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Table 3 Attributable fractions (AF) and population attributable fractions (PAF) of fever to malaria by parasite density (dry 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

Parasite density Cases Controls    
(/μL) n %¥ n %¥ aOR AF PAF
0 666 78 760 84 1   
1-400 99 12 88 10 1.1 0.06  
401-4000 50 6 47 5 0.7  
4001-40000 26 3 12 1 1.3 0.24  
40000+ 11 1 1 0 7.0 0.86  
Total 852   908    0.11 0.02
  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. aOR: odds-ratio (of fever at each stratum of parasite density, versus uninfected patients), adjusted for age; AF: attributable fraction, calculated as: ;
  4. £ (AF by definition ≥ 0)
  5. PrevMal = % febrile patients with malaria infection
  6. PAF: population attributable fraction, calculated as: PAF = AF(PrevMal).