Detect when Pull Requests have been closed

[mig5]

Hello,

Is it possible for Jenkins to detect when a Github Pull Request has been closed, when using the polling method (not Github hooks).

My aim is to detect when a Pull Request has been closed and therefore execute a task accordingly (e.g cleanup on a test server to remove a Docker instance related to that previously-open Pull Request).

As far as I can tell, the 'status' of a Pull Request is not exposed as an Environment variable?

Thanks