Effects of Lumacaftor/Ivacaftor on physical activity and exercise tolerance in three adults with cystic fibrosis

Adapting, restarting, and terminating a randomised control trial for people with cystic fibrosis: Reflections on the impact of the COVID-19 pandemic upon research in a clinical population

Background

Habitual physical activity (PA) and exercise form a cornerstone of the management of cystic fibrosis (CF), a genetically inherited pulmonary and digestive condition - whereby telehealth platforms have been proposed as a mechanism to engage remotely people with CF in PA and exercise.

Methods

To test this, in early 2020, the 'ActivOnline: Physical Activity in Cystic Fibrosis Trial' (ActiOn PACT) randomised control trial was established to examine whether an online intervention was effective at increasing PA in adolescents and adults with CF.

Results

The emergence of the COVID-19 pandemic in 2020 forced this trial to be paused and modified, with the adoption of online recruitment and remote assessment of outcome measures. Despite such adaptations in accord with frameworks developed by the National Institute for Health Research, this trial failed to recruit and was subsequently terminated.

Conclusions

This article details the authors reflections upon the proposed reasons for lack of recruitment, including improved technology and medications for people with CF, and contextualises this finding in relation to the wider issue of non-reporting of trial results in clinical research.

The long-term effect of elexacaftor/tezacaftor/ivacaftor on cardiorespiratory fitness in adolescent patients with cystic fibrosis: a pilot observational study

BACKGROUND

Physical activity is a crucial demand on cystic fibrosis treatment management. The highest value of oxygen uptake (VO2peak) is an appropriate tool to evaluate the physical activity in these patients. However, there are several other valuable CPET parameters describing exercise tolerance (Wpeak, VO2VT1, VO2VT2, VO2/HRpeak, etc.), and helping to better understand the effect of specific treatment (VE, VT, VD/VT etc.). Limited data showed ambiguous results of this improvement after CFTR modulator treatment. Elexacaftor/tezacaftor/ivacaftor medication improves pulmonary function and quality of life, whereas its effect on CPET has yet to be sufficiently demonstrated.

METHODS

We performed a single group prospective observational study of 10 adolescent patients with cystic fibrosis who completed two CPET measurements between January 2019 and February 2023. During this period, elexacaftor/tezacaftor/ivacaftor treatment was initiated in all of them. The first CPET at the baseline was followed by controlled CPET at least one year after medication commencement. We focused on interpreting the data on their influence by the novel therapy. We hypothesized improvements in cardiorespiratory fitness following treatment. We applied the Wilcoxon signed-rank test. The data were adjusted for age at the time of CPET to eliminate bias of aging in adolescent patients.

RESULTS

We observed significant improvement in peak workload, VO2 peak, VO2VT1, VO2VT2, VE/VCO2 slope, VE, VT, RQ, VO2/HR peak and RR peak. The mean change in VO2 peak was 5.7 mL/kg/min, or 15.9% of the reference value (SD ± 16.6; p= 0.014). VO2VT1 improved by 15% of the reference value (SD ± 0.1; p= 0.014), VO2VT2 improved by 0.5 (SD ± 0.4; p= 0.01). There were no differences in other parameters.

CONCLUSION

Exercise tolerance improved after elexacaftor/tezacaftor/ivacaftor treatment initiation. We suggest that the CFTR modulator alone is not enough for recovering physical decondition, but should be supplemented with physical activity and respiratory physiotherapy. Further studies are needed to examine the effect of CFTR modulators and physical therapy on cardiopulmonary exercise tolerance.

Changes in exercise capacity in people with Cystic Fibrosis after one year of Elexacaftor/Tezacaftor/Ivacaftor treatment - A Danish prospective cohort

BACKGROUND

Cystic Fibrosis (CF) is an inherited multiorgan disease that causes lung damage and early death. People with CF (pwCF) experience diminished exercise capacity compared to the general population. This is due to an accelerated decline in lung function resulting from recurrent lung infections, declining lung function and nutritional challenges. Since 2020 the CFTR-modulator Elexacaftor/Tezacaftor/Ivacaftor (ETI) has been approved for pwCF aged 12 and above in Denmark. Initial experiences with the medication have shown promising results, including improved lung function and disease stability. To date a limited number of studies have evaluated the impact of CFTR-modulators on exercise capacity in pwCF.

