A case of severe pulmonary exacerbation in a young patient with cystic fibrosis in the era of CFTR modulators.

The introduction of CFTR modulator drugs like elexacaftor-tezacaftor-ivacaftor (ETI) has transformed the management of cystic fibrosis (CF), significantly improving symptoms, lung function, and quality of life, while reducing reliance on intravenous antibiotics. However, respiratory exacerbations in the CFTR modulators era remain poorly understood from both pathophysiological and clinical perspectives. We present the case of a 20-year-old Caucasian woman with CF (F508del/L1077P) who, after three years of ETI treatment, experienced a severe episode of hemoptysis, despite being almost asymptomatic in the weeks leading up to admission, requiring bronchial artery embolization. Following ETI treatment, auscultatory findings and FEV1 changes may be less significant, making the detection of respiratory exacerbation more challenging. This highlights the need for heightened vigilance in managing such cases and underscores the challenge of diagnosing and managing exacerbations in the era of modulators. Long term real-world studies are essential to comprehend the evolving course of the disease during ETI treatment.

Reported Adverse Events in a Multicenter Cohort of Patients Ages 6-18 Years with Cystic Fibrosis and at Least One F508del Allele Receiving Elexacaftor/Tezacaftor/Ivacaftor.

OBJECTIVE: The objective of this study was to describe reported adverse events (AEs) associated with elexacaftor/tezacaftor/ivacaftor (ETI) in a pediatric sample with cystic fibrosis (CF) aged 6-18 years, with at least one F508del variant, followed at multiple Italian CF centers. STUDY DESIGN: This was a retrospective, multicenter, observational study. All children receiving ETI therapy from October 2019 to December 2023 were included. We assessed the prevalence and type of any reported potential drug-related AEs, regardless of discontinuation necessity. Persistent AEs were defined as those continuing at the end of the observation period. RESULTS: Among 608 patients on ETI, 109 (17.9%) reported at least 1 AE. The majority (n = 85, 77.9%) were temporary, with a median duration of 11 days (range 1-441 days). Only 7 (1.1%) patients permanently discontinued treatment, suggesting good overall safety of ETI. The most common AEs leading to discontinuation were transaminase elevations (temporary 14.1%, persistent 25.9%) and urticaria (temporary 41.2%, persistent 7.4%). Creatinine phosphokinase elevation was uncommon. No significant differences in AEs were observed based on sex, age groups (6-11 vs 12-18 years), or genotype. Pre-existing CF-related liver disease was associated with an increased risk of transaminase elevations. We identified significant variability in the percentage of reported AEs (ANOVA P value .026). CONCLUSIONS: This real-world study highlights significant variability in reported AEs. Our findings suggest that ETI is a safe and well-tolerated therapy in children and adolescents with CF. However, further long-term safety and effectiveness investigations are warranted.

Effectiveness and safety of elexacaftor/tezacaftor/ivacaftor treatment in children aged 6-11 years with cystic fibrosis in a real-world setting.

BACKGROUND: Elexacaftor-tezacaftor-ivacaftor (ETI) is a highly effective cystic fibrosis (CF) transmembrane conductance regulator (CFTR) modulating therapy for people with CF and at least one F508del variant. However, there is limited data about the safety and efficacy of this therapy in pediatric populations and in real-world settings. This study aimed at evaluating the effectiveness, tolerability, and safety of ETI in children with CF. METHODS: This was a prospective observational study including all children aged 6-11 years who initiated ETI therapy between October 2022 and March 2023 at the Pediatric CF Center of Milan (Italy). Study outcomes included changes in sweat chloride concentration, FEV1, LCI2.5, body mass index (BMI), tolerance, and safety. Mean changes in study outcomes from baseline through 24 weeks were estimated using mixed-effects regression models. RESULTS: The study included 34 children with CF (median age: 8.3 years). At Week 12, we observed an average decrease in LCI2.5 of 2.3 units (95% confidence interval [CI]: -3.1; -1.5). At Week 24, sweat chloride concentration decreased by 63 mEq/L (95% CI: -69; -58), FEV1 increased by 8.8 percentage point (95% CI: 3.7; 13.9) and BMI increased by 0.15 standard deviation scores (95% CI: 0.04; 0.25). Skin rashes appeared in 6 patients which spontaneously resolved within a few days. One month after treatment initiation, one patient experienced an elevation in liver function test results, which subsequently decreased during follow-up visits without necessitating discontinuation of therapy. CONCLUSIONS: Our data indicate that ETI therapy is well tolerated by children with CF and is effective in improving signs of lung function abnormalities from early childhood.

