Questions tagged [case-control-study]

An observational study in which two existing groups differing in outcome are identified and compared on the basis of some supposed causal attribute.

Filter by
Sorted by
Tagged with
0
votes
0answers
9 views

Does odd ratio make any sense when risk ration can't be computed?

Guides and reviews often explain that odd ratio is preferable to risk ratio when risk ratio cannot be computed. See for example this paper by Ranganathan et al. (2015): Calculation of risk requires ...
1
vote
2answers
37 views

Matching when there are missing data

In a treatment effects framework, I have a control and treatment group with some covariates on which to match (I'm using nearest-neighbor method). The control group has a no missing data, but some ...
1
vote
0answers
23 views

Controlled Intervention Before/After

I have an intervention that I'd like to determine the effect of (before/after). All of the data has been divided into a treatment or control group. The issue is that the treatment/intervention took ...
0
votes
0answers
8 views

Can someone explain as simply as possible why you use OR in retrospective studies while using RR in prospective studies?

I've really tried to understand why you can't use RR in retrospective studies but for some reason I can't understand it. Has anyone been able to convey this simply to their students?
1
vote
4answers
371 views

Valid conclusions from simple case?

If I have an experiment documenting the recovery of 1,000 patients who were given access to a medication. Results: MEN taking the drug. 2 out of 2 recover (100% recovery). MEN not taking the drug. ...
1
vote
1answer
59 views

Proper Average Treatment Effect estimators (and standard errors) for Generalized Linear Models with log link?

What is the proper formula for estimating the Average Treatment Effect with a simple main effects generalized linear model? My first pass at defining the Average Treatment Effect for a GLM with a log ...
1
vote
0answers
31 views

Finding best conditional logistic regression model with unbalanced strata

I am interested in fitting the best possible model for the case of conditional logistic regression where the strata are unbalanced. Although I have not seen it specified, but I understand that there ...
1
vote
0answers
18 views

The appropriate match ratio between case and controls: the obsession with 1:5 [duplicate]

My intention with this question is to collect relevant references or literature for a recurrent methodological approach commonly applied in health research. The main question is: what is the ...
3
votes
0answers
67 views

Case-Control study with 1:N matching and a continuous outcome variable

I'm interested to compare cases with controls on a continuous outcome variable. The cases are people with a certain disease, while the controls are matched on various criteria (age, sex, etc) thought ...
0
votes
0answers
10 views

Bayesian case control binary regression

tl;dr I would like to evaluate the posterior distribution for the parameters $\theta$ of a binary regression model $P(y_i=1|x_i, \theta)=\rho(x_i, \theta)$ given the features $x_A$ of all positive ...
0
votes
0answers
13 views

case-control matching with stratum of different length

I want to match cases with controls. My restriction is that a case must be assigned k controls. I use the notation $n:m$, being a stratum with $n$ cases and $m$ controls. For some cases I can ...
0
votes
2answers
33 views

Checking if treatment is effective without control group

I am experimenting with few treatments to see which one is effective. I do not have luxury of control group to compare against. In such scenario, is there any method to see if the treatment has been ...
0
votes
0answers
101 views

Regression model for matched case-control study with continuous outcome

I have a matched case-control study design, where the outcome is continuous (and highly skewed), and there are multiple confounding variables. I have found a lot of literature discussing the use of ...
2
votes
2answers
94 views

Sample Size for Case-Control Study

We wanted to perform a case-control study and used the calculation below. Using alpha = 0.05, beta = 0.20, p1-p2 = 0.003, and a ratio of controls to cases of 1000:1, we came up with a sample size of ...
1
vote
0answers
9 views

Question about design choice of Enbrel RWE study

Statisticians in 2015 analyzed real world data, hundreds of thousands of medical insurance claims involving people with rheumatoid arthritis and other inflammatory diseases, according to the Pfizer ...
1
vote
0answers
40 views

Meta-analysis for case control studies

I am working on a method of meta-analysis for case-control studies by stratifying cases and controls then calculating the effect size. Can I do a meta-analysis including only case-control studies for ...
0
votes
0answers
18 views

Correlation analysis using a case-control study-based data

I have a case-control study-based data. This is a data to confirm the association of hypertension and BMI. The definition of the case group (hypertension group) is SBP(systolic blood pressure)>=140. ...
1
vote
1answer
35 views

Difference between N case studies and case series with N patients

Is there any reason to treat data from multiple case studies differently from data from a case series that reports data on multiple patients? Assuming the case-series intervention was the same for ...
2
votes
1answer
289 views

R - multivariate glm, what to use as a p-value and odds ratio?

