in the medium term technological changes play a more important role in explaining growth in the long run risk factors such as obesity and changes in the prevalence of chronic diseases also enter the picture thorpe et al factors influencing the future trajectory of health spending include demandside factors such as ageing and the health status of a population income growth and consumers behaviour supplyside drivers such as technological progress and changes in treatment practices productivity and health prices and regulatory factors such as institutional characteristics of health systems and their financing