Table 5.
Factors associated with influenza infection and tuberculosis-influenza co-infection compared with tuberculosis infection only among patients admitted with severe respiratory illness presenting with symptoms duration ≥7 days and tested for tuberculosis and influenza at four sites in South Africa, June 2010- December 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 | |||
| Hospital duration | <7 | 150/244 (61) | 50/80 (62.5) | Reference | 6/9 (67) | Reference | ||
| ≥7 days | 94/244 (39) | 30/80 (37.7) | 0.99 (0.6-1.7) | 0.991 | 3/9 (33) | 0.6 (0.1-2.7) | 0.520 | |
| HIV status | Negative | 34/233 (83) | 25/78 (32) | Reference | 1/9 (11) | Reference | ||
| Positive | 199/233 (17) | 53/78 (68) | 0.4 (0.2-0.7) | 0.002 | 8/9 (89) | 2.2 (0.2-20.5) | 0.486 | |
| Oxygen therapy | No | 203/246 (83) | 50/81 (62) | Reference | 6/9 (67) | Reference | ||
| Yes | 43/246 (17) | 31/81 (38) | 3.0 (1.7-5.5) | <0.001 | 3/9 (33) | 2.1 (0.5-9.3) | 0.315 | |
| Died | No | 224/245 (91) | 74/80 (92.5) | Reference | 6/9 (67) | Reference | ||
| Yes | 21/245 (9) | 6/80 (7.5) | 0.54 (0.2-1.5) | 0.875 | 3/9 (33) | 5.48 (1.2-25.4) | 0.029 | |
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.