I would select yes for many diseases: Cancer, type 1 diabetes, HIV, TB, hepatitis, copd, all sorts of autoimmune disease, autism, etc. If you have a life-altering disease that requires regular treatment I would consider that a serious disease. Some diseases may be missed by the health screening. Some doctors don't do a very thorough exam and some illnesses may not show on basic testing. What is ultimately important is the cost of treatment. The panel physicians and hopefully most people now know that HIV patients can now lead long productive lives if they seek treatment although AIDS often is life-limiting just significantly less than before. You also may be sent a procedural fairness letter and you may have to provide a breakdown of your health costs. Each HIV+ patient is different and some may be taking the latest combo medication that still is under patent or have other health issues. If you have already looked at your medical costs just think of it as a step in the process and not a refusal. Think you need to stop overthinking things and this is not an attack on HIV+ people.