Questions tagged [medicine]

The tag has no usage guidance.

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

Should I have a "missing" data category when calculating chi-square?

I am looking at the effect of two different drugs on ~1000 patients' pain 48 hours after surgery. There is no missing data regarding which drug the patients received. Pain is recorded as either low, ...
user avatar
  • 1
0 votes
1 answer
26 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 [...
user avatar
  • 15
0 votes
1 answer
32 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 ...
user avatar
  • 119
7 votes
5 answers
1k 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
26 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 ...
user avatar
0 votes
0 answers
16 views

Mixed effects model- control for multiple events

I am working with mixed-effects models (lme4, in R) to model observational data of change over time of biological measures for multiple subjects. This is my reponse variable. At 'random' intervals ...
user avatar
  • 207
0 votes
0 answers
10 views

What is the best way to identify which criteria are more predictive based on a case definition?

I am assessing the validity of a case definition for identifying a suspected fatal overdose. The case definition includes 18 criteria (e.g., reported drug use immediately prior to death, reported ...
user avatar
2 votes
1 answer
83 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 ...
user avatar
0 votes
0 answers
16 views

Book on medical features

As a general outcome prediction problem in the medical field, whenever a patient is a basis of an observation there is also some free-form information on previous medical history. It is clear that ...
user avatar
0 votes
1 answer
75 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, ...
user avatar
  • 3
2 votes
0 answers
44 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 ...
user avatar
0 votes
0 answers
11 views

Finding the contribution of correlated factors

Suppose one has data on some random population subset, where we are given two binary factors "eats healthy" and "is a smoker" for each person as well as data regarding an outcome, ...
user avatar
  • 461
0 votes
0 answers
20 views

Descriptive Analysis of Longitudinal Data

May be a simple question, but I would like some advice on how to best describe longitudinal data for a set of individuals. I have medical data recorded at (somewhat) random time intervals, with a ...
user avatar
  • 207
0 votes
1 answer
36 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 ...
user avatar
0 votes
0 answers
19 views

How and what to test: symptom limited test without symptoms?

I'll try to explain the question as easy as possible with two example patients of my $\approx 100$ patient groups. All patients had a specific operation, prior and a year after operation they ...
user avatar
0 votes
0 answers
14 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 ...
user avatar
1 vote
0 answers
9 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 ...
user avatar
2 votes
0 answers
36 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. ...
user avatar
8 votes
3 answers
562 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 ...
user avatar
  • 183
1 vote
0 answers
30 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 ...
user avatar
0 votes
0 answers
16 views

How to collapse models with different intervals of a key variable?

We have some clinical variables on patients under a disease partially characterized by a key clinical variable. To study how this disease behaves in different levels of the key clinical variable, we ...
user avatar
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, ...
user avatar
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 ...
user avatar
  • 1,780
8 votes
1 answer
80 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 ...
user avatar
6 votes
1 answer
338 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 ...
user avatar
1 vote
1 answer
125 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 ...
user avatar
  • 11
2 votes
1 answer
51 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 ...
user avatar
0 votes
1 answer
36 views

Would it be appropriate with a Chi-2 test in this case?

First of all, thank you for such a warm welcome to this forum. 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 ...
user avatar
3 votes
0 answers
79 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 ...
user avatar
5 votes
2 answers
321 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 ...
user avatar
  • 3,669
1 vote
0 answers
420 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 ...
user avatar
0 votes
0 answers
26 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 ...
user avatar
0 votes
1 answer
20 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 ...
user avatar
0 votes
1 answer
114 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 ...
user avatar
  • 1
1 vote
1 answer
93 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 ...
user avatar
  • 13
6 votes
3 answers
769 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 ...
user avatar
  • 259
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 ...
user avatar
  • 101
3 votes
2 answers
132 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 ...
user avatar
4 votes
1 answer
599 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 ...
user avatar
0 votes
1 answer
178 views

multilevel factor odds ratio - help SPSS

I'm a newbie when it comes to SPSS and Statistics, and in need of some help. I would like to know how to calculate a multi level factor odds ratio in SPSS, for an outcome (0 vs 1 : no disease vs ...
user avatar
0 votes
1 answer
51 views

How to model logistic regression with a predictor that predicts another predictor in the model

I'm trying to answer a question about whether resident (surgical trainee) presence increases the risk of complications during surgery, and I'm trying to figure out how to include total operative time ...
user avatar
  • 13
2 votes
2 answers
122 views

How to do meta-analysis of diagnostic tests with only sensitivity and specificity?

I am a junior physician, and I've run into some problems with the meta-analysis of diagnostic tests and I was hoping to get some input. Some background: Aside from my undergraduate statistics courses ...
user avatar
2 votes
1 answer
28 views

Patient's data anonymisation

Is there any available statistical method for assessing whether anonymisation performed on patient data in a medical dataset is sufficient?
user avatar
  • 617
0 votes
2 answers
398 views

How to interpret regression coefficient when adjusting for baseline

I want to estimate the effects of sex on sodium level at follow-up after starting treatment with a thiazide (diuretic medication). The cohort consists of persons starting thiazide treatment. Follow ...
user avatar
  • 103
1 vote
0 answers
65 views

Want to determine the safest site for a femoral arterial puncture

We collected the data form CT scans of 200 cases as follow: The site of the bifurcation in relation to head of femur in each patient from (1-5) and according to the pubic tubercle (1-3). The site of ...
user avatar
1 vote
0 answers
10 views

Reporting significance values for relative risk (RR) and number needed to treat (NNT)

I have calculated the relative risk & number needed to treat using the log-binomial regression model. NNT is calculated as the reciprocal of the marginal difference. Does it make sense to report ...
user avatar
2 votes
1 answer
114 views

How to determine the best non-linear regression model? Metabolomic analysis of different tumor sites

I have performed some metabolomic analysis of different tumor sites and would like to see if there are any correlations between the metabolite levels and some of the tumor characteristics that I am ...
user avatar
1 vote
0 answers
55 views

Is Group Testing feasible (for a virus) when individual testing is not viable (as was done for disease screening of draftees in WW II)?

Background: Today, Andrew M. Governor of the State Of New York, stated (and he claims for the very first time the use of the word ‘cannot’ in his news briefing), that he could not possibly test on ...
user avatar
  • 1,810
1 vote
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 ...
user avatar
  • 11
1 vote
0 answers
19 views

Procedure to Smooth Noise for Threshold Values

Suppose I am looking at an estimate $\hat\beta$ in a clinical trial data. With $a=.05$, a patient with $\hat\beta>1$ is considered to have some medical condition. A daily example could be a 24-hr ...
user avatar