A quarter of all people in England who may have Diabetes do not know they have the condition, exposing them to heart and kidney disease, Blindness and amputations, a study said on Monday.

A clinical audit from the Healthcare Commission found almost half of women with Diabetes may be undiagnosed and that less than 50 percent of diagnosed people are receiving eye examinations, putting them at risk of going blind.

The report by the NHS watchdog also showed only 56 percent of people with Diabetes were managing their glucose levels within guidelines.

Diabetes is a condition in which the amount of glucose (sugar) in the blood is too high because the body cannot use it properly. About 1.3 million people suffer from Diabetes in England.

On average only 77 percent of people predicted to have Diabetes - according to epidemiological studies - were actually recorded with diabetes.

The report highlighted a need to determine whether there is a systematic under-identification of women aged 40 and above.

The Healthcare Commission audit in 2003-2004 examined 1,700 doctor surgeries and a quarter of a million patients.

The study also found a deficiency in the recording of ethnicity and said the problem needed to be solved because there is a known increased risk of Diabetes for particular ethnic groups, in particular among people from South Asia and those of African-Caribbean descent.

“It is very important that patients and the public are informed of and understand the benefits of treatment and follow-up care for Diabetes, as well as the risks of long term complications that will result without diagnosis and treatment,” Anna Walker, chief executive of the Healthcare Commission said in a statement.