Forecasting the type 2 diabetes mellitus epidemic and the role of key risk factors in Oman up to 2050: Mathematical modeling analyses

Abstract

Aims/introduction: To investigate and forecast type 2 diabetes mellitus epidemic, its related risk factors and cost in Oman by 2050.

Materials and methods: An age-structured mathematical model was used to characterize type 2 diabetes mellitus epidemiology and trends in Oman between 1990 and 2050. The model was parametrized using current and quality data, including six nationally representative population-based epidemiological surveys for type 2 diabetes mellitus and its key risk factors.

Results: The projected type 2 diabetes mellitus prevalence increased from 15.2% in 2020 to 23.8% in 2050. The prevalence increased from 16.8 and 13.8% in 2020 among women and men to 26.3 and 21.4% in 2050, respectively. In 2020, 190,489 Omanis were living with type 2 diabetes mellitus compared with 570,227 in 2050. The incidence rate per 1,000 person-years changed from 8.3 in 2020 to 12.1 in 2050. Type 2 diabetes mellitus' share of Oman's national health expenditure grew by 36% between 2020 and 2050 (from 21.2 to 28.8%). Obesity explained 56.7% of type 2 diabetes mellitus cases in 2020 and 71.4% in 2050, physical inactivity explained 4.3% in 2020 and 2.7% in 2050, whereas smoking accounted for <1% of type 2 diabetes mellitus cases throughout 2020-2050. Sensitivity and uncertainty analyses affirmed these predictions.

Conclusions: The type 2 diabetes mellitus epidemic in Oman is expected to increase significantly over the next three decades, consuming nearly one-third of the national health expenditure. The type 2 diabetes mellitus burden is heavily influenced by obesity. Interventions targeting this single risk factor should be a national priority to reduce and control the burden of type 2 diabetes mellitus in Oman.

Keywords: Forecasting model; Non-communicable disease; Risk factor.

Figure 1

Description of the mathematical modeling methodology applied in the present study. T2DM, type 2 diabetes mellitus.

Figure 2

The projected type 2 diabetes mellitus (T2DM) epidemic among Omanis aged 20–79 years, 1990–2050. (a) Type 2 diabetes mellitus prevalence. (b) Total number of Omanis living with type 2 diabetes mellitus. (c) Type 2 diabetes mellitus incidence rate. (d) Annual number of new type 2 diabetes mellitus cases.

Figure 3

Projected health expenditure on type 2 diabetes mellitus (T2DM) in Oman, 2020–2050. (a) Total expenditure and (b) expenditure per type 2 diabetes mellitus case assuming fixed annual per capita health expenditure between 2011 and 2050. (c) Total expenditure and (d) expenditure per type 2 diabetes mellitus case assuming increasing annual per capita health expenditure between 2011 and 2050 based on extrapolation of the historical trend ²⁷ . (e) Proportion of Oman’s total health expenditure spent on type 2 diabetes mellitus. Health expenditure was calculated as per the Jönsson’s approach ²⁵ . R is the relative ratio of all health expenditures between individuals with and without type 2 diabetes mellitus. It is the key parameter for converting the per capita health expenditure to estimates of type 2 diabetes mellitus‐attributable spending.

Figure 4

Projections for type 2 diabetes mellitus‐related risk factors among Omanis, 2020–2050. The figure shows the projected prevalence of (a) obesity, (b) smoking and (c) physical inactivity, and proportions of type 2 diabetes mellitus cases that are attributable to (d) obesity, (e) smoking and (f) physical inactivity.

Figure 5

Sensitivity analyses. Projected type 2 diabetes mellitus (T2DM) prevalence in Omanis aged 20–79 years, between 1990 and 2050, assuming (a) the age‐specific obesity prevalence remained stable after 2017, (b) lower obesity prevalence than projected in the main analysis between 2017 and 2050, (c) higher prevalence of physical inactivity than that self‐reported in the Omani surveys ⁹ , ¹⁰ , ¹¹ , ¹² , ¹³ , ¹⁴ , and (d) demographic structure similar to that projected by the Population Division of the United Nations Department of Economic and Social Affairs ²⁹ .