OBJECTIVE

The study aims to assess the impact of one year of ETI treatment, without any further intervention, on exercise capacity measured through cardiopulmonary exercise test (CPET) in pwCF aged 12 years and above.

METHODS

A Danish prospective registry cohort study including pwCF from CF-Center Copenhagen, Copenhagen University Hospital and CF-Center Aarhus, Aarhus University Hospital. Participants underwent CPET before initiating ETI and at follow up one year later. Primary outcomes were VO₂ peak (ml/kg/min), secondary outcomes were VO2 peak (ml/min), VO2 peak (% pred), watt-max, HR-max and saturation at max. The difference between baseline and follow-up was assessed using a paired-sample t-test and regression analyses were applied to relevant outcomes.

RESULTS

We included 229 pwCF in the analyses. An increase in oxygen uptake, VO₂ peak (ml/kg/min) from baseline to follow-up was observed; 0.6, 95% CI [0.06; 1.09] p = 0.03. Moreover, significant increase was noted for all other CPET outcomes. Regression analysis showed that changes in FEV₁% pred and BMI could explain some of the differences, 0.05 ml/kg/min, 95% CI [0.01, 0.1] p = 0.02 and -0.5 ml/kg/min, 95% CI [-0.8, -0.2] p = 0.002 respectively.

CONCLUSION

Among Danish pwCF we found a significant, but not clinically relevant, increase in oxygen uptake, after one year of ETI treatment.

Longitudinal changes in habitual physical activity in adult people with cystic fibrosis in the presence or absence of treatment with elexacaftor/tezacaftor/ivacaftor

Background

Habitual physical activity (PA) and exercise training are accepted as important aspects of care for people with cystic fibrosis (pwCF) to improve health-related measures of physical fitness, which in turn have a positive impact on quality of life and prognosis. In the last decade, effective CFTR modulator therapies have become a promising treatment for pwCF by targeting the underlying cause of CF. This highly effective therapy improves clinical outcomes and quality of life in people with specific CFTR mutations. Little is known about the longitudinal pattern of PA or the impact of the highly effective modulator therapy with Elexacaftor/Tezacaftor/Ivacaftor (ETI) on PA in adult pwCF. This study assessed the course of device-based PA measurement in adult pwCF and evaluated the effects of ETI on habitual physical activity in those who were eligible for ETI.

Methods

Data from adult pwCF (aged ≥18 years) were analysed at baseline and follow-up, using identical assessments at both time points. Outcome parameters were PA in steps/day and the intensity of PA. The group that received ETI was treated for an average of 33 weeks and not for the entire duration of the period. The data were collected between 2021 and 2022, following the removal of absolute pandemic restrictions/lockdowns.

Results

Follow-up duration was 5.6 years in pwCF with ETI (ETI group, n = 21) and 6.5 years in pwCF without ETI (non-ETI group, n = 6). From baseline to follow-up, pwCF treated with ETI had a significant increase in steps/day (+25%, p = 0.019) and a non-significant increase in moderate-to-vigorous intensity time (+5.6%, p = 0.352). Conversely, individuals in the non-ETI group showed a non-significant decrease in both steps/day -3.2%, p = 0.893) and moderate-to-vigorous intensity time (-25%, p = 0.207). The ETI group showed a significant decrease in percent predicted forced expiratory volume in 1 s (ppFEV1) and FEV1 z-score before the start of ETI treatment, both of which improved significantly after therapy initiation. Body weight and body mass index also improved significantly with ETI use.

Conclusions

These data suggest that ETI treatment has a positive effect on habitual physical activity behavior in the adult pwCF studied.

Impact of CFTR modulators on exercise capacity in adolescents with cystic fibrosis

Background

Exercise capacity is an independent predictor of clinical worsening in cystic fibrosis (CF). There is limited evidence of the impact of cystic fibrosis transmembrane conductance regulator (CFTR) modulators on exercise capacity in children with CF. The aim of the present study was to assess the impact of CFTR modulators on exercise capacity in a cohort of adolescents with CF.

