Evaluating the Role of Maximal Expiratory Flow at 25% (MEF-25) in Detecting and Managing Patients With Small Airway Disease in the United Arab Emirates

Middle Eastern countries, such as the United Arab Emirates and Oman, are affected by frequent dust storms and extreme hot climatic conditions, which can exacerbate respiratory conditions. These environmental factors are particularly injurious to asthmatic patients, as they can aggravate small airway disease (SAD), leading to increased morbidity and healthcare challenges. The evaluation of maximal mid-expiratory flow (MEF-25) as a diagnostic and therapeutic tool for early-stage small airway dysfunction is of significant clinical importance, particularly in hot and arid metropolitan environments where dusty conditions exacerbate pulmonary issues. This study assesses the value of MEF-25 in clinical practice for detecting SAD and investigates the effectiveness of inhaled bronchodilator therapy with extra-fine particles augmented by a spacer in helping to manage the symptoms of these patients. This retrospective, single-center study was conducted at King's College Hospital Dubai, including 225 patients aged 18 and above, who presented with MEF-25 values less than 80%. Data were collected from the Electronic Medical Record system, including demographics, spirometry findings, and treatment outcomes. MEF-25 values were categorized into moderate (51-80%), severe (35-50%), and very severe (1-34%) grades. Statistical analysis was performed using IBM SPSS software. Results revealed significant correlations between MEF-25 severity and various clinical parameters. Notably, Immunoglobulin E (IgE) and Fractional Exhaled Nitric Oxide (FeNO) levels showed an inverse relationship with decreasing MEF-25 values. Symptoms such as wheezing were more prevalent as MEF-25 values decreased, indicating that MEF-25 is a sensitive indicator of small airway dysfunction (SAD). Additionally, treatment with an inhaled corticosteroid (ICS) combined with a long-acting beta-agonist (LABA), using an inhaler with a fine particle size and augmented by a spacer device, demonstrated substantial and prompt improvement of symptoms. Follow-up data showed a high rate of symptom resolution within one to six weeks after treatment initiation. This study underscores the importance of MEF-25 in the early detection of SAD in the setting of dusty, humid, and hot climatic conditions, and supports the use of beclomethasone-formoterol with a spacer as an effective treatment strategy in optimizing clinical outcomes. The findings advocate for the integration of MEF-25 in routine spirometry evaluation to enhance the diagnosis and management of SAD, particularly in environments prone to high amounts of respiratory allergens.