By Gary Rogers, data reporter

Hundreds of older people in Gravesham may be living with undiagnosed dementia, according to estimates by the NHS.

Figures collected by GPs show that there are 680 people over 65 who have been diagnosed with some form of the illness. But estimates by the NHS, based on the age profile and gender of patients, suggest that the real figure may be 1,401.

That means an estimated 721 pensioners living with a debilitating illness that has not been formally recorded by their doctor.

The figures are being collected in response to the Prime Minister’s Challenge on Dementia set up by the previous PM, David Cameron.

The Department of Health wants GP surgeries in England to increase the rate of diagnosis.

The latest data, for November, shows that the diagnosis rate for the whole of England is 68.2% but area to area this ranges from 25% to 90%. Gravesham is below the national figure with a diagnosis rate of 48.5%.

Sally Copley, Alzheimer’s Society’s director of policy campaigns and partnerships, said: “The essential first step to the care and support everyone should have a right to is a diagnosis.

"People tell us that our support is a lifeline, but we cannot reach them if we do not know who they are." - Sally Copley, Alzheimer's Society

“Research has found that people with dementia who live alone, or in care homes, or from black, Asian and minority ethnic communities, have lower rates of diagnosis – contributing to the variation we’re seeing across the country.

“People tell us that our support is a lifeline, but we cannot reach them if we do not know who they are.

“In areas with low diagnosis rates, the Government has to work with the NHS to find out what’s going on. People with dementia deserve better.”

The Royal College of General Practitioners said doctors realised the importance of spotting the signs of dementia but in some circumstances an early formal diagnosis was not in the best interests of the patient.

Chairman Professor Helen Stokes-Lampard said: “We recognise that timely diagnosis of dementia can be helpful in that it provides an opportunity for some patients to get their affairs in order and make long-term plans for their care.

“But pressuring patients to seek early advice and a diagnostic label, especially for short-time memory lapses, can create considerable worry for both them and their loved ones, especially when follow-on services and treatment options are limited.

“There may also be some instances where GPs might decide to delay giving a formal diagnostic label, especially in the early stages, if there is minimal impact on the quality of a patient’s day-to-day life.”