Methods

A prospective single-centre cohort study was carried out. Cardiopulmonary exercise testing (CPET) was performed at baseline, prior to starting Symkevi or Kaftrio and between 4 and 8 months after starting treatment.

Results

19 adolescents with CF had CPET performed prior to and after CFTR modulator treatment, between December 2019 and March 2022. Breathing reserve improved in the whole cohort, with greater improvement in the modulator-naïve patients after starting treatment with Kaftrio. There was no improvement in peak oxygen uptake and anaerobic threshold after 4 to 8 months of treatment with CFTR modulators.

Conclusion

Exercise testing with CPET can be used as an additional tool to monitor response to CFTR modulators. Breathing reserve on CPET may provide a surrogate marker to monitor the improvement in CF lung disease with CFTR modulator treatment.

Trials and tribulations of highly effective modulator therapies in cystic fibrosis

Highly effective modulator therapies (HEMTs) have revolutionised the management approach of most patients living with cystic fibrosis (CF) who have access to these therapies. Clinical trials have reported significant improvements across multiorgan systems, with patients surviving longer. However, there are accumulating case reports and observational data describing various adverse events following initiation of HEMTs including drug-to-drug interactions, drug induced liver injury, Stevens-Johnson syndrome, and neurocognitive symptoms including psychosis and depression, which have required discontinuation of therapy. Current clinical trials are assessing efficacy in younger patients with CF, yet long-term studies are also required to better understand the safety profile in the real-world setting across all ages and the impact of HEMT dose alteration or discontinuation.

Long-term clinical outcomes of elexacaftor/tezacaftor/ivacaftor therapy in adults with cystic fibrosis and advanced pulmonary disease

BACKGROUND

The combination of cystic fibrosis transmembrane conductance regulator (CFTR) modulators elexacaftor, tezacaftor and ivacaftor (ELX/TEZ/IVA) has been approved for treatment of cystic fibrosis (CF) patients (pwCF) homozygous and heterozygous for Phe508del. We aim to assess the long-term effects of ELX/TEZ/IVA therapy on clinical outcomes in severe pwCF.

METHODS

Lung function, pulmonary exacerbation (PEx), sweat chloride concentration, body mass index (BMI) and the respiratory domain of the cystic fibrosis questionnaire-revised (CFQ-R RD) were prospectively evaluated in a cohort of pwCF who were candidates for inclusion in a compassionate program of ELX/TEZ/IVA therapy. All procedures were performed at baseline and then at 12 and 24 months after initiation of modulator therapy. The number of PExs in the year before the study enrollment was collected from our records.

RESULTS

Thirty-six adult pwCF (median age 36.7 years; BMI 19.8 kg/m2; FEV1 36.5% predicted) were recruited from 2019. At 12 and 24 months after initiation, the absolute change in ppFEV1 (percent predicted forced expiratory volume in 1 s) from baseline was +12.5% (p < 0.0001) and +13% (p < 0.0001), respectively. A median of 4.0 exacerbations per patient was reported in the preceding year, while the median number of PExs was 0.0 and 1.0 after 12 and 24 months, respectively, of modulator therapy (both p < 0.0001). After 12 and 24 months of ELX/TEZ/IVA therapy, the CFQ-R RD score improved by 22.4 points (p < 0.0001) and 16.7 points (p < 0.0001), and sweat chloride levels decreased by 65.5 mmol/L (p < 0.0001) and 60 mmol/L (p < 0.0001), respectively. BMI significantly increased.

CONCLUSIONS

Long-term ELX/TEZ/IVA combination therapy markedly impacts the clinical status of patients with severe CF, showing a sustained improvement in lung function and PEx rate.

