Gender differences in cystic fibrosis: Pseudomonas aeruginosa infection

Outcome in cystic fibrosis liver disease

OBJECTIVES

Evidence suggests that cystic fibrosis liver disease (CFLD) does not affect mortality or morbidity in patients with cystic fibrosis (CF). The importance of gender and age in outcome in CF makes selection of an appropriate comparison group central to the interpretation of any differences in mortality and morbidity in patients with CFLD.

METHODS

This is a 7-year follow-up of 42 children with CFLD and their age- and sex-matched controls. Participants were reviewed clinically, biochemically, and radiologically at follow-up.

RESULTS

Overall, 85% (72 of 84) of the original cohort were included, 36 CFLD participants and 36 CF controls. There was no significant difference in the number of deaths/transplants between groups (7 of 36 (19.4%) CFLD participants, 3 of 36 (8.3%) CF controls). There was a tendency for participants with CFLD to die younger than their respective CF controls. There was no difference in height, weight, body mass index, or pulmonary function between the groups. Nutritional parameters (sum skinfold thickness 31.6 vs. 42.3, P=0.03; mean upper arm fat area 15.08 vs. 10.59, P=0.001; Shwachman score 43.7 vs. 32.1, P=0.001) were worse among CFLD participants than among CF controls. Cystic fibrosis-related diabetes was more common in CFLD participants (11 of 27 (40.7%) vs. 5 of 33 (15.2%), P=0.02). Eight children (22.2%) with evidence of CFLD at baseline had no clinical evidence of liver disease as adults.

CONCLUSIONS

Patients with CFLD have a more severe CF phenotype than do CF patients without liver disease. However, a subgroup of children with CFLD will not manifest clinically significant liver disease as adults.

Clinical significance of microbial infection and adaptation in cystic fibrosis

A select group of microorganisms inhabit the airways of individuals with cystic fibrosis. Once established within the pulmonary environment in these patients, many of these microbes adapt by altering aspects of their structure and physiology. Some of these microbes and adaptations are associated with more rapid deterioration in lung function and overall clinical status, whereas others appear to have little effect. Here we review current evidence supporting or refuting a role for the different microbes and their adaptations in contributing to poor clinical outcomes in cystic fibrosis.

Baseline characteristics and factors associated with nutritional and pulmonary status at enrollment in the cystic fibrosis EPIC observational cohort

SUMMARY BACKGROUND

The EPIC Observational Study is an ongoing prospective cohort study investigating risk factors for and clinical outcomes associated with early Pseudomonas aeruginosa (Pa) acquisition in young children with cystic fibrosis (CF).

OBJECTIVES AND HYPOTHESIS

To describe the baseline characteristics of the cohort and evaluate associations between potential risk factors and nutritional and respiratory characteristics at enrollment. We hypothesized that distinct demographic and environmental risk factors could be identified for poorer nutritional status and lung function at enrollment.

METHODS

During 2004-2006, 1,700 children with CF were enrolled at 59 US CF centers. Children <or=12 years were eligible if they had no prior Pa infection (Pa-Never) or, if prior isolation of Pa from respiratory cultures, at least a 2-year history of Pa negative cultures (Pa-Past).

RESULTS

One thousand one hundred seventeen participants (65.7%) were Pa-Never and 583 (34.3%) Pa-Past. Pa-never patients had a lower proportion of CFTR genotypes with both mutations in functional classes I, II, or III), higher lung function and less respiratory symptoms. Diagnosis after newborn or prenatal screening was associated with significantly higher mean weight, height, and FEV(1) at enrollment, while maternal smoking during pregnancy appeared to worsen these parameters.

CONCLUSIONS

Children in this cohort with a remote history of Pa infection had a higher proportion of CFTR genotypes associated with severely reduced CFTR function as well as lower lung function and more respiratory symptoms than those without prior Pa infection. These observed differences in respiratory indices may reflect the impact of prior Pa airway infection and/or of CFTR genotype or other genetic factors predisposing both to earlier Pa acquisition and more severe lung disease. Key characteristics associated with nutritional and pulmonary status at enrollment included diagnosis after prenatal or neonatal screening (protective) and in utero cigarette exposure (harmful).

