Figure 1.
Flow diagram illustrating the identification of the final analyzed study sample (CPT, Current Procedural Terminology; ICD-9, International Classification of Diseases, 9th Revision; RA, rheumatoid arthritis).
Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.