Here is the design of a clinical trial:

Official Title: MASked-unconTrolled hypERtension Management Based on Office BP or on Out-of-office (Ambulatory) BP Measurement (MASTER Study)

Included conditions:
- Masked Hypertension

Study Armgroups:
- {'label': 'Group 1', 'type': 'ACTIVE_COMPARATOR', 'description': 'Management strategy of blood pressure based on office BP as a guide to treatment', 'interventionNames': ['Other: Optimization of antihypertensive treatment based on office BP']}
- {'label': 'Group 2', 'type': 'EXPERIMENTAL', 'description': 'Management strategy of blood pressure based on 24-hour ABPM as a guide to treatment', 'interventionNames': ['Other: Optimization of antihypertensive treatment based on 24-hour ABPM']}

Interventions:
- {'type': 'OTHER', 'name': 'Optimization of antihypertensive treatment based on office BP', 'description': 'Optimization of antihypertensive treatment based on office BP', 'armGroupLabels': ['Group 1']}
- {'type': 'OTHER', 'name': 'Optimization of antihypertensive treatment based on 24-hour ABPM', 'description': 'Optimization of antihypertensive treatment based on 24-hour ABPM', 'armGroupLabels': ['Group 2']}

Primary Outcomes:
- {'measure': 'changes in LVMI (co-primary endpoint)', 'timeFrame': '12 months'}
- {'measure': 'UAE (albumin/creatinine ratio, co-primary end-point)', 'timeFrame': '12 months'}

Please estimate the sample size based on the assumption: 
An alpha of 0.025 (one-sided t-test), a power of 90%, and a dropout rate of 15%. The SD of LVMI is assumed to be ±25 g/m2.
Sample size calculation
        Sample size calculation was based on the primary study endpoint of changes in left ventricular mass index (LVMI) at 12th month. We do not know what proportion of the enrolled patients will have a diagnosis of LVH; therefore, the primary endpoint has not been based on categorical changes in LVH but rather on changes in LVM as a continuous variable. As the enrolled individualsÂ are hypertensive patients with BP incompletely controlled by treatment, we expect LVM to be often higher than in subjects with sustained BP control (normal OPBÂ and ABP levels). To calculate the sample size, we have assumed a difference of 5âg/m2 in the change of LVMI with the ABP-guided (group 2) compared with the OBP-guided (group 1) management strategy. This has been based on the consideration that SBP will be reduced by about 8âmmÂ Hg more in the ABP-guided group, as well as on the echocardiographic data of studies such as REGAAL and CATCH in which differences in echo LVMI changes between treatments producing similar BP reductions were lower than 3âg/m2.20 21 The SD ofÂ Â±25âg/m2 was also derived from data of REGAAL and CATCH as well as from previous assessment of within operator reproducibility.21 22 Considering a LVMI difference between groups of 5.0âg/m2 and a SD of 25âg/m2, an alpha of 0.025 (one-sided t-test) and a power (1-beta) of 90%, with a dropout rate of 15% during the study period, a minimum of 620 subjects per study group was deemed necessary, for a total number of 1240 subjects to be randomised. However, given the uncertainty about the true LVMI difference we might observe and/or the related SD, performance of an interim analysis has been decided aimed at a possible re-estimation of the sample size. This analysis will be carried out at 18th month when about 30% of randomised patients will achieve 1âyear of follow-up. A re-estimation of the sample size will be calculated using the method of conditional power.23