Questions tagged [case-cohort]

A study design in epidemiology: a subset of a cohort study are more intensely measured at baseline, while the whole cohort is followed for outcomes. Primary analysis compares baseline experience of “controls” to baseline/follow-up experience of cases.

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13 views

How to do propensity score matching for a cohort study?

Suppose I want to look at the relationship between smoking and lung cancer, and want to use propensity score matching to select a similar group of people to study. Knowing that age, and gender are ...
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49 views

Can exact tests compare groups from case-cohort studies?

I have reviewed several helpful threads most related to my question and many thanks to the authors. The first thread suggests odds ratio is valid for cohort studies, but risk ratios or hazard ratios ...
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25 views

How to handle missing data in a small sample

We've conducted a cohort research (single group), with 30 subjects. The study is an observational study, with two measurements (at the beginning and at the end of the study period). 5 of them were ...
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173 views

Case-Cohort analysis in R

I am attempting to conduct a Case-Cohort analysis with Cox's Proportional Hazards Model. The data set looks similar to the one below: ...
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186 views

Simulating a 2x2 contingency table (cohort study)

I want to simulate a 2x2 contingency table with fixed row totals. I know that the distribution would be binomial but I can't seem to do it in a matter than constraints the randomly generated elements ...
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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 ...
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29 views

Characterization of risk factors for a very rare condition

I am looking at a cohort of patients including 13000 patients, out of which only 160 have condition A. Out of these patients, only 6 have condition B. I would like to be able to characterize those ...
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1answer
60 views

How to assess the effect of an intervention when having a control sample is unethical?

I'd like to assess the effect of a medication X on some scalar, nominal and ordinal parameters of disease Y. Problem is, this medication X has proven to greatly reduce mortality in patients with ...
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269 views

Lasso-Regression on a casecohort with interval survival data (Cox-Barlow-Method)

My problem in a nutshell: I would like to do a lasso- regression in R on interval survival data with weights and there seems no package available which can handle lasso, interval survival data and ...
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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 ...
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1answer
886 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 ...
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50 views

Combining intra and inter cohort comparison using panel-data

After reading numerous posts, I still haven't found a conclusive answer to my question. I have panel data for the whole population(multiple years, interlinked by personal identification numbers), ...
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1answer
1k views

Cox Proportional and Pooled logistic regression in a observational cohort study - laymans terms

So my brain is just not understanding the difference between the two above. I am currently writing a literature review and have to explain the significance of what was found in the research. The ...
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109 views

Observational study design method vs hypothesis testing vs other?

I am trying to understand the following: do more customers purchase an item because it is discounted 'now' because they engaged with the product before (viewed it, added to a wishlist etc) vs just ...
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575 views

What's the difference between a (prospective) cohort study and difference-in-differences analysis?

I am an undergraduate economics student and I am familiar with difference-in-difference estimators: For example, to evaluate the effect of a policy change, measure the outcome of interest before and ...
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778 views

Can you use survival analysis (e.g. Cox PH model) on case control data when only cases have an uncensored survival time?

In my data I have $n_1$ people who had an "event" and $n_2$ people who did not. Cases (those with an event) were oversampled substantially (the true prevalence is probably more like 1 in 10000). If it ...
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Overpowering of controls

I am working with the national inpatient sample database. It is a complex survey design with one stage power sampling unit - hospitals - among stratas, with national estimates weights on hospitals. ...
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1answer
460 views

Power calculation (a posteriori) of a cohort study - R software

Does anyone know if there's any R library to calculate the power of a cohort study with n=9511 Reference: 50 year trends in atrial fibrillation prevalence, incidence, risk factors, and mortality in ...
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1answer
478 views

Should cohort studies in diagnosis research be age-matched?

It is clear that cohort studies in epidemiology should be matched for such variables as age, gender, etc. However, cross-sectional cohort studies may also be used to assess the accuracy of a new ...
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28 views

what need to be fixed in a contigency table

I am little bit confused as to what entry (i.e. the "total") are fixed in a contingency table in cohort study and case-control study. I was reading somewhere that different "total" are considered as "...
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363 views

Proportion of controls in case-cohort design for survival analysis

I'm working on a study that is drawing from another very large study, and proposing a case-cohort design in order to reduce the overall number of samples we use (primarily due to cost of sample ...
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86 views

Power of a case control test as a function of P(X=1) & P(Y=1)

For our course in statistics we had to build a simulation which would give insight in the power of a case-control study vs that of a cohort study, both trying to discover an association between 2 ...
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114 views

Epidemiology cohort studies question

If we are conducting a cohort study of factors associated with recurrent myocardial infarctions (MI) following the first one, should our study population at baseline include subjects who had ...
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1answer
345 views

Cohort analysis for media site

I'm trying to find a reasonable way to measure retention of a site (news site). I'm trying to do cohort analysis: I've grouped all visits by year/week, and measured the percent of users that kept ...
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1answer
303 views

Predicting new data using a Case-cohort Proportional Hazards Model

I am fitting a Case-Cohort Proportional Harzards (CCH) model using the Survival (version 2.37-4) package in R 2.15.3. Normally with a Cox Proportional Harzards (coxPH) model, I can use the survfit ...
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1answer
982 views

Dividing controls between two groups of cases

I have a set of data that contains cases and controls. I would like to divide the cases by a particular phenotype before running my tests, to see how these groups differ (but not necessarily to ...
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102 views

R CCH CI Univariable Analysis

Using the survival package in R I am trying to calculate 95% confidence interval (CI) of the proportional hazards model coefficient. Normally this is pretty simple to do with the survival package. <...
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379 views

Follow-up updates in case-cohort designs

In a case cohort, you randomly sub-sample some feasible number of the cohort (say 20%) and then afterwards add all of the cases that were not part of the sub-sampling. So while a case-cohort is easy ...