# Questions tagged [incidence-rate-ratio]

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8 views

### Converting from incidence rates to raw counts using separate datasets?

I wish to estimate the proportion of all breast cancer patients who are white, black, etc. There are many statistics of incidence rates within each race group, e.g. breast cancer incidence within ...
13 views

### Is there a way to compare incidences of 2 diseases in the same cohort?

I would like to compare incidences of 2 diseases in the same cohort for the past 10 years. Eg. I want to see whether there's an association between incidence of heart disease and incidence of ...
40 views

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### Creating confidence intervals for rates per 100,000 with very small numerators? [duplicate]

I am conducting a study comparing rates per 100,000 of new HIV diagnoses over time in certain regions. I intend to calculate 95% confidence intervals for each rate. However, some of my numerators (HIV ...
67 views

### Meta-analysis with random effects on prevalence data with > 2 possible outcomes: is it necessary that the weighted prevalences all add up to 100?

I am running a meta analysis on prevalence data. Participants can belong to one of four groups. Each study produces the percentage of participants that belong to each group (e.g., Group A: 50%; Group ...
23 views

### Which statistical analysis model to use to calculate the relationship between diabetes incidence and endothelial function?

I have longitudinal data with 2 follow ups at year 1 and 3. At baseline we have measure of endothelial function and we want to calculate the relation ship between endothelial function and diabetes ...
47 views

### What is the difference between 1-year partial prevalence and annual incidence?

In cancer research, like in this article, partial prevalence is sometimes used to assess the epidemiological state of a disease in a population. The document I'm trying to understand (link, in french)...
72 views

### Interpreting incidence rate ratios (IRR) in panel data

I am running a negative binomial panel regression (xtnbreg) that includes a pre/post estimator for an intervention (with controls) and am trying to understand how the incidence rate ratio should be ...
23 views

### Standardize prevalence and incidence rates calculation in R

There is a cohort study of 500,000 individuals with over 70 conditions. For each condition, I need to calculate Annual standardized prevalence, with time since birth as the underlying time scale ...
44 views

### How to model counts of a categorical variable?

I'm interested in assessing the impact of various covariates (age, sex, Charlson comorbidity score, etc.) on the incidence rate of a pulmonary event. However, the event is not binary. Each patient ...
32 views

### Calculating the confidence interval for an incident rate ratio for a continuous spline variable from a Poisson GLM

I have a rather large and complicated Poisson GLM with a mix of categorical (many binary, yes-no) and continuous values. To calculate the incident rate ratios (IRR) for the binary variables, I simply ...
26 views

### comparing incidence rate

I have a data set of individual level data for the outcome in question. I also have aggregated data (at a national level) from which I'm obtaining the denominator. Using this information, I've ...
10 views

### Test for yield and disease incidence in block design

I need to analyse a set of data coming from an agricultural experiment, with the intention of assessing the incidence of a certain disease in potatoes under three different treatments (plus blank). I'...
60 views

### Calculate incidence rate per person or in total

For my study I am doubting about the following: First I want to present the incidence rate for patients who received an CT-scan. I thought I would just count all the CT-scans that took place and ...
397 views

### what is x per 100 person years mean?

In medical papers, it is very common to calculate incidence rate and mention it's unit as per 100 person years. What does this means? I know that incidence rate is the amount of people got the event ...
31 views

### Confidence intervals for Ratios of Correlated (nested) Age-Adjusted Rates

I am interested in calculating the incidence of disease in an ethnic subpopulation (denoted $X$) and comparing this with the incidence in the entire population ($\Omega$) (where $X$ is a true subset ...
22 views

### Modeling hip fracture incidence (hospital-based cohort design)

Hoping someone can help me out with a question I have on an analysis looking at prosthetic hip fracture incidence following hip replacement surgery (exposure=type of implant, with reference being the ...
132 views

### Validity of non independent observations in Poisson regression when modelling incidence rates

I have a question regarding fitting a poisson model to non-independent observations when assessing the incidence of an outcome. I am interested in the incidence of some outcome, O, over time. I have ...
242 views

### Calculate probability of disease appearance

I am a doctor so please be kind with me and my basic understanding of statistics. I have a dataset consisting of patients and their visits and I have labelled the presence of a specific kind of mole ...
63 views

### Visualize the rate of reported cases of disease with respect to the population

I have to do some visualizations about vaccines. I downloaded data on reported cases of vaccine-preventable diseases (for example, measles, tetanus, etc.) here. These data are absolute values. I ...
30 views

### Standardized Infection Rate from predicted probabilities. Which method?

I need to calculate the Standardized Infection Rate (SIR), that is the ratio between actual cases of infection and predicted cases based on a predictive model. According to CDC https://www.cdc.gov/...
316 views

### Compare incidence rate

During the follow-up time, event A will happen multiple times, and there are 3 types of A, I call it A1, A2 and A3. I wonder if there is a statistical method that I can calculate the incidence rates ...
402 views

### Interpreting incidence rate ratios in poisson without exposure variable

I have a dataset made up of observations of procedural cases, with a count outcome (variable X carries the number of times a specific finding was detected in one procedure/case). My denominator is the ...
209 views

### Calculation of person years in a cohort study for survival analyses

I am analysing data from a cohort study using primary care data (but I linked them up to secondary care data only for the outcome). Specifically, I am looking at the adoption of a specific care ...
367 views

### How to calculate relative risk if the reference group has an incidence of 0?

this appears to be a quite difficult question. As we know, if 20% of the smokers developed lung cancer and 10% of the non-smokers developed lung cancer, then we say that cigarette smoking is ...
250 views

### Adjusting variable for covariate to calculate rates or metric

In this report by Dartmouth Institute, rates of utilisation (per patient) were reported by year and regions. The input measure of utilisation were said to have been adjusted for differences in age, ...
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### Incident rate ratios with log-transformed variables in Poisson regression

I'm in a bit of a mess with interpreting the output of a Poisson regression model with log-transformed predictors. The predictors are counts, and the log transforms them for the linear part of model. ...
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### Can odds ratio be in different direction to rate ratio?

