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Should systematic screening for active TB be done in household contacts and other close contacts?
Note: For full references to cited studies, see systematic review 1 (Kranzer K et al. A systematic literature review of the benefits to communities and individuals of active screening for tuberculosis disease. International Journal of Tuberculosis and Lung Disease, 2013, 17:432–446.)
Quality assessment Summary of findings
Importance No of cases/population Effect Quality
No of studies Design Limitations Inconsistency Indirectness Imprecision Other Intervention Control Relative (95%CI) Absolute
1. Impact on case detection
Cross sectional studies assessing proportion of detected cases through screening vs. all notified cases
5 studies: Lee 2008 Ottmani 2009 Capewell 1984
Ormerod 1993 Jereb 1999
Cross-sectional Not serious Not serious Serious1 Not serious None 31 NA 78
50 561
1635 NA 816
649 9199
2% of all notified cases 4.5% ≥10 years, 19% of <10 years 9% of all notified cases
7% of all notified cases 6% of all notified cases
VERY LOW
IMPORTANT
2. Impact on time to diagnosis and severity at diagnosis:
2.1. Studies on delay: No studies
2.2. Studies of severity of disease at time of diagnosis
IMPORTANT Proportion sputum smear positive in screening compared to passive case finding
1 (Eang 2012) Cross sectional Not serious Not serious Serious2 Not serious 116/405(29%) 358/602(59%) 0.48(0.41;0.57) 31/100 fewer in screening (25-35 lower) LOW
Smear grade among sputum smear positive cases, reporting percentage scanty, proportion 2+ or 3+ out of all smear positive
1 (Eang 2012) Cross sectional Not serious Not serious Not serious Not serious 50/116(0.43) 203/354(0.57) 0.75(0.60;0.94) 14/100 fewer (3/100 to 23/100 fewer) LOW
Chest X-ray indicating severe disease
1 (Wang 2000) Cross sectional Not serious Not serious Serious3 Not serious 17/284(6%) 620/3903(16%) 0.38 (0.23;0.60) 10/100 fewer severe (6-12/100 fewer) VERY LOW
3. Impact on treatment outcomes: no studies CRITICAL
4. Impact on TB epidemiology
Cluster RCT of screening of household TB contacts, including chemoprophylaxis for those with likely latent infection, over 5 years, in a high incidence area of Rio de Janeiro. Comparing TB notification in intervention and control areas
CRITICAL
1 (Cavalcante
2010)
Cluster RCT Not serious Only one study Serious4 Serious5 Incidence decr.
10%, from 339 to 305/100,0006
Incidence increased
5%from 340 to 358/100,0005
15% difference in change of incidence
(p for difference=0.04)
LOW
Cluster RCT of household intervention (3 visits per household, including screening of household contacts) vs. no household intervention in very high burden setting, comparing prevalence of active TB incidence of TB infection
1 (Ayles 2012)7 Cluster RCT Not serious Only one study Serious8 Serious9 TB prevalence 746/100,000
Infection incidence 0.87%
TB prevalence 883/100,000
Infection incidence 1.71%
Adj RR TB: 0.78 (0.61-1.00)
Adj RR infection: 0.45 (0.20-1.05)
194 fewer prevalent TB cases/100,000 in the intervention areas
0.9 less TB infections/100 population in the intervention areas
LOW
1 The study design does not allow conclusion if detected cases are additional and the reported percentages are only indirect measures of increase in case detection 2 Only one study in one setting 3 Only one study in one setting. 4 Not possible to separate the effect of contact screening for active TB from the other co-interventions; treatment of latent TB. Only one study. 5 Borderline statistical significance 6 Absolute number of cases by year not reported. 7 The household intervention also included HIV counselling, testing and management. The study also included an arm of enhanced case finding, results are not included here 8 Not possible to separate the effect of contact tracing from the other co-interventions; treatment of latent TB, HIV counselling and testing. Only one study. 9 Borderline statistical significance for impact on prevalance of active TB and not statistically significant difference in TB infection prevalance
Should systematic screening for active TB be done in miners?
Note: For full references to cited studies, see systematic review 1 (Kranzer K et al. A systematic literature review of the benefits to communities and individuals of active screening for tuberculosis disease. International Journal of Tuberculosis and Lung Disease, 2013, 17:432–446.)