Elexacaftor-Tezacaftor-Ivacaftor: A Life-Changing Triple Combination of CFTR Modulator Drugs for Cystic Fibrosis

Cystic fibrosis (CF) is a potentially fatal monogenic disease that causes a progressive multisystemic pathology. Over the last decade, the introduction of CF transmembrane conductance regulator (CFTR) modulator drugs into clinical practice has profoundly modified the lives of many people with CF (PwCF) by targeting the fundamental cause of the disease. These drugs consist of the potentiator ivacaftor (VX-770) and the correctors lumacaftor (VX-809), tezacaftor (VX-661), and elexacaftor (VX-445). In particular, the triple combination of CFTR modulators composed of elexacaftor, tezacaftor, and ivacaftor (ETI) represents a life-changing therapy for the majority of PwCF worldwide. A growing number of clinical studies have demonstrated the safety and efficacy of ETI therapy in both short- and long-term (up to two years of follow-up to date) and its ability to significantly reduce pulmonary and gastrointestinal manifestations, sweat chloride concentration, exocrine pancreatic dysfunction, and infertility/subfertility, among other disease signs and symptoms. Nevertheless, ETI therapy-related adverse effects have also been reported, and close monitoring by a multidisciplinary healthcare team remains vital. This review aims to address and discuss the major therapeutic benefits and adverse effects reported by the clinical use of ETI therapy for PwCF.

Elexacaftor-Tezacaftor-Ivacaftor improves exercise capacity in adolescents with cystic fibrosis

OBJECTIVE

Elexacaftor/Tezacaftor/Ivacaftor is a cystic fibrosis transmembrane conductance regulator (CFTR) modulator with the potential to improve exercise capacity. This case series of three adolescents with CF aimed to investigate whether 6 weeks treatment with Elexacaftor/Tezacaftor/Ivacaftor could improve exercise capacity in CFTR modulator naive adolescents with CF.

METHODS

Three adolescents (14.0 ± 1.4 years) with CF (FEV₁ % predicted: 62.5 ± 17.1; F508del/F508del genotype) completed an exhaustive maximal cardiopulmonary exercise test on a cycle ergometer to determine peak oxygen uptake ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:semantics> <mml:mrow><mml:mover><mml:mi>V</mml:mi> <mml:mo>̇</mml:mo></mml:mover> </mml:mrow> <mml:annotation>$\dot{{\rm{V}}}$</mml:annotation></mml:semantics> </mml:math> O_2peak ) and measure changes in gas exchange and ventilation during exercise at 6 weeks. We also analyzed wrist-worn device-based physical activity (PA) data in two of the three cases. Validated acceleration thresholds were used to quantify time spent in each PA intensity category.

RESULTS

Clinically meaningful improvements in <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:semantics> <mml:mrow><mml:mover><mml:mi>V</mml:mi> <mml:mo>̇</mml:mo></mml:mover> </mml:mrow> <mml:annotation>$\dot{{\rm{V}}}$</mml:annotation></mml:semantics> </mml:math> O_2peak were observed in all three cases (+17.6%, +52.4%, and +32.9%, respectively), with improvements greatest in those with more severe lung disease and lower fitness at baseline. Although lung function increased in all cases, inconsistent changes in markers of ventilatory and peripheral muscle efficiency likely suggest different mechanisms of improvement in this case group of adolescents with CF. Device-based analysis of PA was variable, with one case increasing and one case decreasing.

CONCLUSION

In this case series, we have observed, for the first time, improvements in exercise capacity following 6 weeks of treatment with Elexacaftor/Tezacaftor/Ivacaftor. Improvements were greatest in the presence of more severe CF lung disease and lower aerobic fitness at baseline. The mechanism(s) responsible for these changes warrant further investigation in larger trials.

Change in exercise capacity measured by Cardio-pulmonary Exercise Testing (CPET) in Danish people with cystic fibrosis after initiation of treatment with Lumacaftor/Ivacaftor and Tezacaftor/Ivacaftor

BACKGROUND

Since 2015, when the first cystic fibrosis transmembrane conductance regulator (CFTR) modulators were approved for people with cystic fibrosis (CF) homozygous for F508del-CFTR, studies have shown improved lung function after initiation of the treatment and patients experience improved physical capacity. The aim of this study was to investigate change in exercise capacity after initiation of Lumacaftor/Ivacaftor and Tezacaftor/Ivacaftor treatment (LUM/IVA, TEZ/IVA).

