Table 3.
Heterogeneity assessment summary by using sensitivity and subgroup analyses, SSA, 2017
| Subgroup analysis (PICO) | Number of studies | Prevalence of EPTB (95% CI), random-effects model | Heterogeneity | ||
|---|---|---|---|---|---|
| τ2 | I2 (%) | P-value (Q) | |||
| Overall | 31 | 20% (17, 22) | 0 | 94 | <0.00001 |
| Sensitivity analysis by removing one large study | 30 | 20% (17, 23) | 0.01 | 94 | <0.00001 |
|
Clinical heterogeneity by age groups Children <15 years Adults >15 or >18 years All age groups |
3 7 21 |
17% (3, 31) 23% (14, 32) 18% (16, 19) |
0.01 0.01 0 |
97 97 86 |
<0.00001 <0.00001 <0.00001 |
|
Clinical heterogeneity by EPTB types Different EPTB TB of lymph node TB of hepatic or TB of abdomen |
27 2 2 |
22% (19, 25) 14% (12, 16) One each, not estimated |
0.01 0 |
97 0 |
<0.00001 0.65 |
|
Methodological heterogeneity by study design Cross-sectional Retrospective record review Retrospective cohort Prospective cohort |
9 14 5 2 |
20% (13, 27) 19% (16, 22) 23% (17, 29) 16% (11, 20) |
0.01 0 0 0 |
96 91 97 36 |
<0.00001 <0.00001 <0.00001 0.21 |
|
By subregion of SSA Eastern SSA Southern SSA Western SSA Central SSA |
16 4 10 1 |
20% (16, 23) 21% (15, 26) 19% (13, 24) Not estimated |
0 0 0.01 |
92 92 96 |
<0.00001 <0.00001 <0.00001 |
|
By countries of SSA having ≥ two studies Ethiopia Nigeria Cameroon South Africa Uganda Zambia Others |
10 4 3 4 2 2 6 |
23% (17, 29) 15% (7, 24) 25% (12, 37) 17% (14, 20) 12% (7, 17) 15% (12, 18) 17% (14, 20) |
0.01 0.01 0.01 0 0 0 0 |
93 94 97 84 35 0 84 |
<0.00001 <0.00001 <0.00001 0.0003 0.21 0.74 <0.0001 |
|
Study time variation 1990–2000 2001–2010 2011–2017 |
1 3 27 |
Not estimated 19% (3, 34) 20% (18, 23) |
0.02 0 |
94 94 |
<0.00001 <0.00001 |
Abbreviations: EPTB, extrapulmonary tuberculosis; PICO, people, intervention, comparison, outcomes; SSA, sub-Saharan Africa; TB, tuberculosis.