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Table 1 Sample size calculation

From: Study protocol for a randomized controlled trial comparing mindfulness-based cognitive therapy with maintenance anti-depressant treatment in the prevention of depressive relapse/recurrence: the PREVENT trial

Author

Comparison

Mean hazard ratio

ICC

Design factor**

Attrition rate

Sample size per groupa

Conservative scenario

MBCT vs. m-ADM

0.63

.01

1.11

20%

210

Kuyken et al., 2008 [25]

MBCT vs. m-ADM

0.63

-0.02

1.0

7%a

160

Ma & Teasdale, 2004 [22]

MBCT vs. usual care

0.28

-0.008

1.0

3%b

14c

Teasdale et al., 2000 [23]

MBCT vs. usual care

0.47

-0.04

1.0

5%b

41c

  1. Sample size necessary for 90% power at 5% significance at 24 months;
  2. a at 15 months; b at 60 weeks, cassuming exponential survival function.
  3. Note group size of 12
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Trials

ISSN: 1745-6215