Not likely. The word is often applied to a prognosis. It means that the prognosis for the patient is uncertain, and perhaps not that great.Just " discharge condition: guarded" . It must omit some words. I guess it describes about the patient is guarded before being disharged. But I do not know about " guarded" exactly.
The patient may not be ill enough to keep in the hospital (especially these days, when they get you out the door as fast as they can), but the expected long-term outlook for their illness may not be positive, or may be simply unclear. It may not be a life-threatening illness at all. "Guarded" isn't so much a condition as a prognosis.It's commonly used in news articles in the US for people hospitalized with a serious medical situation whose prognosis is still not fully clear. (The "turn for the worse" could be lurking around the corner.) So the weird thing to me in the OP is that no one in guarded condition is in a position to be discharged. They might or might not make a recovery, which is hardly the situation to be considering discharging someone.