Table 4.
Factors associated with influenza infection and tuberculosis-influenza co-infection compared with tuberculosis infection only among patients presenting with symptoms duration <7 days admitted with severe respiratory illness and tested for tuberculosis and influenza at four sites in South Africa, June 2010-2011
| Variables | Laboratory confirmed tuberculosis Reference a | Laboratory confirmed influenza | Laboratory confirmed tuberculosis-influenza co-infection | |||||
|---|---|---|---|---|---|---|---|---|
| n/N (%) | ARRR b | P-value | n/N (%) | ARRR b | P-value | |||
| Duration of symptoms | <7 | 100/165 (61) | 148/194 (76) | Reference | 6/9 (67) | Reference | ||
| ≥7 days | 65/165 (39) | 46/194 (24) | 0.4 (0.3-0.7) | 0.001 | 3/9 (33) | 0.5 (0.2-1.5) | 0.240 | |
| HIV status | Negative | 46/148 (31) | 74/179 (41) | Reference | 5/22 (23) | Reference | ||
| Positive | 102/148 (69) | 105/ 179 (59) | 0.8 (0.5-1.2) | 0.280 | 17/22 (77) | 1.6 (0.5-4.7) | 0.404 | |
| Oxygen therapy | No | 101/166 (61) | 108/194 (56) | Reference | 17/24 (71) | Reference | ||
| Yes | 65/166 (39) | 86/194 (44) | 1.4 (0.9-2.3) | 0.141 | 7/24 (29) | 0.7 (0.3-2.0) | 0.560 | |
| Died | No | 157/166 (95) | 191/194 (98) | 0.5(0.2-1.5) | 24/24 (96) | Reference | ||
| Yes | 9/166 (5) | 3/194 (2) | 0.2 (0.04-1.2) | 0.081 | 1/24 (4) | 0.98 (0.1-8.6) | 0.986 | |
HIV – human immunodeficiency virus.
aTuberculosis only group used as reference for multinomial model analysis (i.e. comparing influenza only to tuberculosis only and tuberculosis–influenza co-infection to tuberculosis only group).
bAdjusted relative risk ratio (ARRR) at multivariable analysis.