How do I run a correlation analysis on medical diagnosis (Dx) codes between two years at patient level. Data runs into 45000+ observations for each patient with different diseases across years and I am trying to establish a correlation using some non parametric approach.
My data would look like:
patient 2013 2014 1 25000 25080 1 49121 49122 1 44490 44490
likewise for another 1000 patients. The codes given are Dx based on the ICD 9 CMS guidelines.