What kind of GFR do these patients have. What sort of Lovenox dosing are we talking? Prophylactic dosing or 1mg/kg BID?
Usually, you're safe to use prophylactic dosing (40 mg) until GFR drops below 30. Then you use 30 until the patient is ESRD. Then, you need to use UF heparin (5000 U q8h).
For treatment doses (PE, ACS), your dosing is 1mg/kg q12 for GFR>30 and 1mg/kg for GFR<30. Unless you have access to FactorX activity (which you wont at at community hospital), I don't think anyone uses Lovenox in ESRD.
Another thing with lovenox is the weight of the patient. Most CKDs are pretty heavy. Using Lovenox for anyone over 120 kg has never been studied. And, honestly, that's like half my patients. I'll (arbitrarily) go up to 150kg but never above that. If they are that heavy, they stay in the hospital for UF heparin bridging.