Study design

Background data including age, sex, duration of CLBP, body mass index, history of malignant tumor, smoking habit, employment status, frequency of exercise, number of live-in family members, hobby, Center for Epidemiologic Studies depression scale (CES-D) score, BS-POP, and medication were collected at baseline¹⁹⁾.

All patients received medications for CLBP with one or a combination of four leading drugs such as loxoprofen, celecoxib, acetaminophen, and a combination of tramadol and acetaminophen for six months. Use of medications for pain (e.g., neuropathic pain) other than these four drugs did not change and no patients underwent surgeries for CLBP during the observation period¹⁹⁾.

The consultation length (in minutes) for all patients was measured at baseline and every month in the 6-month follow-up period. In this study, consultation length was defined as the period starting from the clinician's (or the patient's) entrance into the consulting room to the time the clinician (or the patient) left the room. Medical interview, physical and radiological examinations, and discussion after examinations were included in the consultation length.

Patients followed-up for more than 3 months were included for analysis. Consultation length at first visit (registration period) was excluded from analysis because of the unusually long consultation length-compared with that at the following study sessions-due to detailed physical and radiological examinations (Fig. 1).

Consultation length at each time point. The consultation length in the registration period (first visit) was longer than in the following phases.