Pseudomonas aeruginosa in children with cystic fibrosis diagnosed through newborn screening: assessment of clinic exposures and microbial genotypes

BACKGROUND

Chronic pulmonary infection with Pseudomonas aeruginosa (PA) is responsible for significant morbidity and mortality in cystic fibrosis (CF). Because of the limited studies evaluating early exposure and the progression of genetic variability of PA, our goal was to assess PA in young children with CF followed in two clinic types.

METHODS

A total of 39 infants with CF diagnosed through newborn screening were randomly assigned to either a segregated (PA-free) or mixed (PA-positive) clinic at two different CF centers, one of which replaced an older, mixed clinic where nosocomial acquisition was suspected. Oropharyngeal (OP) swab cultures were examined with subsequent genotyping to characterize the strains of PA isolated.

RESULTS

We found that 13/21 segregated clinic patients and 14/18 mixed clinic patients showed positive PA, with median acquisition ages of 3.3 and 2.2 years, respectively (P = 0.57). The median time to PA acquisition, however, was significantly longer in the new clinic with proper hygiene precautions compared to an old site (5.0 years vs. 1.7 years, P < 0.001). The majority of subjects isolated a single genotype of PA or AP-PCR types during the study period with eight subjects clearing the isolate after only one positive culture. The development of chronic colonization yielded the predominance of a single major genotype or AP-PCR type.

CONCLUSIONS

Segregation of infants and young children with CF in PA-negative or PA-positive clinics did not alter the time to first PA isolation in this randomized assessment of facilities with hygienic precautions. During the early infection period where PA is first isolated in young children with CF, patients cleared different PA strains until a predominant strain established permanent colonization.

Pseudomonas Aeruginosa in Cystic Fibrosis Patients with CFTR 11234V in a Large Kindred Family

To describe the characteristics of Pseudomonas aeruginosa (P. aeruginosa) in cystic fibrosis (CF) patients with CFTR 11234V in a large kindred family in Qatar, medical and laboratory records were reviewed of 46 patients of CF with CFTR 11234V from 25 families arising from a single large Arab kindred tribe who attended the CF clinic between May 2002 and June 2008. Thirty eight CF patients, who were negative for P. aeruginosa at first lower respiratory culture, were enrolled in the study. The diagnosis of CF was confirmed by sweat test and molecular genetic study. Trypticase soy agar with 5% sheep blood, McConkey agar, oxidative-fermentative polymyxin B-bacitracin lactose agar, Hemophilus isolation agar and mannitol salt agar were used as selective media for the isolation of important CF respiratory pathogens. The prevalence of (P. aeruginosa) in lower respiratory cultures from 46 patients was 60.9%. Twenty (52.6%) of 38 CF patients with CFTR 11 234V acquired P\ aeruginosa with no seasonal variation. Positive siblings with P. aeruginosa were found in 70% indicating cross-infection within the family. The median (range) age at first detection of P. aeruginosa was 12.5 (1–19) years. There was no significant difference between males and females in acquisition of P. aeruginosa. P\ aeruginosa of mucoid phenotype was detected in 11 (55%) of 20 with additional organisms, 5. aureusbe'mg the second isolated organism in nine (81.8%) of the 11. Conclusion: A larger prospective study in a cohort of CF patients with CFTR 11234V in the Arabian Gulf region is required to determine the risk factors for acquisition of P. aeruginosa with early aggressive antipseudomonal therapy.

17Beta-estradiol inhibits IL-8 in cystic fibrosis by up-regulating secretory leucoprotease inhibitor

RATIONALE

An unexplained gender gap is observed in cystic fibrosis (CF). Females have poorer lung function, decreased survival, and earlier Pseudomonas colonization.

OBJECTIVES

To evaluate the effect of 17beta-estradiol (E(2)) on CF bronchial epithelial cells in vitro and in vivo.

METHODS

On exposure of CFBE41o- cultures to physiological concentrations of E(2), there was a significant dose-dependent inhibition of IL-8 release induced by toll-like receptor agonists, CF bronchoalveolar lavage fluid, or Pseudomonas-conditioned media. Estrogen receptor (ER)-alpha and -beta expression was quantified in cell lines and bronchial brushings from CF and non-CF patients.