Heterogeneity in response to Elexacaftor/Tezacaftor/Ivacaftor in people with cystic fibrosis.

BACKGROUND: Highly effective modulators of the CFTR channel have been demonstrated to dramatically impact disease progression and outcome. However, real-world data indicates that the magnitude of the clinical benefit is not equal among all patients receiving the treatment. We aimed to assess the variability in treatment response (as defined by the 6-month change in sweat chloride concentration, forced expiratory volume in one second [ppFEV1], body mass index [BMI], and CF Questionnaire-Revised [CFQ-R] respiratory domain score) and identify potential predictors in a group of patients receiving Elexacaftor-Tezacaftor-Ivacaftor (ETI) triple combination therapy. METHODS: This was a single-center, prospective cohort study enrolling adults with CF at a major center in Italy. We used linear regression models to identify a set of potential predictors (including CFTR genotype, sex, age, and baseline clinical characteristics) and estimate the variability in treatment response. RESULTS: The study included 211 patients (median age: 29 years, range: 12-58). Median changes (10-90th percentile) from baseline were: - 56 mEq/L (-76; -27) for sweat chloride concentration, +14.5 points (2.5; 32.0) for ppFEV1, +0.33 standard deviation scores (-0.13; 1.05) for BMI and +17 points (0; 39) for the CFQ-R respiratory domain score. The selected predictors explained 23 % of the variability in sweat chloride concentration changes, 18 % of the variability in ppFEV1 changes, 39 % of the variability in BMI changes, and 65 % of the variability in CFQ-R changes. CONCLUSIONS: This study highlights a high level of heterogeneity in treatment response to ETI, which can only be partially explained by the baseline characteristics of the disease.

Perceived burden of respiratory physiotherapy in people with cystic fibrosis taking elexacaftor-tezacaftor-ivacaftor combination: a 1-year observational study.

BACKGROUND: To limit the progression of disease, people with cystic fibrosis (pwCF) perform daily respiratory physiotherapy, which is perceived as the most burdensome routine in managing their condition. The elexacaftor-tezacaftor-ivacaftor (ETI) combination has changed respiratory management. OBJECTIVE: To investigate how the perceived treatment burden changed in 1 year of treatment with ETI. DESIGN: Prospective observational study. METHODS: Ad hoc questionnaires for the pwCF and for the caregivers of pwCF < 18 years were administered before the initiation of ETI therapy and then at 6-12 months. The Cystic Fibrosis Questionnaire-Revised (CFQ-R) and the Sinonasal Outcome Test (SNOT-22) were administered to explore disease-related symptoms and social limitations. The International Physical Activity Questionnaire was used to determine levels of physical activity. Mixed-effect models were fitted to explore whether the time engaged in respiratory physiotherapy changed during 1 year. RESULTS: The study included 47/184 pwCF aged 21.4 (5.7) years, who completed 1 year of ETI therapy. At 6 months, time on aerosol therapy was decreased by 2.5 (95% CI -32.9 to 27.8) min/day, time on airway clearance therapies (ACTs) was decreased by 8.8 (95% CI -25.9 to 8.3) min/day, and time for cleaning and disinfecting respiratory equipment was decreased by 10.6 (95% CI -26.5 to 5.3) min/day. At 1 year, gains in time saved were nearly 15 min/day on average. At 1 year, 5/47 (10.6%) pwCF reported that they had discontinued positive expiratory pressure mask. CONCLUSION: PwCF on ETI may note less time engaged in their daily respiratory physiotherapy routine. Nonetheless, aerosol therapy, ACTs and maintaining respiratory equipment were still perceived as time-consuming daily activities.

