# Questions tagged [incidence-rate-ratio]

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300 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 ...
11k views

### Comparing incidence rates

I want to compare to incidence rate's between two groups (one without a disease and one with). I was planning to calculate the incidence rate ratio (IRR), i.e. incidence rate group B/ incidence rate ...
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 ...
238 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 ...
1k views

### Incidence Rate Ratio (IRR) in R from linear regression using log-transformed data?

I was wondering if it would make sense to calculate IRR for OLS (not poisson), but the OLS is done using log-transformed data? I have a set of crude death rate data (which I'm still debating whether ...
1k views

### Comparing multiple incidence rates

I asked the following question on stack overflow yesterday: Negative binomial function in R Reading comment 2, I understand that I cannot use a negative binomial modeling approach (a Poisson model ...
651 views

### Alternative name for “incidence rate ratio”

I'm using a negative binomial GLM to predict individual level scores on a psychometric test that ranges from 0-27 and presenting the coefficient "incidence rate ratios". It seems a little strange to ...
247 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 ...
610 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 ...
602 views

### 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. ...
3k 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?
66 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 ...
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 ...
2k views

### Comparing the ratios of occurrences

There are two groups: treatment control. Each group has three categories of outcomes: High medium and low blood pressure. The number of subjects is 100 for each group. Now, let's say, for ...
57 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 ...
239 views

### How to prove that one variable's change is influenced by another variable; that is to say, are they related?

I major in bioinformatics. We all know that temperature changes during a year. I find that a disease incidence is really high when temperature is relatively high, while it becomes really low when the ...
721 views

### Inverse Incidence Rate Ratio

I wondered if it is possible to calculate the inverse of an IRR like we can for odds ratio (inverse = 1/x). For example: IRR = 1.40, 95% CI = 1.18 -1.65 Inverse IRR: = 1/1.40 = 0.71 Thank you (...
62 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 ...
387 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 ...
703 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 ...
409 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 ...
735 views

### How to calculate SE for the ratio of two proportions?

I have evaluated the prevalence (proportion) of a disease in men and women, in different studies available in the literature. So I have sample sizes for men and women (in different studies) and also ...
981 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 ...
61 views

### 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://...
49 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 ...
197 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 ...
49 views

### 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). ...
34 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 ...
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 ...
145 views

### Simulation of woman's age of getting breast cancer (cumulative incidence rate)

I am writing a programme to simulate the age at which women will get breast cancer. I have data on the cumulative incidence rate for the whole population. What I am doing right now is using Monte ...
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'...
29 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 ...
20 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 ...
28 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/...
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 ...
123 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 (...
200 views

### 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, ...
936 views

### 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?
39 views

### 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 ...
46 views

### Rolling twelve-month crime rate

I need to do a 12 month rolling crime rate. I have monthly crime counts and population counts every 3 months. For a calendar year I would usually use a population from mid-year as the denominator and ...
1k views

### Comparing Incidence Rate Ratios

I am trying to compare incidence rate ratios (IRR). This is what I have: Group A (exposed vs. unexposed) IRR and Group B (exposed vs. unexposed) IRR So how would I correctly test for the ...
36 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)...
95 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 ...
328 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 ...
517 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 ...
737 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: ...
994 views

### Negative binomial — IRR interpretation for predictors

I have a zero-inflated negative binomial model. I have used incidence rate ratios and I'm trying to interpret the coefficients in relation to my predictors. Most of my predictors are continuous ...
20 views

### 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 ...