MEASUREMENTS AND MAIN RESULTS

Both receptors were expressed in vitro and in vivo, although ERbeta expression was significantly higher in CF. Using ER isoform-specific agonists and antagonists, we established that ERbeta mediates the inhibition of CF bronchoalveolar lavage fluid-induced IL-8 release. We also showed that secretory leucoprotease inhibitor gene expression and protein localization to the nucleus increased in response to E(2). Secretory leucoprotease inhibitor knockdown abrogated the inhibitory effects of E(2).

CONCLUSIONS

E(2) inhibits IL-8 release by ERbeta in CF bronchial epithelial cells through up-regulation of secretory leucoprotease inhibitor, inhibition of nuclear factor (NF)-kappaB, and IL-8 gene expression. These data implicate a novel anti-inflammatory mechanism for E(2) in females with CF, which predisposes to infection and colonization. This could, in part, account for the observed gender dichotomy in CF.

Influenza-associated cystic fibrosis pulmonary exacerbations

BACKGROUND

Although cystic fibrosis (CF) is the most common inherited respiratory disease, the burden of influenza among individuals with CF is not well characterized.

METHODS

We used the CF Foundation Patient Registry to determine the relationship between pulmonary exacerbation incidence rate and influenza virus season from July 2003 through June 2007. The outcome of interest, pulmonary exacerbation, was defined as treatment of a respiratory illness with IV antibiotics. Each influenza season was defined as all months during which >/= 15% of laboratory tests for influenza virus were positive in the US influenza virologic surveillance system. We calculated incidence rates of pulmonary exacerbation during the influenza and summertime seasons as well as relative rates with 95% CIs. A multivariate regression model adjusted for demographic and clinical predictors.

RESULTS

In 2003, the patient cohort size was 21,506 patients, and 7,727 patients experienced at least one pulmonary exacerbation. The overall pulmonary exacerbation incidence rate in the influenza season was 595.0 per 10,000 person-months compared with a summertime baseline of 549.6 per 10,000 person-months. The incidence rate ratio was 1.08 (95% CI: 1.06, 1.10). Multivariate analysis did not change our estimate of risk (adjusted odds ratio: 1.07; 95% CI: 1.05, 1.10). An estimated annual excess of 147.6 per 10,000 person-months or an excess 2.1% of total exacerbations occur during the influenza season.

CONCLUSION

Our data demonstrate a substantial contribution of the influenza season to CF morbidity. Further studies to determine any causal link between influenza infection and CF pulmonary exacerbations are necessary.

Classic respiratory disease but atypical diagnostic testing distinguishes adult presentation of cystic fibrosis

BACKGROUND

The majority of new cases of cystic fibrosis (CF) are diagnosed before age 2 years. Diagnoses in older individuals have increased because of improved genetic testing and increased awareness of the disease. A comprehensive description of clinical, genetic, and microbiologic characteristics of adult-age presentation of CF does not exist. We compare newly diagnosed CF in adults with newly diagnosed CF in children and adolescents in the United States.

METHODS

This is a cross-sectional study of new CF diagnoses from the Cystic Fibrosis Foundation Patient Registry between 1995 and 2005. Diagnostic, microbiologic, and clinical features during year of diagnosis were analyzed for subjects by age group. Descriptive statistics were calculated for variables on characteristics by age group.

RESULTS

A total of 9,766 new diagnoses of CF were reported to the Registry between 1995 and 2005. The proportion of adult diagnoses increased significantly in the years 2001 to 2005 as compared with 1995 to 2000 (9.0% vs 7.7%, P = .012). FEV(1)% predicted decreased with increasing age at diagnosis (P < .001). Infection with Pseudomonas aeruginosa was most common in adults (P < .001). Both the number of positive sweat chloride tests and prevalence of DeltaF508 mutation, the most common mutation in the United States, decreased significantly with older age at diagnosis (P < .001).