Understanding the challenges of respiratory physiotherapy in individuals with cystic fibrosis using triple therapy: a one-year study.In order to slow down the progression of their disease, people with cystic fibrosis typically do daily respiratory physiotherapy, which they find to be the most challenging part of managing their condition. The elexacaftor-tezacaftor-ivacaftor combination has changed how they manage their respiratory health. We wanted to see how the perceived difficulty of the treatment changed over one year of using elexacaftor-tezacaftor-ivacaftor. We gave questionnaires to people with cystic fibrosis and to their caregivers before they started the triple therapy and again at 6-12 months. We also used two international questionnaires to learn about symptoms and social limitations related to the disease. The International Physical Activity Questionnaire helped us understand their physical activity levels. We used statistical models to see if the time spent on respiratory physiotherapy changed over the year. Our study involved 47 individuals with cystic fibrosis, with an average age of 21 years, who completed one year of elexacaftor-tezacaftor-ivacaftor therapy. After 6 months, time spent on aerosol therapy decreased by 2.5 minutes per day, time on airway clearance therapies decreased by 8.8 minutes per day, and time for cleaning respiratory equipment decreased by 10.6 minutes per day. By the end of the year, they were saving almost 15 minutes per day on average. At one year, 5 out of 47 said they had stopped using the positive expiratory pressure mask. People with cystic fibrosis using elexacaftor-tezacaftor-ivacaftor may find that they spend less time on their daily respiratory physiotherapy routine. However, activities like aerosol therapy, airway clearance therapies, and maintaining respiratory equipment were still seen as time-consuming.

Treatable traits and challenges in the clinical management of non-tuberculous mycobacteria lung disease in people with cystic fibrosis.

INTRODUCTION: Over the last ten years an increasing prevalence and incidence of non-tuberculous mycobacteria (NTM) has been reported among patients with cystic fibrosis (CF) Viviani (J Cyst Fibros, 15(5):619-623, 2016). NTM pulmonary disease has been associated with negative clinical outcomes and often requires pharmacological treatment. Although specific guidelines help clinicians in the process of diagnosis and clinical management, the focus on the multidimensional assessment of concomitant problems is still scarce. MAIN BODY: This review aims to identify the treatable traits of NTM pulmonary disease in people with CF and discuss the importance of a multidisciplinary approach in order to detect and manage all the clinical and behavioral aspects of the disease. The multidisciplinary complexity of NTM pulmonary disease in CF requires careful management of respiratory and extra-respiratory, including control of comorbidities, drug interactions and behavioral factors as adherence to therapies. CONCLUSIONS: The treatable trait strategy can help to optimize clinical management through systematic assessment of all the aspects of the disease, providing a holistic treatment for such a multi-systemic and complex condition.

Cystic fibrosis and CFTR-related disorder with electrolyte imbalance at diagnosis: clinical features and outcome in an Italian cohort.

There is limited information available on the clinical data, sweat test trends, and outcomes of individuals with cystic fibrosis (CF) who present with an isolated episode of hypoelectrolytemia with metabolic alkalosis (HMA). This study describes a cohort of Italian individuals with HMA as presenting symptom. The study is a retrospective multicenter analysis of individuals who presented with HMA as an initial symptom and was followed at 8 Italian CF Centers, from March 1988 to March 2022. Demographic, clinical, microbiological, biochemical, and genetic data were extracted from local health records. Ninety-three individuals were enrolled in the study. At first evaluation, 82 (88.2%) were diagnosed with CF, and 11 received a CFTR-Related Disorder (CFTR-RD) diagnostic label. Twenty-three (85.1%) out of the 27 subjects who underwent CF neonatal screening (NBS) resulted falsely negative. After a mean observational period of 11.5 years, most of subjects had a mild pulmonary phenotype, pancreatic sufficiency, and rarely CF-related complications. Four CFTR-RD changed to a CF diagnosis during the study period, resulting in 86 (92.4%) subjects classified as CF. CONCLUSIONS:  Most CF patients presenting with isolated HMA have a mild course of disease and rarely CF-related complications. WHAT IS KNOWN: • Isolated episode of hypoelectrolytemia with metabolic alkalosis is a well-known onset symptom of Cystic Fibrosis in infancy. • There is limited information available on the clinical data and outcomes of individuals with Cystic Fibrosis who present with electrolyte imbalance at diagnosis. WHAT IS NEW: • Most patients with Cystic Fibrosis presenting with isolated hypoelectrolytemia and metabolic alkalosis have a mild course of disease and rarely CF-related complications. • Electrolyte imbalance at diagnosis of Cystic Fibrosis is a common symptom in children not screened for CF at birth, or in those who received a false negative result from newborn screening.

