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Table 4.10
Prevalence of Diabetes Mellitus and Prediabetes

Parameters Value

Prevalence of prediabetes (IFG) 1.24%
Prevalence of DM with prior diagnosis 2.46%
Prevalence of DM without history of diagnosis 4.86%

Using an average of the growth in prevalence of prediabetes in the data provided by Quan
and colleagues to substitute for the cumulative incidence proportion of prediabetes, we
calculated that the growth in incidence of prediabetes per year would be
0.99% (Quan et al., 2017).

To calculate the progression rate from prediabetes to DM, we used the resultant data from
Okada, Tsushita et al.’s 2017 Japan Ningen Dock study to explore the variation in impact of
prediabetes management and lifestyle modification on prediabetic patients (Okada et al.,
2017). Okada and colleagues’ study faced a four-year timeline and compared the cumulative
incidence of DM progression from prediabetes in two groups, the Ningen Dock study group
that received guidance on lifestyle modification, and a control group without comprehensive
guidance. The researchers found that the cumulative incidence of DM progression
in the study group was 11.2% (95% CI, 10.7–11.7%), compared to a cumulative
incidence in the control group of 14.9% (95% CI, 14.2–15.6%). We do not account
for the progression of prediabetes to DM in patients within the first year given that the
prevalence of different diagnostic states is already set in the 2014/15 PHS. After, our model
assumes that individuals will begin developing DM as early as the second year at an
incidence interval of 2.8% (per annum incidence derived from 11.2% cumulative incidence
every four years). Separately, we expect an annual cumulative incidence of DM progressing
from pre-diabetes as 3.73% for the Base Scenario (per annum incidence derived from 14.9%
cumulative incidence every four years).

The parameters used in the BIA are as follows (Table 4.11) (calculations can be found in
Appendix P):

Table 4.11

Parameters list for model assumptions

Parameters Value
Starting points
Prediabetes prevalence as at 2022 1.24%
Already have diagnosis before 2022 2.46%
Diabetic but without diagnosis before 2022 4.86%
Flow parameters
Incidence of prediabetes from no diagnosis 0.99%
Base Case: Incidence of new DM cases from prediabetes cases 3.73%
Scenario 1 & 2: Incidence of new DM cases from prediabetes cases 2.80%
Regression rate from prediabetes to normoglycaemia 2.82%
Scenario 1 & 2: Remission rate from DM to prediabetes 7.00%
Assumed complication rate multiplier of 20+ years of DM history 150%

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