CONCLUSIONS

Between 1995 and 2005, the proportion of new diagnoses of CF in adults in the United States increased significantly. Adults present with commonly described CF respiratory disease (Pseudomonas aeruginosa infection and reduced lung function), but have lower sweat chloride values and lower frequency of DeltaF508 mutation. Knowledge of clinical characteristics and diagnostic limitations of adult patients presenting with CF will hopefully lead to earlier recognition and intervention.

Health-related quality of life in children with cystic fibrosis: validation of the German CFQ-R

Background

This study evaluates the psychometric properties of the Child and Parent versions of the German CFQ-R (Cystic Fibrosis Questionnaire Revised), a disease-specific measure of Health-Related Quality of Life (HRQoL) in children with cystic fibrosis (CF). Self-Rating is combined with proxy-rating by parents in the use of the questionnaire.

Methods

136 children with CF (6 - 13 years) and their parents were recruited to evaluate internal consistency (Cronbach's α) and validity, 20 children and parents to examine reproducibility (ICC).

Results

Cronbach's α is high in all but two dimensions of the Child version (α = 0.23-0.77) and for all dimensions of the Parent version (α = 0.69-0.89). For both questionnaires, reproducibility is moderate to high (ICC = 0.50-0.94). Factor analysis shows loadings of >0.4 in the majority of items. Higher HRQoL is reported by children with mild disease compared to those with moderate/severe disease and by boys compared to girls. Convergence between self-rating and proxy-rating depends on the dimension.

Conclusion

The German CFQ-R, Child and Parent versions, are reliable and valid measures of HRQoL. They should be administered in combination as both, child and parent, provide important information. The measure offers a new patient-reported outcome for clinical purposes as well as for national and international studies in schoolchildren.

Cystic fibrosis HRCT scores correlate strongly with Pseudomonas infection

BACKGROUND

In order to establish a valid surrogate outcome measure, it must be shown that the outcome measure (chest HRCT scores in cystic fibrosis [CF] patients) demonstrates strong statistical association with established endpoints of disease, such as Pseudomonas aeruginosa (Pa) airway acquisition, acute exacerbations, or mortality.

METHODS

We estimated and tested the association between Pa infection status (Pa+ vs. Pa-) and baseline chest HRCT scores in 25 children with mild-to-moderate CF lung disease. For comparison, we estimated the association between Pa status and pulmonary function tests (PFTs), chest X-rays (CXR) scores, and BMI. Pa acquisition was determined from respiratory culture results and systematic review of clinic notes.

RESULTS

All subjects had respiratory cultures performed prior to or at baseline with a median of 19 months of retrospective culture observation (SD = 15.7 months, range: 0-52.5 months). The difference between age-adjusted mean total HRCT score for Pa+ versus Pa- was highly significant (P < 0.00001) with a near-perfect separation between scores in Pa+ versus Pa- patients. Similar results were found for several HRCT sub-scores. Among PFTs, only residual volume-to-total lung capacity (RV/TLC) had a significant difference between group means (P = 0.03), but the overlap between groups in RV/TLC measurements was large.

CONCLUSIONS

CF HRCT scores correlate highly with Pa acquisition, a clinically meaningful measure of progressing CF lung disease. HRCT scores are highly sensitive at predicting Pa acquisition status, while most PFT measures, chest radiograph (CXR) scores, and body mass index are not. These results provide further evidence that HRCT is appropriate for use in patient care and as an outcome measure in clinical trials.

Proteomic identification of OprL as a seromarker for initial diagnosis of Pseudomonas aeruginosa infection of patients with cystic fibrosis

Identification of new immunogenic antigens that diagnose initial Pseudomonas aeruginosa infections in patients with cystic fibrosis (CF) alone or as an adjunct to microbiology is needed. In the present study, a proteomic analysis was performed to obtain a global assessment of the host immune response during the initial P. aeruginosa infection of patients with CF. Matrix-assisted laser desorption ionization-time of flight mass spectrometry was used to identify outer membrane protein L (OprL), a non-type III secretion system (TTSS) protein, as an early immunogenic protein during the initial P. aeruginosa infection of patients with CF. Longitudinal Western blot analysis of sera from 12 of 14 patients with CF detected antibodies to OprL during the initial P. aeruginosa infection. In addition, also detected were antibodies to ExoS, ExoU, or ExoS and ExoU, the latter indicating sequential P. aeruginosa infections during initial infections. Detection of serum reactivity to OprL, along with proteins of the TTSS, and in conjunction with microbiology may diagnose initial P. aeruginosa infections in patients with CF.

