The minimal clinically important difference of the Severe Respiratory Insufficiency questionnaire

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    Background: The severe respiratory insufficiency questionnaire (SRI) is a validated, commonly used questionnaire for measuring quality of life in patients on long-term noninvasive ventilation (NIV). The minimal clinically important difference (MCID) of the SRI has not been established.

    Aim: To establish the MCID of the SRI-questionnaire in patients with severe chronic obstructive pulmonary disease (COPD) and chronic hypercapnic respiratory failure (CHRF) who use long-term NIV.

    Method: Data were analyzed from 49 stable COPD patients with CHRF who were initiated on long-term home NIV in 2 randomized controlled trials performed at our department. Anchor- and distribution-based methods were used to define de MCID of the SRI-questionnaire. Forced expiratory volume in one second, six-minute walking distance, and the arterial carbon dioxide pressure (PaCO2) at daytime without NIV, were entered as anchors in univariate regression analyses. Additionally, the mean SRI change was calculated in patients who judged their own health as importantly improved of deteriorated according to a global rating scale (GRS) of change. For the distribution based method, the MCID was calculated as 0.5 * the standard deviation of the SRI change.

    Results: Because there was no correlation between the change in PaCO2 and the change in SRI, the PaCO2 could not be used as anchor. The calculated MCID of the SRI-questionnaire ranged from 5-7 points. Using distribution based method, the MCID was 6 points.

    Conclusion: The MCID of the SRI-questionnaire ranged between 5 and 7 points in patients with severe stable COPD. Further research should elucidate whether this cut-off value is valid in other patient groups.
    Original languageEnglish
    Number of pages2
    JournalEuropean Respiratory Journal
    Issue numberSuppl.62
    Publication statusPublished - 15-Sep-2018
    Event28th International Congress of the European-Respiratory-Society (ERS) - Paris, France
    Duration: 15-Sep-201819-Sep-2018

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