From questionnaires to single items: independent use of a walking measure in patients after thoracic surgery

Regular and flexible assessments of patients' physical status remain a significant challenge in clinical care and treatment. Whether measurement items in established Patient-reported outcome (PRO) questionnaires can be used independently to assess physical status remains unclear. This study aimed to evaluate the clinimetric validity of the independent use of a single-item walking measure.

Participants were recruited from a prospective cohort of patients undergoing lung surgery. On postoperative days 1 and 2 (POD 1 and 2), the patients' physical condition was assessed using the Perioperative Symptom Assessment for Lung surgery (PSA-Lung) and the single-item walking measure (SI-walking) derived from these questionnaire. A one-hour washout period separated the assessments. The objective measure of Timed Up and Go Test (TUGT) was performed on POD2.

Of the 214 patients, 181 and 117 completed PSA-Lung and SI-walking on POD1 and POD2, respectively. The mean SI-walking score was higher than the mean PSA-Lung walking (MI-walking) score (4.44 ± 2.38 vs 3.64 ± 2.66, P < 0.001, Cohen's d effect size [ES] = 0.26). TUGT was completed by 111 patients with an average time of 15.17 ± 4.01 s. TUGT had a greater correlation with SI-walking (R_SI = 0.61, P < 0.001) than with MI-walking (R_MI = 0.31, P = 0.001) scores. ES regarding changes in walking function between POD1 and POD2 were higher with SI-walking (5.14 ± 2.37 vs 3.35 ± 1.97, P < 0.001, ES = 0.81) than with MI-walking (4.15 ± 2.77 vs 2.85 ± 2.28, P < 0.001, ES = 0.50). SI-walking (P = 0.002) was better than MI-walking (P = 0.116) in distinguishing hospitalization length.

The SI-walking scale demonstrates validity for measuring physical status. The independent use of a single-item walking measure from an established PRO questionnaire is valid in patients after thoracic surgery.