Intervention-only programmes were in general more cost effective than programmes that also included a screening component .
The longer the period evaluated , the more cost-effective interventions appeared .
There was insufficient evidence to answer the question of ( 1 ) whether lifestyle programmes are more cost effective than metformin or ( 2 ) whether low-intensity lifestyle interventions are more cost effective than the more intensive lifestyle programmes that were tested in trials .
OBJECTIVE Explore the cost-effectiveness of lifestyle interventions and metformin in reducing subsequent incidence of type 2 diabetes  , both alone and in combination with a screening programme to identify high-risk individuals .
Lifestyle modification and prevention of type 2 diabetes in overweight Japanese with impaired fasting glucose levels: a randomized controlled trial.
BACKGROUND Previous studies demonstrated that intensive lifestyle modification can prevent type 2 diabetes mellitus among those with impaired glucose tolerance , but similar beneficial results have not been proved among those with impaired fasting glucose levels . We investigated the efficacy of lifestyle modification on  type 2 diabetes  incidence among those with impaired fasting glucose levels . METHODS The present study was an unmasked , multicenter , r and omized , controlled trial . A total of 641 overweight Japanese ( aged 30 - 60 years ) with impaired fasting glucose levels were recruited nationwide in Japan and r and omly assigned to a frequent intervention group ( n = 311 ) or a control group ( n = 330 ) . For 36 months after r and omization , the frequent intervention group received individual instructions and follow-up support for lifestyle modification from the medical staff 9 times . The control group received similar individual instructions 4 times at 12-month intervals during the same period . The primary outcome was type 2 diabetes incidence in annual 75-g oral glucose tolerance tests , diagnosed according to World Health Organization criteria . RESULTS There were no significant differences between the allocation groups in baseline characteristics and dropout rates . Estimated cumulative incidences of type 2 diabetes were 12.2 % in the frequent intervention group and 16.6 % in the control group . Overall , the adjusted hazard ratio in the frequent intervention group was 0.56 ( 95 % confidence interval , 0.36 - 0.87 ) . In the post hoc subgroup analyses , the hazard ratio reduced to 0.41 ( 95 % confidence interval , 0.24 - 0.69 ) among participants with impaired glucose tolerance at baseline , and to 0.24 ( 0.12 - 0.48 ) among those with baseline hemoglobin A(1c ) levels of 5.6 % or more ( the Japan Diabetes Society method ) . Such risk reduction was not observed among those with isolated impaired fasting glucose findings or baseline hemoglobin A(1c ) levels of less than 5.6 % . CONCLUSIONS Lifestyle modifications can prevent type 2 diabetes  among overweight Japanese with impaired fasting glucose levels . In addition , identifying individuals with more deteriorated glycemic status by using 75-g oral glucose tolerance test findings or , especially , measurement of hemoglobin A(1c ) levels , could enhance the efficacy of lifestyle modifications . TRIAL REGISTRATION umin.ac.jp/ctr Identifier : UMIN000001959
Intervention-only programmes were in general more cost effective than programmes that also included a screening component .
The longer the period evaluated , the more cost-effective interventions appeared .
There was insufficient evidence to answer the question of ( 1 ) whether lifestyle programmes are more cost effective than metformin or ( 2 ) whether low-intensity lifestyle interventions are more cost effective than the more intensive lifestyle programmes that were tested in trials .
OBJECTIVE Explore the cost-effectiveness of lifestyle interventions and metformin in reducing subsequent incidence of type 2 diabetes  , both alone and in combination with a screening programme to identify high-risk individuals .