The number of missed hospital outpatient appointments increases following the clock change in the spring.
Patients are 5% more likely to miss an appointment in the week after the clocks go forward compared with the previous week. NHS figures show that there were 8 million missed appointments in 2016/17.
Each hospital outpatient appointment costs £120 so missed appointments represent a significant financial issue for the NHS and have a negative impact on patient care.
Researchers found that the rate of missed appointments increases significantly after the clocks go forward an hour. The next change occurs on March 25th 2018.
Psychologists at Lancaster and York universities analysed over 2 million appointments in Scotland from 2005 to 2010 before, during and after the spring and autumn clock changes.
Lead author Dr David Ellis said: "More people missed their appointments after the clocks moved forward in spring. Fewer people missed them after the clocks moved back again in the autumn."
He suggested that the increase in missed appointments following the spring clock change might be due to people losing an hour of sleep and having worse sleep quality.
Dr Rob Jenkins said: "However, it may also be the case that people arrive early for appointments after the autumn clock change and late after the clocks go forward in spring."
The effect wears off after a week.
Dr Ellis said: "Missed appointments represent a significant financial issue for healthcare systems and have an adverse impact on patient care."
Even small reductions in missed appointments could have a large impact on reducing these costs along with the health risks to patients.
And Dr Luther concluded "Potential solutions include sending additional reminders to patients as the spring clock change approaches, or scheduling more appointments in the week prior to the spring clock change."