My question is whether it is plausible to have "Rate Ratio" showing an increased risk while "Odds Ratio" (based on the same data) showing decreased risk? I have an example in this article: http://...
47 views

### How to Assess Significance of the Difference in Incidence Rate Ratios?

Imagine we estimate two sequential negative binomial regressions. In the first one, we use say 3 predictors (x1, x2,x3), and in the second, we use the same 3 plus an additional variable (x4). We are ...
54 views

### What type of statistical test should be used to compare successes of two treatments?

Say I have two treatments, "hot" and "cold". I care about a certain outcome, say "success". I have data on the number of successes out of, say 100 trials in the "hot" treatment. Similarly, I have data ...
128 views

### Interpreting categorical x categorical interaction in a poisson regression [duplicate]

I have run a poisson regression with two categorical predictors (treatment and disease severity) and their interaction, controlling for a number of relevant covariates. Treatment has two levels (...
263 views

### Are these negative binomial regression results reasonable?

I did a negative binomial regression on a data set with 4 covariables. The count outcome has values up to 600. I did a mixture model with 2 components, also called a latent class model. However, I am ...
4k views

### How to calculate 95% CI for cumulative incidence rate using R?

for example, 30 events during 10000 person-years, the cumulative incidence rate is 3 per 1000 person-years, how to calculate its 95% CI?
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### Modeling incidence rates in family-based cohort: Poisson vs Cox

I have a cohort made of family trios and affected sib pairs (probands have rheumatoid arthritis - RA). I would like to calculate some incidence densities (for example apparitions of RA, of disease 1, ...
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### Relationship between survival time and incidence rate

I am working on an operations issue. We process patients in care and pay close attention to their discharge rate, which is more or less calculated as an incidence rate (discharges per 100 patients). ...
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### Can you calculate a standard error from confidence intervals?

Specifically, can I calculate a standard error from an incidence rate with known confidence intervals but no population size data?
2k views

### How can I calculate a confidence interval for a rate ratio, if I only have the rates?

I want to calculate the 95% CI for an incidence rate ratio (IRR), but I only have incidence rates per 10,000. (I do not have counts for the 2x2 table.) Specifically, the incident rates were ...
574 views

### Can I compute the p-value for a list of incidence rates?

Coming back to statistics after a long time, so please forgive any ignorance. I'm curious how I might be able to argue for statistical significance of a test. Specifically, I'm after a ...
799 views

### Calculating OR and IRR for a zero-inflated negative binomial model from estimates

I used the PSCL package to run a zero-inflated negative binomial model on some count data I have. This package gives the following output: for the zero part of the model: ...
731 views

### Calculating p-value from chi-square when comparing two incidence rates

I am trying to follow this guide to calculate the p-value from an incidence rate between two samples. The raw data is patients' use of an action plan before and after education. Before education 7 ...
305 views

### Survival rate trends in case-control studies

I submitted an article which was rejected due to the improper way of performing the survival analysis. The referee left no other details or explanations other than: "survival analysis on time trends ...
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### Aggregating rates of events in a population

For every 100,000 people, 4 people succumb to event $X$, a different 10 to $Y$, and 2 others to $Z$. I would like to know the number of people that succumb to any of $X$, $Y$ or $Z$ per 100,000. Is it ...
3k views

### Interpreting negative binomial regression with log transformed independent variables

My independent variables were highly skewed, so to normalise the distribution they were log transformed. Also since there were zeros in the data, I've added + 1 to transform the variables. This is ...
420 views

### Estimating mortality rates with direct age-standardization

I'm attempting to calculate the mortality rates of AMI (acute myocardial infarction) in patients (cases) with high bloodpressure, between the years 2001 to 2008. For every case I have 2 matched ...
628 views

### Interpretation of log transformed predictor in negative binomial regression

I mainly want to make sure that I'm making the correct interpretation here. I built a negative binomial regression model predicting a count variable. There was evidence of overdispersion or I would ...
6k views

### Calculate incidence rates using poisson model: relation to hazard ratio from Cox PH model

I want to calculate incidence rates to present along hazard ratio's in order to present both relative and absolute measures of risk. I saw in other studies that such incidence rates can be calculated ...
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### Considering Age-standardized incidence rates: Will changing the reference population change the incidence rates

Im trying to calculate the mortality rates for males and females in two different disease groups (type 1 and type 2 diabetes). In my primary analyses i forgot to use respective gender as the ...
1k views

### Calculate confidence interval from point estimate and standard error

Im having a problem with calculating a confidence interval for an incidence rate ratio between two populations. Using PROC STDRATE from SAS, I've obtained the Incidence Rate Ratio (the difference in ...