Exercise Capacity, Physical Activity Level and Quality of Life in Children With Primary Immunodeficiency

Primary immune deficiencies (PIDs) are a heterogeneous group of diseases resulting from various abnormalities that affect the development, differentiation, and/or function of cells and components of the immune system. PIDs are clinically characterized by increased susceptibility to infections, autoimmune diseases, auto-inflammatory disorders, allergies, bone marrow failure, and/or malignancies. Although individually rare, the total number of individuals with PIDs constitutes a significant health burden. The prevalence and distribution of PIDs vary among populations, with an estimated prevalence of 1/1,000 to 1/5,000. The specific prevalence of PIDs in Turkey is not well known due to the lack of extensive studies and a national registry system. However, a study encompassing two centers in Turkey reported a prevalence of 30.5/100,000. Currently, approximately 500 PID diseases have been identified, with selective immunoglobulin A (IgA) deficiency being the most common and common variable immunodeficiency (CVID) being the most common symptomatic PID.

Pulmonary complications are highly prevalent among PID patients and significantly contribute to morbidity and mortality. Recurrent respiratory tract infections often serve as the initial warning sign in some PIDs and are a leading cause of mortality in adult PID patients. The presence of two or more pneumonia episodes per year is considered one of the ten warning signs of PID. Acute and chronic infections primarily constitute respiratory system diseases, while non-infectious respiratory complications include asthma, bronchiectasis, bronchiolitis obliterans, interstitial lung disease, granulomatous lung disease, and malignancies. These diseases significantly impact the quality of life of PID patients, limit their working abilities, and restrict their physical and social activities. Health-related quality of life in PID patients is also significantly affected by delays in the diagnosis and treatment of infections.

As survival from infections improves, non-infectious pulmonary complications become more common in PID patients. Particularly in PIDs characterized by antibody deficiencies, permanent lung damage is observed in 20-40% of patients.

Physical activity levels are also affected in PID patients, but there are only survey studies on this topic. Therefore, it is expected that respiratory muscle strength, as well as respiratory muscle endurance, functional exercise capacity, and peripheral muscle strength, would be affected in these patients. There is no research available on maximal exercise capacity, functional exercise capacity, respiratory muscle strength and endurance, and peripheral muscle strength.

The aim of this study is to compare the maximal exercise capacity, functional exercise capacity, respiratory functions, physical activity level, quality of life, respiratory muscle strength and endurance, peripheral muscle strength, muscle oxygenation and dyspnea in patients with primary immune deficiencies with healthy individuals.