IL1B polymorphisms modulate cystic fibrosis lung disease

RATIONALE

Variability in pulmonary disease severity is found in patients with cystic fibrosis (CF) who have identical mutations in the CF transmembrane conductance regulator (CFTR) gene. We hypothesized that one factor accounting for heterogeneity in pulmonary disease severity is variation in the family of genes affecting the biology of interleukin-1 (IL-1), which impacts acquisition and maintenance of Pseudomonas aeruginosa infection in animal models of chronic infection.

METHODS

We genotyped 58 single nucleotide polymorphisms (SNPs) in the IL-1 gene cluster in 808 CF subjects from the University of North Carolina and Case Western Reserve University (UNC/CWRU) joint cohort. All were homozygous for DeltaF508, and categories of "severe" (cases) or "mild" (control subjects) lung disease were defined by the lowest or highest quartile of forced expired volume (FEV(1)) for age in the CF population. After adjustment for age and gender, genotypic data were tested for association with lung disease severity. Odds ratios (ORs) comparing severe versus mild CF were also calculated for each genotype (with the homozygote major allele as the reference group) for all 58 SNPs. From these analyses, nine SNPs with a moderate effect size, OR < or =0.5 or >1.5, were selected for further testing. To replicate the case-control study results, we genotyped the same nine SNPs in a second population of CF parent-offspring trios (recruited from Children's Hospital Boston), in which the offspring had similar pulmonary phenotypes. For the trio analysis, both family-based and population-based associations were performed.

RESULTS

SNPs rs1143634 and rs1143639 in the IL1B gene demonstrated a consistent association with lung disease severity categories (P < 0.10) and longitudinal analysis of lung disease severity (P < 0.10) in CF in both the case-control and family-based studies. In females, there was a consistent association (false discovery rate adjusted joint P-value <0.06 for both SNPs) in both the analysis of lung disease severity in the UNC/CWRU cohort and the family-based analysis of affection status.

CONCLUSION

Our findings suggest that IL1beta is a clinically relevant modulator of CF lung disease.

Early anti-pseudomonal acquisition in young patients with cystic fibrosis: rationale and design of the EPIC clinical trial and observational study'

BACKGROUND

The primary cause of morbidity and mortality in patients with cystic fibrosis (CF) is progressive obstructive pulmonary disease due to chronic endobronchial infection, particularly with Pseudomonas aeruginosa (Pa). Risk factors for and clinical impact of early Pa infection in young CF patients are less well understood.

PURPOSE

The present studies are designed to evaluate risk factors and outcomes associated with early Pa acquisition, and the benefits and harms of four anti-pseudomonal treatment regimens in young CF patients initiated after the first Pa positive respiratory culture.

METHODS

The Early Pseudomonas Infection Control (EPIC) program consists of two studies, a randomized multicenter trial in CF patients ages 1-12 years at first isolation of Pa from a respiratory culture, and a longitudinal cohort study enrolling Pa-negative patients. Using a factorial design, trial participants are assigned for 18 months to either anti-pseudomonal treatment on a scheduled quarterly basis (cycled therapy) or based on recovery of Pa from quarterly respiratory cultures (culture-based therapy). The study drugs include inhaled tobramycin (300 mg BID) for 28 days, combined with either oral ciprofloxacin (15-20 mg/kg BID) or oral placebo for 14 days. The primary endpoints of the trial are the time to pulmonary exacerbation requiring IV antibiotics or hospitalization for respiratory symptoms, and the proportion of patients with new Pa-positive respiratory cultures during the study. The broad goals of the observational study are to describe the risk factors and outcomes associated with early acquisition of Pa. 306 patients were randomized in the clinical trial and 1787 were enrolled in the cohort study.