This is for a case-control study. I need to get a p-value and an odds ratio with confidence intervals from my glm, but I'm unsure of the best approach. I have the <...
2
votes
1answer
180 views

propensity score matching by disease and cox PH regression.. am I right?

Normally I understood propensity score matching is the way to match the treated group and untreated group. But I noticed some studies that used propensity score matching to match disease and non-...
0
votes
0answers
81 views

Ratio of cases to controls in retrospective cohort study

I am conducting a retrospective cohort study in which I have 10,000 cases with exposure to X, and a very large control population (10,000,000+ subjects) without exposure. I am taking an individual ...
1
vote
1answer
46 views

Compare hazard ratios in case-control setup

quick disclaimer: first time poster; i have searched through the forums extensively but please bear with me if this is a silly question or point me towards the solution if it has been answered before. ...
1
vote
0answers
57 views

Variable ratio matching

I am working on a simulated study where I have variable number of control matches for my treatment subjects. I am new to this type of analysis. I realize after matching I can utilize logistic ...
0
votes
1answer
2k views

3:1 matching with MatchIt in R. The number of matched control is not equal to 3 times the number of cases

Hello I'm using the MatchIt package in R I have a total of unmatched 116 treated cases and 462 unmatcehd non-treated case with the command ...
1
vote
1answer
169 views

Interacting treatment variables with independent variables in matched samples

Can we interact the treatment variables with independent control variables that have been used for matching? I have a binary treatment variable called 'medicine'. It indicates whether a person ...
0
votes
0answers
15 views

Any downsides in giving a participant A and B then compare the results?

Almost all the experimental design studies that I came across randomly separates participants into bucket A or B. Then they study the effects to identify a causal relationship. Are there any ...
1
vote
1answer
783 views

Nested Case-Control vs propensity score matching vs inverse probability when comparing differences in incident outcomes

I am not sure about the best design in this case. I have a representative sample (N=15,000) of individuals with a moderately rare condition and I want to match them to controls who do not have this ...
1
vote
0answers
22 views

Matching inflation

I have data on a few millions of patients, about 1000 of them are cases, that is, they were diagnosed having a certain disease at some timepoint in their life. I think I basically have two options: 1)...
1
vote
1answer
60 views

What statistical model to use for assessing the effect of a new tree pesticide?

I have 2 sites with 15 trees on each site. I plan to treat all 15 trees in site 1 with a new pesticide and leave all 15 trees in site 2 untreated. The total number of bugs on each tree is measured ...
1
vote
0answers
48 views

What statistical test should I use for the comparison of multiple dependent variables?

I'm doing research on the influence of one kind of pill on the heart rate. I have two groups: control group and medication group. The control group has 10 subjects while the medication group has 20 ...
2
votes
0answers
60 views

Analysis of Pre-post Likert-type scales: Intervention vs. Control group

I gathered the following data: Intervention group (n= 24, received treatment): pre- and post- scores of different psychometric questionnaires Control group (n=23, inactive): same questionnaires, same ...
0
votes
1answer
38 views

How can I test, that stock price changed significantly after certain event?

