Intersection of Multimorbidity with Function and Frailty

Join Dr. Michael Steinman, from the University of California, San Francisco and Dr. Rebecca Brown, from the University of Pennsylvania Perelman School of Medicine, as they define multimorbidity, frailty, and functional status as three important syndromes in geriatrics that influence health status and quality of life for older adults. Find out more about how these syndromes intersect and their implications for interventions that may reduce incidence of disability.

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Transcript

Michael Steinman, MD: Hello, I'm Mike Steinman. I'm a geriatrician and a professor of medicine at the University of California San Francisco and the San Francisco VA Medical Center. And it's my pleasure to be here with my colleague, Dr. Rebecca Brown. Rebecca is an assistant professor of medicine in the division of Geriatric Medicine at the University of Pennsylvania, and she's a core investigator and a staff physician at the Philadelphia VA Medical.

Today we'll be discussing the key points from the Data Measures and Measurements module that was authored by Dr. Brown around the Intersection of Multimorbidity with Function and Frailty. Rebecca it's so nice to have you today. Can you just take a few words to introduce yourself? 

Rebecca Brown, MD, MPH: Absolutely. Thanks so much for having me.

As Mike shared, I am a geriatrician and a researcher at University of Pennsylvania in the Philadelphia VA, and my research focuses broadly on optimizing functional status, which we'll be talking about for socioeconomically vulnerable older adults. [00:01:00] 

Michael Steinman, MD: So to start off, Rebecca, people talk about multimorbidity and frailty and functional status, but many people who use these terms may be unclear what's the exact distinction between each of those concepts. So to start us off, could you just define what each of these terms mean and tell us why they're important?

Rebecca Brown, MD, MPH: Sure. So let's start with multimorbidity. So the most common definition of multimorbidity- there are different definition, is having two or more concurrent physical or mental health conditions.

So you can imagine that's a broad range of different conditions someone can have. And it's quite common among adults age 65 and older in the United States. So to give you an idea, in one pretty recent review, there were 92% of adults in that age group who had two or more chronic medical or physical health conditions. So that's multimorbidity. 

Frailty is [00:02:00] defined as having decreased physiologic reserve and increased vulnerability to stressors. So, for example, an older adult who is frail may be very vulnerable to having bad outcomes after a surgery, for example. And it's usually defined in two common ways. The first is frailty indices, and the second is called deficit accumulation models.

And just very briefly to give you an idea of what those are, the most common frailty index is called the Fried Frailty Index. This was first published back in 2001, and it looks at whether older people have any of five common criteria. And these are unintentional weight-loss, self-reported exhaustion, weakness, slow walking speed, and low physical activity.

So you can kind of get an idea that the more of those conditions that you [00:03:00] have, the more of those criteria that you have, the higher your risk of frailty. So having three or more indicates frailty and having one to two indicates pre frailty. 

And then the other way that frailty is commonly defined, and actually we see it more and more being defined in this way because it's easier to measure than the frailty indices is using what's called a deficit accumulation model. And that's kind of just a fancy way of saying how many of a list of deficits- and these are often drawn from survey data, but increasingly from clinical data or administrative data that you can get from electronic health records - How many of a list of deficits does an older adult have? In one of the earliest deficit accumulation models, which was developed by Rockwood, they look at 70 deficits. And these include chronic medical conditions, lab test abnormalities and so forth, and they look to see how [00:04:00] many of those conditions does a person have. So it can range from zero to all 70. So these typically range from zero to one on a scale, and the more you have, the more frail you. 

And then the last condition we'll talk about is functional status. So this is in geriatrics defined as the ability to perform daily tasks that are needed for someone to live independently. And usually we divide those into basic tasks and instrumental tasks. The basic tasks are things like bathing, dressing, transferring, toileting, eating, sometimes walking across a room is included there. And the instrumental tasks are more cognitively complex tasks like managing medications, managing finances.

And functional status can be assessed either by a survey or a questionnaire, like self-report, or it can be assessed objectively, quote unquote, for example, by an occupational therapist or a physical therapist. So all three of these things, [00:05:00] multimorbidity, frailty, and functional status are core concepts in the care of older patients because all of them are associated with adverse downstream outcomes.

