what data structure to use

[eluser]frist44[/eluser]
[quote author="pbreit" date="1281397981"]I'd suggest one table with a status column. I don't see the need to move patients or visits to different tables.[/quote]

Agreed. This will keep the table normalized.

Alternatively, you could have a visits table that references the patients table. You could check the visits table for each user and then do something based on how many records were found.