About this repo

This repo contains the R code (as Quarto files, both qmd and html) used to conduct analyses in the pre-print. The major research questions we attempt to address are:

1. Do ALS-like symptoms appear in insurance claims before a person is diagnosed with ALS?

2. Does the risk for ALS vary between urban and non-urban areas?

3. Does the effect of ALS-like symptoms on future odds of being diagnosed with ALS vary between urban and non-urban areas?

How to use the code

This repo contains four main files:

1. build_cohort.qmd and the rendered build_cohort.html contain the R code used to identify ALS cases and find matching non-ALS controls. Also removes any ALS cases with <365 days of enrollment between their first enrollment date and the first ALS date,

2. extract_covariates.qmd and the rendered extract_covariates.html contain the R code used to extract covariates used in the analysis. Also builds the data sets used in the analysis.

3. main_analysis.qmd and the rendered main_analysis.html include the main analysis reported in the paper and also all the non-survival sensitivity analyses.

4. age_at_als_dx.qmd and the rendered age_at_als_dx.html include the age-at-diagnosis survival analyses.

Links and references

• The pre-print can be found on medRxiv
• Hosted versions of the HMTL can be found here