Reliability of self-measured objective functional impairment using the timed up and go test in patients with diseases of the spine

Background: Accurate assessment of a patient's functional status is crucial for determining the need for treatment and evaluating outcomes. Objective functional impairment (OFI) measures, alongside patient-reported outcome measures (PROMs), have been proposed for spine diseases. The Timed-Up and Go (TUG) test, typically administered by healthcare professionals, is a well-studied OFI measure. This study investigates whether patient self-measurement of TUG is similarly reliable.

Methods: In a prospective, observational study, patients with spinal diseases underwent two TUG assessments: one measured by a healthcare professional and one self-measured by the patient. Interrater reliability was assessed using the intraclass correlation coefficient (ICC) with a two-way random-effects model, considered excellent between 0.75 - 1.00. Paired t-tests directly compared both measurements. The impact of variables such as age, sex, disease type, symptom severity (via PROMs), comorbidities, and frailty on reliability was also analysed.

Results: Seventy-four patients were included, with a mean age of 62.9 years (SD 17.8); 29 (39.2%) were female. The majority (64.9%) were treated for degenerative disc disease. The lumbo-sacral region was most affected (71.6%), and 47.3% had previous surgeries. Patient self-measurement reliability was excellent (ICC 0.8740, p < 0.001), and the difference between healthcare professional (19.3 ± 9.4 s) and patient measurements (18.4 ± 9.7 s) was insignificant (p = 0.116). Interrater reliability remained high in patients > 65 years (ICC 0.8584, p < 0.001), patients with ASA grades 3&4 (ICC 0.7066, p < 0.001), patients considered frail (ICC 0.8799, p < 0.001), and in patients not using any walking aid (ICC 0.8012, p < 0.001). High symptom severity still showed strong reliability (ICC 0.8279, p < 0.001 for Oswestry Disability Index > 40; ICC 0.8607, p = 0.011 for Neck Disability Index > 40).

Conclusions: Patients with spine diseases can reliably self-measure OFI using the TUG test. The interrater reliability between self-measurements and those by healthcare professionals was excellent across all conditions. These findings could optimize patient assessments, especially in resource-limited settings.