Predictors of participation in, adherence to and outcomes of cardiac rehabilitation in older adults: a scoping review
This scoping review of 366 studies reveals that while evidence on cardiac rehabilitation in older adults is extensive, it is unevenly distributed, heavily favoring outcome prediction over participation and adherence, and largely overlooking frailty as a determinant of access.
Original paper licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). This is an AI-generated explanation of the paper below. It is not written or endorsed by the authors. For technical accuracy, refer to the original paper. Read full disclaimer
The Heart's Second Chance: A Map of the Missing Pieces
Imagine your heart is like a high-performance engine that has just taken a hard hit. It's sputtering, maybe even stalled. Doctors have a special toolkit called cardiac rehabilitation to help fix it. Think of this toolkit not just as a gym, but as a guided training camp where patients learn to move safely, manage their stress, and rebuild their strength after a heart attack or surgery. Science has already proven that this training camp works wonders: it helps people live longer, feel stronger, and get back to their lives faster.
However, there's a catch. Just like a popular summer camp that everyone says is amazing, not everyone actually shows up. This is especially true for older adults. As people get older, they often face extra hurdles like having multiple health issues, feeling physically weak (a state doctors call frailty), or simply feeling too tired to start a new routine. The big question scientists have been asking is: What stops older people from joining this life-saving camp, and what helps them stick with it until the end? To answer this, we need to look at the "predictors"—the clues or signs that tell us who will show up, who will stay, and who will get the best results.
The Big Map of Missing Clues
In this study, a team of researchers decided to act like cartographers, drawing a massive map of all the existing research on this topic. They didn't just look at one small town; they scoured the entire scientific world, hunting down 366 different studies published between 2005 and 2026. Their goal was to organize a chaotic pile of information into a clear picture of what predicts three specific things: participation (showing up for the camp), adherence (sticking with the training until it's done), and outcomes (how well the heart actually heals).
Here is what their map revealed, and it's a bit of a surprise.
The Great Imbalance
The researchers found that the scientific community is obsessed with the finish line but ignores the starting line. Out of 1,534 different clues (or "predictor associations") they found in the studies, a whopping 934 were about outcomes. Scientists love to study how frailty or age affects how much a patient improves after they have already started. It's like having a thousand books on how fast a car can go once it's on the highway, but almost no books on how to get the car out of the driveway.
In stark contrast, only 175 clues were about adherence (staying in the program), and 425 were about participation (getting enrolled). The authors suggest that this is a huge gap because if an older patient signs up but quits halfway through, all the knowledge about "great outcomes" doesn't matter to them. They never get to the finish line.
The "Older Adult" Mystery
Another confusing part of the map is that nobody agrees on who counts as an "older adult." Some studies set a hard line at age 65, others just say "the average person in our study was 71," and some didn't even say! The researchers found that in the studies that did give a specific number, the average age was 71.8 years. Because the definitions are so messy, it's hard to compare studies, like trying to compare apples to oranges when you aren't even sure which fruit is which.
The Barriers to Entry
When the researchers finally looked at what stops people from joining the rehab camp, the clues were mostly about who the person is, rather than how strong they are. The most common barriers were female sex and older age. Being a woman or being older was frequently cited as a reason people didn't join. Other barriers included living alone or having mild memory issues.
Interestingly, the researchers found that frailty (feeling weak or physically fragile) was almost never studied as a reason for not joining. Out of the few clues about frailty and participation, there were only 15. Instead, frailty was studied mostly as a reason for how much a patient improved once they were already there. The authors point out that this feels backward: common sense suggests that if you are very frail, you might not even be able to get to the gym in the first place, yet science has mostly ignored this link.
The "Adherence" Desert
The area of the map dedicated to adherence (sticking with the program) was the emptiest. With only 175 clues, it's a desert compared to the lush forests of outcome data. The few clues they did find were scattered and didn't point to one single solution. While things like having social support or a peer mentor seemed to help, the evidence is thin. The authors suggest we need to do more work here because staying in the program is the key to getting the benefits.
What This Means
The study concludes that while we have a mountain of data on how cardiac rehab helps people after they start, we are flying blind on how to get older adults to start and stay. The authors suggest that future research needs to stop just looking at age as a barrier and start looking at physical strength and frailty as the real keys to getting people through the door. They also call for better definitions of "older adult" so scientists can finally speak the same language.
In short, the science has mapped the destination beautifully, but it's still figuring out the best route to get the passengers there.
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