Quality assessment Summary of findings
Importance No of cases/population Effect
Quality No of studies Design Limitations Inconsistency Indirectness Imprecision
Other considerations
Intervention Control Relative (95%CI)
Absolute
1. Impact on case detection
No studies IMPORTANT
2. Impact on time to diagnosis and severity at diagnosis
No studies IMPORTANT
3. Impact on treatment outcomes
11 Cohort No No Serious2 No - 12/1225 (1.0%) 69/1011 (6.8%) Adjusted RR: 5.6(2.6-12.2)
5.5 fewer deaths per 100 treated ( 4.2 to 6.3 fewer per 100 treated)
VERY LOW CRITICAL
5. Impact on TB epidemiology
No studies CRITICAL
1 Churchyard 2000. Study population: miners. 2 Only one study
Should systematic screening for active TB be done in prisoners?
Note: For full references to cited studies, see systematic review 1 (Kranzer K et al. A systematic literature review of the benefits to communities and individuals of active screening for tuberculosis disease. International Journal of Tuberculosis and Lung Disease, 2013, 17:432–446.)
Quality assessment Summary of findings
Importance No of cases/population Effect
Quality No of studies Design Limitations Inconsistency Indirectness Imprecision
Other considerations
Intervention Control Relative (95%CI)
Absolute
1. Impact on case detection
No studies
2. Impact on time to diagnosis and severity at diagnosis
2.1. Studies of delay from reported onset of symptoms to start of treatment IMPORTANT
1 Story 20081 Cross sectional
Serious2 Only one study Serious3 Serious4 - - 3 time longer
average delay in passive case finding group
- VERY LOW
2.2.Proportion sputum smear positive in screening compared to passive case finding
1 Story 2008
Cross sectional
Serious Only one study Serious Serious4 44%4 66% 0.67 22/100 fewer in screening groups VERY LOW
3. Impact on treatment outcomes
2 studies Koffi 1997 Harries 2004
Cross-sectional Serious5 Not serious Serious5 Not serious 80/108=74%
181/296=61%
NA
NA
NA
VERY LOW CRITICAL
5. Impact on TB epidemiology
1 study6 Yanjindulam 2012
Longitudinal surveillance
Serious7 Only one study Serious8 Serious9 900/100,000 in prisons 201010
2,500/100,000 in prisons in 2001
0.36 1600/100,000 notified cases less after ten years implementation
VERY LOW CRITICAL
1 This study screened hard-to-reach groups, including homeless, drug users, in shelters, and prisoners 2 Only a conference abstract is available so design details cannot be assessed. 3 The study did not report results separately for the different subgroups. 4 Absolute numbers not available 5None of the studies compared change in treatment success rate when introducing screening or through a trial design comparing screening vs. no screening. 6Yanjindulam 2012. Introduction of systematic screening at both detention and conviction combined with improved TB management and improved living conditions in the prisons, between 2001 and 2010, across 23 prisons and 16 detention centres with a total of about 6000 prisoners. Assessed trend in TB notification within prisons and compared to national trend. 7 No control group, only compared before and after in prisons and with national trend during the same time period 8 Only one study in one setting. It is not possible to separate the impaxct of screening from the impact of improved living conditions and improved TB treatment. 9 Avaiable data do not allow calculation of statistical uncertainty. 10 Absolute numbers not reported
Stable national notification in same period
Should systematic screening for active TB be done in people with previously untreated fibrotic CXR lesion?
Note: For full references to cited studies, see systematic review 1 (Kranzer K et al. A systematic literature review of the benefits to communities and individuals of active screening for tuberculosis disease. International Journal of Tuberculosis and Lung Disease, 2013, 17:432–446.)
Quality assessment Summary of findings
Importance No of cases Effect
Quality No of studies Design Limitations Inconsistency Indirectness Imprecision
Other considerations
Screening in risk group
Other case detection Relative (95%CI)
Absolute
1. Impact on case detection
Studies of contribution to overall case detection IMPORTANT
4 studies1:
Ontario Kolin Netherlands Cambodia
Cross sectional
Not serious Serious Not serious Not serious 1206
96 109 981 20
6246
1020 319
4872 35
19% of all notified bacteriological positive cases
10% of all notified bacteriological positive 34% of all notified bacteriological positive
20% of all notified bacteriological positive 57% of all notified bacteriological positive
LOW
2. Impact on time to diagnosis and severity at diagnosis
No studies IMPORTANT
3. Impact on treatment outcomes
1202/1496
No studies CRITICAL
5. Impact on TB epidemiology
No studies CRITICAL
1 Meijer (1971) reported contribution from routine CXR screening in chest clinics, including people with previous fibrotic lesions on CXR, but also contacts and recent TST converters, from Canada (Ontario), Czechoslovakia (Kolin district) and The Netherlands in various time periods in the 1950s and 60s. Okada (2012) reported contribution of re-screening two years after a prevalence survey, of people who had been identified with active TB and people with CXR abnormalities but no active TB, in the initial survey.
