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Table 3 Univariate and multivariate analysis of factors associated with nasopharyngeal S. pneumoniae and S. aureus colonisation

From: Prevalence and antimicrobial resistance profiles of respiratory microbial flora in African children with HIV-associated chronic lung disease

Variable No. observations (n = 410) § Streptococcus pneumoniae Staphylococcus aureus
No. isolates (n = 173)φ OR [95% CI] p Adjusted OR [95% CI] p No. isolates (n = 86)λ OR [95% CI] p Adjusted OR [95% CI] p
Group
 CLD- 18% (74) 11% (19) Reference   Reference   10% (9) Reference   Reference  
 CLD+ 82% (336) 89% (154) 2.5 [1.4–4.4] 0.002 2.0[1.1–3.9] 0.04 90% (77) 2.2 [1.1–4.8] 0.04 1.8 [0.8–4.5] 0.17
Study site
 Malawi 28% (114) 32% (56) Reference   Reference   31% (27) Reference   Reference  
 Zimbabwe 72% (296) 68% (117) 0.7 [0.4–1.1] 0.08 1.3 [0.7–2.4] 0.42 69% (59) 0.8 [0.5–1.4] 0.40 0.7 [0.4–1.5] 0.39
Sex
 Female 52% (212) 54% (94) Reference   Reference   41% (35) Reference   Reference  
 Male 48% (198) 46% (79) 0.8 [0.6–1.2] 0.36 0.7 [0.4–1.0] 0.07 59% (51) 1.8 [1.1–2.9] 0.02 1.7 [1.0–2.9] 0.05
Season of sample collection
 Dec - Apr - Rainy season 36% (149) 32% (56) Reference   Reference   36% (31) Reference   Reference  
 May–Aug - Cool season 39% (160) 43% (74) 1.4 [0.9–2.3] 0.30 1.7 [1.0–2.9] 0.13 29% (25) 0.7 [0.4–1.3] 0.03 0.9 [0.5–1.6] 0.11
 Sep - Nov - Hot season 25% (101) 25% (43) 1.2 [0.7–2.1] 1.3 [0.7–2.3] 35% (30) 1.6 [0.9–2.9] 1.7 [0.9–3.2]
Enrolment age category
 17-19y 32% (131) 20% (35) Reference   Reference   28% (24) Reference   Reference  
 13-16y 41% (168) 47% (81) 2.6 [1.6–4.2] <0.001 2.2 [1.3–3.8] <0.001 43% (37) 1.3 [0.7–2.3] 0.66 1.1 [0.6–2.1] 0.83
 6-12y 27% (111) 33% (57) 2.9 [1.7–5.0] 3.2 [1.8–5.8] 29% (25) 1.3 [0.7–2.4] 1.2 [0.6–2.5]
Number of years on ART
 6 m- < 2y 9% (35) 14% (23) Reference   Reference   7% (6) Reference   Reference  
 2- < 4y 18% (72) 18% (30) 0.4 [0.2–0.9] 0.02 0.4 [0.2–1.0] 0.04 18% (15) 1.3 [0.5–3.9] 0.94 1.2 [0.4–3.9] 0.78
 4y- < 6y 20% (81) 22% (36) 0.4 [0.2–0.9] 0.4 [0.2–1.0] 22% (18) 1.4 [0.5–4.1] 1.4 [0.5–4.4]
 6y+ 53% (214) 47% (78) 0.3 [0.1–0.6] 0.3 [0.1–0.7] 53% (44) 1.3 [0.5–3.5] 1.0 [0.4–3.0]
CD4 count
  > 500 63% (257) 62% (108) Reference     63% (54) Reference    
 200–500 27% (112) 24% (42) 0.8 [0.5–1.3] 0.09    30% (26) 1.1 [0.7–1.9] 0.55   
  < 200 10% (40) 13% (23) 1.9 [1.0–3.7]    7% (6) 0.7 [0.2–1.6]   
Enrolment viral load
 Unsuppressed 42% (174) 46% (80) Reference   Reference   55% (47) Reference   Reference  
 Suppressed 58% (236) 54% (93) 0.8[0.5–1.1] 0.18 0.6 [0.4–1.0] 0.03 45% (39) 0.5 [0.3–0.9] 0.01 0.5 [0.3–0.9] 0.02
ART regimen
 PI-based regimen - 2nd line 24% (98) 25% (44) Reference   Reference   33% (28) Reference   Reference  
 NNRTI-based regimen -1st line 76% (312) 75% (129) 0.9 [0.6–1.4] 0.55 0.8 [0.5–1.4] 0.44 67% (58) 0.6 [0.3–1.0] 0.03 0.6 [0.3–1.1] 0.07
Ever treated for TB
 No 74% (302) 70% (120) Reference   Reference   71% (61) Reference   Reference  
 Yes 26% (106) 30% (52) 1.5 [0.9–2.3] 0.10 1.5 [0.9–2.5] 0.12 29% (25) 1.2 [0.7–2.1] 0.46 0.9 [0.5–1.7] 0.83
Enrolment weight- for-age- z-score
 Not underweight 54% (220) 49% (85) Reference     49% (42) Reference    
 Underweight 46% (190) 51% (88) 1.4 [0.9–2.0] 0.12    51% (44) 1.3 [0.8–2.1] 0.31   
Enrolment height-for-age- z-score -
 Not stunted 54% (220) 45% (78) Reference   Reference   52% (45) Reference   Reference  
 Stunted 46% (190) 55% (95) 1.8 [1.2–2.7] 0.003 1.6 [1.1–2.6] 0.03 48% (41) 1.1 [0.7–1.7] 0.78 0.8 [0.5–1.3] 0.39
Ever repeated a grade
 No 46% (183) 41% (69) Reference     42% (36) Reference    
 Yes 54% (218) 59% (100) 1.4 [0.9–2.1] 0.10    58% (49) 1.2 [0.7–1.9] 0.49   
MRC dyspnoea score
 1 or 0 60% (244) 53% (91) Reference   Reference   56% (48) Reference   Reference  
  > 1 40% (165) 47% (81) 1.6 [1.1–2.4] 0.02 1.3 [0.7–2.2] 0.36 44% (37) 1.2 [0.7–1.9] 0.50 1.0 [0.5–1.8] 0.94
  1. § Missing values: Number of years on ART (8), CD4 count (1), Ever treated for TB (2), Ever repeated a grade (9) and MRC dyspnoea score (1). φ Number of years on ART (n = 167), ART regimen(n = 172), Ever treated for TB (n = 172), Ever repeated a grade (n = 169), MRC dyspnoea score (n = 172). λn = 83, 85 and 85 for the number of years on ART, ever repeated a grade and MRC dyspnoea score. Variables with two levels where a level is less than 10% of total observations are not tested for associations. These included current school attendance and taking cotrimoxazole. Variables that have values in the adjusted odd ratios column were included in the multivariate model for that bacteria. Variables with p values <0.25 were included in the multivariate model except where they are colinear with another variable within the model. Weight-for-age was colinear with height-for-age and hence excluded from the model. Ever repeated a grade was excluded because of co-linearity with MRC score. CD4 count is colinear with viral load suppression. Clinically relevant variables (a priori-defined) that were included in the multivariate model regardless of significance were group, age, sex, site, season of sample collection, number of years on ART, enrolment viral load, ART regimen, ever treated for TB, enrolment height-for-age z-score and MRC dyspnoea score