If you don't want to read this article, check this presentation. It is one of the best efforts to understand persistence of health expenditures. Summarised findings:
First, persistence by demographic characteristics is generally lower than persistence by co-morbidities. Because co-morbidities are harder to assess, particularly for new enrollees, than demographics, this highlights the need for robust risk prediction models.
Second, people with a co-morbid condition relative to those without the condition are considerably more likely to be in the top 10 per cent of spenders in year t regardless of whether they were in the top 10 per cent in year t–1. However, people with a co-morbid condition are even more likely to be in the top 10 per cent in year t if they were also in the top 10 per cent in year t–1.
Third, those most likely to be in and remain in the top 10 per cent are those with myocardial infarction, congestive heart failure and peptic ulcer disease and in several psychiatric diagnostic groupings, which indicates that these conditions might be appropriate targets for longer-term disease management programmes.
Fourth, although most conditions are less common at younger ages, when they do occur they are more predictive ofpersistently high spending at younger ages, as almost all conditions have the highest predicted probabilities on being in the top 10 per cent of spenders in the following year when they occur at ages under 25 and the lowest predicted probabilities when they occur in the 65-and-over population. Essentially, the presence of a condition at a younger age more clearly differentiates a person’s health care trajectory from that of their peers.These are conclusions for US population, closer studies are needed.
PS. An article written 23 years ago, on concentration and an abstract 11 years ago.