The Second Prevention of Syncope Trial (POST II)--a randomized clinical trial of fludrocortisone for the prevention of neurally mediated syncope: rationale and study design.
BACKGROUND
Neurally mediated syncope is a common and frequently distressing problem. It is associated with a poor quality of life, which improves when the frequency of syncope is reduced. Few therapies for neurally mediated syncope have been proven effective. Fludrocortisone is commonly used to prevent recurrences of syncope but with little evidence to support its use. A placebo-controlled clinical trial of fludrocortisone for the prevention of neurally mediated syncope is needed.


METHODS
POST II is a multicenter, international, randomized, placebo-controlled study of fludrocortisone in the prevention of neurally mediated syncope. The primary end point is the time to first recurrence of syncope. Patients will be randomized 1:1 to receive fludrocortisone 0.05 to 0.2 mg or matching placebo and followed for 1 year. Secondary end points include syncope frequency, presyncope, and quality of life. Primary analysis will be performed with an intention-to-treat approach, with a secondary on-treatment analysis.
Assuming a 40% risk of syncope in the control arm, a relative reduction of 40% by fludrocortisone, and a dropout rate of 20%, the enrollment of 310 patients will give an 80% power of reaching a positive conclusion about fludrocortisone therapy, with P = .05.


BACKGROUND
POST II is registered with both (ISRCTN 51802652) and (NCT00118482).


CONCLUSIONS
This study will be the first adequately powered trial to determine whether fludrocortisone is effective in preventing neurally mediated syncope. If it is effective, then fludrocortisone may become the first-line medical therapy for this condition.
Raj
Satish R
SR
Division of Clinical Pharmacology, Department of Medicine, Vanderbilt University, Nashville, TN, USA.
Rose
Sarah
S
Ritchie
Deborah
D
Sheldon
Robert S
RS
D005438:Fludrocortisone / Q000627:therapeutic use*; D006801:Humans; D015337:Multicenter Studies as Topic; D011446:Prospective Studies; D016032:Randomized Controlled Trials as Topic / Q000379:methods*; D012107:Research Design; D019462:Syncope, Vasovagal / Q000517:prevention & control*
D005438:Fludrocortisone