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Table 2 Performance of the PHQ-9 and PHQ-2 to detect major depressive disorder among chronic care patients (n = 676)

From: The validity of the Patient Health Questionnaire for screening depression in chronic care patients in primary health care in South Africa

 

PHQ-9

PHQ-2

Cut point

Sensitivity (%)

Specificity (%)

Correctly classified (%)

LR + a

LR-b

Sensitivity (%)

Specificity (%)

Correctly classified (%)

(≥0)

100.0

0.0

11.4

1.000

 

100.0

0.0

11.4

(≥1)

100.0

21.4

30.3

1.2718

0.0000

80.5

57.9

60.5

(≥2)

97.4

37.1

43.9

1.5476

0.0701

59.7

83.5

80.8

(≥3)

90.9

52.4

56.8

1.9107

0.1734

39.0

91.7

85.7

(≥4)

87.0

63.3

66.0

2.3691

0.2053

19.5

97.8

88.9

(≥5)

80.5

71.8

72.8

2.8539

0.2714

9.1

99.3

89.1

(≥6)

71.4

79.1

78.2

3.4229

0.3611

0.0

100.0

88.6

(≥7)

64.9

85.6

83.3

4.5228

0.4094

   

(≥8)

53.2

90.6

86.4

5.6955

0.5157

   

(≥9)

49.3

93.7

88.6

7.7792

0.5408

   

(≥10)

41.6

96.5

90.2

11.8540

0.6056

   

(≥11)

36.4

98.2

91.1

19.8016

0.6483

   

(≥12)

32.5

98.5

91.0

21.6090

0.6856

   

(≥13)

26.0

98.5

90.2

17.2872

0.7516

   

(≥14)

24.7

98.8

90.4

21.1150

0.7622

   

(≥15)

19.5

99.5

90.4

38.8963

0.8092

   

(≥16)

14.3

99.7

89.9

42.7863

0.8600

   

(≥17)

9.1

99.7

89.4

27.2276

0.9121

   

(≥19)

9.1

99.4

89.5

54.4541

0.9106

   

(≥20)

3.9

99.8

88.9

23.3375

0.9626

   

(≥21)

2.6

99.8

88.8

15.5583

0.9757

   

(≥22)

1.3

100.0

88.8

 

0.9870

   

(≥22)

0.0

100.0

88.6

 

1.0000

   
  1. The SCID depression module was used as the diagnostic reference standard
  2. aLikelihood Ratio Positive
  3. bLikelihood Ratio Negative