Should systematic screening for active TB be done in communities with high TB burden?
Note: For full references to cited studies, see systematic review 1 (Kranzer K et al. A systematic literature review of the benefits to communities and individuals of active screening for tuberculosis disease. International Journal of Tuberculosis and Lung Disease, 2013, 17:432–446.)
Quality assessment Summary of findings
Importance No of cases Effect
Quality No of studies Design Limitations Inconsistency Indirectness Imprecision
Other considerations
Through screening
Total in same population
Relative (95%CI)
Absolute
1. Impact on case detection
1.1. Studies assessing proportion of detected cases through screening out of all notified cases
Cross sectional studies
10 studies Meijer 1971a1 Meijer 1971b2
Meijer 1971c3 Krivinka 19744 Meijer 1971d5 Aneja 19846 Santha 20037
Harper 19968 Gonzalez 20099 Garcia 200010
Cross-sectional11
Serious12 Serious13 Serious14 Not serious None 90
140
229 19
1682 26
211
71 24 92
646
1020
618 96
4872 13
508
1175 19 15
NA Proportion of cases through screening: 14% of bacteriologically positive cases 14% of bacteriologically positive cases
37% of bacteriologically positive cases 20% of bacteriologically positive cases 35% of bacteriologically positive cases
67% of all notifies cases 25% of all notified cases
6% of all notified cases 56% of all notified cases 86% of all notified cases
VERY LOW IMPOPRTANT
1 Canada 1960-69. Mass miniature radiography screening in selected communities with a previous known case of TB , excluding in those <30 years who were TST negative, covering 18% of the population annually. Numbers do not include the reported routine hospital admission screening, covering 4% of the population, which yielded additional 66 (10%) of the total cases. 2 Canada 1967-68. MMR screening in community, industries, pre-employment and “others”, reaching about 10% of the population. Numbers in the table do not include yield from other than community screening, hospital admission screening (90 cases), “routione Xray” in hospitals , private clinics and chest clinics (136 cases) prison screening (16), contact investigation (35 cases). These cvases constitute an additional 277 (27%) of all bacteriologically positive cases. 3 Czechoslovakia 1961-69. MMR community screening in Kolin district, every 2-3 years, reaching 95% of population >15 years. Screening of people with known fibrotic lung lesions (191 cases) not included here. 4 Czechoslovakia 19729. MMR community screening in Kolin district, reaching 95% of population >15 years. Screening of people with known fibrotic lung lesions (8 cases) cases) not included here. 5 Netherlands 1951-67. MMR screening in community, people >14 years, covering ¼-1/3 of population each year 6 Lay health care workers identified TB suspects in the community, prepared microscopy slides and facilitated transport to microscopy centres. 7 Door-door in approx one third of the population 8 Temporary microscopy camps were put up in remote villages 9 Home visits only to specific risk groups (elderly, heavy alcohol users, ex-prisoners, HIV positive, socio-economically vulnerable) 10 Screening in mixed risk groups on community level or institutions: jails, shelters, orphanages, alcohol support groups and other risk groups. 11 Comparing number of TB cases detected through screening with total number of TB detected through screening and passive case f inding combined in the intervention area. 12 None of the studies compared screening with an alternative intervention since in settings screening was combined with passive case detection. It is unknown in all studies if cases detected through screening would have been detected through
passive case finding had screening not been done. The study design does not allow a direct assessment of effect of screening on additional case detection. Many studies are from the pre-DOTS era 13 Large variation in proportion of cases detected through screening, related to the differences across studies in type and size of target population and differences in screening method. 14 Due to inherent limitation of study design
Quality assessment Summary of findings
Importance No of cases/population Effect
Quality No of studies Design Limitations Inconsistency Indirectness Imprecision
Other considerations
Intervention Control Relative (95%CI)
Absolute
1. Impact on case detection
1.2. Community randomized trials
CRITICAL
