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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Cases number in sub-cohort of a case cohort study

We are planning a study to assess the association between metabolites and cardiovascular disease. Due to budget limitations, we are only able to measure a limited number of blood samples from a cohort....
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Is it possible to "adjust" batch effect as random in survival analysis?

My attempt is to define a survival analysis model from a case-cohort study, where a subcohort is initially selected randomly. Later on, all cases from the entire cohort are added non-randomly to the ...
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Is it possible to have a hybrid case-control cohort study?

In a cohort study, you take 500 people and tell them to smoke cigarettes and you take 500 people and tell them not to smoke cigarettes: you then wait to see how many people in the future get cancer in ...
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How to design study to predict development of a condition B given a condition A

Overall aim: I have patients with a very common condition and I want to see if it is significantly associated with a reduction in a certain type of cancer between 6 months to 5 years later when ...
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Survival sample size calculation

I want to calculate the sample size for a survival study of patients with acute myeloid leukemia, with two cohorts, one receiving chemotherapy and the other not. I want an event-free survival (EFS) at ...
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What does look back mean observational studies?

Consider I am doing observational study either case control or cohort in either of the following cases. Case. 1 Suppose I found enrollment/rate of population with disease is too low where disease ...
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Fitting a Prentice-weighted PH Cox regression to case-cohort data and predicting scores based on new data

I am trying to fit a proportional hazards regression model to case-cohort data (where cases are oversampled and not representative of the population). I am using the Survival package and cch() ...
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Survival analysis of a stratified case-cohort study in R

I am trying to perform a survival analysis for a stratified case-cohort study (1:2) where cases are patients with distant recurrence (DR) and the cohort is composed by patients without distant ...
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When there are many more controls than cases, can I take only part of the controls?

I've tried to build a predictive logistic regression model. However, there are only 500 observations with disease (+) and over 60,000 observations with disease (-). Can I take a random sample (e.g., ...
new_user's user avatar
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Matching across groups on R to control the influence of confounders

I have a cohort of individuals whose exact glucose measurements I have. I want to look at the influence of a variable (which I can call Var1) on the variation of glucose in this group. However, i don'...
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What is cohort effect in general?

I have run into cohort effect in longitudinal data analysis book for quite a while. However, I still could not quite grasp what is cohort effect. What is the meaning of cohort effect and how it will ...
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Retrospective cohort study and case control study

What study would best suit looking at the association between low birthweight and later academic performance? Note - 1000 low birth weight children and 3000 normal birthweight children were included ...
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How to treat random estimates from Estimator III of Borgen et al (2000)?

My question refers to the paper Borgan et al (2000). In short, consider this rather general form of the pseudo-likelihood for estimating coefficients of a Cox model in a case-cohort design (equation ...
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Using an RCT and a retrospective cohort in the same study

I have seen that in RCT’s with very long follow up times the power of the study can be impacted by various factors in Herbet, Kasza, and Bø, 2018, and I was wondering if anyone has heard of comparing ...
luke skywalker's user avatar
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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 ...
Peppershaker's user avatar
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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 ...
oustella's user avatar
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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 ...
Uri Gottlieb's user avatar
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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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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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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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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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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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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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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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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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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 ...
Dino Abraham's user avatar
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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 ...
Lucas's user avatar
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6 votes
2 answers
3k 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. ...
Paris Char's user avatar
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Power calculation (a posteriori) of a cohort study - R software [closed]

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 ...
Happy Cretine's user avatar
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592 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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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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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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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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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 ...
user41301's user avatar
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1 answer
375 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 ...
Miguel Ping's user avatar
1 vote
1 answer
430 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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1 answer
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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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6 votes
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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 ...
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