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Table 3 Factors associated with influenza infection and tuberculosis-influenza co-infection compared with tuberculosis infection only in patients admitted with severe respiratory illness (acute and chronic) and tested for tuberculosis and influenza at four sites in South Africa, June 2010- December 2011

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

Variables

 

Laboratory confirmed tuberculosis Referencea

Laboratory confirmed influenza

Laboratory confirmed tuberculosis-influenza co-infection

n/N (%)

RRRb

ARRRc(95% CI)

n/N (%)

RRRb

ARRRc(95% CI)

Age group (years)

0-4

47/423 (11)

46/275 (10)

Reference

Reference

8/34 (22)

Reference

Reference

5-24

44/423 (10)

28/275 (11)

0.6 (0.3-1.2)

1.3 (0.6-2.9)

3/34 (9)

0.4 (0.1-1.6)

0.5 (0.1-2.5)

 

25-44

231/423 (55)

121/275 (44)

0.5 (0.3-0.8)

1.5 (0.8-2.8)

18/34 (53)

0.5 (0.2-1.2)

0.5 (0.2-1.7)

 

45-64

86/423 (20)

57/275 (21)

0.7 (0.4-1.1)

1.3 (0.7-2.5)

4/34 (12)

0.3 (0.1-0.9)

0.3 (0.1-2.5)

 

65+

15/423 (3)

23/275 (8)

1.6 (0.7-3.4)

3.9 (1.6-9.8)

1/34 (3)

0.3 (0.04-3.4)

9.53e-07

Sex

Female

247/423 (58)

176/275 (64)

Reference

 

20/34 (59)

Reference

 
 

Male

176/176 (42)

99/275 (36)

0.8 (0.6-1.1)

 

14/34 (41)

1.0 (0.5-1.9)

 

Site

Chris Hani Baragwanath

124/423 (29)

169/275 (61)

Reference

 

17/34 (50)

Reference

 
 

Mapulaneng & Matikwana

21/423 (5)

11/275 (4)

0.4 (0.2-0.8)

 

2/34 (6)

0.7 (0.1-3.2)

 
 

Edendale

48/423 (11)

22/275 (8)

0.3 (0.2-0.6)

 

1/34 (3)

0.2 (0.01-1.2)

 
 

Klerksdorp/Tshepong

230/423 (54)

73/275 (27)

0.2 (0.2-0.3)

 

14/34 (41)

0.4 (0.2-0.9)

 

HIV status

Negative

82/392 (21)

99/257 (39)

Reference

Reference

7/32 (22)

Reference

Reference

Positive

310/392 (79)

158/257 (61

0.4 (0.3-0.6)

0.6 (0.4-0.9)

25/32 (78)

0.9 (0.4-2.3)

1.6 (0.5-4.9)

Underlying medical conditionsd

No

394/423 (93)

240/275 (87)

Reference

 

32/34 (94)

Reference

 

Yes

29/423 (7)

35/275 (13)

1.98 (1.2-3.3)

 

2/34 (6)

0.8 (0.2-3.7)

 

Duration of symptoms prior to admission

<7

166/412 (40)

194/275 (71)

Reference

Reference

24/33 (73)

Reference

Reference

≥7

246/412 (60)

81/275 (29)

0.3 (0.2-0.4)

0.4 (0.2-0.4)

9/33 (27)

0.3 (0.1-0.6)

0.3 (0.1-0.7)

Pneumoccocal co-infection on PCRe

No

371/388 (96)

233/246 (95)

Reference

Reference

29/30 (97)

  

Yes

17/388 (4)

13/246 (5)

1.2 (0.6-2.6)

 

1/30 (3)

0.8 (0.1-5.8)

 

Oxygen therapy

No

313/423 (74)

158/275 (57)

Reference

Reference

24/34 (71)

Reference

Reference

 

Yes

110/423 (26)

117/275 (43)

2.1 (1.5-2.9)

1.9 (1.3-2.8)

10/34 (29)

1.2 (0.5-2.6)

0.97 (0.4-2.3)

Tuberculosis treatment

No

185/422 (44)

243/274 (89)

Reference

 

20/34 (59)

Reference

 

Yes

237/422 (56)

31/274 (11)

0.1 (0.1-0.2)

 

14/34 (41)

0.5 (0.3-1.1)

 

Hospital duration (days)

≤

257/420 (61)

198/274 (72)

Reference

 

22/33 (67)

Reference

Reference

>7

163/420 (39)

76/274 (28)

0.6 (0.4-0.8)

0.6 (0.4-0.9)

11/33 (33)

0.8 (0.4-1.7)

0.7 (0.3-1.5)

Died

No

391/422 (73)

265/274

Reference

Reference

30/34 (88)

Reference

Reference

 

Yes

31/422 (7)

9/274

0.4 (0.2-0.9)

0.5 (0.2-1.1)

4/34 (12)

1.7 (0.6-5.1)

3.2 (1.1-10.0)

  1. 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).
  2. bUnadjusted relative risk ratio (RRR) at multivariable analysis.
  3. cAdjusted relative risk ratio (ARRR) at multivariable analysis.
  4. dUnderlying conditions included any of the following: Asthma, other chronic lung disease, chronic heart disease (valvular heart disease, coronary artery disease, or heart failure excluding hypertension), liver disease (cirrhosis or liver failure), renal disease (nephrotic syndrome, chronic renal failure), diabetes mellitus, immunocompromising conditions excluding HIV infection (organ transplant, immunosuppressive therapy, immunoglobulindeficiency, malignancy), neurological disease (cerebrovascular accident, spinal cord injury, seizures, neuromuscular conditions) or pregnancy. Comorbidities were considered absent in cases for which the medical records stated that the patient had no underlying medical condition or when there was no direct reference to that condition.
  5. elyt A PCR positive for Streptococcus pneumoniae on blood specimen.
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BMC Infectious Diseases

ISSN: 1471-2334

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