Coughlan D, Saint-Maurice PF, Carlson SA, et al. Leisure-time physical activity throughout adulthood is associated with lower medicare costs: evidence from the linked NIH-AARP diet and health study cohort. BMJ Open Sport & Exercise Medicine 2021;7:e001038. doi:10.1136/ bmjsem-2021-001038.
Tell us more about yourself and the author team
So, I am Diarmuid Coughlan. I am a health economist and aspirational athlete!
From 2015-17, I was a Cancer Prevention Fellow at the National Cancer Institute (NCI), where I worked with Chuck Matthews and Pedro Saint-Maurice. Both are wonderful epidemiologists interested in physical activity and are great colleagues. Chuck oversaw the NIH-AARP Diet and Health Study and invited me to analyze data that involves Medicare data. He also introduced me to Janet Fulton and Susan Carlson from the Centers for Disease Control and Prevention (CDC). Both are accomplished physical activity researchers. It was my absolute pleasure to work with all of them on this project.
What is the story behind your study?
NIH-AARP Diet and Health Study asked permission of respondents to link their survey responses to Medicare data. This data linkage had never been explored before. I was happy to get involved. However, I was moving back to the UK to get married! We, therefore, worked entirely remotely on the project way before the pandemic!
We developed an analysis plan and received study approval in late 2017. The preliminary analysis was conducted in early 2018. We noted several issues that needed resolving. The sample of 21,750 is far less than the 500,000 that responded to the initial questionnaire. This is because our study question applied to those aged 65 years (eligible for Medicare entry) and consented for data to be linked. We also needed to account for end-of-life costs which are usually very high. This involved cutting a second dataset removing the last 12 months of claims. We conducted numerous analysis (e.g. Quintile regression) of the data and perform many sensitivity analyses throughout 2019. At the start of 2020, we were ready to submit our findings to the world.
In your own words, what did you find?
We found that trajectories, where respondents maintained or increased leisure-time physical activity throughout adulthood were associated with lower healthcare costs in later life. We estimate about $824 to $1874 per annum (10 to 22%). Pedro had previously led the sister article looking at premature mortality and found that increasing physical activity is associated with longer life. To me, this is a compelling finding and public health message for physical activity advocates. This study shows that it is also beneficial for healthcare payers such as Medicare that the public stays active throughout adulthood.
What was the main challenge you faced in your study?
The main challenge that we faced in this study was tried to get it published! The paper was rejected by Health Affairs, IJBNPA and BJSM. As my wife was having our second child in February 2021, we decided to pay for open access rather than reformatting and submitting in a higher impact journal. I think the move towards format free submission process is to be welcomed.
To get some attention for the paper, we also engaged with social media by making a video and publishing an article in The Conversation:
Video of paper: https://www.youtube.com/watch?v=7txBb47a6IY
If there is one take-home message from your study, what would that be?
Staying active throughout adulthood is associated with lower healthcare costs. It’s in everyone’s interest to promote leisure-time physical activity throughout adulthood.