Here is the design of a clinical trial:

Official Title: Effectiveness of Routine Measurement of Health-Related Quality of Life in Improving the Outcomes of Patients With Musculoskeletal Problems - A Randomized Controlled Trial

Included conditions:
- Quality of Life
- Musculoskeletal Disease
- Outcome

Study Armgroups:
- {'label': 'Intervention group', 'type': 'EXPERIMENTAL', 'description': 'EQ-5D-5L HRQOL results be available to the attending doctor', 'interventionNames': ['Behavioral: EQ-5D-5L HRQOL results be available to the attending doctor']}
- {'label': 'Control group', 'type': 'NO_INTERVENTION', 'description': 'usual care. All subjects attending the control clinics will not need to complete the electronic EQ-5D-5L before seeing the doctor during their follow-up visits. The doctor will manage the patient as usual, based on the usual clinical information. The doctor will complete the clinician-reported follow-up clinical data form (CRF) for each subject at the end of the consultation.'}

Interventions:
- {'type': 'BEHAVIORAL', 'name': 'EQ-5D-5L HRQOL results be available to the attending doctor', 'description': 'all subjects attending the intervention clinics will complete the electronic EQ-5D-5L before seeing the doctor during each follow-up visit for the musculoskeletal problem, a print out of the longitudinal EQ-5D-5L data (Table 1) since recruitment will be given to the patients to show to the attending doctors during the consultation. The doctors will provide the management based on the usual clinical information and the additional EQ-5D-5L HRQOL results. The doctor will complete the clinician-reported follow-up clinical data form (CRF) of each eligible patient at the end of the consultation.', 'armGroupLabels': ['Intervention group']}

Primary Outcomes:
- {'measure': 'The change in HRQOL measured by the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) global score', 'description': 'The WOMAC is a widely used condition specific HRQOL measure to assess pain, stiffness and physical function of patients with MS problems. It has been applied to patients with hip and/or knee osteoarthritis, low back pain, rheumatoid arthritis and fibromyalgia. It consists of 24 items on 3 domains: pain (5 items), stiffness (2 items) and physical function (17 items). Each question is rated on a 5-point Likert scale from 0 to 4, with lower scores indicating lower levels of symptoms or impairment. The item scores in each domain subscale are summated to a domain score. The global WOMAC score is calculated by summating the three domain scores. A Chinese version of WOMAC is available and has been shown to be valid, reliable and sensitive in Chinese patients.', 'timeFrame': 'At baseline, and 3 months, 6 months and 12 months after baseline'}

Please estimate the sample size based on the assumption: 
The sample size calculation assumes 80% power, a 5% significance level, and a 20% attrition rate. The calculation also adjusts for an intracluster correlation coefficient (ICC) of 0.0321 due to clustering from six clinics.
Sample size calculation
        The sample size calculation was based on the primary outcome of a difference in WOMAC total score between the intervention and control groups. A previous RCT study evaluating a rehabilitation programme integrating exercise, self-management and active coping strategies for patients with chronic knee pain showed that the average change in WOMAC total score at 6 months after baseline for the intervention and control groups was â3.4 (mean: 35; SD: 16 at 6 months) and â8 (mean: 30.4; SD: 17 at 6 months), respectively,20 indicating an effect size of 0.3. Using this, a minimum of 380 (190 in each group) patients are needed to achieve 80% power at 5% significant level, by two-sample t-test. There were no studies that provided an intracluster correlation (ICC) coefficient for WOMAC scores, but a review showed the ICC coefficient of pain outcome was 0.0321; to adjust for the clustering effect from six clinics, a larger sample size of 1098 (549 patients per group, and 183 subjects per clinic) will be required. We plan to recruit 1374 (687 in each group) subjects to allow for a 20% attrition rate.