Peripheral muscle strength is associated with aerobic fitness and use of antibiotics in patients with cystic fibrosis

Effect of Trikafta on bone density, body composition and exercise capacity in CF: A pilot study

BACKGROUND

While the positive effect of Trikafta on cystic fibrosis (CF) pulmonary disease is well established, there is limited data about its effect on bone mineral density (BMD), body composition and exercise capacity.

METHODS

A pilot single center study. BMD and body composition were measured three months after the initiation of Trikafta (study group) and compared to values obtained 2 years earlier. CF patients not treated with Trikafta, for whom BMD was measured 2 years apart, served as controls. Spirometry, lung clearance index (LCI), sweat test, six-min walk test (6MWT) and cardio-pulmonary exercise test (CPET) were performed before and three months after the initiation of Trikafta.

RESULTS

Nine study patients, aged 18.6 ± 4.7 years, and nine controls. For the study group, BMI and hip and spine BMD increased significantly (19.4 ± 2.6 to 20.3 ± 2.19 BMI, p = 0.05; 0.73 ± 0.098 to 0.81 ± 0.12 gr/cm² hip, p = 0.017; 0.76 ± 0.14 to 0.82 ± 0.14 gr/cm² spine, p = 0.025). For the control group, there was no difference in hip or spine BMD. Lean body mass, %fat z-score and fat mass/height² z-score increased significantly (34770.23 ± 10521.21 to 37430.16 ± 10330.09gr, p = 0.017; -0.8 ± 0.75 to 0.46 ± 0.58, p = 0.012; and -0.98 ± 0.66 to -0.04 ± 0.51, p = 0.025, respectively). 6MWT improved from 541.1 ± 48.9 to 592.9 ± 54.5 m (p = 0.046). As expected, FEV1%pred increased (p = 0.008) and sweat chloride decreased significantly (p = 0.017). In CPET, VE/VCO₂ improved, indicating better ventilatory efficiency.

CONCLUSIONS

To the best of our knowledge, this is the first study evaluating the metabolic effects of Trikafta. The results are encouraging and offer hope beyond the well-established effect on pulmonary disease. Larger long-term studies are warranted to unpin the underlying physiological mechanisms.

Does the effect of comprehensive respiratory physiotherapy home-program differ in children with cystic fibrosis and non-cystic fibrosis bronchiectasis?

Bronchiectasis is a form of airway damage as a consequence of endobronchial infection and inflammation and may be present in different diseases. The underlying aetiologies include both cystic fibrosis (CF) and a group of non-cystic fibrosis diseases (NCFB) such as immunodeficiency, primary ciliary dyskinesia, or severe pulmonary infection. Although children with CF and non-cystic fibrosis bronchiectasis (NCFB) have many similar clinical features, their responses to exercise may be different. The aim of this study was to compare the efficacy of a comprehensive respiratory physiotherapy (CRP) home-program in children with CF and NCFB. Thirty children with CF and thirty children with NCFB were included in the study. Both groups performed the CRP home-program twice daily for 8 weeks. Pulmonary function, exercise capacity, and respiratory and peripheral muscle strength were assessed at baseline and after 8 weeks of training. Both groups experienced significant improvements in pulmonary function, exercise capacity, and respiratory and peripheral muscle strength (p < 0.001). Maximum expiratory pressure, exercise capacity, and peripheral muscle strength were further improved in NCFB group compared to CF (p < 0.05); however, there was a great variability in the improvements for each variable.

CONCLUSION

CRP is beneficial both for children with CF and NCFB and adherence to the program was high in both groups.

WHAT IS KNOWN

• Different physiotherapy approaches in the management of non-cystic fibrosis bronchiectasis have been based on the experience gained from the research studies performed in cystic fibrosis. • Although having similar pathophysiology, these two diseases show variation in some pulmonary and extrapulmonary features.

WHAT IS NEW

• The respiratory muscle strength and the efficacy of comprehensive respiratory physiotherapy have been compared for the first time in children with cystic fibrosis and non-cystic fibrosis bronchiectasis. • Comprehensive respiratory physiotherapy provides higher increases in children with non-cystic fibrosis bronchiectasis in exercise capacity and expiratory and peripheral muscle strength; however, there was a great variability in these improvements. Nevertheless, it can be concluded that both groups significantly benefited from the CRP program.

Aerobic fitness is associated with extracellular DNA levels in the sputum of patients with cystic fibrosis

AIMS

Patients with cystic fibrosis (CF) develop with progressive loss of lung function and aerobic fitness. However, the precise mechanisms of exercise intolerance are still controversial and appear to be influenced by several factors. This study aimed to evaluate the association of aerobic fitness with free DNA levels in the sputum of patients with CF.

METHODS

This cross-sectional study included patients with CF older than 6 years, free from active exacerbations, but who were able to produce spontaneously expectorated sputum. Extracellular DNA in the sputum was quantified. Lung function (spirometry) and aerobic fitness (cardiopulmonary exercise testing [CPET]) were performed. In addition, demographic, anthropometric and clinical data were collected.

RESULTS

Sixteen patients with a mean age of 19.4 ± 6.9 years and mean forced expiratory volume in the first second (FEV₁ ) of 51.8 ± 28.1 (% of predicted) were included. Mean peak oxygen consumption (VO₂ peak) was 32.8 ± 5.2 mL• kg^-1 • min^-1 , oxygen saturation at the end of the test was 90.6% ± 6.3% and mean extracellular DNA levels was 305.3 ± 153.6 μg/mL. Individuals with a VO₂ peak ≤ 30 mL• kg^-1 • min^-1 (P = .03) and a SpO₂ ≤ 90% at the end of the test (P = .03) had a greater amount of extracellular DNA in the sputum. The proportion of patients with reduced VO₂ peak in the group of patients with the lowest concentration of DNA in the sputum (<243 μg/mL) was significantly lower (0% vs 100%; P = .04).

CONCLUSION

There is an association between the presence of free DNA in sputum and aerobic fitness in patients with CF.