Effects of elexacaftor / tezacaftor / ivacaftor triple combination therapy on glycaemic control and body composition in patients with cystic fibrosis-related diabetes.

Cystic fibrosis transmembrane conductance regulator (CFTR) modulators are a group of new drugs for the treatment of cystic fibrosis (CF) and elexacaftor + tezacaftor + ivacaftor (ETI) triple combination therapy has been approved as first choice therapy in the treatment of patients with at least 1 copy of F508del variation. Data on the effects of CFTR modulators on glucose metabolism are limited to small studies with conflicting results. We conducted a prospective observational study on 24 CF patients with CF-related diabetes requiring insulin therapy, with the aim to evaluate the effectiveness of ETI on glucose metabolism, glucose variability and body composition. After six months of treatment, HbA1c and coefficient of variation, measured through flash or continuous glucose monitoring, significantly decreased (median changes: -0.5, P = 0.029 and -6.3, P = 0.008, respectively), despite unchanged insulin requirements. Over the treatment period, percent of fat mass increased by a median value of 3% (p = 0.029).

Unplanned pregnancies following the introduction of elexacaftor/tezacaftor/ivacaftor therapy in women with cystic fibrosis.

Cystic fibrosis (CF) causes infertility and subfertility due to various factors, including altered cervical mucus, delayed puberty, and hormonal imbalances. With the introduction of the CFTR modulator therapy elexacaftor-tezacaftor-ivacaftor, we have observed an increase in unplanned pregnancies among women undergoing ETI treatment in our CF center, despite repeated recommendations for strict fertility monitoring. It appears that these pregnancies are more likely attributed to reduced attention to the possibility of conception rather than contraceptive failure. The perception of subfertility developed by women with CF over time, before the era of modulators, can influence their long-term habits and lead to the underuse of contraceptive methods. While further research is needed to fully understand the effects of ETI on fertility, healthcare providers should be attentive to the fertility concerns of women with CF, particularly those treated with modulators in adulthood.

Cepacia syndrome in cystic fibrosis: A systematic review of the literature and possible new perspectives in treatment.

BACKGROUND: Cepacia syndrome (CS) is an acute, necrotizing pneumonia with a high mortality rate, occurring in patients with cystic fibrosis (CF) infected with Burkholderia cepacia complex (BCC). Due to its low incidence, data on this condition are limited. METHODS: We conducted a systematic review of the reported cases of CS by searching MEDLINE, Embase and the Cochrane Library to improve knowledge of this rare but potentially lethal condition. RESULTS: We included 15 eligible articles, describing 18 cases (9 females) of CS. Median age at onset was 22 years (range: 10-60 years); median time to CS after first infection by BCC was 5 years (range: 1-26 years). Burkholderia cenocepacia was the most frequently reported causative agent. All patients received intravenous antibiotic treatment (most frequently including cotrimoxazole), while inhaled antibiotics were used in five patients (27.8%). Immunosuppressant agents were the most commonly prescribed supportive treatment (n = 7, 38.9%). Half of the patients died (9/18, 50%). CONCLUSIONS: This study describes epidemiological, clinical characteristics, and prognosis of CS cases reported over the last 24 years. CS is a rare yet severe complication of BCC infection in patients with CF, which occurs several years after BCC colonization and has a negative outcome in 50% of the patients. Data are too scanty to identify the most effective therapeutic approach.

