Questions tagged [diagnosis]

medical diagnosis: diagnostic accuracy and diagnostic research

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Could we calculate the sensitivity and specificity when the test result of gold-standard is binary but the new test is 3-class classification?

Now we want to create a new test (Method A) to screen for a disease. In fact, there is a ‘gold-standard’ screening test for the disease (Method B). And the test result of gold-standard (Method B) is ...
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3 votes
1 answer
37 views

The different usage of ROC between diagnotic tests and machine learning

I am currently very confused about the ROC usage in diagnostic tests and machine learning. In the scenario of medical diagnostic studies, many tutorial does not mention the data split procedure as ...
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1 vote
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P-curve analysis for meta-analysis of diagnostic accuracy study

I tried to do a meta-analysis of diagnostic accuracy study. I found out that I have a publication bias based on the Deek's regression test. Thus, I want to supplement my analysis with P-curve analysis ...
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Demonstrating that proposed cutoff score is non optimal

I have a small data set with a test score and classification (positive or negative diagnosis). There is already clinical evidence that the cut point suggested by the test manufacturer produces too ...
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2 answers
61 views

Probability of disease in a patient with risk factor

I'm a doctor so I'm sorry for my basic knowledge of statisctics. I have a prior probability of the disease D $$P(D) = 0.12$$ I know that risk factor RF can cause the disease. Total probability of ...
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4 votes
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Correction for multiple testing required for combined metrics

Let's say I compare two diagnostic procedures (A and B) and want to check if one outperforms the other one using the metric diagnostic accuracy where diagnostic accuracy is commonly described using ...
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1 vote
2 answers
179 views

Network meta-analysis of correlation coefficients: a logical paradox?

A colleague of mine wishes to conduct a network meta-analysis of correlation coefficients for a set of imaging tests (eg ultrasound, computed tomography, magnetic resonance imaging, and so forth). ...
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28 views

Assess sensitivity of a binary screening result across other continuous covariate(s)

I want to assess the sensitivity of a diagnostic screening test, which is a binary test (screen +ve and screen -ve). There is no continuous measure from this test - it is literally yes or no. My ...
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1 vote
1 answer
120 views

Post-hoc power calculation for AUC analysis, to evaluate a new diagnostic test in a cohort

I need some urgent advice for a grant application. I am evaluating a new diagnostic test and at the last minute a Professor has offered me the dataset from a completed prospective study of the disease ...
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1 vote
1 answer
292 views

Network meta-analysis of diagnostic test accuracy studies

I need to make a network meta-analysis of diagnostic studies. Is there a good explanation to do it with R?
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1 vote
0 answers
712 views

Calculating sensitivity and specificity from survival data

I have a diagnostic test performed on 100 participants at baseline. I then follow up these participants for variable periods of time and have data regarding survival. I have used a Cox regression ...
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Handling incomplete information properly when using Bayes' theorem

Just for fun I'm trying to do some simple medical diagnosis using Bayes' theorem. Right now I'm calculating ...
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  • 197
1 vote
1 answer
413 views

Over-fitting diagnosis method

How much difference between train and test set errors can indicate over-fitting? For example in logistic regression. I am trying to classify 11746 comments based on their sentiments in three classes ...
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  • 181
2 votes
1 answer
36 views

Conflicting definitions of logistic regression

I do diagnostic research and am interested in determining how the probability of a patient having cancer is related to the concentration of different molecules in the blood. I have received ...
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2 votes
1 answer
24 views

when add-on test is necessary? better diagnosis strategy

Suppose there are two types of tests available. Test A: low-cost, but relatively less precise; Test B: high-cost, but more precise. Test B can be considered as the good standard with 100% accuracy. ...
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11 votes
5 answers
3k views

Interpretation of Bayes Theorem applied to positive mammography results

I'm trying to wrap my head around the result of Bayes Theorem applied to the classic mammogram example, with the twist of the mammogram being perfect. That is, Incidence of cancer: $.01$ ...
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5 votes
2 answers
264 views

Which statistical model to use when trying to find the beginning of a time-dependent increase

I have a repeated measures data set with time as the independent variable and a single dependent variable, y. That is, for each subject, I have a certain (small, from 1 to 3) number of measurements. ...
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3 votes
2 answers
545 views

What happens with sensitivity and specificity after a second test?

What happens with sens/spec and PPV/NPV if one performs a test twice (or three times etc.)? I will give an example from my own clinical practice. At many hospitals we have a problem with ...
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1 vote
2 answers
859 views

Estimate ROC curve using binormal distribuiton

I am conducting a meta-analysis on diagnostic studies but for each study I have only mean and standard deviation reported. How can I estimate the ROC curve using the binormal assumption in R ? Tks,
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2 votes
2 answers
903 views

Relationship between ROC curve and statistical significance in comparison of two groups

My question is about any possible relationship between the significance of a comparison test (Mann-Whitney U) and the ROC curve. If the comparison test is strongly significant, should we expect a ...
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