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Table 2 Adherence* to study supplements by pill counts

From: A randomized controlled trial of vitamin E and selenium on rate of decline in lung function

 

Placebo

Vitamin E

Selenium

Selenium + vitamin E

Selenium/matching placebo

% adherent (range)

Year 1 (n = 2,920)

92 (87–92)

89 (84–90)

91 (85–91)

87 (82–88)

Year 2 (n = 2,920)

90 (84–91)

87 (81–87)

89 (83–90)

87 (81–88)

Year 3 (n = 2,910)

90 (83–91)

87 (81–88)

89 (82–89)

87 (80–88)

Year 4 (n = 2,887)

85 (78–87)

84 (76–85)

86 (77–87)

87 (77–88)

Year 5 (n = 2,216)

84 (76–85)

80 (73–82)

82 (75–84)

83 (73–85)

Year 6 (n = 901)

82 (72–85)

79 (68–82)

82 (74–84)

86 (75–87)

Vitamin E/matching placebo

% adherent (range)

Year 1 (n = 2,920)

92 (87–92)

89 (84–90)

90 (86–91)

87 (82–88)

Year 2 (n = 2,920)

90 (85–91)

88 (81–88)

88 (82–89)

87 (80–88)

Year 3 (n = 2,910)

88 (82–89)

87 (81–88)

86 (79–87)

86 (78–87)

Year 4 (n = 2,887)

84 (76–85)

81 (74–83)

84 (76–86)

84 (75–86)

Year 5 (n = 2,216)

81 (74–83)

79 (71–81)

81 (74–83)

79 (69–81)

Year 6 (n = 901)

81 (69–83)

76 (66–79)

78 (70–81)

80 (69–82)

  1. *Adherence defined as report of taking ≥80% of study pills; decreasing denominators over time reflect varying amounts of follow-up on participants.
  2. Percent adherent (range); percent calculated for all participants with data, and ranges estimated by including participants with missing data and assuming missing were either all non-adherent (low estimate) or all adherent (high estimate).