A diabetic grandmother is believed to have died after missing a meal and then having an insulin injection in her Mansfield Woodhouse home, an inquest heard.
Margaret Brown, 84, stayed in bed that day and is thought to have only eaten an apple when given insulin to control her condition.
Her husband Victor found her "unresponsive" and called paramedics who gave her an insulin antidote on the way to hospital on February 14.
She was found to be in a coma and died nine days later.
Hospital records referred to her only eating an apple that day.
When her care worker arrived that morning, Mrs Brown said that she had decided to stay in bed.
Consultant Dr Nicola Fischer-Orr said that Mrs Brown had "a complex medical history" which included lung disease and heart trouble as well as type two diabetes.
She told the inquest that it was important to change insulin doses when sufferers have not eaten. It should correctly be given just before a meal.
Family doctor Dr James Sidaway said Mrs Brown initially handled her treatment but her husband recorded details in a diary which showed that "timings of insulin injections were erratic."
He said: "I gave advice to Mr Brown, a fixed dose at fixed times, increased frequency of monitoring blood sugars, four to five readings a day."
It was best to give insulin first at breakfast with the second dose being provided with the evening meal. Sugar levels should be monitored, the doctor said.
Assistant Coroner Laurinda Bower asked: "Did Mr Brown appear to understand it?"
The doctor replied: "He appeared to understand."
Specialist nurse Valerie Tremelling said that Mrs Brown was handling the medication when she first met her in March last year. She told the hearing: "She was dosing incorrectly."
But she "understood about meal time" and was told not to vary the amount of insulin she took.
Miss Tremelling told the inquest: "I did explain to Victor if she has taken her insulin she should have a meal, she has to eat.
"Victor was very caring. He was making sure she was having a meal with the carers twice a day."
When the inquest resumes next month, evidence will be given by Mr Brown and his wife's family. She lived in Collier Avenue, Mansfield Woodhouse.