Those most likely to be confronted with all three problems were under 65 and were either uninsured or had public insurance like Medicaid, the researchers found.
"Adults aged 18 to 64 had the highest rates of these experiences with physician availability, whereas the rates among those 17 and younger and 65 and older were right about the same," she said.
Uninsured adults were more likely to have problems finding a doctor or to be told a doctor would not accept them as new patients, compared with adults who had private health insurance.
The number of people with public insurance who had problems finding a doctor was also high, Gindi noted.
McCanne said that the number of people facing these difficulties in finding a doctor is likely to increase as out-of-pocket costs rise and insurance companies cut doctors from their plans.
"The greater exposure to out-of-pocket costs, along with a new trend of reducing the numbers of physicians and hospitals in the provider networks established by the private insurers, will impair access for more individuals who have coverage through their private plans," McCanne said.
The researchers, however, did find that patients aged 65 and older had fewer problems finding and being accepted by a doctor.
"A bit of good news is that individuals over 65 who have Medicare still have good access to physicians. Although Medicare can certainly stand some improvements, it still remains a very viable alternative to replace our current fragmented system of financing health care. Under an improved Medicare that covered everyone, these statistics on the uninsured would not be so depressing each time they are released," McCanne said.