CONCLUSIONS

These companion studies will provide valuable epidemiological and microbiological information on early CF lung disease and Pa acquisition, and safety and clinical efficacy data on anti-pseudomonal treatment strategies for early Pa infections in the airways of young children with CF.

Impact of Pseudomonas and Staphylococcus infection on inflammation and clinical status in young children with cystic fibrosis

OBJECTIVE

To assess the effects of Pseudomonas aeruginosa and Staphylococcus aureus infection on lower airway inflammation and clinical status in young children with cystic fibrosis (CF).

STUDY DESIGN

We studied 111 children age < 6 years who had 2 P aeruginosa-positive oropharyngeal cultures within 12 months. We examined bronchoalveolar lavage fluid (BALF) inflammatory markers (ie, cell count, differential, interleukin [IL]-8, IL-6, neutrophil elastase), CF-related bacterial pathogens, exotoxin A serology, and clinical indicators of disease severity.

RESULTS

Young children with CF with both upper and lower airway P aeruginosa infection had higher neutrophil counts, higher IL-8 and free neutrophil elastase levels, increased likelihood of positive exotoxin A titers, and lower Shwachman scores compared with those with positive upper airway cultures only. S aureus was associated with increased lower airway inflammation, and the presence of both P aeruginosa and S aureus had an additive effect on concentrations of lower airway inflammatory markers. BALF markers of inflammation were increased with the number of different bacterial pathogens detected.

CONCLUSIONS

Young children with CF who have upper and lower airway P aeruginosa infection have increased endobronchial inflammation and poorer clinical status compared with those with only upper airway P aeruginosa infection. The independent and additive effects of S aureus on inflammation support the significance of polymicrobial infection in early CF lung disease.

Recurrent exacerbations affect FEV(1) decline in adult patients with cystic fibrosis

Obstructive lung disease is the major cause of morbidity and mortality in cystic fibrosis (CF). To identify risk factors contributing to FEV(1) decline in CF patients, we carried out a retrospective analysis of clinical and pulmonary function data in a population of CF patients followed up for 5 years and studied the correlation between clinical data and FEV(1) decline. Fifty-one adult CF patients were studied. The FEV(1) decline was related to the following clinical characteristics: CFTR genotype, age, gender, weight, height, age at diagnosis, baseline FEV(1), pancreatic function, presence of airway infection, pancreatic insufficiency and diabetes, number of exacerbations/year and intravenous (i.v.) antibiotic courses/year. Both the number of exacerbations/year and the number of i.v. antibiotic courses/year were strongly related to the FEV(1) decline. Patients with airway infection or with diabetes had significantly lower FEV(1) values during the study as compared with non-infected patients or patients without diabetes; however, both the presence of airway infection or diabetes did not affect the FEV(1) decline. These results suggest that the aggressive treatment of disease exacerbations is crucial for delaying lung function decline in CF.

17beta-Estradiol inhibits Ca2+-dependent homeostasis of airway surface liquid volume in human cystic fibrosis airway epithelia

Normal airways homeostatically regulate the volume of airway surface liquid (ASL) through both cAMP- and Ca2+-dependent regulation of ion and water transport. In cystic fibrosis (CF), a genetic defect causes a lack of cAMP-regulated CFTR activity, leading to diminished Cl- and water secretion from airway epithelial cells and subsequent mucus plugging, which serves as the focus for infections. Females with CF exhibit reduced survival compared with males with CF, although the mechanisms underlying this sex-related disadvantage are unknown. Despite the lack of CFTR, CF airways retain a limited capability to regulate ASL volume, as breathing-induced ATP release activates salvage purinergic pathways that raise intracellular Ca2+ concentration to stimulate an alternate pathway to Cl- secretion. We hypothesized that estrogen might affect this pathway by reducing the ability of airway epithelia to respond appropriately to nucleotides. We found that uridine triphosphate-mediated (UTP-mediated) Cl- secretion was reduced during the periovulatory estrogen maxima in both women with CF and normal, healthy women. Estrogen also inhibited Ca2+ signaling and ASL volume homeostasis in non-CF and CF airway epithelia by attenuating Ca2+ influx. This inhibition of Ca2+ signaling was prevented and even potentiated by estrogen antagonists such as tamoxifen, suggesting that antiestrogens may be beneficial in the treatment of CF lung disease because they increase Cl- secretion in the airways.

