Table 3.
Secondary outcomes and additional outcomes collected from study participants.
| No # | Outcome | Details |
|---|---|---|
| Secondary outcomes | ||
| 1 | Change in participant-reported knee pain intensity | Calculated from baseline to weeks 1 through to 11 on a 100-point VAS (0 = no pain to 100 = worst pain possible). |
| 1 | Change in knee pain | Collected at weeks 2, 6 and 12. Change in other knee symptoms calculated from baseline to weeks 2, 6 and 12. Derived from the relevant (pain) sub-scale of the KOOS questionnaire. The KOOS is a knee-specific instrument developed to assess participants symptoms and functional limitations related to knee OA, with 42 questions across five separately scored subscales [36]. Each question is measured using Likert responses (0–4), and questions pertain to the previous seven days. The KOOS is a widely used disease-specific instrument whose reliability, validity and responsiveness have been demonstrated [37]. |
| 2 | Change in other knee symptoms | Collected at weeks 2, 6 and 12. Change in other knee symptoms calculated from baseline to weeks 2, 6 and 12. Derived from the KOOS other symptoms subscale. |
| 3 | Change in knee function in daily living | Collected at weeks 2, 6 and 12. Change in other knee symptoms calculated from baseline to weeks 2, 6 and 12. Derived from the KOOS function in daily living (ADL) subscale. |
| 4 | Change in knee function with sport and recreation | Collected at weeks 2, 6 and 12. Change in other knee symptoms calculated from baseline to weeks 2, 6 and 12. Derived from the KOOS function with sport and recreation subscale. |
| 5 | Change in knee-related quality of life | Collected at weeks 2, 6 and 12. Change in other knee symptoms calculated from baseline to weeks 2, 6 and 12. Derived from the KOOS knee-related Quality of Life subscale. |
| 6 | Change in Patient Global Assessment (PGA) of disease activity | Collected at weeks 2, 6 and 12. Change calculated from baseline to week 12 in response to the question, “Considering all the ways your knee osteoarthritis affects you, how have you been during the past week?”. The single question is scored on a 100-point VAS (0 = very well to 100 = very poor) [38]. |
| 7 | Change in the health-related quality of life | Collected at weeks 2, 6 and 12. Change calculated from baseline to weeks 2, 6 and 12 from the Assessment of Quality-of-Life measure (AQoL-8D) [39]. The AQoL is a health-related multi-attribute utility QoL instrument with 35 questions across 8 separately scored dimensions [39]. Higher scores indicate better quality of life. |
| 8 | Treatment response | Fulfilment of Outcome Measures in Rheumatology-Osteoarthritis Research Society International (OMERACT-OARSI) responder criteria at week 12. |
| Other outcomes collected from participants | ||
| 1 | Treatment satisfaction | Will be assessed at weeks 6 and 12 by the Patient Acceptable Symptom State [40] (PASS, yes/no) question: “Taking into account all the activities you have during your daily life, your level of pain, and also your functional impairment, do you consider that your current symptom state is satisfactory?”. If “no”, the follow-up question “Would you consider your current symptom state as being so unsatisfactory that you think the treatment has failed?” will determine treatment failure. |
| 2 | Perceived improvement in the index knee | Will be assessed at weeks 6 and 12 by the Global Rating of Change (GRC) question: “Which option best represents the change in PAIN in your RIGHT/LEFT knee since you began the study?”. Participants will score this question using a 5-point Likert scale (1 = much better to 5 = much worse). |
| 3 | Participant safety | Assessed through weekly self-reported adverse events monitoring from baseline through to week 12. |
| 4 | Use of rescue pain medication | Self-reported in weekly surveys. |
| 5 | Treatment adherence | Measured by self-reported intake of the number of capsules taken in the morning and night for each day in the past week and confirmed by self-reported capsule count at the end of the study (week 12). |
| 6 | Psychological traits and states, contextual, and social factors | Assessed by the MPsQ (Cognivia questionnaire associated with the placebo response) and administered via the Placebell® technology. Items are self-reported by participants on a 5-point scale (1 = strongly disagree to 5 = strongly agree). |
| 7 | Participants' technology self-efficacy | Will be measured at baseline only using a modified Computer self-efficacy scale [41]. |
| 8 | OA knee flare occurrence | Assessed at baseline, week 6 and week 12 using a self-report Flare-OA 16 questionnaire [42,43]. This questionnaire has been developed to investigate and characterize a knee or hip osteoarthritis flare occurrence in the past 4 weeks, from the participant's perspective. It comprises items in five dimensions: pain, swelling, stiffness, psychological aspects, and impact of symptoms, with answers on a numerical rating scale (0–10). |
All outcomes are collected via participant self-report. KOOS: Knee Injury and Osteoarthritis Outcome Score; VAS: Visual Analog Scale; PGA: Patient global assessment; AQoL-8D: Assessment of Quality of Life; GRC: Global Rating of Change; e-PCF: Electronic Participant Consent Form; PASS: Patient Acceptable Symptoms State; MPsQ Cognivia questionnaire associated with placebo response subscales; VAS: Visual Analogue Scale.