Discussion
Frailty, respiratory muscle function
RECRUITMENT, RECRUITMENT, POSTOPERATIVE COMPLICATIONS
This single arm pilot study demonstrates the feasibility of a novel multifaceted home-based prehabilitation intervention that effectively improved the functional capacity of Veteran participants who completed a median 5 weeks of intervention before surgery. In no circumstance did prehabilitation delay surgery beyond the date selected by the surgeon and patient. The effective recruitment rate of 38% was modest; however, retention through surgery (84%) and 90-day follow-up (74%) demonstrated that most participants were able to complete the intervention despite the burdensome protocol. Adherence to the prescribed prehabilitation regimen for supervised activities (94%) and for at-home activities (74–78%) also demonstrated that the intervention was feasible. Although not powered to detect differences in postoperative outcomes, participants achieved clinically meaningful and statistically significant improvements in TUG (2.3 seconds), gait speed (0.1 meters/second), 6MWT (41.7 meters), chair rise (1.6 seconds), and respiratory muscle function (4.5–14.1 cm H2O). These improvements approach or exceed the MCID for each measure and thus might plausibly translate to improved perioperative outcomes, as in fact has been shown for respiratory muscle function changes of this magnitude (Recruitment was more challenging than anticipated for two reasons. First, the prevalence of frailty was lower than expected in this medical center, and second, the patients were generally reluctant to participate, perhaps due to their perceptions of the burdensome nature of the intervention and the assessment schedule, including travel to the hospital. For some, the risks of upcoming surgery provided motivation to participate, but for others, even these risks were insufficient to overcome barriers manifested by many years of sedentary behavior. Others maintained unrealistic expectations that they had no personal responsibility to prepare for surgery, deferring responsibility for outcomes to the clinicians. We therefore reduced the eligible RAI score from 21 to 16 to accommodate these realities and increase recruitment by expanding eligibility. However, this concession also limited our ability to assess the feasibility of prehabilitation in phenotypically frail patients. In addition, our experience suggests that nursing homes were unable or unwilling to facilitate the “at-home” training exercises, and this lack of capacity may be a barrier for implementing similar protocols for institutionalized patients. Any subsequent trials of prehabilitation techniques such as those piloted here will need to plan for these barriers to participation.We explored a variety of frailty assessments from both the deficit accumulation and physical models of frailty in order to examine their comparative relevance and utility in the perioperative setting. We also explored changes over time in these frailty measures, a factor of frailty assessment for which there are few prior examples. We found few differences between the scales and little change over time in the Clinical Frailty Scale, the Edmonton Frailty Scale, or the Frailty Phenotype. In fact, the baseline scores indicated little if any substantial frailty, and the lack of change is consistent with the conceptual model of frailty as relatively stable, if slowly declining. By contrast, the more granular scoring system of the RAI detected and quantified values consistent with elevated mortality risk even though the phenotype was not demonstrably frail, suggesting that it may be ideally suited for detecting “pre-clinical” frailty that might otherwise go undetected. In addition, functional measures (TUG, gait speed, and chair rise) also improved. These functional indices are often applied as indices of frailty, potentially providing vital perspective for pre-op surgical assessment and tracking (Quality of life, quality of surgical care, preference for operative management, and satisfaction with the multidisciplinary preoperative clinic were high and stable, suggesting that participants were satisfied with their care and the experience of prehabilitation did not detrimentally change patient perioperative experience. In addition to demonstrating the feasibility of these patient reported outcome measures, the absence of a statistically significant deterioration is a clinically meaningful finding, reassuring clinicians and investigators that at least among the willing participants, the intervention was well-received.As has been noted in prior work (Several limitations temper conclusions from this study. The relative robustness of the population prevents confident conclusions regarding the feasibility of prehabilitation in more phenotypically frail patients. The absence of a control group and limited sample size prevent analysis of postoperative outcomes like mortality, readmission, or postoperative complications. The predominantly male and White sample limits conclusions about feasibility among women and other racial or ethnic populations, and although it is likely that the approach described here would be feasible among civilian participants, such an application has not yet been tested. Self-selection bias may overestimate the impact such techniques would achieve in less motivated samples.