Inflammatory myopathies are rare autoimmune diseases leading to progressive muscle weakness, often including the respiratory muscles. This study aims to investigate whether inspiratory muscle training (IMT) using a threshold device can improve functional status in patients with inflammatory myopathy. Thirty-three patients will undergo a 3-month home-based IMT program with progressive resistance. Functional capacity, inspiratory muscle strength, lung function, diaphragmatic mobility, fatigue, and quality of life will be assessed at baseline and during follow-up. The primary hypothesis is that IMT will enhance inspiratory muscle strength and translate into better functional performance and quality of life.
Idiopathic inflammatory myopathies (IIM) are rare autoimmune disorders characterized by progressive, symmetrical proximal muscle weakness, frequently affecting the respiratory muscles. Diaphragmatic dysfunction and reduced inspiratory muscle strength contribute to impaired ventilation, fatigue, and reduced exercise tolerance. While exercise training has proven beneficial in patients with various neuromuscular conditions, evidence regarding inspiratory muscle training (IMT) in IIM is lacking. This pilot interventional study will prospectively evaluate the impact of a 3-month IMT program on respiratory and functional outcomes in patients with IIM. The intervention consists of daily inspiratory resistance training (30 breaths/day, 7 days/week) using the Threshold IMT device (Philips Respironics, USA). Training intensity is set at 30% of maximal inspiratory pressure (MIP) and adjusted progressively based on patient-reported exertion. Participants receive individualized instruction, follow-up phone consultations every 2 weeks, and record adherence in exercise diaries. Assessments include inspiratory muscle strength (MIP measured with Powerbreathe KH2 and RP Check), spirometry (FEV1, FVC, FIVC, IRV), diaphragm ultrasound (mobility and thickness fraction), six-minute walk test (6MWT), fatigue assessment (Borg scale, Fatigue Severity Scale), and quality of life (SF-36). Outcomes will be measured 3 months before training, at baseline, after 3 months of training, and during extended follow-up (up to 6-12 months). The primary endpoint is change in MIP. Secondary endpoints include pulmonary function parameters, diaphragmatic function, exercise tolerance, fatigue, and health-related quality of life. The study will be conducted in the Neurology Clinic of the Medical University of Warsaw (WUM). A total of 33 patients with IIM, diagnosed according to EULAR/ACR criteria, will be recruited. Inclusion requires age ≥18 and written informed consent. Exclusion criteria include cognitive impairment, acute respiratory infection, prior respiratory training, pneumothorax, pulmonary hypertension, or contraindications to IMT. This trial is expected to provide the first structured evidence on the role of IMT in improving functional status in patients with inflammatory myopathy, potentially guiding individualized rehabilitation strategies for this patient population.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
SUPPORTIVE_CARE
Masking
NONE
Enrollment
33
Inspiratory muscle training performed with a threshold loading device (Threshold IMT, Philips Respironics). Participants perform 30 breaths once daily, 7 days per week, for 3 months. The training load is set at 30% of maximal inspiratory pressure (MIP) and increased by 10% if the perceived exertion decreases on two consecutive training days. Participants receive individualized instruction and regular follow-up consultations (every 2 weeks) to adjust load and verify adherence.
University Clinical Center of the Medical University of Warsaw
Warsaw, Poland
RECRUITINGChange in maximal inspiratory pressure (MIP)
Maximal inspiratory pressure measured at the mouth using Powerbreathe KH2 and RP Check devices. MIP reflects inspiratory muscle strength and is expressed in cmH₂O.
Time frame: 3 months before training, baseline, 3 months (end of training), 6 months, 9 months, 12 months
Change in forced vital capacity (FVC)
Spirometric measurement of forced vital capacity performed using the NDD EasyOne device. Results expressed as absolute and percent predicted values.
Time frame: 3 months before training, baseline, 3 months (end of training), 6 months, 9 months, 12 months
Change in forced expiratory volume in 1 second (FEV1)
Spirometric assessment of airway function, expressed as FEV₁ (L and % predicted).
Time frame: 3 months before training, baseline, 3 months (end of training), 6 months, 9 months, 12 months
Change in diaphragm thickness
Ultrasound assessment of diaphragm thickening fraction using Philips Lumify linear probe.
Time frame: 3 months before training, baseline, 3 months (end of training), 6 months, 9 months, 12 months
Change in 6-Minute Walk Distance (6MWD)
Functional exercise capacity assessed by the 6-Minute Walk Test (6MWT), conducted on a 25 m corridor. Distance covered in 6 minutes is recorded in meters.
Time frame: 3 months before training, baseline, 3 months (end of training), 6 months, 9 months, 12 months
Change in perceived exertion (Borg Scale)
Subjective fatigue during exertion assessed using the modified Borg Rating of Perceived Exertion (0-10).
Time frame: 3 months before training, baseline, 3 months (end of training), 6 months, 9 months, 12 months
Change in fatigue severity (Fatigue Severity Scale)
Assessment of perceived fatigue using the Fatigue Severity Scale (FSS).
Time frame: 3 months before training, baseline, 3 months (end of training), 6 months, 9 months, 12 months
Change in quality of life (SF-36)
Assessment of health-related quality of life using the 36-Item Short Form Health Survey (SF-36), including physical and mental health domains.
Time frame: 3 months before training, baseline, 3 months (end of training), 6 months, 9 months, 12 months
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