Will glucose meter strips be safe in the Airplane Cargo Hold?

There are two aspects to this, risk of damage to the strips, and risk of damage to you if your checked luggage is lost, stolen, or even substantially delayed.

Check the package for temperature range and any other limitations on storage for the strips you are using.

For anything medically necessary, you need to have enough in your carry-on and under your direct control to survive without affecting your health until you can replace what was in your checked luggage. Depending on where you are traveling and the nature of the item that may mean consulting a local doctor to get a new prescription then getting that prescription filled. At the other extreme you may only need a few days supply if the item is sold over-the-counter at your destination.