Rapid Diagnosis Of Multidrug-Resistant Tuberculosis Impacts Expenditures Prior To Appropriate Treatment: A Performance And Diagnostic Cost Analysis

Figures & data

Figure 1 Diagnostic algorithms of MDR-TB. (A) The first diagnostic algorithm of MDR-TB with phenotypic DST. (B) The second diagnostic algorithm of MDR-TB with HAIN test and phenotypic DST.

Table 1 Performance Of HAIN Test For Detecting Rifampin Resistance

Classification	HAIN	DST		Total	Sensitivity (%, 95% CI)	Specificity (%, 95% CI)	PPV (%, 95% CI)	NPV (%, 95% CI)	Kappa value
		R	S
Smear-positive	R	174	14	188	94.1(90.6–97.5)	98.8(98.1–99.4)	92.6(88.8–96.3)	99.0(98.4–99.6)	0.92
	S	11	1108	1119
	Total	185	1122	1307
Smear-negative	R	43	3	46	97.7(93.3–100.0)	99.1(98.0–100.0)	93.5(86.3–100.0)	99.7(99.1–100.0)	0.95
	S	1	316	317
	Total	44	319	363
Total	R	217	17	234	94.8(91.9–97.6)	98.8(98.3–99.4)	92.7(89.4–96.1)	99.2(98.8–99.7)	0.93
	S	12	1424	1436
	Total	229	1441	1670

Abbreviations: DST, drug susceptibility test; R, resistant; S, sensitive; PPV, positive predictive value; NPV, negative predictive value.

Table 2 Performance Of HAIN Test For Detecting Isoniazid Resistance

Classification	HAIN	DST		Total	Sensitivity (%, 95% CI)	Specificity (%, 95% CI)	PPV (%, 95% CI)	NPV (%, 95% CI)	Kappa value
		R	S
Smear-positive	R	179	46	225	88.6(84.2–93.0)	95.8(94.7–97.0)	79.6(74.3–84.8)	97.9(97.0–98.7)	0.81
	S	23	1059	1082
	Total	202	1105	1307
Smear-negative	R	51	16	67	92.7(85.9–99.6)	94.8(92.3–97.3)	76.1(65.9–86.3)	98.6(97.3–100.0)	0.98
	S	4	292	296
	Total	55	308	363
Total	R	230	62	292	89.5(85.7–93.2)	95.6(94.5–96.7)	78.8(74.1–83.5)	98.0(97.3–98.8)	0.81
	S	27	1351	1378
	Total	257	1413	1670

Abbreviations: DST, drug susceptibility test; R, resistant; S, sensitive; PPV, positive predictive value; NPV, negative predictive value.

Table 3 Performance Of HAIN Test For Detecting Multidrug Resistance

Classification	HAIN	DST		Total	Sensitivity (%, 95% CI)	Specificity (%, 95% CI)	PPV (%, 95% CI)	NPV (%, 95% CI)	Kappa value
		R	S
Smear-positive	R	128	12	140	89.5(84.5–94.5)	99.0(98.4–99.5)	91.4(86.8–96.1)	98.7(98.1–99.4)	0.89
	S	15	1152	1167
	Total	143	1164	1307
Smear-negative	R	34	4	38	94.4(87.0–100.0)	98.8(97.6–100.0)	89.5(79.7–99.2)	99.4(98.5–100.0)	0.91
	S	2	323	325
	Total	36	327	363
Total	R	162	16	178	90.5(86.2–94.8)	98.9(98.4–99.4)	91.0(86.8–95.2)	98.9(98.3–99.4)	0.90
	S	17	1475	1492
	Total	179	1491	1670

Abbreviations: DST, drug susceptibility test; R, resistant; S, sensitive; PPV, positive predictive value; NPV, negative predictive value.

Table 4 Comparison Of Turnaround Time To Identify MDR-TB Cases With Conventional DST And HAIN Test

Classification	No. Of Cases	Mycobacterial Culture Mean (IQR, Day)	Conventional DST Mean (IQR, Day)	HAIN Mean (IQR, Day)
Smear-negative case	40	26(21–33)	56(51–63)	32(25–38)
Smear-positive case	155	23(19–30)	53(49–60)	3(2–4)

Notes: P<0.01(Conventional DST vs. HAIN for smear-negative case); P<0.01(Conventional DST vs. HAIN for smear-positive case).

Abbreviation: IQR, inter-quartile range.

Table 5 Costs Of Algorithms For The Diagnosis And Treatment Of MDR-TB Patients Enrolled In This Study

Algorithm	Classification	Cost Of Diagnosis ($US)	Cost Of Empirical Treatment ($US)	Total ($US)
Conventional DST	Smear-negative case	50.72	419.03	469.75
	Smear-positive case	50.72	396.58	447.30
Conventional DST+HAIN	Smear-negative case	108.70	239.44	348.14
	Smear-positive case	108.70	22.45	131.14

Abbreviation: DST, drug susceptibility test.