Korea ranks at the top of the world when it comes to treating cancer, stroke and heart attack but trails behind in terms of preventing chronic illnesses.

According to the annual OECD "Health at a Glance" report out Monday, only 6.2 percent of Korean patients over 45 die within 30 days of being hospitalized with ischemic stroke, the lowest fatality rate in the group of rich countries.

And Koreans' survival rate five years after being diagnosed with rectal cancer stood at 71 percent, the highest in the OECD compared to the average of 61 percent.

The survival rate for colorectal cancer stood at 71.6 percent and for breast cancer at 86.3 percent, also way above the OECD average of 63 percent and 85 percent.