Health extension workers informed community about TB and identified TB symptomatics and collected sputum samples at health posts once a month over 20 months. Sputum smear positive notification detection rate
1 (Datiko 2009)
RCT Serious15 Only one trial Serious16 Not serious None 230/178138
(129/100,000)
88/118673
(74/100,000)
RR 1.5517
Case detection rate 53% higher in
intervention clusters (95% CI; 40 to 65%)18
LOW
Community promoters informed about TB symptoms, sputum collection in monthly outreach clinics in rural areas over 1 year. Sputum smear positive case notification rate
1 (Shargie 2006)
RCT Serious19 Only one trial Serious16 Serious8 None 159/127607 (125/100,000)
221/225284 (98/100,000)
RR 1.27 (0.81;1.72)
27 more cases detected per 100,000 population
(from 19 fewer to 72 more)
VERY LOW
Door-to-door screening for symptomatics in poor urban areas
1 (Miller 2010) During intervention 27d Intervention +60d
RCT Not serious Only one trial Serious16 Serious20 None N=11249 19: 934/100000 32: 516/100000
N=12304 16: 604/100,000 41: 493/100,000
Rate Ratio 1.55(1.10;1.99) 1.05(0.56;1.54)
330 more cases detected per 100,000 population per year (from 60 more to 598
more) during intervention, no difference 60 days after
LOW
Infants screened 3 monthly through household visits; suspected TB disease was investigated as inpatient
1 (Moyo 2012) RCT Serious21 Only one trial Serious22 Not serious None 89/4109 PY (2166/100000)
36/4372 PY (823/100,000)
2.6 (1.8-4.0) 1,317 more cases detected per 100,000 population per year (from 659 more to 2470
more per 100,000)
LOW
Repeat information campaigns about TB to the community, decentralised sputum collection points with easy access, sputum collection in health camps, over 3 years
1 (Ayles 2012) RCT Not serious Only one trial Serious23 Serious None Cases at 0 vs.
3 years 875/946 (0.92)
Cases at 0 vs. 3 years
2024/2181 (0.93)
1.0 No difference in the change in case
notification between intervention and control
LOW
15 Method of calculating the main outcome is unclear. The actual method of screening/identification of TB symptomatic is not clearly described. Randomization is described, but little baseline data is provided 16 only been assessed in one setting 17 Crude ratio of case notification rates. Not enough data to calculate CI, adjusted for clustering 18 Authors only report difference in mean case detection rate, which conventionally is the ratio of case notification to the estimated TB incidence, though it is not stated in the paper exactly how it has been calculated 19 The method for choosing which communities received the intervention is not described. Few baseline comparison data are given, but the map suggests a non-random selection and differences between intervention and control communities. The communities were contiguous so there could be contamination. 20 Borderline significance for short term impact and no significant impact after 60 days. 21 Case definition includes main criteria for positive screen. Overdiagnosis possible 22 Only been assessed in one setting, and concerns young children only. 23 Only been assessed in one setting.
Quality assessment Summary of findings
Importance Cases/population, mean or median Effect Quality
No of studies Design Limitations Inconsistency Indirectness Imprecision Other Intervention Control Relative (95%CI) Absolute
2. Impact on time to diagnosis and severity at diagnosis
2.1. Studies of delay from reported onset of symptoms to start of treatment
Studies of proportion of patients with delay more than 90 days, general community screening
1 (Shargie 2006a) Cross sectional Serious 24 Only one study Serious25 Serious 7/13(54%) 14/24(58%) 0.93 4% less in the screening group VERY LOW
MPORTANT
Studies of median delay, door-to-door, RCT community screening
1 (Miller 2010) RCT Serious24 Only one study Serious25 No serious 56 days 56 days No difference LOW
Studies of mean time from birth to diagnosis in cohort of newborn children
1 (Moyo 2012) RCT Serious26 Only one study Serious25 No serious 13.2 months 16.6 months 3.4 months shorter in screening group (0.3 to 6.5 months shorter)
LOW
Study of proportion of patients with delay more than 90 days, RCT community screening
1 (Shargie 2006b) RCT Serious Only one study Serious25 No serious 65/159 (41%) 139/221 (63%) 0.65 (0.49- 0.81 22% less in the screening arm (12-32% less) LOW
Proportion with cough <3 weeks at time of diagnosis, community screening
1 (Santha 2003 Cross sectional Serious Only one study Serious No serious 37% 58% 2.06 19/100 more with short duration in screened VERY LOW
