Questions tagged [medicine]

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2answers
55 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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0answers
15 views

Heart rate vs sleep quality ( need advise about statistical strategy for better compare)

I LIKE TO KNOW ABOUT how to compare result of some detected patters in heart rate for sleep quality,for something like this work: Image-based sleep motion and Slope detection on Hammock, hill and ...
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0answers
16 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
6 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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0answers
9 views

Create synthetic data based on general description of molecular characteristic for modeling

I have a modeling task that classifies cancer subtype based on several molecular features. However, I do not have raw data of tumor sample to extract these features. All I have are several published ...
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1answer
51 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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0answers
39 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
41 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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0answers
10 views

Finding Model/Technique to find effect of alcohol prohibtion on health outcomes

As a study project, using Stata, I'm trying to figure out the effect alcohol prohibition in Kerala state had on health outcomes of Keralans. I did some preliminary descriptive statistics with Stata ...
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0answers
12 views

How to correlate multiple time series data for medical data?

I am working on a university project and the next step is to find the correlation between 1) and 2): ...
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0answers
10 views

Is it possible to perform indirect comparison of before-after/pre-post studies with continuous outcomes (e.g. mean difference)?

I'm currently in progress to perform a simple pooled analysis between surgical approach A and surgical approach B in treating bone fractures. However, as the technique compared involved surgical ...
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0answers
14 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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0answers
25 views

Which test I should use

I have a big clinical data file with 96 columns like age, gender, BMI, etc I want to see which of these clinical characteristics relate to response to chemotherapy....
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1answer
40 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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0answers
27 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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0answers
27 views

I want to analyze the relationship between diabetes mellitus and hypertension?

I have data of blood pressure, fasting blood glucose and post prandium ( which means blood glucose level after 2hrs of having lunch). I wonder if I have to analyze with each data such as fasting ...
2
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1answer
38 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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0answers
32 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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0answers
30 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
29 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 ...
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1answer
14 views

Unsupervised Odd-one-out - paper recommendation

Abstract Problem: I have several series (sharing the same class) of about 400 small images each. Each one of my series has >390 images, that belong together. The rest of the images shares the style of ...
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1answer
30 views

Admissions per year before and after antibiotics?

I need to compare hospital admissions per year before and after the introduction of antibiotics in 100 patients (antibiotics introduced at various time points in the past). Eg. Before antibiotics: ...
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0answers
46 views

Bland-Altman analysis in critical scenario?

I am analyzing some medical data about distance of tumor lesions from surgical resection margins, measured with two different protocols (say, protocols A and B). The overall idea would be to compare ...
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0answers
16 views

Looking for statistics suggestion for data set: EEG “Diagnostic” measurement comparison - non-parametric/ordinal - large proportion of zeroes

I was hoping to get some input on handling a particular data set that falls outside of the purvue of the a lab I am apart of (usually outcomes research). The data consists of a pair of repeated ...
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0answers
6 views

Picking variables to proceed with in a “shotgun” type of study

In medicine, we often have a question such as "I wonder if any of these variables have an effect on the health of these patients". In short, we don't really have a solid hypothesis, we just want to ...
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0answers
110 views

“Unselected sample” vs “random sample”

I've just encountered the term "unselected sample" for the first time, which seems to be fairly commonly used in medicine. Example usages: Climacteric symptoms in an unselected sample of Swedish ...
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1answer
23 views

number of samples needed to show difference between two samples

I am an opthalmologist not trusting what the drug companies are telling me so need some help I am looking a papers on glaucoma where the pressure of the eye is measured. The SD of the measurements is ...
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1answer
74 views

Visualization associations between the symptoms - categorical data in R

I have a data frame with presence of symptoms which are categorical data (1 = present, 0 = absent). For instance: ...
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0answers
82 views

book recommendation - statistics in medicine

Could you recommend a book about the implementation of basic statistic concepts in medicine? In particular, I want to find a book that covers principal component analysis, correspondence analysis and ...
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0answers
14 views

Significance test for Patient Years

Previously, I had a question about CI for Patient-Years (py) and there was a great answer from @TamasFerenci. Now I need to find out the $p$ value for the py of two different groups. I have a table ...
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2answers
325 views

How to get confidence intervals for Patient-Years?

