Disease definitions in respiratory and sleep medicine: changes in diagnostic criteria and categories over time and clinical implications

[摘要] We often think of disease definitions as absolute and unchangeable, however, diagnostic criteria and categories for diseases are not static [1]. They change over time, and different definitions can coexist at the same time. Have you ever wondered how diseases get defined? Often definitions are based on several diagnostic criteria, which might include symptoms and/or results of diagnostic tests. They are created and revised by expert panels, for example guideline committees or professional society groups. Determining the presence of disease is not always as straightforward as one might think. How “high” does the pulmonary arterial pressure have to be before it is pulmonary hypertension? How many apnoeas and hypopnoeas are considered “normal” during sleep and when is it labelled obstructive sleep apnoea? Changes in disease definitions/diagnostic criteria can significantly impact the conceptualisation of a condition. For example, the inclusion of symptoms as a diagnostic requirement means that asymptomatic patients do not receive a disease label. The change of thresholds to distinguish normal variation from disease can change the incidence and prevalence of a disease, as well as the perceived effectiveness of treatment. For example, as the forced expiratory volume in 1 s (FEV1)/forced vital capacity (FVC) ratio is known to decline with age, the prevalence of COPD in a population could be higher when using the fixed FEV1/FVC ratio compared with using an age-adjusted definition of airflow obstruction or the lower limit of normal [2]. Including earlier and/or milder disease cases by lowering disease thresholds might bias results to suggest better treatment efficacy.

[学科分类] 外科医学