Development of a screening score for undiagnosed diabetes and its application in estimating absolute risk of future type 2 diabetes in Japan: Toranomon Hospital Health Management Center Study 10 (TOPICS 10).

OBJECTIVE: The objective of the study was to develop a screening score for undiagnosed diabetes by eliciting information on noninvasive clinical markers and to assess its effectiveness for identifying the presence of diabetes and predicting future diabetes. DESIGN, SETTING, AND PARTICIPANTS: A screening score was cross-sectionally developed for 33 335 Japanese individuals aged 18-88 years without known diabetes who underwent a health examination. We validated its utility and compared it with existing screening tools in an independent population (n = 7477). After initial assessment of the instrument, 7332 nondiabetic individuals were followed up for a mean 4.0 years. RESULTS: Prevalence of undiagnosed diabetes (fasting plasma glucose ≥ 7.0 mmol/L or glycated hemoglobin ≥ 6.5%) was 2.9% (n = 965). Diabetes score included age, sex, family history of diabetes, current smoking habit, body mass index, and hypertension with an area under the receiver-operating characteristics curve of 0.771. Screening with 8 or more points yielded a sensitivity of 72.7% and a specificity of 68.1%. In the validation cohort, the area under the receiver-operating characteristics curve was 0.806. The developed score with 8 or more points had better positive predictive value (9.6%) and positive likelihood ratio (2.52) compared with existing tools (positive predictive value, from 6.9% to 9.4%; positive likelihood ratio, from 1.77 to 2.46) in which each tool's highest combination of sensitivity and specificity was observed. The 4-year cumulative risk of developing diabetes gradually escalated in association with higher screening scores at the initial examination. CONCLUSIONS: Our algorithm could serve as a self-assessment tool for undiagnosed diabetic patients needing timely medical care and as a prognostic tool for individuals without present diabetes who must be closely followed up to prevent future diabetes.