I need to test whether stock price changed statistically significant after certain event. I got time series of stock price before and after that event. What test or methodology should I use? (not very ...
1
vote
1answer
107 views

Population stratification: adjustment via principal components analysis

I'm new to statistical genetics and trying to learn more about using principal components to adjust for population stratification in case-control studies. My understanding is that the PCA approach ...
2
votes
1answer
1k views

Odds ratios are inappropriate for a cross-sectional or cohort study

I'm aware of the issues regarding the use of relative risk in a case control study. But a colleague recently told me that odds ratios are inappropriate for cross-sectional and cohort studies but can't ...
2
votes
0answers
75 views

Any R packages that can perform generalized linear mixed model with Firth correction? [closed]

I am performing a genetic association analysis with binary outcomes (case-control study) and would like to include a genetic relatedness matrix (GRM or kinship matrix) as a covariate along with others....
1
vote
0answers
24 views

Selecting controls from a case-cohort study when location is important

I am looking at the causes of a disease in cows, both 'environmental' (ie ground-drainage, bedding type etc) and 'biological' (previous disease, sex, weight etc). Most environmental variables are the ...
0
votes
0answers
64 views

Potential bias in a study design

I am trying to design a study regarding Diabetes. I have patients with test results of some indicator about their situation - sugar levels, but not in the classic sense that you may know. Every ...
0
votes
1answer
360 views

Covariates in regression difference in difference

I am posting today because I got some issues to understand how to add covariates in a regression difference in difference. I understand the primary goal of the regression difference in difference. I ...
1
vote
0answers
105 views

How can I combine point estimates and standard errors from non-independent datasets?

I will conduct a 1:2 or 1:3 matched case-control study in order to examine risk factors related to a rare disease. Under this study, I'm planning to repeat selection of matched controls for at least ...
1
vote
1answer
236 views

General Additive Model problems with case-control data in r

I am trying to run the following code using R packages mgcv and survival: ...
4
votes
1answer
413 views

During oversampling of rare events, why are the beta coefficients of the independent variables not affected, but only the intercept?

I have followed the King and Zeng paper and understand the consistency of the prior correction after oversampling in logistic regression. But I am trying to understand why the beta coefficients of the ...
1
vote
0answers
77 views

Can I use the eigenvectors of a principal component for gene discovery?

I am working on a microarray dataset with n samples x m genes, with metadata including a grouping of interest and other summary statistics, e.g. age, bmi. My objective is to find genes that may be ...
1
vote
0answers
40 views

Interpret case control study statistic result

In unmatched case control study, calculating odds ratios, CI and chi-squared values and found out the statistically significant variables. In next step performing multiple logistic regression some of ...
1
vote
0answers
76 views

R or spss? For a conditional regression with 2 dependent variables?

Maybe you find my question a bit simple but I'm really confused as I'm not statistician. I have 2 SNPs (can be proposed 2 genes instead) that are related to a primary disease (like major depression), ...
1
vote
0answers
110 views

Comparing pre/post percentage change between pairs of random samples

I am studying cycling rates along a street that recently received a bike lane. The data I have consists of 4 random samples of people intersected on the sidewalk. For each person, we know if they rode ...
6
votes
4answers
4k views

Why is relative risk not valid in case control studies?

I'm getting my information from: http://sphweb.bumc.bu.edu/otlt/mph-modules/ep/ep713_analyticoverview/EP713_AnalyticOverview5.html It says that in a case-control study, you can not compute the ...
0
votes
1answer
22 views

Case control study for a beginner student

I am a medical student and new to this site so please be patient with me. I am doing a study on effect of zinc on bronchiolitis in children,taking clinical findings over time period in patients given ...
0
votes
1answer
416 views

Interpretation of Random Forest model-predicted probabilities based on case-control training data

I am training a binary classifier using random forest. I'm interested in a clinical event, and my raw data is longitudinal electronic medical records. The goal for this classifier is to be able to ...
2
votes
0answers
40 views

How to improve structural bias correction using propensity scores

Given a control group and a treatment group, which are not equivalent (different distributions on a number of variables), I want to estimate the probability of an event given that the observation was ...
1
vote
0answers
99 views

Correcting bias in non-equivalent group analysis with logistic regression

I have constructed two groups based on observational data: control (C) and treatment (T). T was exposed to a feature that C was not exposed to. My total number of observations is very high (> 300K). ...