Patients could gain the equivalent of an extra fortnight of perfect health over the course of the lifetime, the researchers believe.
A team including GP Kamlesh Khunti, professor of diabetes medicine at the University of Leicester, studied the diabetes education and self management for ongoing and newly diagnosed (DESMOND) programme.
The researchers compared outcomes of newly diagnosed type-2 diabetes patients receiving usual care with those of patients who went on the programme.
The DESMOND intervention involves six hours of education on food choices, physical activity and cardiovascular risk factors related to diabetes. It is thought to have benefits in terms of illness beliefs, weight loss, physical activity, smoking status and depression.
The researchers used data collected from 824 patients over 12 months to model the average lifetime cost of the intervention, and its effects on health and life expectancy.
They estimated that the average person would gain 0.0392 quality-adjusted life years (QALYs) or 14.2 days over the course of a lifetime.
Writing in the BMJ, the researchers said the cost for each person going on DESMOND was £203, but would be just £76 when economies of scale and training costs had been taken into account.
The average cost per QALY would then be £2,092, with the £30,000 threshold used by NICE and other bodies.