Questions tagged [medicine]

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17 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 ...
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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 ...
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5 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 ...
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33 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. ...
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524 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 ...
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29 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 ...
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15 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 ...
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27 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, ...
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14 views

How to specify a (e.g. GEE) model for subjects and longitudinal observation **with data on 2 eyes**

I have the following study: $n$ patients with data on usually both eyes. A disease can affect either eye (usually one, but can be both simultaneously), at any time, i.e. in January left eye affected, ...
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44 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 ...
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34 views

Feature engineering and longitudinal data

I need some advice for my feature engineering. Suppose I have 90 days follow-up data. on 12 patients and I have the vital status of the patients at the end of these 90 days (deceased=1, alive=0) ...
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1answer
71 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 ...
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27 views

Linear Regression: Use a Subscale of a Questionnaire to Predict Another Subscale

for one of our projects we are planning to use a questionnaire that has two subscales. For an example lets say we assess the Hospital Anxiety and Depression Scale (HADS). It has the subscale Anxiety ...
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1answer
315 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 ...
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1answer
96 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 ...
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9 views

To measure the efficacy of each doctor, why deliberately ignore which doctor treats a particular patient?

I don't understand the last para. Wilfully ignoring "which doctor actually treats a particular patient", in other words "the specific doctor-patient match", still feels "...
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7 views

How to compute cohort study sample size for proportion metric and continuous metric?

I'm trying to design an retrospective cohort study to investigate the effect of smoking on lung cancer, and I've built an propensity score matching model that can match users, shown as follows. $$ P(...
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17 views

Which type of regression to run?

For context, I'm using the Andersen healthcare utilization model, specifically focusing on the three "panels" of predisposing, enabling, and need. Each panel has its own associated variables ...
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1answer
47 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 ...
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1answer
34 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 ...
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12 views

What could be a good way to interpret this neurophysiological data?

We are looking at different combinations of neurophysiological tests, and trying to find out which combinations of variables are best suited for clinical use (diagnosing diabetic polyneuropathy). To ...
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77 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 ...
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1answer
187 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 ...
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227 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 ...
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8 views

Number of preventable events

How would you calculate the following problem? I want to calculate the number of potential preventable events with increasing medication use in a population. For example, say there are 1000 people in ...
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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 ...
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21 views

Deriving Peto odds ratio?

I read the paper using Peto odds ratio method for a research. (Yusuf S, Peto R, Lewis J, Collins R, Sleight P. Beta blockade during and after myocardial infarction: An overview of the randomized ...
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1answer
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 ...
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1answer
43 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 ...
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517 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 ...
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32 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 ...
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2answers
127 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 ...
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1answer
236 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 ...
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1answer
101 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 ...
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1answer
49 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 ...
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2answers
78 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 ...
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1answer
24 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?
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201 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 ...
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36 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 ...
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0answers
7 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 ...
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1answer
97 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 ...
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53 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 ...
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2answers
53 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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16 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 ...
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1answer
50 views

What's the appropriate test to be used in this study?

I was asked by an acquaintance of mine for support in interpreting a medical study. I don't work in healthcare, thus of course this was not professional advice. Two groups of people of size $n_1$ and ...
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29 views

Research question: We measured heart rate variability parameters

In my research we measured heart rate variability parameters (4 different numerical variables) in 4 different situations in 50 subjects - newborns who were of different age. How to control the sample ...
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1answer
40 views

statistical comparison of overtime response to contrast media injection

I'm a medical doctor with no statistical skills, and I need some help on what kind of test to run. I have a set of 20 patients who underwent CT brain perfusion multiple times (twice in most cases, ...
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33 views

What statistical model is this study using?

I am new to statistics and I need to know how to describe the statistical model of this study in my abstract. A retrospective medical study assessing the risk factors predisposing someone to a an ...
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52 views

Is the shrinkage of subgroup analyses in meta-analysis an example of Stein's paradox?

This paper writes (edited for concision): Consider, a doctor in Germany confronted by a meta-analysis of long term‚ $\beta$ blockade after myocardial infarction. Although a robust beneficial effect ...
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1answer
33 views

Would "correcting" for patient characteristic in a cohort study always strengthen the study?

If we are doing a cohort study and investigating whether a variable has an effect on an outcome (say tumor size on nausea), and we run a regression (or chi2) with nausea as a dependent variable and ...