Objective functional impairment in lumbar degenerative disease: concurrent validity of the baseline severity stratification for the five-repetition sit-to-stand test

Abstract

<jats:sec><jats:title>OBJECTIVE</jats:title><jats:p>The five-repetition sit-to-stand (5R-STS) test provides a new dimension of clinical assessment by capturing objective functional impairment (OFI). Through the utilization of data from two prospective studies, the authors sought to evaluate the concurrent validity of the proposed 5R-STS baseline severity stratification (BSS) for OFI with the following levels based on time to completion in seconds: none, ≤ 10.4; mild, 10.5–15.2; moderate, 15.3–22.0; and severe, &gt; 22.0 seconds.</jats:p></jats:sec><jats:sec><jats:title>METHODS</jats:title><jats:p>Patients with degenerative diseases of the spine performed the 5R-STS test and completed visual analog scales (VASs) for back and leg pain, the Oswestry Disability Index (ODI), the Roland-Morris Disability Questionnaire (RMDQ), and EQ-5D questionnaires. The degree of OFI severity was assessed based on the previously proposed BSS, and its association with patient-reported scales was evaluated using ANOVA as well as crude and adjusted linear regression models.</jats:p></jats:sec><jats:sec><jats:title>RESULTS</jats:title><jats:p>Our sample included 240 patients, of whom 101 exhibited no OFI, whereas 80, 34, and 25 were judged to have mild, moderate, and severe OFI, respectively. A higher baseline severity was strongly associated with loss of working ability (p &lt; 0.001), as well as results of all patient-reported scales (p ≤ 0.001), with the exception of the VAS for leg pain (p = 0.556). Crude and adjusted regression analyses corroborated these findings, although only patients with moderate and severe OFI as judged by using the 5R-STS BSS demonstrated clinically relevant differences compared with patients without OFI.</jats:p></jats:sec><jats:sec><jats:title>CONCLUSIONS</jats:title><jats:p>The degree of OFI—based on the 5R-STS BSS—is strongly associated with measures of back pain, subjective functional impairment, and health-related quality of life. However, leg pain severity is not reflected within the dimension of OFI measured by the 5R-STS. The proposed BSS appears to be a concurrently valid and clinically relevant measure of OFI in patients with degenerative spinal pathologies.</jats:p></jats:sec>

Five-Repetition Sit-to-Stand Test Performance in Healthy Individuals: Reference Values and Predictors From 2 Prospective Cohorts

“…a range of medical conditions, including lumbar degenerative spine disease, stroke, chronic obstructive pulmonary disease (COPD), Parkinson disease, rheumatoid arthritis, postkidney transplant, and posttotal knee replacement to not only objectively assess functional impairment, but also to monitor recovery and progress. [4][5][6][7][8][9][10][11][12] It is also used in the pediatric setting. 13 Objective functional tests can eliminate subjectivity that is at times captured in questionnaires, and account for symptoms such as foot drop missed by common Patient-Reported Outcome Measures.…”

Machine learning–augmented objective functional testing in the degenerative spine: quantifying impairment using patient-specific five-repetition sit-to-stand assessment

“…This compares with approximately 50% to 60% of the spinal patient population that was deemed to be objectively functionally impaired using the standard ULN of 10.5 seconds. 8,12 Those patients that were additionally classified as having OFI by our personalized testing strategy-and not by the usual fixed 10.5-second cutoff-were mostly younger and shorter patients who would indeed realistically be expected to complete the test in 7 or 8 seconds. Conversely, some very tall patients who normally would initially have been classified as impaired were now deemed not to have OFI, because a test time of 13 seconds, for example, is still considered normal, given their height.…”

“…[27][28][29][30] Correspondingly, back pain severity increased with each level of OFI, while leg pain severity was not affected. 12 As machine learning methods become more broadly adopted in many fields of medicine, 17,[31][32][33] it is feasible that clinical and scientific patient assessment-including laboratory studies, radiological studies, and physical examination-will move from simple fixed thresholds (e.g., a ULN for D-dimer of < 250 ng/mL 25 ) to personalized cutoffs based on comparable individuals from a normative population (e.g., with age-adjusted D-dimers). 34 We also expect that integration of other machine learning techniques will enable even more automated testing; the 5R-STS could be automatically rated using machine vision or accelerometers for motion tracking, 35 and demographic data about a particular patient could be pulled from electronic health records.…”

“…For example, in degenerative lumbar spine disease, the presence of objective functional impairment (OFI) is normally determined by comparing the five-repetition sit-to-stand (5R-STS) test time of a particular patient with the upper limit of normal (ULN) of test times in a spine-healthy population (10.5 seconds). [7][8][9][10][11][12] If the patient takes longer than these 10.5 seconds to complete the 5R-STS, OFI can be diagnosed and further classified based on fixed thresholds. 8,12 The advantages of such thresholds are their simplicity, generalizability, ease of derivation and validation, and simple anchoring to a representative normative population.…”

“…[7][8][9][10][11][12] If the patient takes longer than these 10.5 seconds to complete the 5R-STS, OFI can be diagnosed and further classified based on fixed thresholds. 8,12 The advantages of such thresholds are their simplicity, generalizability, ease of derivation and validation, and simple anchoring to a representative normative population. However, there are inherent disadvantages.…”