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Table 4 Attributable fractions (AF) and population attributable fractions (PAF) of fever to malaria by parasite density and age group (rainy season)

From: Accuracy of a rapid diagnostic test on the diagnosis of malaria infection and of malaria - attributable fever during low and high transmission season in Burkina Faso

Age Parasite density Cases Controls    
(years) (/μL) n %¥ n %¥ OR AF PAF
< 1 0 27 17 32 64 1   
  1-400 14 9 1 2 16.6 0.94  
  401-4000 40 25 9 18 5.3 0.81  
  4001-40000 41 26 4 8 12.1 0.92  
  40000+ 37 23 4 8 11.0 0.91  
  Total 159   50    0.88 0.73
1 - 4 0 111 22 88 55 1   
  1-400 40 8 14 9 2.3 0.56  
  401-4000 132 26 32 20 3.3 0.69  
  4001-40000 100 20 21 13 3.8 0.74  
  40000+ 121 24 6 4 16.0 0.94  
  Total 504   161    0.77 0.60
5 - 14 0 77 28 66 48 1   
  1-400 34 12 31 23 0.9 0£  
  401-4000 57 21 26 19 1.9 0.47  
  4001-40000 52 19 12 9 3.7 0.73  
  40000+ 55 20 2 1 23.6 0.96  
  Total 275   137    0.59 0.43
15+ 0 261 69 434 74 1   
  1-400 36 10 98 17 0.6 0£  
  401-4000 36 10 36 6 1.7 0.40  
  4001-40000 41 11 21 4 3.2 0.69  
  40000+ 5 1 1 0 8.3 0.88  
  Total 379   590    0.40 0.12
All 0 476 36 620 66 NA   
  1-400 124 9 144 15 NA 0.29  
  401-4000 265 20 103 11 NA 0.62  
  4001-40000 234 18 58 6 NA 0.76  
  40000+ 218 17 13 1 NA 0.94  
  Total 1317   938    0.69 0.44
  1. Cases: with fever, axillary temperature ≥ 37.5°C at hospital visit.
  2. Controls: without fever, axillary temperature < 37.5°C at hospital visit and no reported history of fever during the preceding 3 days.
  3. ¥ Percentage of patients in a certain parasite density class among cases/controls.
  4. OR: odds-ratio (of fever at each stratum of parasite density and age, versus uninfected patients); AF: attributable fraction, calculated as: ;
  5. ORs not calculated as overall AF calculated from results by age-category.
  6. £ AF by definition ≥ 0.
  7. PAF: population attributable fraction (calculated as showed in Table 3).
  8. NA: Not applicable.