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Table 1 Baseline characteristics of study participants

From: Drug*placebo interaction effect may bias clinical trials interpretation: hybrid balanced placebo and randomized placebo-controlled design

Characteristics

Hydroxyzine Group

Placebo Group

Blinded Hydroxyzine/Placebo Group

Age, mean (SD), yr.

31.5 (6.4)

30.8 (6.1)

31.8 (7.2)

Sex, no. (%)

 Female

50 (32)

56 (35)

58 (36)

 Male

106 (68)

102 (65)

101 (64)

Completed education, no. (%)

 High school

36 (23)

38 (24)

30 (19)

 College

85 (55)

72 (46)

88 (55)

 University

35 (22)

48 (30)

41 (26)

Occupational status, no. (%)

 Professional, technical, managerial

32 (22)

45 (29)

37 (24)

 Clerical, sales

1 (1)

0 (0)

2 (1)

 Service

107 (72)

99 (63)

101 (66)

 Agricultural, fishery, related

0 (0)

1 (1)

2 (1)

 House wife

0 (0)

1 (1)

2 (1)

 Student

5 (3)

6 (4)

7 (5)

 Unemployed

4 (3)

4 (3)

3 (2)

 

Told hydroxyzine

Told placebo

Told placebo

Told hydroxyzine

Received hydroxyzine

Received placebo

Drowsiness level, mean (SD), mma

4.5 (6.0)

6.3 (10.1)

4.7 (6.6)

5.1 (8.5)

4.9 (7.3)

4.6 (8.0)

Mouth-dryness level, mean (SD), mm a

5.9 (9.5)

8.5 (15.5)

6.2 (10.2)

6.1 (11.5)

5.5 (8.8)

5.7 (11.6)

Nausea level, mean (SD), mm a

2.8 (4.4)

3.0 (5.8)

2.9 (4.9)

3.5 (7.4)

2.3 (5.2)

3.0 (6.4)

Itchiness level, mean (SD), mm a

2.8 (3.8)

2.6 (4.3)

2.8 (4.5)

3.1 (5.3)

2.7 (4.5)

2.7 (4.4)

  1. Hydroxyzine group (group-1, n = 156): received 25 mg hydroxyzine twice and told its hydroxyzine on one time and placebo on the other, in a randomized crossover design. Placebo group (group-2, n = 158): received placebo twice and told its placebo on one time and 25 mg hydroxyzine on the other, in a randomized crossover design. Blinded hydroxyzine/placebo group (group-3, n = 159): received 25 mg hydroxyzine and placebo in a randomized single-blinded crossover design. Numbers may not sum up to group totals because of missing data and percentages may not add to 100% because of rounding
  2. a Measured on 100 mm visual analog scale