305-25
Publication Type
Article
Date
1990
Author
H. Johansen
P. Paddon
K. Chagani
D. Hamilton
L. Kiss
S. Krawchuk
Author Affiliation
System Development Division, Statistics Canada.
Source
Health Rep. 1990;2(4):305-25
Date
1990
Language
English
French
Publication Type
Article
Keywords
Acute Disease
Adult
Age Factors
Aged
Coronary Artery Bypass - statistics & numerical data
Data Interpretation, Statistical
Feasibility Studies
Female
Heart Function Tests - statistics & numerical data
Hospitalization - statistics & numerical data
Humans
Male
Manitoba - epidemiology
Medical Record Linkage
Middle Aged
Myocardial Infarction - epidemiology - mortality
Sex Factors
Abstract
Manitoba's hospital separations and physician medical files were linked for the fiscal years 1984-85 and 1985-86. The result was a study file consisting of records for 5,293 males and 3,143 females, who, during this period, suffered an Acute Myocardial Infarction (AMI), commonly called a heart attack. Merging the two types of files created a comprehensive data base for these AMI victims. The Manitoba age-sex standardized AMI rate was 38.0 per 10,000 population. Age-specific rates were higher for males than for females for all age groups. Hospitalized cases accounted for 7,201 individuals or 85.4% of AMI victims. Age-sex standardized rates of hospitalization per 10,000 population ranged from 27.1 in the Central region to 36.0 in the Westman region. The Manitoba age-specific rates of hospitalization for males in the 35-54 and 55-64 age groups were about three times the female rates for the same age groups. One quarter of AMI hospitalized victims died in hospital. The Manitoba age-specific death rates for males in the 35-54, 55-64 and 65-74 age groups were double the rates for females in the same age groups. Of the 8,436 AMI victims under study, 86.4% had at least one other concurrent medical condition such as angina, other forms of ischemic heart disease, diabetes, or hypertension. Of AMI victims, 93.8% underwent at least one of the following procedures: coronary artery bypass surgery, angiogram, electrocardiogram, cardiac catheterization, arteriography, or blood cholesterol testing. A higher percentage of procedures was performed on males than on females.
Notes
Erratum In: Health Rep 1991;3(1):97
PubMed ID
2101289 View in PubMed
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Adaptation of the Psoriatic Arthritis Quality of Life (PsAQol) instrument for Sweden: comments on the article by Billing et al.

https://arctichealth.org/en/permalink/ahliterature137797
Source
Scand J Rheumatol. 2011 Jan;40(1):80
Publication Type
Article
Date
Jan-2011

Adaptations for finding irregularly shaped disease clusters.

https://arctichealth.org/en/permalink/ahliterature162615
Source
Int J Health Geogr. 2007;6:28
Publication Type
Article
Date
2007
Author
Nikolaos Yiannakoulias
Rhonda J Rosychuk
John Hodgson
Author Affiliation
School of Geography and Earth Sciences, McMaster University, Hamilton, Canada. niwiyi@gmail.com
Source
Int J Health Geogr. 2007;6:28
Date
2007
Language
English
Publication Type
Article
Keywords
Canada - epidemiology
Cluster analysis
Data Interpretation, Statistical
Disease Outbreaks
Female
Humans
Male
Models, Statistical
Sensitivity and specificity
Abstract
Recent adaptations of the spatial scan approach to detecting disease clusters have addressed the problem of finding clusters that occur in non-compact and non-circular shapes--such as along roads or river networks. Some of these approaches may have difficulty defining cluster boundaries precisely, and tend to over-fit data with very irregular (and implausible) clusters shapes.
We describe two simple adaptations to these approaches that can be used to improve the effectiveness of irregular disease cluster detection. The first adaptation penalizes very irregular cluster shapes based on a measure of connectivity (non-connectivity penalty). The second adaptation prevents searches from combining smaller clusters into large super-clusters (depth limit). We conduct experiments with simulated data in order to observe the performance of these adaptations on a number of synthetic cluster shapes.
Our results suggest that the combination of these two adaptations may increase the ability of a cluster detection method to find irregular shapes without affecting its ability to find more regular (i.e., compact) shapes. The depth limit in particular is effective when it is deemed important to distinguish nearby clusters from each other. We suggest that these adaptations of adjacency-constrained spatial scans are particularly well suited to chronic disease and injury surveillance.
Notes
Cites: Lancet. 1988 Feb 6;1(8580):272-32893085
Cites: Stat Med. 2006 Mar 15;25(5):723-4216453376
Cites: Stat Med. 1996 Apr 15-May 15;15(7-9):717-269132899
Cites: Am J Epidemiol. 1990 Jul;132(1 Suppl):S136-432356825
PubMed ID
17615077 View in PubMed
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1004 records – page 1 of 101.