Tom you are right that there are new pattern of diseases which come with an ageing society: many emerging economies are facing a "dual burden", communicable diseases (Malaria, AIDS, etc.) are still high even though they are declining while non-communicable diseases (diabetes, cancer, etc.) are rising (see here the example form Kenya: https://blogs.worldbank.org/africacan/punished-twice-kenya-s-dual-health-burden).
Everything else being equal, healthcare costs are set to raise rapidly. At the same time, this sector has so much waste in the healthcare that you can get a lot of efficiency savings with new and smarter systems: (see: http://blogs.worldbank.org/futuredevelopment/can-computers-outperform-humans).