METHODS

We performed a single group prospective observational cohort study with follow-up at six and 12 months. The study examined change in exercise capacity in people with CF initiating treatment with LUM/IVA and TEZ/IVA, measured by cardio-pulmonary exercise testing (CPET). Inclusion criteria were people with CF homozygous for F508del-CFTR aged 12 years or older eligible for LUM/IVA and TEZ/IVA treatment from June 2017 until June 2019. Primary outcomes were change in VO_2peak and maximal workload. Secondary outcomes were change in muscle strength, muscle power and body composition in a subgroup of the study population.

RESULTS

A total of 91 patients were included in the analysis. The mean change in VO_2peak and VO_2peak divided by body weight from baseline to 12-months follow-up was 145.7 (91.2;200.2) ml/min and 1.07 (95% CI 0.19;1.95) ml/min/kg, respectively. The mean change in maximal workload between baseline and 12 months was 14.2 Watt (95% CI 9.1;19.2). All improvements in exercise capacity were statistically significant.

CONCLUSIONS

Patients in this study improved their exercise capacity by a statistically significant increase in VO_2peak and maximal workload 12 months after initiation of treatment with LUM/IVA and TEZ/IVA.

Exercise intolerance in cystic fibrosis-the role of CFTR modulator therapies

Exercise intolerance is common in people with CF (pwCF), but not universal among all individuals. While associated with disease prognosis, exercise intolerance is not simply a reflection of the degree of lung disease. In people with severe CF, respiratory limitations may contribute more significantly to impaired exercise capacity than in those with mild-moderate CF. At all levels of disease severity, there are peripheral factors e.g., abnormal macro- and micro-vascular function that impair blood flow and reduce oxygen extraction, and mitochondrial defects that diminish metabolic efficiency. We discuss advances in understanding the central and peripheral mechanisms underlying exercise intolerance in pwCF. Exploring both the central and peripheral factors that contribute to exercise intolerance in CF can help inform the development of new therapeutic targets, as well as help define prognostic criteria.

Emerging non-pulmonary complications for adults with cystic fibrosis

Improved treatments of cystic fibrosis (CF) related lung disease have resulted in increased longevity, but also increasing prevalence and severity of extrapulmonary manifestations of CF, treatment related complications, age-related conditions and psychosocial effects of longstanding chronic disease. Likewise, the recognition of mild CF phenotypes has changed the landscape of CF disease. This review outlines our current understanding of the common extrapulmonary complications of CF, as well as the changing landscape and future directions of the extrapulmonary complications experienced by patients with CF.

The effectiveness of exercise interventions to increase physical activity in Cystic Fibrosis: A systematic review

Physical activity (PA) and exercise have numerous benefits in Cystic Fibrosis (CF) including improved lung function, exercise capacity and quality of life. Despite these benefits, the effectiveness of interventions to promote PA in this population are still largely unknown. The objective of this review was to synthesise existing research and determine whether exercise interventions are effective in promoting PA in people with CF. Using the PRISMA guidelines, a comprehensive search was conducted. Fifteen studies (463 participants) met the inclusion criteria. Eleven studies demonstrated improvements in PA in both short- and long-term interventions. However, the interventions were variable across the included studies, with a large inconsistency in PA assessment tools used. Aerobic training and activity counselling were the two elements identified in this review which most consistently improved PA. Future research should consider larger sample sizes and the use of accurate instruments to assess and track PA levels longitudinally.

Rethinking physical exercise training in the modern era of cystic fibrosis: A step towards optimising short-term efficacy and long-term engagement

Exercise is considered as an important component of the package of care delivered to people with cystic fibrosis (pwCF). However, despite the well-known short-term physiological and psychological benefits, training effects are heterogenous and the transfer of structured exercise programmes to the daily life of pwCF is challenging. Training concepts and strategies developed over the last decades must be adapted to consider the aging population of pwCF with associated comorbidities, and also a new generation of young pwCF that are healthier than ever. In the present review we propose a new framework for optimising the choice among available exercise training procedures and we provide a theoretical and scientifically justified rationale for considering and testing new exercise training modalities. We propose a multidisciplinary approach, considering various physiological, psychological and logistical factors, with the aim to increase effects of exercise training and build positive long-term exercise behaviour.

