From what my doctor said, losing weight helps or even cures most cases of sleep apnea. It all really depends on why you have sleep apnea. Is it strictly weight related or is there a defect with your airway?
To give an example, I was diagnosed with sleep apnea, machine set at 17 (high). I had a rough preop period for unrelated reasons (they found a mass in my stomach during first preop tests on 2010, nothing to worry about thankfully!) so through the time I waited for surgery, I worked and worked and actually lost 76 pounds.
I will tell you that I sleep wonderful now. I haven't had a second sleep study and I no longer sleep with cpap which are huge no-no's. Sleep apnea doctor told me with every 20 pound weight loss, you need a new study. I'm being rebellious I guess but I do not recommend it! Call your sleep apnea doctor, let them know about your journey and see what point you should come in for another sleep study.
Congratulations and best of luck to you!