Here is the design of a clinical trial:

Official Title: HED-Start: A Randomised Controlled Trial to Evaluate a Positive Skills Intervention for Patients New on Haemodialysis

Included conditions:
- End Stage Renal Disease on Dialysis
- End Stage Renal Failure on Dialysis
- End Stage Renal Disease
- End Stage Kidney Disease

Study Armgroups:
- {'label': 'HED-Start Intervention arm', 'type': 'EXPERIMENTAL', 'description': 'Participants assigned to the intervention arm will undergo 4 sessions of the HED-Start program. Each session is 2 hours long and will be conducted fortnightly.', 'interventionNames': ['Behavioral: HED-Start']}
- {'label': 'Standard care arm', 'type': 'NO_INTERVENTION', 'description': 'Participants assigned to the standard care arm will proceed with routine standard care.'}

Interventions:
- {'type': 'BEHAVIORAL', 'name': 'HED-Start', 'description': 'The HED-Start Program is a cognitive-behavioral intervention based on self-management and motivational interviewing principles.', 'armGroupLabels': ['HED-Start Intervention arm']}

Primary Outcomes:
- {'measure': 'Change in Anxiety and Depression (HADS) scores from baseline', 'description': 'Hospital Anxiety and Depression Scale (HADS). The HADS comprises two subscales (anxiety; depression) and can be totaled to produce an overall scale score. Scores range from 0 to 21 for each subscale, and from 0 to 42 for the overall score. Higher scores are indicative of worse anxiety and depression symptoms.', 'timeFrame': 'Participants will be assessed at two time points: [T1] Baseline and [T2] 3 months post-randomization'}

Please estimate the sample size based on the assumption: 
Two-tailed significance level of 5%, power of 80%, and an attrition rate of 30%.
Sample size
        Sample size calculation was performed using G*Power V.3.19.7. The selected medium effect size (standardised effect size=â0.6) was based on the pooled effect estimate obtained from most recent systematic reviews and meta-analyses on psychosocial interventions on reducing depression and anxiety symptoms in those with CKD ranging from d=â0.48âto â0.60.41â43 Assuming a medium effect size of 0.6 and adopting a 1:2 allocation ratio, 34 and 68 participants will be allocated to control and intervention arm, respectively for a (two-tailed) significance level of 5% and a power of 80%. An unequal allocation ratio is to be adopted to account for the potential higher attrition rates in the intervention arm than those of the usual care. Assuming an attrition rate of 30%, a sample size of 148 participants will be sought for the RCT (50 and 98 participants for control and intervention, respectively).