The Extrapulmonary Effects of Cystic Fibrosis Transmembrane Conductance Regulator Modulators in Cystic Fibrosis

The effects of cystic fibrosis (CF) transmembrane conductance regulator (CFTR) modulators on lung function, pulmonary exacerbations, and quality of life have been well documented. However, CF is a multiorgan disease, and therefore an evidence base is emerging on the systemic effects of CFTR modulators beyond the pulmonary system. This is of great clinical importance, as many of these studies provide proof of concept that CFTR modulators might be used one day to prevent or treat extrapulmonary manifestations stemming from CFTR dysfunction. In this concise review of the literature, we summarize the results of key publications that have evaluated the effects of CFTR modulators on weight and growth, pancreatic function, the gastrointestinal and hepatobiliary systems, sinus disease, bone disease, exercise tolerance, fertility, mental health, and immunity. Although many of these studies have reported beneficial extrapulmonary effects related to the use of ivacaftor (IVA) in patients with CF with at least one gating mutation, most of the evidence is low or very low quality, given the limited number of patients evaluated and the lack of control groups. Based on an even smaller number of studies evaluating the extrapulmonary effects of lumacaftor-IVA, the benefits are less clear. Although limited, these studies may provide the basis for future clinical trials to evaluate CFTR modulators on the extrapulmonary manifestations of CF.

VO2max as an exercise tolerance endpoint in people with cystic fibrosis: Lessons from a lumacaftor/ivacaftor trial

BACKGROUND

The impact of lumacaftor/ivacaftor on exercise tolerance in people with cystic fibrosis (CF) has not been thoroughly studied.

METHODS

We conducted a multisite Phase 4 trial comparing the impact of lumacaftor/ivacaftor on exercise tolerance with that of placebo in participants ≥ 12 years of age with CF homozygous for F508del-CFTR. The primary endpoint was relative change from baseline in maximum oxygen consumption (VO_2max) during cardiopulmonary exercise testing (CPET) at Week 24. The key secondary endpoint was relative change from baseline in exercise duration during CPET at Week 24. Other secondary endpoints included changes in other indices of exercise tolerance and changes in CF assessments; safety and tolerability were assessed as an endpoint.

RESULTS

Seventy participants were randomized to receive lumacaftor/ivacaftor (n = 34) or placebo (n = 36). The least-squares mean difference for lumacaftor/ivacaftor versus placebo in relative change in VO_2max from baseline at Week 24 was -3.2% (95% CI: -9.2, 2.9; P=0.3021); the least-squares mean difference in relative change from baseline in exercise duration at Week 24 was -3.2% (95% CI: -8.0, 1.6). Safety results were consistent with the known lumacaftor/ivacaftor safety profile.

CONCLUSIONS

Definitive conclusions regarding the impact of lumacaftor/ivacaftor on exercise tolerance cannot be drawn from these results; however, multicenter studies using CPETs can be reliably performed with multiple time points and conventional methods, provided that calibration can be achieved. Future studies of exercise tolerance may benefit from lessons learned from this study. NCT02875366.

How Clinically Efficient Is Lumacaftor/Ivacaftor for Cystic Fibrosis Patients? An Updated Literature Review

Cystic fibrosis (CF) is an autosomal recessive illness caused by the defective cystic fibrosis transmembrane conductance regulator (CFTR) gene. These patients suffer from repeated chronic sinuses and lung infections, resulting in frequent hospital admissions and antibiotic (Abx) courses. These are the major contributing factors responsible for a low health-related quality of life (HRQoL) and increasing the disease burden. The introduction and approval of CFTR modulators-lumacaftor (LUM) and ivacaftor (IVA) in 2015 by the US Food and Drug Administration (FDA) reduced the mortality and morbidity rates associated with the disease. In 2018, the FDA approved these drugs from age two and five years with two copies of F5806 del. This literature review aims to present the studies centered on the clinical effects of LUM/IVA. We searched for the relevant articles, from 2016 to 2020, in PubMed Central (PMC), Google Scholars, and Journal of Cystic Fibrosis. LUM/IVA has a broader range of effects. They showed marked improvement in the reduction of pulmonary exacerbations (PEx), Hospitalization rates, Abx use, and modification in forced expiratory volume in one second (FEV1) status of pre-existing severe lung disease. Now, there is a need for an initiative to conduct more clinical trials and studies in the future to assess and evaluate the long-term clinical benefits and safety of LUM/IVA therapy in all age groups.