2.2. Studies of severity of disease at time of diagnosis
Proportion sputum smear positive in screening compared to passive case finding
7 studies Den Boon 2008 Meijer 1971a27 Meijer 1971b28
Meijer 1971c29 Krivinka 197430 Meijer 1971d31 Moyo 2012
Cross sectional
Not serious Not serious Serious32 Not serious 813/2128 (0.38) 18/27(67%) 47/90(52%)
63/140(45%)
25/81(31%) 4/19(21%)
646/1682(38%) 10/89 (11%)
2479/3865(0.64) 446/473(94%) 265/425(62%) 420/603(70%)
44/98(45%) 8/21(38%)
1288/2209(58%) 8/36(22%)
0.60(0.56;0.63) 0.71 0.84 0.64
0.69 0.55 0.65 0.46
40/100 lower in screening 27/100 lower in screening 10/100 lower in screening 25/100 lower in screening
14/100 lower in screening 17/100 lower in screening 20/100 lower in screening 11/100 lower in screening
VERY LOW
IMPORTANT
Smear grade among sputum smear positive cases, reporting percentage scanty, proportion 2+ or 3+ out of all smear positive IMPORTANT
2 studies: Den Boon 2008 Shetty
Cross sectional
Not serious Not serious Not serious Not serious 97/229 (0.42) 10/18(0.56)
87/211(0.41)
665/954(0.79) 314/446 (0.70) 351/508(0.69)
0.61(0.52;0.71)
30/100 fewer smear grade 2+ or 3+ in screened (122/100 to 36/100 lower)
LOW
24 Self reported onset of disease may not be reliable, and recall bias may vary between screened cases and those passively detected. No study assessed changed in delay after introduction of screening 25 Only one study 26 Most cases were diagnosed on the bases of symptoms and not on the bases of microbiology, and case definition thus included the maincriteria for positive screen. Overdiagnosis is likely. 27 Canada 1960-69. Mass miniature radiography screening in selected communities with a previous known case of TB , excluding in those <30 years who were TST negative, covering 18% of the population annually. The passive case detection group does not include patients detected through routine hospital admission screening. 28 Canada 1967-68. MMR screening in community, industries, pre-employment and “others”, reaching about 10% of the population. The passive case detection group does not include patients detected through hospital admission screening, “routine Xray” in hospitals , private clinics and chest clinics, prison screening, contact investigation.. 29 Czechoslovakia 1961-69. MMR community screening in Kolin district, every 2-3 years, reaching 95% of population >15 years. The passive case detection group does not include patients detected through screening of people with known fibrotic lung lesions. 30 Czechoslovakia 19729. MMR community screening in Kolin district, reaching 95% of population >15 years. The passive case detection group does not include patients detected through screening of people with known fibrotic lung lesions. 31 Netherlands 1951-67. MMR screening in community, people >14 years, covering ¼-1/3 of population each year 32 Method of diagnosis not necessarily the same in screened and non-screened groups.
Quality assessment Summary of findings
Importance No of cases/population Effect
Quality No of studies Design Limitations Inconsistency Indirectness Imprecision Other Intervention Control Relative (95%CI) Absolute
3. Impact on treatment outcomes
633
den Boon 2008 Ayles 2012
Santha 2003 Cassles 1982 Harper 1996 Eang 2012
Cross-sectional Serious34 Not serious Serious35 Not serious Treatment success
16/20 (80%) 597/771(77%)
107/153(70%) 62/100(62%) 50/68(74%)
370/384(96%)
Treatment success
380/473(80%) 2406/3151(77%)
361/508(71%) 110/159(69%)
997/1306(76%) 573/602(95%)
Pooled 1.00(.98;1.02)
RR=1.0 (0.83;1.2) RR=0.98 (0.95;1.01)
RR=0.99 (0.91;1.08) RR=0.95 (0.83;1.08) RR=0.98 (0.87;1.09 RR=1.01 (0.99;1.04)
Same number of successfully treated
patients among those identified through screening and those
identified through passive case finding
VERY LOW CRITICAL
4. Impact on TB epidemiology
4.1. One time household screening in randomly selected clusters in high burden setting, comparing smear-positive notification rate in intervention clusters with baseline and national rate two years after screening
CRITICAL
1 (Okada 2012) Cohort study Serious Only one study Serious Not serious 34 (154/100,000)
89.5 (404/100,000) Standardized notification rate
0.38 (0.27-
0.52)
250 less smear positive cases per 100,000 population 2 years after one-off screening
VERY LOW
4.2. 6-mothly community screening with mobile van or door-door vs. baseline pre-intervention, in a high burden setting, over 3 years, comparing TB prevalence before and after intervention
1 (Corbett 2010) Cluster randomised trial
