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Table 2 Demographic and clinical characteristics associated with laboratory-confirmed tuberculosis among patients admitted with severe respiratory illness (acute and chronic) that were 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

Characteristic   Laboratory confirmed tuberculosis n/N (%) Unadjusted odds ratio (95% CI) P value Adjusted odds ratios (95% CI) P value
Age group (years) 0-4 55/571 (10) Reference   Reference  
  5-24 47/270 (17) 1.97 (1.3-3.0) 0.001 1.36 (0.8-2.3) 0.233
  25-44 249/1378 (18) 2.1 (1.5-2.8) <0.001 1.37 (0.9-2.06) 0.120
  45-64 90/611 (15) 1.6 (1.1-2.3) 0.008 1.11 (0.7-1.7) 0.628
  65+ 16/129 (12) 1.3 (0.7-2.4) 0.348 0.94 (0.5-1.9) 0.872
Site Chris Hani Baragwanath 141/1618 (9) Reference   Reference  
Mapulaneng & Matikwana 23/144 (16) 1.99 (1.2-3.2) 0.005 1.4 (0.8-2.3) 0.228
Edendale 49/385 (13) 1.5 (1.1-2.2) 0.016 0.9 (0.6-1.4) 0.668
Klerksdorp/Tshepong 244/812 (30) 4.5 (3.6-5.6) <0.001 1.9 (1.4-2.6) <0.001
Influenza status Negative 423/2650 (16) Reference    
  Positive 34/309 (11) 0.7 (0.5-0.9) 0.023   
HIV status Negative 89/862 (10) Reference    
  Positive 335/1877 (18) 1.9 (1.5-2.4) <0.001   
Underlying medical condition* No 426/2652 (16) Reference    
Yes 31/307 (10) 0.6 (0.4-0.9) 0.007   
Duration of symptoms prior to admission <7 190/1884 (10) Reference    
≥7 255/1012 (25) 3.0 (2.4-3.7) <0.001   
Pneumococcal co-infection on PCR** No 400/2435 (16) Reference   Reference  
Yes 18/214 (8) 0.5 (0.3-0.8) 0.003 0.5 (0.3-0.9) 0.016
Oxygen therapy No 337/1869 (18) Reference   Reference  
Yes 120/1086 (11) 0.6 (0.4-0.7) <0.001 0.7 (0.5- 0.9) 0.007
Receiving TB treatment at time of admission No 25/158 (16) Reference    
Yes 10/49 (20) 1.4 (0.6-3.1) 0.456   
Started on TB treatment No 205/2301 (9) Reference   Reference  
Yes 251/647 (39) 6.5 (5.2-8.0) <0.001 4.6 (3.5-6.0) <0.001
Duration of hospitalisation (days) ≤7 279/1913 (14) Reference    
>7 174/1029 (17) 1.2 (0.96-1.6) 0.096   
Season Summer 57/366 (15) Reference    
  Autumn 78/449 (17) 1.1 (0.8-1.6) 0.492   
  Winter 178/1027 (17) 1.1 (0.8-1.6) 0.441   
  Spring 144/1117 (13) 0.8 (0.6-1.1) 0.194   
Died No 421/2757 (15) Reference    
  Yes 35/195 (18) 1.2 (0.8-1.8) 0.318   
  1. HIV – human immunodeficiency virus; ICU– Intensive Care Unit, TB-Tuberculosis, CI – confidence interval.
  2. Analysis includes 2029 individuals with severe acute respiratory illness and 930 with severe chronic respiratory illness.
  3. *Underlying 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, immunoglobulin deficiency, 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.
  4. **lyt A PCR positive for Streptococcus pneumoniae on blood specimen.
  5. Other variables that were evaluated but not presented in the table because they were not significant on univariate analysis were sex, influenza type, concurrent bacterial infection, antibiotic prescribed on admission, admission to intensive care unit, and smoking and alcohol intake for patients ≥12 years.