My wife knows some women who are working in near-minimum wage jobs just to pay their health premium. In view of that, this article makes perfect sense.
I know people who have MS (I have MS, so I have acquaintances in the MS community) who are working their jobs to keep insurance. Because even though they'd qualify for disability, you don't get insurance along with the disability...I believe you have to wait 2 years for Medicare to kick in. And to file for disability you have to be unemployed. So they work, and for some they're perfectly able, but for others, it's a struggle.
I work because I like to work, but I work from home. If my job involved going to my office and working in the office environment, working would not be an option. I'd still be covered by insurance because we use my husband's group insurance.
All that to say some people continue working with medical conditions just because without the job they would not be able to purchase insurance due to a pre-existing condition.