Meaning that people who have multimorbidity, people who have frailty, people who have impairments in function are at higher risk for a whole host of things, including using more acute care, like being admitted to the hospital, going to the emergency room, being admitted to the nursing home, and often have lower quality of life and may be at higher risk for death.

Michael Steinman, MD: So, I mean, these be really interesting concepts and on the face of it they sound very distinct. So multimorbidity is just the presence of two or more chronic conditions. Frailty is the sort of complex idea of decreased ability to respond to physiologic stressors and functional status, just the ability to do daily activities.

So on one hand they sound really different, but on the other hand we [00:06:00] sort of, when we have like a mental model of like a older adult, we might sort of put the, all of those things sort of together. So when you think about these different concepts, what's the relationship between the three of them and where do they overlap and where are there distinctions that people should be thinking about as they think about understanding these concepts and measuring them for research in clinical care?

Rebecca Brown, MD, MPH: Sure. So for multimorbidity and frailty, they have a lot of very similar risk factors. So for example, people who are older, people who are women are both at higher risk for multimorbidity and frailty, people who have lower socioeconomic status, and it goes on. So they have a bunch of similar risk factors, and they also have very similar outcomes.

One of the key differences when you think about these three concepts is that, functional impairment, like having difficulty with those basic daily activities we were talking about before, that is an adverse outcome that can be seen with both frailty and [00:07:00] multimorbidity, that people who are frail, people who have multiple chronic conditions, are at increased risk for downstream functional impairment.

So I think that's one of the core features, one of the core distinctions to take away. Is that multimorbidity and frailty are actually risk factors for downstream functional impairment or it's as it's often called disability. 

Michael Steinman, MD: That's interesting. And so when you think about sort of developing a new intervention for older adults, or you are say reading or journal article or hearing a presentation where someone else has talked about intervention that they've developed, how do you think about sort of these three concepts, multimorbidity, frailty, and functional status in terms of the role they play in, for example, who might be included in this study and what is sort of the upstream factors, like the risk factors or the things you're trying to intervene on, and what are the downstream factors? What's the outcome you're trying to prevent? In other words, should we be trying to prevent frailty or should we [00:08:00] be trying to prevent multimorbidity or is that really kind of the wrong way of thinking about it?

Rebecca Brown, MD, MPH: So I think that's a really interesting question, Mike. Thinking about what studies have focused on as typical outcomes in the geriatrics literature and where we're headed in this field. Many of the studies in the field of geriatrics and gerontology have often looked at disability or functional impairment as the outcome.

We talked about how in the conceptual model, often frailty and multimorbidity are considered upstream, and so disability is kind of the ultimate outcome, and that's often been conceptualized as the outcome in trials such as the capable intervention led by Dr. Szanton at Johns Hopkins, or the life study, which looked at major mobility disability as an outcome.

And the interventions in these cases are often physical activity interventions or interventions that try to [00:09:00] address risk factors (in) the environment to modify the outcome of functional impairment. What I would say is that sometimes these studies consider multimorbidity and frailty as risk factors and look at those as intermediate outcomes to see if frailty, for example, is also improved on the pathway to improving disability, but not always. So I think maybe in terms of future directions, incorporating measures of multimorbidity and frailty in studies that are seeking to modify the ultimate outcome of functional impairment and disability could be one way to make our field even more rigorous.

Because some of the studies so far have had kind of mixed outcomes in terms of whether frailty is improved in studies that look at disability as the ultimate outcome. And then I think that an emerging area is also looking at [00:10:00] frailty as an outcome in itself and seeing what interventions might improve frailty.

So we're seeing an increasing number of studies in that area sometimes with mixed results, but there's a lot of exciting work coming out in that area, looking at frailty as an outcome in itself. 

Michael Steinman, MD: Yeah, it's very interesting and it's sort of hard to sometimes wrap one's mind around, particularly given that the two ways that frailty are commonly measured are quite distinct from one another.

The deficit accumulation model versus sort of the specific domains that are measured in, in the Fried model of frailty. And so, understanding, you know, how to even measure frailty as an outcome of the study is not always a straightforward question. 