In medicine patient-years is a popular concept. Example: $100$ patients are followed for $2$ years. In this case, there are $200$ patient-years in total. If there were $8$ myocardial infarctions in ...
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0answers
15 views

How to analyze time series data with very few samples for response variable

I want to use R to model a person's blood-iron level to predict how it changes over time. My response variable is blood-iron level and my explanatory variables are related to diet, use of different ...
3
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2answers
73 views

Medical efficacy confusion

On this page one can find the following statement: Magnitude of Effect: Vaccination against HPV-16 and HPV-18 reduces incident and persistent infections with efficacy of 91.6% (95% confidence ...
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0answers
44 views

Particle filter for diagnosis

I have two annual measurements taken on medical images depicting a lung cancer tumor 's condition. I have likelihood function that taken in the measurement values and estimates malignancy of the tumor....
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0answers
33 views

How do I divide a density/frequency plot?

I have a frequency plot, which is essentially a smooth histogram. There are three very clear features (divided with a line by eye). Please note, there are two groups, male and female. The data used to ...
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1answer
204 views

Ordinal regression or multiple regression?

I'm using STATA and this page to find a proper test, but I'm not sure which is better fitting, an ordered logistic regression or multiple regression? My dependent variable is life quality (ordinal ...
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0answers
20 views

Compare change between 2 timepoints with two (paired) variables for paired subjects

This was a difficult question to search for, so my apologies if it has already been posted. Hi, I have the following data in R: I ...
1
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1answer
52 views

Why are likelihood ratios weighted for prevalence?

I notice LLR's are weighted for prevalence if the prevalence differs from 0.5 (see: http://vassarstats.net/clin2.html) Can someone explain why this is? I'm a medical student, not a statistician, so I'...
1
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1answer
39 views

Is this test muddying the water?

In the case of a neurological disease called idiopathic normal pressure hydrocephalus, if the patient is suspected positive for the condition, they are administered a test called the spinal tap test. ...
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0answers
14 views

Demonstrating improved agreement on clinical decision making using the Kappa coefficient

I have a large number of respiratory doctors - some from University hospitals and some from community non-academic hospitals. They have been asked to evaluate 60 patients with various different lung ...
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1answer
43 views

How to compute Nth percentile data from other percentile data of a normal distribution?

I am trying to compute the 98 percentile value of a normal distribution data set. The data is from this website https://www.cdc.gov/growthcharts/percentile_data_files.htm, file No.8 called "BMIAGE". ...
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0answers
33 views

Seeking statistical approach for prediction: (categorical, quantitative) -> quantitative

I am trying to find a good statistical approach for predicting a quantitative outcome from composite variables consisting of a categorical variable and a quantitative variable. Specifically, I want ...
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0answers
34 views

Statistics in medicine, any literature recommendations?

I work in the field of medicine as Ph.D. student. My primary work right now is modeling. And the more I get into it, and its statistics, I can see that I lack a lot, and what I have done, and others (...
4
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1answer
290 views

Univariate or multivariate regression for this project?

I'm looking at the risk of seizure in patients with metastasizing brain cancer and so far have several variables that I want to check to my dependent variable of seizure yes/no. These are variables ...
1
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1answer
74 views

ICD10 (categorical) encoding

I am trying to figure out how best to encode ICD10 codes for input into a machine learning model. It isn't ordinal by any means, however, there is a sort of logic you can apply to just the labels ...
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0answers
31 views

Inferring incidence from prevalence

I have a data set of patients with a risk factor for disease "A", which can be of grade 1, 2 or 3. The grade is determined by a lab value, i.e. Healthy <20, <...
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0answers
9 views

Choice of model for prognostic value of asymptomatic recurrence detection

I am involved in the final step of a project that evaluates the prognostic value of asymptomatic vs. symptomatic recurrence detection; all subjects experienced recurrence. The project proposed a ...
1
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1answer
88 views

What is exactly 30-day post procedure period?

In medical literature early adverse events are often counted for 30-day post procedure period. I was sure that the period's days are as follows: day of procedure, 1st day after, 2nd day after, ..., ...
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0answers
18 views

Deliberately creating unbalanced class size

I'm working on a logistic regression model to predict a certain disease, binary classification (Present/Not_Present). The disease has a normal occurrence rate of about 10% in the general population. ...
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1answer
22 views

Dealing with Varability in Predicting Deaths

I hope this is the best place to ask a question like this and will not be to vague for this type of forum. I am hoping for some corrective guidance with an issue I am having. I work for a non-profit ...