Developing and Validating a Novel Tool to Enhance Functional Status Assessment: The Tennessee Functional Status Questionnaire (TFSQ)

Discussion

We developed the TFSQ to enhance functional status assessment by evaluating both functional performance and functional capacity in METs and provide actionable information on activity, pain, and acute care effects on function. We validated the METs reported by the TFSQ by correlating them with the MET values calculated from the DASI. We further used the TFSQ to assess how both components of functional status relate to change in activity, presence of pain affecting activity, and recent ED visits, hospitalization, or surgery. In doing so we were able to capture a quantifiable functional status snapshot of the participating subjects while also gaining insight into factors that may affect their functional status.

Our data showed a strong correlation between functional capacity (TFSQ 2) and DASI METs (r = 0.69, P < .001). This provides robust psychometric evidence that the self-selection of best activity level from 1 of the 5 TFSQ activity columns (Table 1) provides an adequate estimation of patient functional status compared with the 12-question DASI. There was also a statistically significant correlation between functional performance (TFSQ 1) and DASI METs (r = 0.565, P < .001), although this correlation was expected not to be as strong as the correlation between functional capacity (TFSQ 2) and DASI because functional performance is often not as intense as functional capacity.

Indeed, one key finding in our study was the difference in distribution between functional performance (TFSQ 1) and functional capacity (TFSQ 2) in the sample (Figure 3). We found that TFSQ-reported functional performance was skewed to lower MET values, with 40% of respondents selecting column A (<3 METs), and only 5% of patients selecting column E (>6 METs). However, when the same patients were asked to report their functional capacity, only 25% of patients selected column A, with 22.5% of patients indicating they could perform activities of > 6 METs. These findings suggest there is an opportunity to encourage additional physical activity in our patients, as many patients have the capacity and functional reserve (Figure 1) to be more active in their daily lives. Another finding of interest was the discordance between TFSQ 1 and 2 (53.9%), with there being a minimum of 2-column difference in functional performance and functional capacity 20.6% of the time. Although some of the discordances may be explained by the physiologic barriers to function assessed in this tool (pain, acute care, and so forth), behavioral science suggests that there are also psychological barriers to physical activity that may need to be addressed.¹⁴

We also investigated the link between recent changes in activity (TFSQ 3) and functional capacity (TFSQ 2). We found that those participants who reported being less active in the previous 60 days had significantly lower functional capacity and functional performance than those who reported no change or increased activity. This reported decrease in physical activity may serve as an early warning sign of a negative functional trajectory. Awareness of this trajectory may in turn lead to opportunities for the clinician to intervene to prevent further functional decline.

Analysis of responses to pain (TFSQ 4), showed that patients who had pain that affected their daily physical activity reported significantly lower functional performance (TFSQ 1) and functional capacity (TFSQ 2) than those who did not report pain (P < .001). TFSQ 4 prompts the clinician to assess whether the decreased physical activity is due to an inability to perform at a higher level because of limitations from pain versus being due to a possible lack of effort (see the difference between MET frequencies in TFSQ 1 and 2 [Figure 2]). Studies show that pain frequency and intensity are negatively associated with disability, and early intervention of pain is known to result in better functional outcomes.¹⁵

Acute care (TFSQ 5) asks about recent ED visits, hospitalization, or surgery. Affirmative answers to this question were also associated with lower functional capacity than those who answered no (P = .017). This is consistent with the findings of Brown et al,⁴ who noted that participants more than 75 years old with either ED visits or hospitalization had a decrease in function that did not return to baseline even after 1 year. This finding highlights the importance of clinicians proactively identifying such patients and initiating functional restoration measures such as posthospitalization rehabilitation and active physical therapy to prevent further functional decline.

This study has important limitations. One limitation of this study is the relatively homogeneous patient sample in which it was initially validated (Table 3). Further validation efforts would ideally include more diverse patient samples, along with translation to other languages. Additional versions of the table of activities (Table 1) could also be created to reflect appropriate activities for different populations or geographical regions. In addition, 47.1% of respondents were patients at a chronic pain clinic (Table 3), which may have magnified the effect of chronic pain on function, as these patients were seeking specialist treatment for their chronic pain. Another limitation of this study is the effect that recall bias and subjectivity play on patient-reported outcomes.⁹ Other studies have shown that patient-reported outcomes often slightly underestimate the actual functional capacity.¹⁶ Conversely, using that same rationale, if a patient reports a functional capacity of >4 METs on the TFSQ (column C or higher), we can more readily conclude that they are at lower risk of perioperative complications.⁶ In the same vein, a TFSQ functional capacity of >5 METs (column D or E) aligns with a lower risk of all-cause and cardiovascular-related death.⁵ A third limitation is that this study only assessed patients’ functional status at 1 point in time. Repeated assessments in the same patients may provide more robust and reliable data. This is 1 reason why trending TFSQ results over time may provide more valuable insight into the patient’s functional status, such as in situations where aberrances in life circumstances may have an undue effect on overall activity.

In summary, the 5-question TFSQ is a novel tool that enhances functional status assessment by establishing a robust yet efficient functional snapshot that is relevant across multiple settings in health care. With this tool, clinicians can quickly assess whether patients has have potential to increase their usual physical activity, and potentially their overall health and well-being,² by addressing any difference observed between functional performance (TFSQ 1) and capacity (TFSQ 2). In addition, by assessing both components of functional status regularly in preventive care, chronic care, and acute visits, clinicians can monitor for subtle signs of decline and establish the urgency of a referral for rehabilitation, intervention, or specialty referral to avoid permanent disability. The TFSQ may be used with various patient populations across different medical settings. For example, a family medicine physician could use the questionnaire as a tool to track patient functional status longitudinally, and an anesthesiologist might use it as a snapshot of functional status in evaluating a patient’s risk level for surgery.

The TFSQ provides insight into potential reasons for functional decline, such as pain affecting activity (TFSQ 4) or recent acute care (TFSQ 5). It also allows for functional reassessment after an acute event such as hospitalization, trauma, or surgery. It is important to note that the TFSQ is not a substitute for a detailed history and physical examination. However, it may facilitate focusing those efforts on factors that may be limiting a patient’s function and quality of life. To date, we know of no other validated instrument that succinctly measures all of the components assessed on the TFSQ.

Future research and clinical applications for the TFSQ may include preoperative assessment, cardiac rehab, pain management outcomes, and palliative care interventions, where objective documentation of functional status can be beneficial for both care planning and tracking outcomes. It could also be used as a measure of the effectiveness of pain management treatments or other therapies designed to improve overall function. This tool could be used to follow patients throughout their lives, helping to establish goals of care, assess the efficacy of treatments, and engage patients in their care. It may also provide patients with insight into how change in activity, pain, or recent acute care exposure can impact their functional status and prompt educational interventions and motivation for patients to restore their function appropriately. Together, these insights can help patients and clinicians “Focus on Function” when addressing the health needs and goals of individual patients.