{
  "abstract": "Introduction and Objectives Misdiagnosis of paediatric asthma is a well-recognised problem. Current NICE guidelines recommend single occasion tests which may not represent a child’s full clinical picture. Monitoring lung function variation over time provides clinicians with additional information. This can be done using home spirometry, but little is known about its role as a diagnostic tool.We hypothesised that lung function variation has greater diagnostic accuracy than single occasion tests. This study aimed to assess the sensitivity and specificity of lung function variability over a 4-week monitoring period compared to single occasion tests.Methods In this retrospective cohort study, children aged 5–16, referred to hospital asthma clinics for diagnostic confirmation or management optimisation, carried out supervised home spirometry for a 4-week period using a NuvoAir spirometer. Forced expiratory volume in 1 second/forced vital capacity (FEV 1/FVC) ratio, FEV1 and peak expiratory flow (PEF) were measured 4 or 5 times weekly and when symptomatic. FEV1 and FVC were graded using the American Thoracic Society (ATS)/European Respiratory Society (ERS) guidelines. Baseline FeNO was assessed at the first clinic. A paediatric respiratory clinician used all available data to determine diagnosis. The diagnostic accuracy of baseline FEV1/FVC z-score and fraction of exhaled nitric oxide (FeNO) and variation of FEV1 and PEF were calculated using receiver operating characteristic (ROC) curves.Results 43 children were recruited with 34 (mean age 9.97 years, 20 male) producing sufficient home spirometry for inclusion in the analysis. The ‘confirmed asthma’ group (27) had lower baseline lung function values but only home spirometry results were significantly lower than the ‘no asthma’ group. FEV 1 variation had the highest area under the curve (AUC) of 0.96 (p=0.003) and would have correctly diagnosed 19/25 children with asthma. FeNO had the lowest (0.55, p=0.7) and would have only correctly diagnosed 8/25 children with asthma. Sensitivity and specificity based on ERS/ATS cut-offs for FEV1 variation were 1.00 and 0.14 compared to 0.42 and 0.67 for baseline FeNO.Abstract P141 Figure 1Receiver operating characteristic (ROC) curves for a, FEV1 variation (ampl%mean) b, PEF variation (ampl%mean) c, FeNO and d, FEV1/FVC ratio (z-score). P-value and area under the curve (AUC) for each test is written in the bottom left of the graphs. Numbers in the graph represent the associated cut-off values for the different parameters with the same units as listed in the graph titles. The red dotted line represents an AUC of 0.5 and is the diagnostic accuracy equivalent to that of an algorithm based on chanceConclusion Home spirometry measurements have greater utility for diagnosing asthma in children than single occasion testing. Further research is needed to assess the utility and cost-effectiveness of home spirometry.",
  "authors": [
    {
      "affiliations": [
        "Imperial College London, London, UK"
      ],
      "name": "RT Tuli"
    },
    {
      "affiliations": [
        "Imperial College Healthcare Trust, London, UK",
        "Royal Brompton Hospital, London, UK"
      ],
      "name": "SS Salehian"
    },
    {
      "affiliations": [
        "Imperial College Healthcare Trust, London, UK"
      ],
      "name": "ZA Awan"
    },
    {
      "affiliations": [
        "Medway Maritime Hospital, Gillingham, UK"
      ],
      "name": "SS Singham"
    },
    {
      "affiliations": [
        "NuvoAir Medical Inc, London, UK"
      ],
      "name": "E Raywood"
    },
    {
      "affiliations": [
        "NuvoAir Medical Inc, London, UK"
      ],
      "name": "C Oliver"
    },
    {
      "affiliations": [
        "Imperial College Healthcare Trust, London, UK"
      ],
      "name": "C Mclean"
    },
    {
      "affiliations": [
        "Imperial College London, London, UK",
        "Imperial College Healthcare Trust, London, UK",
        "Royal Brompton Hospital, London, UK"
      ],
      "name": "LF Fleming"
    }
  ],
  "title": "P141 The utility of home spirometry monitoring in children with respiratory symptoms",
  "uid": "6d07f4b8-c6d4-5932-9fd8-df707871cb60"
}