In general creatine is excreted in your urine. You can drink more water and it will help. That's what most doctors recommend. Take vitamin D 2000 IU every day and it will help HBEAG to get negative.
The main connection that I know of is that if your kidneys are bad then your vitamin D level will be low as a result. I have seen some studies that support that vitamin D supplementation even helps people with kidney disease. The only thing that you have to be cautious of is that you are not taking too much. So if your vitamin D level is not over 100 then I would not worry.