Using the provisions of a Business Associate Agreement, Google slurps up data from Ascension Health, the second-largest health group in the US. Patients are not (and don’t have to be informed), and don’t have a way to opt-out.
Layer on the recent acquisition of Fitbit by Google and the privacy picture of Google as a company gets very murky, especially without the prospect of any proactive opt-out, or even better an explicit opt-in instead.