Rebecca Brown, MD, MPH: Absolutely. And I think many trials that particularly look at physical activity interventions to modify function, they often use something similar to the Fried frailty index.

So you know, they might have a dynamometer to measure your hand grip strength, and they might be [00:11:00] measuring gate speed and using those as an index of frailty. There is a hypothesis that physical activity can also reduce the incidence of frailty because as you can, thinking back to those components that go into the frailty index: grip strength, walk speed, weight loss- physical activity is a great tool that can potentially improve all of those components and lead also to decreased disability.

So that's something I would say that studies so far have been mixed and we're still, there's still more work going on and more work to be done to understand the real relationship of frailty to functional status and how intervening on frailty might improve function as well. 

Michael Steinman, MD: To close out, one of the things I've been thinking about as we've been talking is this really nice slide you had in the presentation you prepared on this module, which shows the relationship between multimorbidity, frailty and [00:12:00] functional status. And it was a Venn diagram that shows, you know, how many people have just one of them or two of them, or all three of them. And in that Venn diagram, there are some areas where all three overlap, or two of the three overlap, but there's a lot of people who only have multimorbidity but not the other two, or who only have say, frailty but not multimorbidity or functional impairment.

Can you talk a little bit about how you think about that intersection and the extent to which we should be thinking about these concepts as sort of all driving at the same thing, or whether they truly are distinct. 

Rebecca Brown, MD, MPH: So I think there's, you know, sometimes a temptation to oversimplify, you know, further on in the slide set I also have some conceptual models that show how, you know, frailty and multimorbidity might be upstream from functional status, but this slide that you're pointing to, which comes from Fried's original 2001 study using data from the cardiovascular health study shows that really there is [00:13:00] not a perfect overlap, right?

Not everybody who has frailty has disability. Not everybody who has multimorbidity has disability. And I mean, there may be reasons for that as we talked about, part of it is that frailty and multimorbidity are risk factors, so it's possible that they have not yet developed disability, but are at risk for disability.

But there also are so many different phenotypes and so much variation in how people can present. I mean, you can imagine if multimorbidity is being defined as having coronary artery disease and having high blood pressure or something like that, that those two conditions together, they don't necessarily manifest in either frailty or functional impairment.

And the same thing for someone who has just a couple features of frailty, maybe they don't actually have disability yet. So I think that [00:14:00] there's so much heterogeneity that it can be hard. This might be part of the reason that we're seeing some of those results in the trial where there's not a clear effect that improvements in frailty also translate into improvements in functional status because people may be relatively early in the pathway or there just may be cases where these things are not risk factors, depending on how you're defining frailty or how you're defining multimorbidity.

And this is still something that we're working on, defining subtypes of frailty. That's a very active area of research where people are trying to understand using some of those deficit accumulation models, what different phenotypes and pathways people may have when they have different types of frailty. Or similarly for multimorbidity, people are still working to figure out what's the best way to define multimorbidity, which combinations of chronic conditions are most predictive of downstream disability and other adverse outcomes.

[00:15:00] So I think it's just important for us to keep this complexity in mind. At the same time, we're also understanding more simplistically that frailty and multimorbidity may be upstream in this causal pathway. 

Michael Steinman, MD: I think that's a really great summary. You know, it's- you can get super deep down in the weeds and there's a tremendous amount of complexity with each of these concepts, not to mention how each of them sort of intersect with each other. But sort of at the basis, what you had mentioned at the beginning part, if we just think about multimorbidity as the presence of multiple chronic conditions, functional status as decreased ability to do daily activities and frailty as a decreased ability to respond to physiologic stressors. And that can be measured in different ways. That at least provides us kind of a big picture grounding for thinking about how we can then sort of take a deeper dive and to get into all the nuances and details of each of these concepts. 

Rebecca Brown, MD, MPH: Absolutely and ultimately achieve our overall goal of improving quality of life and function for older [00:16:00] adults. We have to keep all that complexity in mind. 

Michael Steinman, MD: That's a really nice way to end at keeping our eyes on the prize about what's important. Thank you, Rebecca. It was so nice to have this time to talk with you. 

Rebecca Brown, MD, MPH: Thank you, Mike, for having me. It was great to have this conversation.