Table 3.
Smear grade 3+ and smear positivity among culture confirmed TB patients reported in n=8 observational studies
| First author, country and population, screening tool | Group | Smear grade 3+ / all smear positives |
Smear + / culture confirmed |
Prevalence ratio (screen/PCF) | Comments | ||
|---|---|---|---|---|---|---|---|
| n/N* | % (95%CI) | n/N⁎⁎ | % (95%CI) | ||||
| General population | |||||||
| Abdurrahman 2016 Nigeria Symptoms |
Screen | 101/480 | 21% (17-25%) | - | - | 0.46 | Diagnosed TB patients Screened vs PCF - screened group more likely to be older, married and less likely to be HIV infected. |
| PCF | 96/208 | 46% (39-53%) | - | - | |||
| den Boon 2008 South Africa Smear & culture |
Screen | 6/18 | 33% (13-59%) | - | - | 0.63 | Denominator for smear grade - screened group includes those lost to follow-up pre-treatment; PCF those starting treatment only Diagnosed in screened and on treatment in PCF groups - no difference in age and gender. |
| PCF | 234/446 | 52% (48-57%) | - | - | |||
| Santha 2003 India CXR and symptoms |
Screen | 3/96 | 3% (1-9%) | - | - | 0.07 | Denominator for smear grade - screened group includes those lost to follow-up pre-treatment; PCF those starting treatment only All (smear +ve and -ve) diagnosed in screened and on treatment in PCF groups - screened group more likely to be older, male, illiterate, sole earner, have poor quality house and a 1 room house |
| PCF | 139/330 | 42% (37-48%) | - | - | |||
| Risk groups | |||||||
| Shewade 2019 India: Marginalised/vulnerable† Symptoms |
Screen | 39/233 | 17% (12-22%) | - | - | 0.84 | On treatment TB patients Screened vs PCF- screened group more likely to be older, from rural areas and live further from microscopy units. |
| PCF | 53/265 | 20% (15-25%) | - | - | |||
| Paiao 2016 Brazil: Prisoners Symptoms |
Screen | - | - | 4/40 | 10% (3-24%) | 0.20 | Diagnosed TB patients |
| PCF | - | - | 27/53 | 51% (37-65%) | |||
| Story 2012 UK: Homeless people, drug users, prisoners, asylum seekers CXR |
Screen | - | - | 11/23 | 48% (27-69%) | 0.67 | On treatment TB patients Association between screening and smear positivity maintained after adjusting for age and gender |
| PCF | - | - | 104/146 | 71% (63-78%) | |||
| Verver 2001 Netherlands: Migrants CXR |
Screen | - | - | 60/159 | 38% (30-46%) | 0.68 | On treatment TB patients Screened vs PCF - screen detection varied by country of origin, decreased with increasing length of stay and was less likely among illegal migrants. |
| PCF | - | - | 59/107 | 55% (45-65%) | |||
| Capewell 1986 UK: Hostel dwellers CXR |
Screen | 11/16 | 69% (41-89%) | 0.87 | On treatment TB patients | ||
| PCF | 15/19 | 79% (54-94%) | |||||
n/N=number with smear grade 3+/total number with smear grade scanty, 1+, 2+ and 3+.
n/N=number smear positive/total number culture positive; 95%CI = 95% confidence interval; PCF=passive case-finding.
included slums, tribal areas, scheduled caste communities, areas where occupational lung diseases is high, areas where individuals with high risk of acquiring TB reside including stone crushing/mining/weaving industry/unorganized labour (construction workers etc)/homeless, high HIV/AIDS burden areas, areas or communities with high TB incidence (including prisons) and among household contacts of sputum smear positive TB patients; CXR=chest radiograph.