According to my own knowledge base on most refusal letter I have observed ...
If you recieve correspondence letter before medical update is likely a refusal.
Ideally a biometric Validity correspondence should be received immediately after your biometrics exercise. But due to haphazard notifications on the cic portal it comes at a different time. However, the recent trend is if it comes after a passed medical then it is deemed positive and followed by Passport request most times and if it comes before then it is maybe not a good sign( please this is based on my own idea .. .