Effects of prolonged proton pump inhibitor treatment on nutritional status and respiratory infection risk in cystic fibrosis: A matched cohort study.

BACKGROUND: Evidence on the effectiveness of proton pump inhibitors (PPI) as adjuvant therapy to improve maldigestion in people with cystic fibrosis (pwCF) is limited and there is increasing concern on possible side effects. METHODS: We conducted a matched cohort study based on paediatric and adult pwCF who received PPI for ≥3 months. Treated patients were matched to a group of patients who never received PPI using a nearest neighbour propensity score matching based on sex, year of birth, CFTR genotype and pancreatic insufficiency. RESULTS: The study included 160 pwCF: 80 treated and 80 untreated patients. Over a median follow-up of 2 years, no significant differences in changes in BMI z-score were detected between groups (adjusted mean difference: 0.06, 95% CI: -0.17-0.30). At baseline 25% (n = 20) of the treated patients and 22.5% (n = 18) of the untreated patients had a positive culture for P. aeruginosa (Pa). At follow-up percentages of Pa positive cultures increased to 47.5% (n = 38) in the treated group and to 26.3% (n = 21) in the untreated group (adjusted mean difference: 23.1%, 95% CI: 10.8-35.3). CONCLUSIONS: Prolonged PPI therapy should be used cautiously in pwCF since it may increase the risk of respiratory infection by Pa. In addition, such treatment does not seem to improve nutritional status.

Impact of COVID-19 on Lung Disease in People with Cystic Fibrosis: A 6-Month Follow-Up Study on Respiratory Outcomes.

BACKGROUND: The impact of COVID-19 on respiratory outcomes in people with cystic fibrosis (pwCF) has not been clearly characterized. We evaluated changes in respiratory function indicators derived from spirometry and pulmonary exacerbation rates 6 months after SARS-CoV-2 infection. METHODS: This multicentre prospective study was based on pwCF enrolled between October, 2020 and June, 2021 in the DECO COVID-19 project. PwCF complaining of COVID-like symptoms were tested with real-time polymerase chain reaction (RT-PCR) for SARS-CoV-2 on nasopharyngeal swab. Mean changes in respiratory function indicators and time to first episode of pulmonary exacerbation were compared in RT-PCR-positive and RT-PCR-negative patients. Regression models were used to adjust for baseline percent predicted forced expiratory volume in one second (ppFEV1) values, number of comorbidities, and initiation of CFTR modulator therapy during the follow-up. RESULTS: We enrolled 26 pwCF with RT-PCR-confirmed infection and 42 with a RT-PCR-negative test. After 6 months of follow-up, mean ppFEV1 changes were not significantly different between groups (+0.3% in positive vs. +0.2% in negative patients, p = 0.19). The 6-month cumulative probabilities of a first episode of pulmonary exacerbation were: 0.425 among RT-PCR-negative patients and 0.465 among those with a positive test (adjusted hazard ratio: 0.88, 95% CI: 0.44-1.75). CONCLUSIONS: COVID-19 did not appear to negatively influence respiratory outcomes of pwCF at 6 months from infection.

Immunogenicity of BNT162b2 mRNA-Based Vaccine against SARS-CoV-2 in People with Cystic Fibrosis According to Disease Characteristics and Maintenance Therapies.

