Older people who receive care from the same GP are less likely to be admitted to hospital, research suggests.
Being cared for by a known family doctor cuts the chance of being hospitalised for a range of conditions such as flu, pneumonia or diabetes.
Experts behind the study said older people cared for in smaller GP practices tend to see the same GP more often than those in larger practices.
And they said one of the reasons for a reduction in trips to hospital could be because a GP who knows a patient well can better understand their health needs in a short appointment.
People who know and trust their GP may also be more likely to finish a course of treatment.
The research, published in the British Medical Journal (BMJ), looked at the care received by 230,472 patients aged 62 to 82 for illnesses known as "ambulatory conditions".
These include illnesses that can often be managed by GPs in the community, such as flu, pneumonia, diabetes and asthma.
Other ambulatory conditions include gastroenteritis, urinary tract infections, dehydration, high blood pressure and anaemia.
All the patients had contact with a GP at least twice between April 2011 and March 2013, and this was compared with hospitalisations for ambulatory conditions per patient.
The results showed that patients cared for by the same GP more often were less likely to be admitted to hospital than those who saw the same GP less often.
Compared with patients with low continuity of care, those with medium continuity of care experienced 9% fewer hospital admissions. Those with the highest continuity of care experienced just over 12% fewer admissions.
In those practices with between one and three full-time GPs, 50% of patients enjoyed high continuity of care compared to 30% in practices with seven or more full-time GPs.
Adam Steventon, director of data analytics at the Health Foundation, which carried out the study, said there was evidence continuity of care is declining.
He added: "Improving continuity of care is not just what patients and GPs want, it could also help to reduce pressure on hospitals.
"An ongoing relationship between patients and GPs is important. However, general practices are under considerable pressure, and people are finding it increasingly difficult to see their preferred GP."
He said Government policy "should not lose sight of the crucial role of continuity of care."
The study suggested ways to improve continuity of care, including GPs setting prompts on their booking systems and encouraging receptionists to book patients with their usual GP.
Large practices could also organise themselves into smaller teams, each dealing with a subset of patients.
Professor Helen Stokes-Lampard, chairwoman of the Royal College of GPs, said: "The relationship that GPs have with their patients is unique, and in many cases built over time.
"We know that continuity of care is highly valued by patients and GPs and our teams alike with 80% of UK family doctors deeming it one of the most essential components of general practice.
"Good continuity of care can be particularly beneficial to the growing number of patients who are living with multiple, long-term conditions.
"But delivering continuity of care is becoming increasingly difficult as GPs and our teams struggle to deal with increased patient demand, with fewer resources, and not enough GPs or practice staff."
Dr Richard Vautrey, deputy chairman of the British Medical Association's GP committee, said: "This provides further evidence of the importance and value of the long-term relationship with patients that a GP practice can provide, which benefits not only individual patients but also the wider healthcare system."
He said the BMA had consistently "called for investment directly in to practices rather than funding separate and often fragmented access schemes."