Table 4

 Risk factors identified by conditional multiple logistic regression for being viral RNA negative by RT-PCR on day five. Important non-significant factors are also included. Patients with no detected influenza were excluded from analysis

Factor No of patients*No of events*OR (95% CI)P value
Nose viral load†3042130.73 (0.62 to 0.86)<0.01
Karnofsky score <50‡35150.24 (0.08 to 0.78)0.02
Child236490.62 (0.17 to 2.22)0.46
Double dose oseltamivir1561121.27 (0.73 to 2.20)0.39
Virus type:
 B51360.88 (0.32 to 2.41)0.80
 H3N2132910.72 (0.30 to 1.70)0.45
 H5N11520.03 (0.00 to 0.64)0.03
 H1200968571.01 (0.34 to 2.97)0.99
 H1N1-pdm3827Reference

RT-PCR=reverse transcriptase polymerase chain reaction.

*Total number of patients in group and total number negative for viral RNA by RT-PCR on day 5; 304 patients with 213 events were included in analysis.

†After log10 (x+1) transformation, odds ratio corresponds to change in odds associated with 10-fold increase in viral load.

‡Patients with score <50 require frequent medical attention.