# incidence rate

1. ### Calculating sample size based on incidence rate?

I would like to calculate the necessary sample size for a retrospective cohort analysis. I will be comparing male with female and my outcome will be extra-articular manifestations (EAMs) in patients with spondyloarthritis (more specifically, axial spondyloarthritis and psoriatic arthritis)...
2. ### Probability given an occurrence rate (small airplane fatal accidents)

Hi All, I would like to know if the method I’m using to calculate a probability based on an occurrence rate is correct or if there is a better method to use. Here is some context to give you an idea of what I’m working with: I am looking at determining the probability of a fatal accident...
3. ### P values from 95% CI using poisson distribution

Hi, Hope I'm in the best place for an answer :) I have a study across 10 years. I have an incidence rate that was calculated for each year along with the 95% confidence interval using a Poisson distribution. My question is how do a get p-values for pairwise comparisons? I understand I can say...
4. ### Patient-year Incidence rates comparisons and p value

Dear all, I would like to statistically compare two incidence rates from two different groupes. I found the Incidence rate difference (IRD) formula from "Sahai and Kurshid, 1996". The way to calculate (with examples) are presented in the following page ...
5. ### Statistical analysis and playing around with incidence rates

Dear TalkStats Members, I am a bloody noob to R (used SPSS till now) and decided to learn R now. My first quest would be following: I have incidence rates in an Excel file for a disease, which look quite like this: Year Total Male Female 2003 0.3 0.4 0.2 2004 0.3 0.3 0.3...
6. ### Confidence interval for person time incidence rate

Dear everyone, I would like to estimate a 95%CI of person time incidence rate (as 45 death per 10,000 person year) Anyone knows a way to estimate it ? Same question for Kaplan Meier estimate.. Thanks a lot for your help!
7. ### Incidence rate in a cohort with small sample size

I have a small cohort of people with a specific disease (n=300) and studying the incidence of a related disease (which is kind of rare and normally occur only as a subsequence of this main disease). I have longitudinal data for this cohort over 4 years and I am fine with the study design in...
8. ### Calculate Incidence rate for disease with fertility/mortality data

I am trying to calculate disease incidence in a certain country. I have the number of cases detected over 10 year period. The disease affects children mostly age 5 and younger, but my inclusion criteria are for children <10 years. I also have the country's fertility rates and child mortality...
9. ### little help, incidence rate with lost to follow-up

hi there, i hope you can help me. I am studying for a test and there is an answer that i cannot solve... it asks to calculate the annual incidence rate of a disease, when there are 275 new cases in a year, the number of exposed to the risk factor at the beginning of the year is 2400 and the...
10. ### 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 what the model looks like (negative binomial regression): Dependant_var ~ log(Independent_var_1 +...
11. ### Incidence rate and Kaplan Meier

Hello, I have a question about what we call "incidence rate" at the end of a longitudinal study. If there are a number of censored data, how do you calculate this IR. Is that the same calculation as Kaplan Meir estimate at the end of the study, or there is another way to calculate it...
12. ### Confused with meta-analysis (Hedges); credibility intervals

Dear All, Many thanks in advance for reading this - any help is gratefully received! I'm trying to combine the incidence rates for a complication of surgery (a ratio that i'm using as r). I am using the Hedges method Random Effects Model (as i have hetrogeneity in my studies). I want to...
13. ### Incidence rates - best way to do trend analysis?

Hi everyone, I have a series of admitted patient data and notifiable diseases data over a time period for 3 different study areas. For each year, I have calculated case counts by: overall, male overall, female overall, then each age grouping (<1, 1-4, 5-9,....85+), as well as each age group...