Nine scenarios were considered (Low-Low, Low-Medium, Low-High, Medium-Low, Medium-Medium, Medium-High, High-Low, High-Medium, and High-High) by combining the levels of incidence of diabetes and its complications. For instance, High-High refers to a high incidence of diabetes and high incidence of complications. These combinations are given by different values of the parameters I for incidence of diabetes and A for incidence of complications. The model shows clearly the differences in the global number of diabetics (N) and the number of diabetics with complications(C) as illustrated by Tables 4. The number of diabetics resulting from a strategy with high incidence may be reduced by half if a strategy with medium incidence is applied during a dozen of years. A further reduction by three can be obtained by a strategy with low incidence. But, more importantly, the rate of complications reaches 78% in a high strategy of complications, it can be reduced to 63% (respectively 53%) with a medium (respectively a low) strategy of complications. Now, are we really able to act on these incidences and how? Precise answers have been given at different levels.
For the incidence of diabetes, worldwide, it is now commonly admitted that efforts must be conjugated to reverse or at least to attenuate its growing trend, otherwise, health authorities will be unable to provide care and treatments for millions of people who will be affected by diabetes in the future [1,2,7,16,34]. Propositions are mainly directed towards risk factors like obesity, tobacco inactivity, alcohol, blood pressure, cholesterol, inheritance and diet habits in general [4,6,35]. Many authors have dealt with complications [1,2,36,37]. The strategy can be summarized by the recommendations of The Saint Vincent Declaration  which fixed in 1989 the following objectives:
– Reduce new blindness due to diabetes by one third or more
– Reduce numbers of people entering end-stage diabetic renal failure by at least one third
– Reduce by one half the rate of limb amputations for diabetic gangrene
– Cut morbidity and mortality from coronary disease in the diabetic by vigorous programmes of risk factor reduction
– Achieve pregnancy outcome in the diabetic woman that approximates that of the non-diabetic woman.
However, although most of developed countries have reacted by pragmatic measures, the trend remain globally passive mainly because developing countries have been, so far, satisfied with adopting national conventions and adhering to international recommendations instead of working in the field. As stressed earlier, this behaviour can be partly explained by lack of means and poor budget affected to health care but, in general, bad management and absence of goodwill assume a large part of responsibility. The illustration yielded by our mathematical model confirms the diagnosis and the recommendations given by specialists and experts in the field of diabetes and health management in general. Moreover, it gives to health decision makers guide lines of comparison between the social and economic costs of uncontrolled diabetes, and the benefit gained by a productive investment in primary healthcare.