Here is the design of a clinical trial:

Official Title: Multimodal Prehabilitation for Major Surgery in Elderly Patients to Lower Complications and to Increase Cost Effectiveness: a Randomised, Prospective, Multicenter, Multidisciplinary Trial (PREHABIL Trial).

Included conditions:
- Frail Elderly Syndrome
- Major Surgery

Study Armgroups:
- {'label': 'Intervention', 'type': 'EXPERIMENTAL', 'description': 'Patients that meet the inclusion criteria will be randomised and scheduled for surgery at least 2 weeks after the diagnosis/decision to proceed to surgery. This timeframe allows the implementation of a minimal 2 weeks (up to 4 weeks) multidisciplinary prehabilitation program. Prehabilitation program is composed of 4 elements: exercise training, nutritional intervention, correction of anaemia and smoking cessation. An individual treatment strategy will be proposed to the patient by a multidisciplinary team consisting of surgeon, anesthesiologist, dietitian and physiotherapist.', 'interventionNames': ['Procedure: Multimodal Prehabilitation']}
- {'label': 'Control', 'type': 'NO_INTERVENTION', 'description': 'Perioperative care of the control group will be based on standardized, multi-element, ERAS recommendations as already implemented in the different participating clinics.'}

Interventions:
- {'type': 'PROCEDURE', 'name': 'Multimodal Prehabilitation', 'description': 'A multimodal prehabilitation program (exercise, nutrition, anemia correction and smoking cessation).', 'armGroupLabels': ['Intervention']}

Primary Outcomes:
- {'measure': 'Comprehensive Complication Index (CCI)', 'description': 'The comprehensive complication index (value from 0 = no complication to 100 = death) is a valuable, validated index for the assessment of multiple postoperative complications. It has been developed based on Swiss hospital data and has been validated internationally.', 'timeFrame': '30 days after surgery'}

Please estimate the sample size based on the assumption: 
Significance level alpha of 0.05, power of 0.80, and a dropout rate of 20%.
Sample size
        Based on internal data (Bern University Hospital), median CCI is expected to be 30 (IQR 21â37). Assuming an average clinically relevant improvement of 15% in the intervention group compared with the control group, the sample size calculation for a non-parametric Wilcoxon-Mann-Whitney test resulted in a total patient sample of 388 (assuming a significance level alpha of 0.05 and power of 0.80). We expect a dropout rate of 20%. We, therefore, need 466 patients: 233 in each arm. We aim to complete the inclusion within 3 years.