New strategies of physical activity assessment in cystic fibrosis: a pilot study

Background

Regular physical activity (PA) is a valued part of cystic fibrosis (CF) care. Although the accelerometer, SenseWear Armband (SWA), accurately measures habitual PA in CF, it is mostly used for research purposes. For the first time, we analyzed different methods of measuring PA in daily life by the use of smartphones and other electronic devices such as smartwatch and Fitbit.

Methods

Twenty-four stable adults with CF (mean age 37.5 ± 11.5SD yrs.; FEV₁ 58 ± 19% predicted, BMI 22.9 ± 3.2) were studied. Daily PA was monitored for seven consecutive days. All patients wore the accelerometer SWA and at the same time they monitored PA with the electronic device they used routinely. They were allocated into one of four arms according to their device: Smartwatch, Fitbit, Android smartphones and iOS smartphones. PA related measurements included: duration of PA, energy expenditure, number of steps.

Results

There was a good agreement between SWA and Fitbit for number of steps (p = 0.605) and energy expenditure (p = 0.143). iOS smartphones were similar to SWA in monitoring the number of steps (p = 0.911). Significant differences were found between SWA and both Smartwatch and Android smartphones.

Conclusions

Fitbit and iOS smartphones seem to be a valuable approach to monitor daily PA. They provide a good performance to measure step number compared to SWA.

Supplementary information

Supplementary information accompanies this paper at 10.1186/s12890-020-01313-5.

Exercise testing for children with cystic fibrosis: A systematic review

BACKGROUND

Exercise testing is routinely used to measure exercise capacity in children with cystic fibrosis (CF). Various tests are available, however the psychometric properties of these measures have not been systematically reviewed for this population.

METHOD

A systematic search of electronic databases (PubMed, Web of Science, Medline, CINHAL, Cochrane, and PEDro) was performed to identify papers that: (a) reported original psychometric data, (b) examined a measure of exercise capacity, (c) examined children with CF aged eight to 18 years; and (d) were published in English after 1950. The level of psychometric evidence was evaluated using the COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) checklist.

RESULTS

Searches identified 1025 papers. Forty-six papers were included, covering 15 tests: incremental cardiopulmonary exercise test using a cycle ergometer (CPET(cycle)) or treadmill (CPET(treadmill)), 6 minute walk test (6MWT), modified shuttle test (MST), 3-minute step test (3MST), 2 minute walk test (2MWT), Bratteby walk test, intermittent sprint test, speed ramp test, incremental step test, forward-backwards jump test (FBJT), astride jump test (AJT), motor quotient test, Munich fitness test, and Glittre ADL test.

CONCLUSION

There is a plethora of exercise tests available with varying psychometric robustness. The CPET, 6MWT, and MST have fair to good psychometric properties, but each with their clinical advantages and limitations. Thus, a Selection Guide was developed to assist clinicians and researchers in selecting the most appropriate exercise test for various situations.

Short-term effects of Lumacaftor/Ivacaftor (Orkambi™) on exertional symptoms, exercise performance, and ventilatory responses in adults with cystic fibrosis

RATIONALE

Lumacaftor/ivacaftor (LUM/IVA) modestly improves lung function following 1 month of treatment but it is unknown if this translates into improvements in exercise endurance and exertional symptoms.

METHODS

Adult CF participants completed a symptom-limited constant load cycling test with simultaneous assessments of dyspnea and leg discomfort ratings pre- and 1 month post-initiation of LUM/IVA.

RESULTS

Endurance time, exertional dyspnea and leg discomfort ratings at submaximal exercise did not change significantly. There was a significant inverse correlation between changes in leg discomfort and endurance time (r = - 0.88; p = 0.009) following 1-month of LUM/IVA.

