It simply means this. The addiction of heroin keeps him from leaving the life of possibly killing himself and heroin addiction. The " needle " is a slang term that means heroin. So use the word heroin instead of needle and it will make sense to you...

Taking OD to mean "drug overdose", it means his addiction to the (injected) drug got worse. I don't see a specific reference to heroin, but it could be that, no doubt. The "needle" refers to the hypodermic needle used for intravenous injection. The use of "draw" (obj. + direction) is defined by its etymology here; a figurative use meaning "to attract". (draw c. 1200, spelling alteration of Old English dragan "to drag, to draw") (attract (v.) early 15c., from Latin attractus, past participle of attrahere "to draw, pull; to attract," from ad- "to" (see ad-) + trahere "draw" ). Similar to "tractor", "traction", etc.

Sorry it seems different from what I thought at first. He had nearly died of several ODs before but the needle is still attractive for him. seems to be correct after I read the context. Is this sentence from Deep in a Dream: The Long Night of Chet Baker?

draw 引っ張る　back後ろ・元へ draw sb back sbを引き戻す So I think it means His life had been in danger but he was alive because of the injection. His life was drawn back from near-death to life. I'm not a native English speaker, sorry if I'm wrong.