*2.2. Patients*

Patients who had a reservation in the clinic, were visiting our spine clinic for the first time, or had a return visit to the clinic were enrolled in this study after providing written informed consent. Patients who could not understand the questionnaires were excluded from the analysis in order to ensure that the data obtained was accurate. Patients with new symptoms after the outbreak were excluded from the analysis investigating outcome changes.

Among 1103 patients who visited our spine clinics, 747 patients were enrolled in this study. Among those 747 patients with spinal disorders, 141 patients were excluded since their symptoms had developed after the COVID-19 outbreak. Therefore, we included 606 patients in the analysis. There were 281 and 325 patients in the <65- and ≥65-year groups, respectively (Table 1); the respective average ages were 49.0 (standard deviation, SD: 10.7) and 75.9 (6.3) years. The proportion of females was higher in the <65-year group (45%) than in the ≥65-year group (53%) (*p* = 0.039). There was no between-group difference in the ratio of patients who refrained from visiting clinics (37% and 32%, *p*-value = 0.228). Regarding exercise habits, 46% and 48% of patients in the <65- and ≥65-year groups, respectively, did not change their exercise habits. In contrast, 40% and 32% of patients in the <65- and ≥65-year groups, respectively, decreased their exercise habits. Compared with pre-pandemic symptoms, the current symptoms were worse in 8% and 7% of patients in the <65- and ≥65-year groups, respectively, with no significant between-group difference (*p*-value = 0.988).


**Table 1.** Comparison of the patient characteristics between individuals aged <65 and ≥65 years.

#### *2.3. Procedures for Data Collection*

The study coordinator gave short instructions and the patients filled out the paper questionnaire forms with pencils. The paper questionnaires were returned on the day of the clinic visit. To deal with the risk of social-desirability bias, the questionnaires guaranteed anonymity and responses were compiled [10].
