Lamar Odom Has A 50/50 Chance for Survival

Lamar Odom's survival is right on the line.

Sources at the hospital tell us doctors are now saying Lamar has a 50/50 chance of surviving after enduring multiple medical problems ... the apparent result of complications from drug use.

Our sources say doctors are saying 4 of Lamar's organs, including his kidneys, are failing. As we reported, he's had a series of strokes in the hospital and has heart problems as well.

The doctors are saying with each failing organ the chances of survival go down significantly.

We're also told doctors are having trouble determining the extent of any brain damage because the organ issues make it difficult to test and get an accurate reading on brain function.