Almost 75% of older children in England and Wales with diabetes are not getting key health checks, a study suggests.
Data from 27,682 children and young people showed 25.4% of 12-year-olds have all seven recommended annual health checks, such as eye screenings.
However, the Royal College of Paediatrics and Child Health, which carried out the audit, says the overall picture is one of improving care.
Diabetes UK said missed health checks for children was “very worrying”.
Health officials recommend all children with diabetes should be assessed to ensure they are managing their condition properly.
Guidelines from NICE (National Institute for Health and Care Excellence) state that all children with diabetes should have their blood sugar levels checked every year and those over the age of 12 should also have six other annual health checks.
These include measures of growth, blood pressure, kidney function, cholesterol, as well as an eye screening and a foot examination.
The report looked at data from children and young people with diabetes up to the age of 24 who attended paediatric diabetes units in England and Wales between April 2014 and the end of March 2015.
Nearly all had type 1 diabetes requiring daily injections of insulin.
It found that those achieving “excellent diabetes control” – equivalent to a blood glucose level of less than 7.5% – rose from 15.8% in 2012-13 to 23.5% in 2014-15.
It also showed that 23% were now reducing their risk of future complications from the disease.
Experts say the average blood glucose level (HbA1C) – a marker that measures overall diabetes control – in children with diabetes fell for the fifth consecutive year.
Despite the improving picture, Dr Justin Warner, consultant in paediatric endocrinology and diabetes at the University Hospital of Wales and clinical lead at the Royal College of Paediatrics and Child Health, said annual health checks for children should not be missed.
“They form part of a lifetime of screening for complications which, if recognised early, are amenable to interventions that reduce progression,” he said.
But he said the rate of improvement of those achieving “excellent diabetes control” had exceeded that seen in some other European countries.
The report also noted that worryingly high numbers of children over the age of 12 were already showing signs of early complications.
And children and young people living in the most deprived areas were found to have worse blood glucose test results than those living in more affluent areas.
Bridget Turner, director of policy and care improvement at Diabetes UK, said: “There remains considerable variation in the level of care provided.
“This is very worrying because if children and young people are not supported to manage their diabetes well in early life, they are more likely to be at risk of debilitating and life-threatening complications in adult life such as amputations, blindness and stroke.”
She said it was essential that the parents of children and young people with diabetes were supported to help them deal with the illness.