Questions tagged [medicine]
The medicine tag has no usage guidance.
146
questions
2
votes
1
answer
123
views
Conditional probability of having intellectual disability
I'm reading this paper about a genetic disease. In the paper, there's the following table
where $DD$ means developmental delay and $ID$ means intellectual disability.
From the table (last column) we ...
- 306
1
vote
1
answer
35
views
Comparing binary and continuous predictors for diagnostic test
There is a "traditional" biomarker (binary predictor) used in the diagnosis of a disease (binary outcome) that has a high cost to perform for the clinical labs. I'm studying alternatives, ...
- 13
0
votes
0
answers
16
views
What kind of predictive model can I use to recommend one intervention vs another?
Study question: build a model that predicts if a patient would benefit from treatment A vs treatment B.
Outcome: numerical survey score at 24 months
Other variables: demographics, potentially imaging.
...
- 1
2
votes
1
answer
32
views
How to deal with patients falling out of the study more frequent in one treatment arm
I'm doing a retrospective comparison of two treatments (A and B) for eye disease. Both procedures have the same most common side effect (dependent variable) but their indications differ slightly ...
- 23
1
vote
1
answer
60
views
How do I modify logistic regression in my case (for repeated measures)?
I am a physician conducting some research in Critical Care patients (I have full ethical approval, none of my results will be used to inform patient treatment, etc).
When a person's lungs are ...
0
votes
0
answers
20
views
Selecting correct study design and statistical analysis for my project
I am analyzing risk factors associated with surgical site infections where we want to have a 3:1 case-control study. Other than some brief lectures in my classes, the only thing we were taught about ...
- 1
0
votes
0
answers
15
views
How to compare one continuous variable between two groups when there are gender-specific reference values for the variable?
I want to compare two groups of patients - hospitalized and non-hospitalized - by one laboratory parameter value. There are male and female patients in both groups. But, for this laboratory parameter, ...
0
votes
0
answers
34
views
The choice of a statistical test to verify if there is significant difference between two categorical variables in a single population
Hello everyone I need some help with the choice of a statistical test to verify if there is significant difference between two categorical variables in a single population.
I need to compare the ...
0
votes
0
answers
19
views
Evaluating the potential of a generic diagnostic test while incorporating baseline population prevalence
We have a dataset of 250,000 pregnant hospital patients who were admitted for delivery of the baby. Each patient was admitted only once to the hospital at the time of delivery and all medical ...
1
vote
0
answers
30
views
Caveats in analyzing 2x2 contingency tables
after reading this paper https://onlinelibrary.wiley.com/doi/10.1111/1440-1681.12052 I have real troubles deciding which test is most suitable for my analysis.
The data is following: a group of ...
- 111
2
votes
1
answer
114
views
Medical experimental design with non-comparable control
My population consists of people at high risk of cardiovascular disease who are identified through standard blood tests. These people, when identified, are prescribed some standard medication.
I will ...
- 7,118
2
votes
1
answer
27
views
How to correlate on sharp data changes
I'm trying to correlate changes in atmospheric pressure with headache intensity. I 'know' that there is a strong correlation in my case but out of curiosity I'm willing to take data for as long as I ...
- 123
0
votes
0
answers
68
views
Advice on logistic / multinomial regression regarding death as competing risk
Suppose we want to estimate the effect of a previous exposure on the probability of a disease in a pre-specified study population of patients admitted to hospital. The disease can sometimes be cause ...
- 189
3
votes
1
answer
37
views
Estimating the percentage of a specific factor being related to a condition
I am working on a medical research project where I am trying to find the associations between specific maternal factors and neonatal limb ischemia (NLI) to declare the maternal factors as "risk ...
- 207
1
vote
1
answer
15
views
Correlating two variables
Im doing a medical research in which i have a cohort of 59 patients. I have data for each one about their blood level of a specific marker and data for each one about how many organs the disease I'm ...
- 11
0
votes
0
answers
23
views
How to identify variables with prognostic predictive value?
We have collected biopsy data and clinical data from 232 patients. The are in total 45 different clinical and histopathological variables available. What statistical method(s) is recommended to ...
0
votes
0
answers
36
views
What test can I use to compare experimental group 1 to placebo and to experimental group 2 but not compare experimental group 2 to the placebo group?
