Table 3 TB transmission control measures and tuberculin skin test (TST) conversion: Risk of bias assessment and results (nā=ā10)
Studies | Risk of bias | Results | Notes | |||||||
|---|---|---|---|---|---|---|---|---|---|---|
First author, year. | Similar baseline outcome measures | Similar baseline characteristics | Incomplete outcome data (attrition bias) | Blinding or objective assessment of outcome | Protected against contamination | Selective outcome reporting (reporting bias) | Selection and confounding bias | Conversion rate per 100 person years or proportion converting (%) (Bā=ābefore, Aā=āafter) | Relative rate or proportion (A/B) | B1, B2, A1, A2, etc., if more than two cycles. |
Studies reporting rates of conversion | ||||||||||
Bangsberg, 1997 [31] | N/A | N/A | Unclear | Low | N/A | Low | High | B1: 5.8 | B1:1.00 | Ā |
B2: 5.1 | B2: 0.88 | |||||||||
A1: 0.0 | A1: 0.00 | |||||||||
A2: 2.3 | A2: 0.40 | |||||||||
A3: 0.0 | A3: 0.00 | |||||||||
Louther, 1997 [32] | N/A | N/A | Unclear | Low | N/A | Low | High | B: 7.2 (65/898) | B: 1.00 | Fella et al. [20] describing same study, mention possible overestimate of conversions in before period. |
A: 3.3 (32/971) | A: 0.46 | |||||||||
Blumberg, 1998 [34] | N/A | N/A | Unclear | Low | N/A | Low | High | B: 5.98 | B: 1.00 | Ā |
A: 1.09 | A: 0.18 | |||||||||
Yanai, 2003 [35] | N/A | N/A | Unclear | Low | N/A | Low | Low | Ā | Univariate: | Multivariate adjustment for sex, age, area TB risk, BCG scar, duration of work (ā¤ā12 vsā>ā12Ā months) and frequency of patient contact. aDiscrepancy between rates and rate ratios in Table 2 of article ā figures here are recalculations. |
B: 9.3 | B: 1.00 | |||||||||
A1: 6.4 | A1: 0.69a | |||||||||
A2: 2.2 | A2: 0.24a Multivariate: A1: 0.40 A2: 0.01 | |||||||||
da Costa, 2009 [15] | N/A | N/A | High | Low | N/A | Low | High | B: 4.8c | B: 1.00 | cConverted from person-months to person-years. High loss to follow up reported. |
A: 3.1 | A: 0.65 | |||||||||
Studies reporting only counts, i.e. proportions converting in each period | ||||||||||
Blumberg, 1995 [27] | N/A | N/A | Unclear | Low | N/A | Low | High | B: 118/3579 (3.3%) | 1.00 | Each period 6Ā months. |
A1: 51/2975 (1.7%) | 0.51 | |||||||||
A2: 67/4715 (1.4% | 0.42 | |||||||||
A3: 30/4775 (0.6%) | 0.18 | |||||||||
A4: 23/5153 (0.4%) | 0.12 | |||||||||
Jarvis, 1995 [28] | High | Unclear | Highd | Low | Low | Low | High | Intervention groups: Hospital āAā | Ā | dAuthors reported insufficient TST data from control hospital. After period unspecified. |
B: 7/29 (24.1%) | 1.00 | |||||||||
A: 0/23 (0%) | 0.00 | |||||||||
Hospital āDā | Ā | |||||||||
B: 15/123 (12.2%) | 1.00 | |||||||||
A: 5/150 (3.3%) | 0.27 | |||||||||
Control: Hospital āBā | Ā | |||||||||
B: 2/22 (9.1%) | 1.00 | |||||||||
A: 6/33 (18.2%) | 2.00 | |||||||||
Maloney, 1995 [29] | High | Unclear | Unclear | Low | Unclear | Low | High | Intervention group: Wards with TB patients | ā | ePeriods differed in duration: 18 vs 14Ā months. Before proportion standardised to 14Ā months. |
B: 15/90 (16.7%) 12e/90 (13.3%) | - 1.00 | |||||||||
A: 4/78 (5.1%) | 0.38 | |||||||||
Controls: Other wards | Ā | |||||||||
B: 7/254 (2.8%) | 1.00 | |||||||||
A: 9/228 (3.9%) | 1.39 | |||||||||
Wenger, 1995 [30] | N/A | N/A | Unclear | Low | N/A | Low | High | B: 7/25 (28%) | 1.00 | Periods differed in duration: 5 vs 9 and 16Ā months. Given zero count in A2, no period adjustment needed. |
A1: 3/17 (17.6%) | 0.63 | |||||||||
A2: 0/23 (0%) | 0.00 | |||||||||
Behrman, 1998 [33] | High | Low | Unclear | Low | Unclear | Low | Low | Intervention group: Emergency Department | Ā | Each period 12Ā months. Possible co-intervention via increased staff vigilance regarding early diagnosis and use of respirators. |
B: 6/50 (12%) | 1.00 | |||||||||
A: 0/64 (0%) | 0.00 | |||||||||
Controls: Other hospital employees | Ā | |||||||||
B: 51/2514 (2.0%) | 1.00 | |||||||||
A: 36/3000 (1.2%) | 0.60 | |||||||||