I am one of the winners in the Oregon lottery [winners could get Medicaid]. Going from no insurance to insurance is very confusing. When you have no money every health question starts with "would I rather live with this problem and have electricity, or treat this problem and keep my milk in a cooler for a month or so?" Stepping back into healthcare was like hopping on a merry-go-round. The doctor wanted to do test after test to come up with baselines for me, and I had a hard time showing up at the lab.
I hadn't been going to the doctor to find out new things about what was wrong with me. A huge part of living without insurance is not thinking about your high blood pressure damaging your kidneys. It takes a while to change that. It took me 6 months to change my level of co-operation with my doctor, and she said I was faster than many. Most people got into the groove about their 2nd physical. Then we had year-to-year values for blood tests and weight and blood pressure. Those numbers getting better helped.
I lost 40 pounds the first year, regained 15, and lost another 10 the next year. Now my doctor wants me to try for another 10 pound loss. I have gone from 3 blood pressure medicines to 1, and that's at a half dose. This whole time my blood pressure stayed the same, but dropping 2 pills and keeping the same score is a health upgrade. My blood sugar is still pre-diabetic, but diabetes is a progressive disease. If you keep your blood sugar at the same level for 2 years, you are making progress with managing diabetes. The study would have found me to make no progress, but my doctor thinks I have improved.
The last point is that diabetes and cholesterol are both food-based diseases. The Oregon Medicaid project enrolled very poor adults, I think the income cutoff was much lower than the SNAP benefit limit. So none of us have access to unlimited fresh fruit and low fat meat. We still eat nothing but carbs for most meals.
The mental health benefits are enormous. Changing how you eat and exercise is hard for everyone, but most people can throw a bit of money at the problem and grease their way. With no money for better food, no money for good shoes to go on walks, no rain gear, no walkman for listening to music as a distraction while walking, change is harder.
What I would like to see is a study that shows the changes in these measurements over a 2 year period for people who have insurance. People with insurance for the last 20 years are not always improving their health, either.