The frailty phenotype is an important prognostic tool to identify individuals at risk for adverse health outcomes and is an independent predictor of premature mortality in older populations.[6], [7] To our knowledge, our study is the first to evaluate the prevalence of frailty and prefrailty among a large cohort of YACS enrolled in a physical activity intervention trial. In this cross-sectional analysis of participants’ baseline data, we observed high prevalence of both frailty (14%), prefrailty (24%) and comorbid conditions (55%).
The overall prevalence of frailty and prefrailty in this sample of 280 YACS are consistent with the findings of Smitherman et al. in a cohort of AYA cancer survivors (10% frailty and 21% prefrail)[10] and among young adult survivors of childhood cancers (8% frail, 18–22% prefrail).[9] These prevalence estimates of frailty in the current study are higher than those found among older adults (11%) without a history of cancer.[9], [26] Systematic reviews of older adults from high-income countries, have found global frailty rates of 7–10%.[27][7] Across cohorts, frailty is higher among women, increases with age, and increases with the number and severity of comorbidities.[28]
Our findings concerning comorbidities in this population expand on prior work by Smitherman et al. that similarly found that prevalence was higher among women, and that women reported more medication use for comorbidity management.[10] The prevalence of at least one comorbidity was 55% in the present study, similar to the UNC AYA cohort (60%)[10] and lower than the St. Jude CCS cohort (82%).[9] Comorbidities may be higher in the St. Jude cohort due to diagnosis at earlier ages, longer times since diagnosis/age at assessment, and because individuals were specifically recruited to examine treatment-related cardiac and cognitive outcomes.[9] Additionally, we found similar prevalence of comorbidities requiring medication (39%) in our study as in the UNC AYA cohort (38%), indicating a need to identify and manage these conditions to prevent progression, chronic illness, and frailty.[10]
In this sample, self-reported BMI and MVPA were both associated with frailty status. Compared to participants with BMI < 25, those at every higher level of BMI had an increased likelihood of frailty status, ranging from a 1.7–2.4-fold increase. This finding is similar to previous studies showing frailty status was associated with having overweight and obesity for young adult cancer survivors and older adults without a history of cancer.[10], [29] We found that MVPA was associated with lower likelihood of being classified as frail or prefrail. This finding builds on prior work in this population that did not examine physical activity levels. Previous studies have demonstrated that the underlying physical symptoms of the frailty phenotype can be rehabilitated through physical activity and nutritional intervention.[30], [31] For instance, in older frail populations, physical activity programs and nutritional supplements have been shown to be effective for preventing the progression of frailty, improving frailty status, functional status, and mobility.[32] Our findings indicate that even in the absence of in-person or objective measures, self-reported physical activity levels and BMI can identify individuals at risk for comorbidities and frailty who might benefit from intervention. The high prevalence of frailty at baseline in a sample of YACS motivated to participate in a lifestyle intervention trial highlights the need to develop interventions to address frailty and mitigate adverse health outcomes in this population. Future work should prospectively examine whether engagement in PA over time is associated with reduced risk of frailty and prefrailty.
Several cancer-related characteristics emerged that could be useful in risk stratification in this population. Being diagnosed with more than one malignancy was associated with increased likelihood of comorbid conditions and frailty status. Further, having more than one comorbidity requiring medication management was associated with increased frailty. Compared to those 5 years post-diagnosis, corresponding to important clinical milestones for survivors, individuals were more likely to have frailty the closer they were to diagnosis. Prospective assessment of frailty early in survivorship could potentially be used for risk stratification, and to identify individuals in need of targeted interventions.
This is one of the few studies to evaluate frailty in YACS. A strength of this study was use of remote assessments, which enabled the recruitment of participants from around the United States and evaluation of a subgroup of cancer survivors that are understudied relative to other age groups. Additionally, the components used to evaluate the FRAIL index were consistent with previous versions, using measures that have been validated in the YACS population. This survey-based measure facilitated assessment of frailty status in a relatively large sample of YACS without requiring in-person assessments. In this cross-sectional study we characterized the prevalence of frailty status and comorbidities in a sample of YACS. However, the temporality of the relationships between participant characteristics, frailty status, and comorbidities cannot be determined with this analysis and should be the focus of future work.
Our findings should be interpreted with consideration of certain limitations. First, while our criteria for frailty is consistent with the FRAIL measure previously described [10], [33] (i.e., ≥ 5% weight loss in last 6 months), our time period for weight loss is shorter and potentially more conservative than other frailty classifications that consider unintentional weight loss of at least 10 pounds in the previous year.[6] In the current study, it was not possible to determine if weight loss in the previous six months was intentional or an indicator of low lean body mass as considered in other frailty measures including those used in the CCSC.[34], [35] Future validation of self-reported weight and objectively measured body composition is necessary to confirm reliability of this self-reported tool and establish relevant lean body mass cut points for this specific population. In general, there is a need for consensus around frailty measures and assessments.
Second, an eligibility criterion for the larger randomized controlled trial was not meeting the American Cancer Society’s recommendation of ≥ 150 minutes/week of MVPA for cancer survivors. Therefore, by nature of inclusion in the intervention, participants had to have low energy expenditure, which is a criterion for frailty in other measures. Similarly, our study sample volunteered to participate in an mHealth physical activity intervention trial and may be systematically different from YACS that would not choose to participate; they did not have comorbid conditions that would preclude them from participation, and they may be more active than some YACS while still being below guideline levels.
Data on comorbidities were collected for the purpose of screening for eligibility to the parent trial, and only two participants reported \(\ge\) 5 comorbidities). The list of comorbidities assessed was not exhaustive, thus, there was potential for under identification of comorbidities as a component of the FRAIL index. Future research should assess non-cancer comorbidities more comprehensively among YACS and test validity and reliability of frailty measurement in this population. Ness et al. found that frailty was associated with the onset of new chronic conditions over time in the CCS cohort.[9] Identifying individuals with risk factors for frailty and providing appropriately tailored interventions could potentially prevent the onset or progression of chronic diseases, declines in physical function, and premature frailty.
In conclusion, we found that YACS enrolled in an mHealth physical activity intervention trial had high prevalence of frailty, prefrailty, and non-cancer comorbid conditions, similar to those found previously in samples of childhood cancer survivors and AYA cancer survivors.[10], [35], [36] These findings suggest the FRAIL index may be a useful tool for identifying individuals at risk for chronic diseases and morbidity. Results from this study indicate that among YACS, a higher likelihood of frailty was associated with increased BMI while engagement in any MVPA was associated with decreased likelihood of frailty. Findings may guide the development of future lifestyle interventions to address frailty in YACS by promoting improved body composition or physical activity.