CONCLUSIONS

Overall, 1-month of LUM/IVA did not increase endurance time or modify exertional dyspnea or leg discomfort ratings. However, individuals who experienced a reduction in leg discomfort following LUM/IVA had an improvement in endurance time. Future studies with a larger sample size are needed to verify these findings and to assess the long-term effects of LUM/IVA on exercise outcomes.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02821130. Registered July 1, 2016.

Re-imagining cystic fibrosis care: next generation thinking

Cystic fibrosis (CF) is a common multi-system genetically inherited condition, predominately found in individuals of Caucasian decent. Since the identification of the cystic fibrosis (CF) transmembrane conductance regulator (CFTR) gene in 1989, and the subsequent improvement in understanding of CF pathophysiology, significant increases in life-expectancy have followed. Initially this was related to improvements in the management and systems of care for treating the various affected organ systems. These cornerstone treatments are still essential for CF patients born today. However, over the last decade, the major advance has been in therapies that target the resultant genetic defect: the dysfunctional CFTR protein. Small molecule agents that target this dysfunctional protein via a variety of mechanisms have led to lung function improvements, reductions in pulmonary exacerbation rates and increases in weight and quality-of-life indices. As more patients receive these agents earlier and earlier in life, it is likely that general CF care will increasingly pivot around these specific therapies, although it is also likely that effects other than those identified in the initial trials will be discovered and need to be managed. Despite great excitement for modulator therapies, they are unlikely to be suitable or available for all; whether this is due to a lack of availability for specific CFTR mutations, drug-reactions or the health economic set-up in certain countries. Nevertheless, the CF community must be applauded for its ongoing focus on research and development for this life-limiting disease. With time, personalised individualised therapy would ideally be the mainstay of CF care.

Exercise Physiology Across the Lifespan in Cystic Fibrosis

Cystic fibrosis (CF), a severe life-limiting disease, is associated with multi-organ pathologies that contribute to a reduced exercise capacity. At present, the impact of, and interaction between, disease progression and other age-related physiological changes in CF on exercise capacity from child- to adult-hood is poorly understood. Indeed, the influences of disease progression and aging are inherently linked, leading to increasingly complex interactions. Thus, when interpreting age-related differences in exercise tolerance and devising exercise-based therapies for those with CF, it is critical to consider age-specific factors. Specifically, changes in lung function, chronic airway colonization by increasingly pathogenic and drug-resistant bacteria, the frequency and severity of pulmonary exacerbations, endocrine comorbidities, nutrition-related factors, and CFTR (cystic fibrosis transmembrane conductance regulator protein) modulator therapy, duration, and age of onset are important to consider. Accounting for how these factors ultimately influence the ability to exercise is central to understanding exercise impairments in individuals with CF, especially as the expected lifespan with CF continues to increase with advancements in therapies. Further studies are required that account for these factors and the changing landscape of CF in order to better understand how the evolution of CF disease impacts exercise (in)tolerance across the lifespan and thereby identify appropriate intervention targets and strategies.

Two novel and correlated CF-causing insertions in the (TG)mTn tract of the CFTR gene

Two novel and related pathogenic variants of the Cystic Fibrosis Transmembrane conductance Regulator (CFTR) gene were structurally and functionally characterized. These alterations have not been previously described in literature. Two patients with diagnosis of Cystic Fibrosis (CF) based on the presence of one mutated allele, p.Phe508del, pathological sweat test and clinical symptoms were studied. To complete the genotypes of both patients, an extensive genetic and functional analysis of the CFTR gene was performed. Extensive genetic characterization confirmed the presence of p.Phe508del pathogenic variant and revealed, in both patients, the presence of an insertion of part of intron 10 in intron 9 of the CFTR gene, within the (TG)m repeat, with a variable poly-T stretch. The molecular lesions resulted to be very similar in both patients, with only a difference in the number of T in the poly-T stretch. The functional characterization at RNA level revealed a complete anomalous splicing, without exon 10, from the allele with the insertion of both patients. Consequently, the alleles with the insertions are expected not to contribute to the formation of a functional CFTR protein. Molecular and functional features of these alterations are compatible with the definition of novel CF-causing variants of the CFTR gene. This also allowed the completion of the genetic characterization of both patients.