During the SARS-CoV-2 vaccination campaign, people with CF (pwCF) were considered a clinically vulnerable population. However, data on the immunogenicity of anti-SARS-CoV-2 vaccines in pwCF are lacking. We conducted a prospective study enrolling all patients aged > 12 and who were followed-up in our CF center and received two doses of the BNT162b2 vaccine in the period of March−October 2021. Blood samples were taken from them for the quantification of antibodies to the SARS-CoV-2 spike protein receptor binding domain immediately before receiving the first dose and 3 and 6 months after the second dose. We enrolled 143 patients (median age: 21 years, range: 13−38), 16 of whom had had a previous infection. Geometric mean antibody titer (GMT) 3 months after vaccination was 1355 U/mL (95% CI: 1165−1575) and decreased to 954 U/mL (95% CI: 819−1111) after 6 months (p < 0.0001). GMT was higher among previously infected patients as compared to those naïve to SARS-CoV-2 (6707 vs. 1119 U/mL at 3 months and 4299 vs. 796 U/mL at 6 months, p < 0.0001) with no significant differences in the rate of decline over time (p = 0.135). All pwCF mounted an antibody response after two doses of the BNT162b2 vaccine, which waned at 6 months from vaccination. Age ≥ 30 years and the use of inhaled corticosteroids were associated with a lower humoral response. Between the second and the third doses, nine episodes of vaccine breakthrough infections were observed.

A successful treatment of a lobar atelectasis in a patient with cystic fibrosis.

Lobar atelectasis may be a complication of pulmonary exacerbations in cystic fibrosis (CF). There are no established guidelines on the management of this condition in patients with CF. Therapeutic bronchoscopy with recombinant human deoxyribonuclease (rhDNase) instillation has been described to be successful in patients not responding to conservative measures. We describe a case of a young man with CF, with previously mild impaired lung function, presenting with cough, desaturation, and worsening dyspnea, persisting for over 6 weeks, despite conservative therapy. Thoracic imaging showed right lower lobe atelectasis, which was successfully treated with bronchoscopy and instillation of rhDNase. Long-term resolution of the atelectasis was confirmed with chest magnetic resonance imaging follow-up.

Clinical course and risk factors for severe COVID-19 among Italian patients with cystic fibrosis: a study within the Italian Cystic Fibrosis Society.

PURPOSE: To describe the clinical course of COVID-19 in patients with cystic fibrosis (CF) and to identify risk factors for severe COVID-19. METHODS: We conducted a prospective study within the Italian CF Society. CF centers collected baseline and follow-up data of patients with virologically confirmed SARS-CoV-2 infection between March 2020 and June 2021. Odds ratios (ORs) for severe SARS-CoV-2 (as defined by hospital admission) were estimated by logistic regression models. RESULTS: The study included 236 patients with positive molecular test for SARS-CoV-2. Six patients died, 43 patients were admitted to hospital, 4 admitted to intensive care unit. Pancreatic insufficiency was associated with increased risk of severe COVID-19 (OR 4.04, 95% CI 1.52; 10.8). After adjusting for age and pancreatic insufficiency, forced expiratory volume in one second (FEVp) < 40% (OR 4.54, 95% CI 1.56; 13.2), oxygen therapy (OR 12.3, 95% CI 2.91-51.7), underweight (OR 2.92, 95% CI 1.12; 7.57), organ transplantation (OR 7.31, 95% CI 2.59; 20.7), diabetes (OR 2.67, 95% CI 1.23; 5.80) and liver disease (OR 3.67, 95% CI 1.77; 7.59) were associated with increased risk of severe COVID-19, while use of dornase alfa was associated with a reduced risk (OR 0.34, 95% CI 0.13-0.88). No significant changes were observed in FEVp from baseline to a median follow-up of 2 months (median difference: 0, interquartile range: - 4; 5, P = 0.62). CONCLUSION: Clinical features indicative of severe form of CF are associated with increased risk of COVID-19 hospitalization. SARS-CoV-2 infected patients do not experience a deterioration of respiratory function.

Prevalence and factors associated with urinary incontinence in females with cystic fibrosis: An Italian single-center cross-sectional analysis.

