Table 2.

Univariate analysis of factors that may confound the association between early sputum culture conversion and pyrazinamide use with susceptibility^a

Factor	Total no. of subjects for row	Z use with susceptibility			Early sputum culture conversion
		No. (%) of subjects	RR	P	No. (%) of subjects	RR	P
Sex
Male	129	59 (46)	0.94	0.75	91 (71)	1.08	0.48
Female	42	18 (43)			32 (76)
Age group (yr)b
≤44	81	40 (49)	0.83	0.28	60 (74)	0.95	0.55
>44	90	37 (41)			63 (70)
Ethnicity
Chinese	155	69 (45)	1.05	1.00	113 (73)	0.82	0.37
Others	15	7 (47)			9 (60)
Permanent resident
No	143	62 (43)	1.24	0.32	104 (73)	0.93	0.77
Yes	28	15 (54)			19 (68)
Ever a smoker
No	59	26 (44)	1.04	0.84	46 (78)	0.87	0.16
Yes	105	48 (46)			71 (68)
Adverse social factorc
No	115	54 (47)	0.87	0.47	88 (77)	0.82	0.06
Yes	56	23 (41)			35 (63)
Comorbidityd
No	85	35 (41)	1.19	0.31	59 (69)	1.07	0.47
Yes	86	42 (49)			64 (74)
Second-line drug naïve and <1 mo of first-line drugs
No	90	41 (46)	0.98	0.88	56 (62)	1.33	0.003
Yes	81	36 (44)			67 (83)
Initial sputum smear
Negative	40	21 (53)	0.82	0.30	29 (73)	0.99	0.91
Positive	130	56 (43)			93 (72)
Disease on initial chest radiograph more than RUL/equivalent
No	92	42 (46)	0.97	0.85	66 (72)	1.00	0.96
Yes	77	34 (44)			55 (71)
Cavitation on initial chest radiograph
No	80	36 (45)	1.00	0.99	57 (71)	1.02	0.85
Yes	91	41 (45)			66 (73)
>50% treatment supervised by trained personnel
No	33	16 (48)	0.91	0.65	23 (70)	1.03	0.96
Yes	136	60 (44)			98 (72)
Use of SLIDs
No	61	34 (56)	0.70	0.04	44 (72)	1.00	0.97
Yes	110	43 (39)			79 (72)
Use of thioamide
No	27	10 (37)	1.26	0.36	16 (59)	1.25	0.17
Yes	144	67 (47)			107 (74)
Use of streptomycin
No	138	60 (43)	1.18	0.40	99 (72)	1.01	1.00
Yes	33	17 (52)			24 (73)
Use of ethambutol
No	73	28 (38)	1.30	0.13	47 (64)	1.20	0.06
Yes	98	49 (50)			76 (78)
Use of cycloserine
No	65	50 (77)	0.33	<0.001	53 (82)	0.81	0.03
Yes	106	27 (25)			70 (66)
Use of PAS
No	86	55 (64)	0.40	<0.001	66 (77)	0.87	0.16
Yes	85	22 (26)			57 (67)
Use of linezolid
No	167	76 (46)	0.55	0.63	120 (72)	1.04	1.00
Yes	4	1 (25)			3 (75)
Hepatotoxicity complicating TB treatment
No	146	65 (45)	1.08	0.75	103 (71)	1.13	0.47
Yes	25	12 (48)			20 (80)
Use of <4 drugs with activity in vitro
No	125	64 (51)	0.55	0.01	100 (80)	0.63	<0.001
Yes	46	13 (28)			23 (50)
Susceptible to ofloxacin
No	29	6 (21)	2.42	0.004	12 (41%)	1.89	<0.001
Yes	142	71 (50)			111 (78)
Susceptible to SLIDs
No	20	4 (20)	2.40	0.03	9 (45)	1.67	0.01
Yes	150	72 (48)			113 (75)
Susceptible to ethionamide
No	22	5 (23)	2.13	0.04	10 (45)	1.67	0.007
Yes	149	72 (48)			113 (76)
Susceptible to streptomycin
No	122	53 (43)	1.13	0.51	86 (70)	1.07	0.51
Yes	49	24 (49)			37 (76)
Susceptible to ethambutol
No	69	26 (38)	1.33	0.11	43 (62)	1.26	0.02
Yes	102	51 (50)			80 (78)
Susceptible to cycloserine
No	6	1 (17)	2.74	0.23	5 (83)	0.86	1.00
Yes	164	75 (46)			117 (71)
Z use with susceptibility
Yes	77	NA	NA	NA	61 (79)	0.83	0.06
Others	94	NA			62 (66)

^aLess than 5% of data were missing. Unless otherwise specified, use of drugs refers to use for >1 month. Factors with risk ratios of ≥1.2 or ≤0.9 in both exposure factor and outcome are shown in bold. Abbreviations: NA, not applicable; PAS, para-aminosalicylic acid; RR, risk ratio; RUL, right upper lobe; SLIDs, second-line injectable drugs; TB, tuberculosis; Z, pyrazinamide.

^bThe median age of the cohort of 194 patients was 45 years.

^cAdverse social factors refer to financial difficulty that meets social security criteria, history of imprisonment, or history of drug addiction.

^dComorbidity refers to diabetes mellitus, renal impairment, lung cancer, other malignancy, obstructive/restrictive lung disease, use of cytotoxic or steroids, liver disease, or HIV infection. The prevalence of HIV infection was less than 1%.