Influenza virus infection is associated with increased risk of death amongst patients hospitalized with confirmed pulmonary tuberculosis in South Africa, 2010–2011

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
Variables		Laboratory confirmed tuberculosis Reference^a	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
Duration of symptoms	≥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
Oxygen therapy	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.

ISSN: 1471-2334