The aim of this study is to examine the difference between two different polyphenol supplements on exercise recovery (measurements taken at pre, immediately post, 1 week and 2 weeks post-)
The study ...
- 1
4
votes
1
answer
1k
views
Is reporting univariate regression next to multivariate regression acceptable methodology?
In a paper published in Ebiomedicine (part of the Lancet family journals), the researchers built a logistic model including a variety of predictors and then reported both "univariate" ...
- 410
0
votes
1
answer
78
views
Validity of external cross validation using data generated by the fit model?
Context:
A paper I'm reading uses PDEs to characterise the effects of cancer treatments on the tumour microenvironment. The exact wording used in the paper is:
The predictive power of the [...
- 15
0
votes
1
answer
109
views
Fitting a linear mixed model on repeated measurements data, do I in- or exclude patients with only 1 observation?
I have a dataset of about 300 patients of which 100 have repeated observations of the outcome (2-6 observations per patient) and 200 have only 1 observation of the outcome.
To determine what the risk ...
- 129
7
votes
5
answers
2k
views
How to learn statistics for medical research?
I'm a last year medical student, as we say "Intern doctor". In the future I want to do research on the issue that I want to get in.
Therefore I want to learn mathematics, statistics, R ...
3
votes
1
answer
28
views
Analysing non-outcome variables in meta-analysis
I am working on a meta-analysis project in suicidology. This is more like an academic exercise and will not necessarily be submitted for publication, but I try to be as rigorous as possible.
Now here ...
- 95
2
votes
1
answer
112
views
Help Requested - Bayes' Theorem posterior odds > 1 when applied to covid test
I took an antigen test yesterday and was trying to create a tool to help me interpret the results via Bayes' Theorem. I used actual sensitivity and specificity numbers from the CDC, calculated odds of ...
1
vote
1
answer
100
views
One Feature to Rule Them All: Too Good to be True?
I am trying to build a ML model for diagnosing a certain group of several related but distinct diseases. Using a publicly available medical dataset, I performed data cleaning and feature extraction, ...
- 13
2
votes
0
answers
49
views
Ratio of means for a medical meta-analysis
I am in the process of pooling and analysing data from various studies for a meta-analysis I am working on.
My supervisor (non-statistician) is keen for us to have the ratio of means which was ...
- 21
0
votes
1
answer
71
views
Comparing median scores in two groups and estimating/quantifying the difference
I have two groups (A and B) and data on 3 different biomarkers (a, b and c). What I need to investigate if there is any difference between the groups in each biomarker, and if the difference between ...
0
votes
0
answers
15
views
Question about Most Appropriate Analysis for Repeated Measures (heart function)?
More of a general question.
I have a dataset in which each subject undergoes a specific intervention. I have their pre-intervention heart function and then their 6-month and 12-month post-intervention ...
- 11
1
vote
0
answers
12
views
Growth mixture model to establish trajectories of maternal depressive symptoms
We have been trying to conduct a growth mixture model to establish trajectories of maternal depressive symptoms. We have managed to set up a model in MPlus and it runs, but we have a few theoretical ...
2
votes
0
answers
40
views
Analysis for time to event
In a study I am conducting, I am looking at the time to event (use of opioid analgesic) as a marker of effective analgesia (pain relief) effect for morphine given intrathecally prior to the operation. ...
- 21
8
votes
3
answers
626
views
Is it possible to have 1e-15 p-value when difference is about 1 SD?
The question is about the 2nd data table from the article Symptom improvement in children with autism spectrum disorder following bumetanide administration is associated with decreased GABA/glutamate ...
- 183
1
vote
0
answers
31
views
Using surgeon-level outcome rate as a predictor of outcome in logistic mixed model regression
I'm working on a study that involves predicting a surgery binary outcome (bailout yes vs. bailout no) in a hospital patient dataset. We wanted to include surgeon-level variables in a mixed model and ...
- 11
1
vote
1
answer
49
views
Hypothesis testing - Thesis
I am doing a thesis project in which I need to answer three hypothesis, one measures the direct effect of health consciousness (high vs. low level) on healthy grocery shopping behaviour (high vs. low)...
- 11
0
votes
0
answers
28
views
How should this confidence interval be understood?
In a recent article called Association of Childhood Growth Hormone Treatment With Long-term Cardiovascular Morbidity (behind a paywall, unfortunately), the authors conclude
In this cohort study, ...
