Kaiser Family Foundation chart shows who has insurance in the United States, and how it is obtained.
Health Coverage Guide goes into ways that having insurance saves individuals versus those without insurance.
The wikipedia entry lists a variety of facts from different angles about the uninsured.
Florida, Georgia, Texas, New Mexico, Nevada and California are listed as states with larger numbers of uninsured. Possibly this could be because of high populations of undocumented workers, or other assumptions based on census data, or other causes.
An explanation of a base cost of a procedure (appendectomy) across sectors of the population (indigent vs uninsured vs insured).
This article looks at the higher probability of uninsured to have less favorable outcomes due to lack of routine following for treatment and medical care.
This considers the types of insurance versus the outcomes. At the time of the writing, Fee For Service insurance was better than care obtained through a Health Maintenance Organization type of plan. But those with HMOs tended to have better outcomes than those on Public Assistance health care plans, and those people tended to do better than the uninsured.
People without insurance are more likely to forgo preventative care, avoid seeking care, continue with bad habits, continue engaging in self-destructive behaviors without admonishment from physicians.
This site has many hyperlinks to many studies which probably support the case for expanding insurance coverage.
There are probably many more reasons to consider getting insurance if one does not have it, but when times are tough, and money is scarce, finding extra to afford insurance premiums (payments for future promised benefits) might be difficult for the unemployed or underemployed or working poor.
Most people probably do not want to be diagnosed as diabetic. Yet, many people probably experience issues with blood sugars.