Something jumped out at me in these two charts from “Health Care Spending: Historical Trends and New Directions,” by Alice Chen and Dana Goldman (NBER, 2015):
Yes, there are differences between the history of US and OECD health spending, relative to GDP. But, there are a lot of commonalities too. Both charts exhibit a lot of similarities between the two time series. Look, in particular, at what happened in OECD countries in the 1990s: nearly the same thing as in the US. Why?
Two big things come to mine: (1) common economic trends (like global booms and busts) and (2) spillover of health care technology innovation (i.e., diffusion). Are there other factors in common that would explain the similarities between US and OECD spending? Maybe (3) shared health trends (higher BMI, more diabetes?). What else?