- 233
1
vote
0
answers
48
views
How to predict the "when" and "why" of hospital admission?
I already posted in another FORUM but no response. So, posting it here in CV
I have a database that has info on
a) Patient visit records (Inpatient, outpatient, Emergency, etc) and why did he visit ...
- 2,412
8
votes
1
answer
96
views
How can I model negative binomial sampling with a maximum number of attempts until success?
This question is motivated by a study my colleague was working on.
A surgeon intends to examine tissue samples within patients in hopes of finding the presence of some disease within the tissue. The ...
- 31.3k
7
votes
1
answer
366
views
When are ROC curves to compare imaging tests valid? (Focus on the example below)
I would like to ask what criticism could be raised in the following case example: In this paper they test a way of detecting narrowing of the cervical canal on radiographs using a ratio of ...
- 25.3k
1
vote
1
answer
178
views
Post-hoc Power analysis to question a non-significant difference?
so we did this study about surgical success-rates in two groups (n=84 respectively).
The outcome is binary (success vs. failure).
A priori we expected them not to differ and, indeed, there was no ...
- 11
2
votes
1
answer
60
views
Efficiency / Accuracy of Medical Tests for unknown diseases
Context : A few days ago, a few friends and I were trying to conduct a little study on the possible distribution of number of asymptomatic people infected by COVID-19 with the help of a slightly ...
- 581
0
votes
1
answer
44
views
Would it be appropriate with a Chi-2 test in this case?
I am doing a study to see what diagnoses are the most common in a specific group (1) compared to another group (2). I want to show that there is a statistical difference in certain diagnoses between ...
3
votes
0
answers
80
views
Working with tiered data
I have data on a sample of individuals infected with a disease, which has several serovars (distinct variations of the bacteria - e.g., Bratislava, Hardio, Grippo). An infected individual can test ...
- 235
5
votes
2
answers
654
views
Why we use precision/recall in binary classification but sensitivity(=recall)/specificity in medicine?
Sensitivity=recall is used in both fields, but the second metric is different. Why? Both tasks (classification and medicine) look same - data has two classes and we do some predictions on it and want ...
- 3,739
1
vote
0
answers
656
views
What happens when you do a linear regression with duplicate response variables?
Does doing linear regression on data with duplicate response variable given different independent variables even make sense? I was asked to fit a linear regression to data and the first thing I ...
- 720
0
votes
0
answers
32
views
Drop or impute predictor that is missing around 70% of values, but which is known to be highly relevant?
Suppose we have a medical dataset and we are interested in predicting blood pressure using the following variables: age, sex, weight, height, volume of circulating blood, cardiac output, parent with ...
- 883
0
votes
1
answer
24
views
Which test fits the best here? (oncogenic signalling pathways)
I have a list of patients in rows and oncogenic signalling pathways in columns of two independent matrices
One for responders to a drug
one for non-responders to the same drugs
If a patient gets ...
0
votes
1
answer
555
views
What statistical test to use to compare baseline rate to changes over time?
I am working on a project for school and am having a hard time figuring out what statistical test will be conducted in order to find out if changes in the measurement rates are statistically ...
- 1
1
vote
1
answer
262
views
Regression with maximum value for the output variable? (Clinical score)
I am trying to regression an output variable which has a set maximum value (say 100). But when I try to predict it (using both linear and non-linear regression), the predicted values are sometimes ...
- 13
6
votes
3
answers
1k
views
Regression in Causal Inference
I was recently introduced to the topic of causal inference in statistics and I am currently learning about the importance of the backdoor criterion (BDC), as applied to the following DAG. Interest ...
- 269
0
votes
0
answers
33
views
Is there a way to deal with spiking growth rates due to small sample numbers?
I'm looking at plotting county coronavirus case density growth rates (moving 7 day window) and am finding that when cases first appear the new case growth rate is very large due to the fact that there ...
- 101
3
votes
2
answers
207
views
Understanding Medical Testing
While reading a textbook on probability I came across a question:
There is a probability that a certain percentage of the population has a disease. Then a test for this disease could have a certain ...
- 95
3
votes
1
answer
1k
views
Comparing data with two timepoints in two groups with categorical classification
I'm hoping you can help me find an analysis best suited for my purpose. I have a dataset structured like this:
Basically, subjects are measured twice and get a score. If the score remains roughly the ...
- 33