Differences in clinical predictors of influenza in adults and children with influenza-like illness

Abstract

<jats:title>Abstract</jats:title><jats:p>Influenza contributes significantly to morbidity and mortality in the winter season. The aim of the study was to identify clinical signs and symptoms most predictive of influenza infection in children and adults with influenza-like illness. A prospective systematic sampling analysis of clinical data collected through sentinel surveillance system for influenza in 32 primary care centers and one tertiary care hospital in Slovenia during two consecutive influenza seasons (2004/2005 and 2005/2006) was carried out. Children and adults who had influenza-like illness, defined as febrille illness with sudden onset, prostration and weakness, muscle and joint pain and at least (cough, sore throat, coryza) were included and tested for influenza A and B virus, adenovirus, respiratory syncytial virus and enterovirus by RT-PCR. Clinical data were evaluated in statistical models to identify the best predictors for the confirmation of influenza for children (under age of 15) and adults. Of 1,286 patients with influenza-like symptoms in both seasons 211 were confirmed to have influenza A or B alone and compared to 780 influenza-negative patients. A fever over 38°C, chills, headache, malaise and sore eyes revealed a significant association with positive RT-PCR test for influenza virus in children. In adults, only three symptoms were significantly related to PCR-confirmed influenza infection: fever, cough and abnormal breath sounds. The stepwise logistic regression analysis showed that four symptoms predicted influenza in children: fever (38°C or more) (p=0.010), headache (p=0.030), cough (p=0.044) and absence of abnormal breathing sounds (p=0.015) with sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of 5.1%, 98.1%, 57.1% and 80.1%, respectively. For adults, the strongest impact on influenza positivity was found for fever (p=0.008) and cough (p=0.085). The model for adults had less favorable characteristics, with sensitivity, specificity, PPV and NPV of 0%, 100%, 0% and 76.4%, respectively. Differences in clinical predictors of influenza in children compared to adults were found. The model for adults was acceptable but not a good one. The model for children was found to be more reliable than the prediction model for adults.</jats:p>

Clinical Practice Guidelines by the Infectious Diseases Society of America: 2018 Update on Diagnosis, Treatment, Chemoprophylaxis, and Institutional Outbreak Management of Seasonal Influenzaa

“…Influenza is associated with a variety of signs and symptoms that may vary by age, underlying chronic disease, complications, host immune status, and influenza virus type or influenza A virus subtype. Abrupt onset of fever with cough is most predictive of uncomplicated influenza in adult outpatients, with a sensitivity of >70% during the influenza season [26–29]. A retrospective, cross-sectional study in a single urban US emergency department found that the best predictive model for identifying influenza for all ages consisted of cough (diagnostic odds ratio [DOR], 5.87), fever (DOR, 4.49), rhinorrhea (DOR, 1.98), and myalgias (DOR, 1.44) [30].…”

Viral aetiology of influenza-like illness in Belgium during the influenza A(H1N1)2009 pandemic

“…Previous studies reporting on symptoms associated with influenza showed cough and fever as the best predictors for influenza infection in adults [11][12][13][14], or muscle/joint pain and nasal congestion to be associated with influenza in all age groups [15]. In children, fever, headache, cough and absence of abnormal breathing sounds [14] or cough, headache and pharyngitis [16] or myalgia (among 1-5-year-olds) [17] were reported to be associated with influenza.…”

“…Previous studies reporting on symptoms associated with influenza showed cough and fever as the best predictors for influenza infection in adults [11][12][13][14], or muscle/joint pain and nasal congestion to be associated with influenza in all age groups [15]. In children, fever, headache, cough and absence of abnormal breathing sounds [14] or cough, headache and pharyngitis [16] or myalgia (among 1-5-year-olds) [17] were reported to be associated with influenza. Recent reports on the clinical features associated with A(H1N1) 2009 influenza in children showed that headache and myalgia were positively associated [18] or fever, rhinorrhoea, a normal chest radiograph and the absence of leukocytosis or significant gastrointestinal symptoms were positively associated [19].…”

Signs and symptoms predicting influenza in children: a matched case–control analysis of prospectively collected clinical data

“…In children 5-12 years of age, fever ≥38.2°C, cough, and headache were found to be predictive of influenza, whereas in children 1-4 years of age, the only symptom that increased the likelihood of influenza was myalgia. Recently, Sočan et al reported on the clinical predictors of influenza in primary care and tertiary hospital clinic patients who were selected for influenza testing by several predetermined clinical criteria [18]. Fever ≥38°C, headache, cough, and lack of abnormal breathing sounds were found to be predictive of influenza in children less than 15 years of age.…”

“…Besides optimizing the use of antiviral drugs, increased accuracy of identifying influenza virus infections would help avoid the unnecessary use of antibiotics and laboratory tests in children [15] and also improve the proper cohorting of patients on wards. Although some previous studies have assessed the predictive value of signs and symptoms for influenza in selected groups of children [16][17][18], few data are available on unselected outpatient children who form the majority of pediatric patients seeking medical care during any influenza outbreak [8,19]. Further, age is an important confounding factor because the clinical features of influenza in children vary with age [20].…”