Americans are increasingly frustrated about the subpar performance of this country’s fragmented health care system, and with good reason. A new survey of patients in seven industrialized nations underscores just how badly sick Americans fare compared with patients in other nations. One-third of the American respondents felt their system is so dysfunctional that it needs to be rebuilt completely — the highest rate in any country surveyed. The system was given poor scores both by low-income, uninsured patients and by many higher-income patients.

The survey, the latest in a series from the Commonwealth Fund, is being published today on the Web site of Health Affairs, a respected health policy journal. Researchers interviewed some 12,000 adults in Australia, Canada, Germany, the Netherlands, New Zealand, the United Kingdom and the United States.

Given the large number of people uninsured or poorly insured in this country, it was no surprise that Americans were the most likely to go without care because of costs. Fully 37 percent of the American respondents said that they chose not to visit a doctor when sick, skipped a recommended test or treatment or failed to fill a prescription in the past year because of the cost — well above the rates in other countries.

Patients here were more likely to get appointments quickly for elective surgery than those in nearly all the other countries. But access to primary care doctors, the mainstay of medical practice, was often rocky. Only half of the American adults were able to see a doctor the same day that they became sick or the day after, a worse showing than in all the other countries except Canada. Getting care on nights and weekends was problematic.