BACKGROUND: Individuals with cystic fibrosis (CF) are deemed to have a higher risk of developing urinary incontinence (UI), likely due to repeated increasing pressure on the pelvic floor. We aimed to determine the prevalence of female UI in a large CF referral center, and to assess the association between UI and severity of CF disease. METHODS: We consecutively recruited female patients regularly attending our CF center, aged ≥6 years and with a confirmed diagnosis of CF. Prevalence, severity, and impact of UI were assessed by administering two validated questionnaires. Relationship between variables was evaluated by means of multiple correspondence analysis, whereas a logistic model was fitted to capture the statistical association between UI and independent variables. RESULTS: UI was present in 51/153 (33%, 95% confidence interval [CI]: 26%-41%) females. Among children and adolescents, the prevalence was 12/82 (15%, 95% CI: 8%-25%) whereas among adults was 39/71 (55%, 95% CI: 43%-67%). The only explanatory variable associated with UI was age, with children presenting the lowest risk (odds ratio, 0.32; 95% CI: 0.05-0.93). Females presenting low or high nutritional status show higher profile risk of having UI. CONCLUSIONS: Stress UI is a common complication in females with CF since childhood. Although it frequently occurs in older patients with a more severe phenotype, much attention should be paid to adults and to their nutritional status.

Multiple, random spot urine sampling for estimating urinary sodium excretion.

The measurement of sodium intake may be important for the management of hypertension. Dietary surveys and 24-h urinary collection are often unreliable and/or impractical. We hypothesized that urinary sodium excretion can be accurately estimated through multiple spot urine samples from different days. All enrolled subjects were children of the coauthors of the study. Fifty-two 24-h urinary collections (4 per subject) for measuring sodium excretion and the 297 related urinary samples (1 per voiding) were collected for calculating the urinary sodium/urinary creatinine ratio in 13 children. The mean of 4 measured sodium excretions served as the individual "gold standard". Twenty-four urinary collections were used to generate the equation predicting the mean measured sodium excretion from the mean of 4 urinary sodium/urinary creatinine [= 0.016 × urinary sodium (mmol/L) / urinary creatinine (mmol/L) ratio + 3.3)]; the remaining 28 urinary collections and 153 urinary samples were used for the external validation. All subjects underwent an additional validation procedure involving 12 urinary samples randomly collected on different days 6 months apart. The performance of sodium excretion calculated from a total of over 22,000 possible means of 4 out of all the available urinary samples, randomly taken on different days, was analyzed as to precision (by means of the coefficient of variation) and as to accuracy (by means of the P30). The coefficients of variations of measured vs. calculated sodium excretion were 25.3% vs. 25.8%, and the P30 of calculated sodium excretion was 100%. The excellent performance of calculated sodium excretion was confirmed both by external validation and by samples collected 6 months apart with mean P30s, all between 86 and 100%.Conclusion: In the described experimental conditions, urinary sodium excretion was estimated with equal precision and more accurately (and practically) by the mean of 4 urinary sodium/urinary creatinine ratios from random samples from different days than by a single urinary collection. In real life, with several errors systematically affecting urinary collection, the superiority of calculated sodium excretion is likely to be even greater. What is Known: • The measurement of sodium intake with the current standards of care (dietary survey or 24-h urinary collection) is laborious and can be inaccurate. What is New: • The study provides evidence that sodium intake can be estimated equally precisely, more accurately and more practically with the urinary sodium-to-urinary creatinine ratio from 4 urine samples taken on different days than with a single urinary collection.

SARS-CoV-2 antibodies among people with cystic fibrosis prior to the vaccination campaign: A seroprevalence study in two specialized centres in Northern Italy.

The prevalence of anti-SARS-CoV-2 antibodies in people with cystic fibrosis (CF) is largely unknown. We carried out a cross-sectional study between March and June 2021 with the aim of estimating the seroprevalence of anti-SARS-CoV-2 antibodies in two CF centres in Northern Italy. Total serum anti-SARS-CoV-2 (spike) antibodies levels were measured and values ≥0.8 U/mL were considered positive. Among 434 patients aged >12 years, 64 patients had a positive result (14.7%, 95% CI: 11.5-18.4), 36 (56.3%) without experiencing any COVID-19-related symptoms. Three out of 49 transplanted patients tested positive with an odds ratio for a positive result among transplanted as compared to non-transplanted patients of 0.35 (95% CI: 0.07-1.14). No significant differences were observed between sexes, age groups, socioeconomic status and lung disease severity. In conclusion, SARS-CoV-2 has infected a relatively high proportion of our patients but in most cases the infection was asymptomatic.