title: Clinical characteristics of influenza A H1N1 versus other influenza-like illnesses amongst outpatients attending a university health center in Oman.
abstract: OBJECTIVE
  To identify the clinical characteristics of outpatients with flu-like illnesses stratified by influenza A H1N1 status.
  
  
  METHODS
  The study was conducted at the H1N1 staff clinic of Sultan Qaboos University Hospital in Muscat, Oman. The population consisted of university students and university/hospital staff and their family members. All adult patients who presented to the H1N1 clinic with an influenza-like illness over a 4-month period (from August until the end of November 2009) were included. Real-time reverse transcriptase (rRT) PCR was used for the diagnosis of H1N1 influenza. Demographic data, clinical signs and symptoms, history of exposure to H1N1, history of recent travel, and co-morbid conditions were documented. Analyses were conducted using univariate and multivariate statistical techniques.
  
  
  RESULTS
  Out of the 2318 patients identified, 27% (n=616) were positive for H1N1 influenza. The mean temperature in the H1N1-positive group was significantly higher than in the negative group (38.3 °C vs. 37.2 °C; p<0.001). Proportions of patients who reported cough, sore throat, headache, myalgia, gastrointestinal symptoms, exposure to a confirmed case of H1N1, and a history of travel were significantly higher in the H1N1-positive group as compared to the swab-negative group. However, the multivariable logistic model identified only the following significant predictor variables of H1N1 infection: younger age, fever (≥ 37.8 °C), sore throat, myalgia, diarrhea, and exposure to a confirmed H1N1 case within the last 7 days.
  
  
  CONCLUSIONS
  This study provides useful data on the clinical characteristics of H1N1 influenza in a large outpatient population from the Middle East. Patients who tested positive for H1N1 were more likely to have fever, sore throat, diarrhea, and myalgia compared to those with other influenza-like illnesses.
authors.affiliation: Department of Family Medicine and Public Health, College of Medicine and Health Sciences, Sultan Qaboos University, PO Box 38, PC 123, Al-Khod, Muscat, Oman. abdulaziz@squ.edu.om
authors.forename: Abdulaziz
authors.initials: A
authors.lastname: Al-Mahrezi
authors.forename: Nafisa
authors.initials: N
authors.lastname: Samir
authors.forename: Ibrahim
authors.initials: I
authors.lastname: Al-Zakwani
authors.forename: Zakaria
authors.initials: Z
authors.lastname: Al-Muharmi
authors.forename: Abdulla
authors.initials: A
authors.lastname: Balkhair
authors.forename: Mohammed
authors.initials: M
authors.lastname: Al-Shafaee
mesh_terms: D000328:Adult; D003371:Cough; D005260:Female; D005334:Fever; D006785:Hospitals, University; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype / Q000145:classification / Q000235:genetics / Q000302:isolation & purification* / Q000472:pathogenicity*; D007251:Influenza, Human / Q000503:physiopathology* / Q000821:virology; D008297:Male; D009850:Oman; D010045:Outpatients; D010612:Pharyngitis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D055815:Young Adult