Table 1.
Distribution of primary study designs and number of participants by comorbidity and country income level from included systematic reviews and meta-analyses
| Low- and middle-income countries |
High-income countries* |
|||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
Cohort |
Case-control |
Cross-sectional |
Primary studies |
Participants |
Cohort |
Case-control |
Cross-sectional |
Primary studies |
Participants |
% LMIC primary studies |
% LMIC participants |
|
|
Depression |
0 |
3 |
183 |
186 |
528 987† |
8 |
7 |
1 |
16 |
838 399 |
86.1 |
38.2 |
|
Chronic kidney disease |
4 |
1 |
9 |
14 |
5 189 |
69 |
0 |
0 |
69 |
820 138 |
2.82 |
0.14 |
|
Cardiovascular disease‡ |
6 |
6 |
10 |
22 |
3 108 248 |
20 |
1 |
21 |
42 |
1 440 950 |
34.4 |
68.3 |
|
Tuberculosis |
16 |
15 |
17 |
47§ |
300 659 |
19 |
15 |
26 |
53 |
58 286 930 |
47 |
0.51 |
| TOTAL (%) | 26 (9.67%) | 25 (9.29%) | 219 (81.4%) | 269 | 3 943 083 | 116 (64.4%) | 23 (12.8%) | 48 (26.7%) | 180 | 61 386 417 | 59.9 | 6.42 |
LMIC – low- and middle-income country
*These primary studies are from the systematic reviews and meta-analyses which included studies from high-income countries and were included in this umbrella review.
†This number does not include the participants from Uphoff et al. [29] since they did not provide individual study characteristics.
‡One primary study from Einarson et al. [24] included low, middle, and high-income countries and was thus not included in this table.
§One primary study from McMurry et al. [34] included data on two separate cross-sectional studies, so both were included in the cross-sectional but not primary study count.