Validity and utility of instruments for screening of depression in women attending antenatal clinics in Blantyre district in Malawi

Figures & data

Table 1: Relationship between demographic characteristics of respondents and depression

Item	Depression	No depression	Total	Chi-square statistic	p-value
	25 (25.8)	72 (74.2)	97 (100)
Occupation				1.4	0.53
Unemployed	20 (80)	49 (68.1)	69 (71.1)
Employed	2 (8)	7 (9.7)	9 (9.3)
Small-scale business	3 (12)	16 (22.2)	19 (19.6)
Education level				1.3 0	0.26
Primary school or none	14 (56)	31 (43.1)	45 (46.4)
Secondary school or above	11 (44)	41 (56.9)	52 (53.6)
Marital status				1.9	0.33
Married	3 (12)	69 (95.8)	72 (74.2)
Unmarried	22 (88)	3 (4.2)	25 (25.8)
Setting				1	0.32
Urban	15 (60)	51 (70.8)	66 (68)
Rural	10 (40)	21 (29.2)	31 (32)
Age in years	26±5.7	25.8±5.1	25.8±5.2	2.7	0.45
Gestation period in weeks	27±7.4	27.9±8.1	27.7±7.9	1.8	0.62
Number of pregnancies	2.5±1.4	2.4±1.3	2.5±1.3	4.7	0.19

Note: Data = n (%) or mean ± standard deviation, MINI = Mini International Neuropsychiatric Interview.

Table 2: Validity of screening instruments

Instrument cut-off	Sensitivity % (95% CI)	Specificity % (95% CI)	PPV % (95% CI)	NPV % (95% CI)	AUC (95% CI), p-value	Optimum cut-off (Se, Sp, J)	Cut-off @ Se 80% Sp in %	Cut -off Se in % @ Sp 80%
EPDS ≥ 10	68 (47–85)	88 (78–94)	65 (44–83)	89 (79–95)	0.850 (0.763–0.915), < 0.001*	> 6 (88%, 74%, 0.62)	> 7, 80, 81	> 7, 81, 80
HSCL-15 ≥1.75	72 (51–88)	93 (85–98)	78 (56–93)	91 (82–97)	0.910 (0.835–0.959), < 0.001*	> 1.7 (72%, 93%, .65)	> 1.5, 80, 82	> 1.5, 82, 80
SRQ ≥ 10	60 (39–79)	97 (90–99)	88 (64–99)	88 (78–94)	0.912 (0.837–0.960), < 0.001*	> 9 (72%, 96%, .68)	> 6, 80, 83	> 6, 83, 80
3-item
screener ≥1	80 (59–93)	81 (70–89)	59 (41–75)	92 (82–97)	0.854 (0.768–0.918), < 0.001*	> 1 (80%, 81%, .61)	> 1, 80, 81	> 1, 80, 80

Notes: Se = sensitivity, Sp = specificity, AUC = area under curve, CI = confidence interval, HSCL-15 = Hopkins Symptoms Checklist-15, EPDS = Edinburgh Postnatal Depression Scale, SRQ = Self Reporting Questionnaire, * = significance set at ≤ 0.05, J = Youden index, PPV = positive predictive value, NPV = negative predictive value.

Table 3: Performance of individual instruments and various combinations of screening instruments

Instrument	Optimum cut-off	Se % (95% CI)	Sp % (95% CI)	AUC (95% CI), p-value
Individual test
EPDS	> 6	88 (69–98)	74 (62–83)	0.850 (0.763–0.915), < 0.001*
HSCL-15	> 1.7	72 (51–88)	93 (85–98)	0.910 (0.835–0.959), < 0.001*
SRQ	> 9	72 (51–88)	96 (88–99)	0.912 (0.837–0.960), < 0.001*
3-item screener	> 1	80 (59–93)	81 (70–89)	0.854 (0.768–0.918), < 0.001*
Compensatory rule testing (either test is positive)
3-item screener or EPDS (n = 49, 50.5%)	> 1/> 6	96 (78–100)	50 (30–70)	0.769 (0.627–877), < 0.001*
3-item screener or HSCL-15 (n = 48, 49.5%)	> 1/> 1.4	91 (72–99)	56 (35–76)	0.866 (0.737–0.947), < 0.001*
3-item screener or SRQ (n = 48, 49.5%)	> 1/> 6	87 (66–97)	68 (69–98)	0.885 (0.760–0.959), < 0.001*
Conjunctive rule testing (positive on both tests)
3-item screener and EPDS (n = 29, 29.9%)	> 1/> 15	42 (20–67)	90 (56–100)	0.608 (0.410–0.783), 0.33
3-item screener and HSCL-15 (n = 23, 23.7%)	> 1/> 2.5	33 (13–59)	100 (49–100)	0.772 (0.552–0.919), 0.03*
3-item screener and SRQ (n = 21, 21.6%)	> 1/> 15	33 (13–59)	100 (29–100)	0.685 (0.449–0.867), 0.28
Probability combination
3-item screener and EPDS		88 (69–97)	82 (71–90)	0.877 (0.794–0.960), < 0.001*
3-item screener and HSCL		88 (69–97)	88 (78–94)	0.917 (0.852–0.982), < 0.001*
3-item screener and SRQ		92 (74–99)	83 (73–91)	0.920 (0.856–0.983), < 0.001*
Sequential rule
3-item screener → EPDS (n = 48→29, 60.4%)	> 1/> 6	96 (78–99)	52 (31–72)	0.775 (0.631–0.883), < 0.001*
3-item screener → HSCL-15 (n = 48→23, 47.9%	> 1/> 1.7	78 (56–93)	80 (59–93)	0.866 (0.737–0.947), < 0.001*
3-item screener → SRQ (n = 48→21, 43.7%)	> 1/> 9	78 (56–93)	88 (69–98)	0.885 (0.760–0.959), < 0.001*

Notes: AUC = area under curve, CI = confidence interval, HSCL-15 = Hopkins Symptoms Checklist-15, EPDS = Edinburgh Postnatal Depression Scale.

SRQ = Self Reporting Questionnaire, PPV = positive predictive value, NPV = negative predictive value, Se = sensitivity, Sp = specificity, * = significance set at ≤ 0.05.

Table 4: Predictive ability of probability combinations of instruments

Instrument	Wald	OR (95% CI), p-value	Correctly classified depression cases (%)
3-item screener and EPDS	26.5	358 (38–3 365), < 0.001*	80.4
3-item screener and HSCL-15	28.9	401 (45–3 569), < 0.001*	87.6
3-item screener and SRQ	33.9	479 (49–4 689), < 0.001*	86.6

Notes: CI = confidence interval, HSCL-15 = Hopkins Symptoms Checklist-15, EPDS = Edinburgh Postnatal Depression Scale, SRQ = Self Reporting Questionnaire, * = significance set at ≤ 0.05.