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Table 2 Sensitivity, specificity, PPV and NPV of self-report, pharmacy refill and RTMM at viral load ≥ 20 copies/ml

From: Predicting viral load suppression by self-reported adherence, pharmacy refill counts and real time medication monitoring among people living with HIV in Tanzania

Cut-off %

Adherence measure

Viral load

Sensitivity

Specificity

PPV

NPV

 ≥ 20

 < 20

Self-report

  < 80%

4

0

5.8

100

100

70.3

  ≥ 80%

65

154

    

Pharmacy refill

  < 80%

14

26

19.7

83.6

35.0

70.0

  ≥ 80%

57

133

    

RTMM

  < 80%

10

16

41.7

70.9

38.5

73.6

  ≥ 80%

14

39

    

Cut-off 85%

 

Viral load

Sensitivity

Specificity

PPV

NPV

 ≥ 20

 < 20

Self-report

  < 85%

4

1

5.8

99.3

80.0

70.2

  ≥ 85%

65

153

    

Pharmacy refill

  < 85%

17

29

23.9

81.8

37.0

70.6

  ≥ 85%

54

130

    

RTMM

  < 85%

11

19

45.8

65.4

36.7

73.5

  ≥ 85%

13

36

    

Cut-off 90%

 

Viral load

Sensitivity

Specificity

PPV

NPV

 ≥ 20

 < 20

Self-report

  < 90%

4

1

5.8

99.3

80.0

70.2

  ≥ 90%

65

153

    

Pharmacy refill

  < 90%

21

34

29.6

78.6

38.2

71.4

  ≥ 90%

50

125

    

RTMM

  < 90%

12

22

50.0

60.0

35.3

73.3

  ≥ 90%

12

33

    

Cut-off 95%

 

Viral load

Sensitivity

Specificity

PPV

NPV

 ≥ 20

 < 20

Self-report

  < 95%

5

8

7.2

94.8

38.5

69.5

  ≥ 95%

64

146

    

Pharmacy refill

  < 95%

29

40

40.8

74.8

42.0

73.9

  ≥ 95%

42

119

    

RTMM

  < 95%

13

26

54.2

52.7

33.3

72.5

  ≥ 95%

11

29

    

Cut-off 100%

 

Viral load

Sensitivity

Specificity

PPV

NPV

 ≥ 20

 < 20

Self-report

  < 100%

12

22

17.4

85.7

35.3

69.8

 100%

57

132

    

Pharmacy refill

  < 100%

35

62

49.3

61.0

36.1

72.9

 100%

36

97

    

RTMM

  < 100%

18

39

75.0

29.1

31.6

72.7

 100%

6

16

    
  1. PPV positive predict value, NPV negative predict value, RTMM real time medication monitoring.