Serious36 Only one study Serious Not serious 3.7/1000 (2.6-5.0)
(41 cases)
Baseline prevalence 6.5/1000 (5.1-8.3)
(66 cases)
Adj RR 0.59 (0.40-0.89)
p=0.01
280 fewer prevalent cases per 100,000 population after 3 years
LOW
Repeat information campaigns about TB to the community, decentralised sputum collection points with easy access, sputum collection in health camps, over 3 years
1 Ayles 2012 RCT No serious Only one study Serious37 Serious38 TB prevalence 927/100,000
Infection incidence 1.41%
TB prevalence 711/100,000
Infection incidence 1.05%
Adj RR TB: 1.11 (0.87-1.42)
Adj RR infection: 1.36 (0.59-3.14)
216/100,000 higher prevalance in the intervention are (from 92 less to 299 more)
3.6/1000 higher infection incidence in the intervention arm (from 4.3/1000 less to
22/1000 more)
LOW
33 Only including studies comparing a cohort of patients among identified through screening and a cohort of patients identified through passive case finding 34 Not controlled for severity at time of diagnosis and other patient related factors 35None of the studies compared change in treatment success rate when introducing screening. 36 No control area without intervention, only two different interventions. Difficult to control for secular trend. 37 Only studies in one setting. The major part of the intervention is information campaign combined with decentralized sputum collection points 38 Not powered to detect small difference in prevalance or infection incidence
Should systematic screening for active TB be done among homeless, in shelters, or among drugusers?
Note: For full references to cited studies, see systematic review 1 (Kranzer K et al. A systematic literature review of the benefits to communities and individuals of active screening for tuberculosis disease. International Journal of Tuberculosis and Lung Disease, 2013, 17:432–446.)
Quality assessment Summary of findings
Importance No of cases/population Effect
Quality No of studies Design Limitations Inconsistency Indirectness Imprecision
Other
considerations Intervention Control
Relative
(95%CI) Absolute
1. Impact on case detection
1.1. Cross sectional studies assessing proportion of detected cases through screening vs. all notified cases
1.1.1. Community-based screening, including screening in specific risk populations
1 (de Vries 2007)
Cross-sectional1
Serious Only one study Serious Serious None 28 562 5% of all notified cases VERY LOW IMPORTANT
2. Impact on time to diagnosis and severity at diagnosis
2.2. Studies of severity of disease at time of diagnosis
IMPORTANT
2.2.1. Proportion sputum smear positive in screening compared to passive case finding
3: Ross 1977
Capewell 1986 Story 2008
Cross sectional
Not Serious Not Serious Serious Not Serious 58/131(0.44) 31/54(0.58)
10/41(0.26) 15/25(0.44)
220/337(0.65) 46/71(0.85)
15/26(0.58) 158/240(0.66)
0.67(0.55;0.83) 0.68
0.45 0.67
21/100 fewer in screening (From 11/100 to 35/100 fewer)
VERY LOW
2.2.3. Chest X-ray indicating severe disease
1 Ross 1977 Cross sectional
Serious Not Serious Serious Not Serious 7/54 (0.13) 22/71(0.31) 0.51(0.24;1.10) 15/100 fewer severe in screening group (24/100 fewer to 3/100 more)
3. Impact on treatment outcomes
No study
4. Impact on TB epidemiology
Impact on TB in the general community, incidence decline
1 (Rendelman 1999)
Secular trend, before-after
1985-1995
Serious2 Only one study Serious3 Not serious 29/100,000 (5 cases)
227/100,000 (39 cases)
0.13 (0.05 to 0.32)
34 fewer cases, or 198/100,000 pop. In the intervention district 10 years after screening
was introduced (between 154 and 215/100,000 fewer) No downward trend in
other districts.
VERY LOW
CRITICAL
Impact within the risk group, incidence decline
1 (De Vries 2007) Secular trend,
before-after 2002-2005
Serious4 Only one study Serious5 Not serious 11/4500
244/100,000
24/4500:
553/100,000
0.46
(0.22 to 0.93)
309/100,000 fewer incident cases after
intervention. (between 34 and 431 fewer)
1 Comparing number of TB cases detected through screening with total number of TB detected through screening and passive case f inding in the intervention area. All studies targeted specific subpopulations, none covered the whole population. The
proportion of the population covered varied but was not consistently reported in the studies. 2 No control group, only before after and compared with overall trend in the state of Oregon. No control for other possible confounding events 3 Only one study in one setting. 4 No control group, only before after with the risk group. 5 Only one study in one setting.