Why would medical records be worth handing-over to a hostile government? What could they do with that sort of information?
My first thought is for blackmail purposes: especially if the records contained sensitive information about sex, drugs, or mental health issues. Secondarily, to an enemy power, it may useful to know if someone who might be facing you on the battlefield or diplomatic conference room has something like cancer, and therefore may have a limited life expectancy or cognitive issues. Look at all the surmising here about Biden's and Putin's health and impact on their decision-making capability.