Growing old with cystic fibrosis - the characteristics of long-term survivors of cystic fibrosis

BACKGROUND

The proportion of patients with cystic fibrosis (CF) who are middle-aged is increasing - and is likely to continue to do so. We surveyed a population of long-term CF survivors to assess their burden of illness and profile their disease characteristics.

METHODS

A case series (n=112) of patients from one specialist centre who had reached their 40th birthday without transplantation. Hospital records and annual review data were examined.

RESULTS

The median age of the group was 43.1 years (range 40-71.1); 57% were men. 68% were diagnosed before 16 years of age. 30% were DeltaF508/DeltaF508, 76% having at least one DeltaF508 allele. When compared with the total adult CF population, the older patients were significantly less likely to have a DeltaF508 mutation or colonisation with Stenotrophomonas maltophilia and MRSA; but more likely to have pancreatic sufficiency, colonisation with Pseudomonas aeruginosa or allergic bronchopulmonary aspergillosis. On average they required less than one hospital admission a year; lung function and body mass index were relatively well preserved. Many were married and working.

CONCLUSIONS

We describe one of the largest surveys to date of CF patients aged more than 40 years. The full spectrum of disease is represented in this population and, importantly, 30% are DeltaF508 homozygous. Provision needs to be made for the healthcare needs of this increasing population of older patients.

Life satisfaction of adolescents and adults with cystic fibrosis: impact of partnership and gender

BACKGROUND

This is the first study to assess the impact of gender and partnership on life satisfaction in adolescents and adults with CF, using a model combining subjective importance and satisfaction ratings.

METHODS

Life satisfaction of 243 CF patients (16-58 years, M=29.6, SD=7.4, 46.9% male) was assessed with the Questions on Life Satisfaction (FLZ(M)). The effects of gender and partnership on life satisfaction were calculated.

RESULTS

Significantly less males than females reported living with a partner (chi(2)=16.5, p<001). Gender only had a significant effect on health-related life satisfaction, with females reporting worse life satisfaction. Partnership had small to large effects on general, health-related and CF-specific life satisfaction (eta(2)=.049-.144). Participants with partners always reported higher life satisfaction than those without partner. However, no significant interaction effect of partnership and gender could be shown.

CONCLUSIONS

Having a partner is associated with higher life satisfaction, regardless of the patient's gender and might have beneficial effects on medical outcomes.

Disease surveillance using bronchoalveolar lavage

The role of pulmonary infection and inflammation in the pathogenesis of destructive lung disease in cystic fibrosis (CF) is undisputed. The use of bronchoscopy and bronchoalveolar lavage (BAL) has demonstrated that these processes may begin early in life and be present in the absence of overt clinical symptoms. Some children diagnosed following newborn screening can be infected with Pseudomonas aeruginosa in infancy. Studies using BAL have demonstrated a relationship between lower airway inflammation and bacterial load in the lungs; however, inflammation may occur in the absence of obvious current infection. BAL has the potential to provide a greater understanding of the pathogenesis of CF lung disease and microbiological surveillance provides the opportunity for early detection and eradication of P. aeruginosa. Lack of standardization inhibits the ability to compare data from different centres and to optimize treatment strategies. This review discusses the recommendations from a workshop held in early 2007 aimed at achieving a standardized approach to BAL in infants and young children with CF.

Shifting patterns of inhaled antibiotic use in cystic fibrosis

RATIONALE

Antibiotic inhalation has become widely accepted as a standard treatment for cystic fibrosis (CF) airway infection. We assessed the prevalence and context of inhaled antibiotic use in the North American CF population. Our working hypothesis was that a shift from acute to chronic use of inhaled antibiotics has coincided with increased prevalence of use among CF patients.

METHODS

Descriptive statistics were collected for 30,833 patients enrolled in the Epidemiologic Study of CF (ESCF) during 1996 through 2005. A multivariate analysis was performed on data from a subgroup of 18,021 patients enrolled in ESCF during 2003 through 2005.

RESULTS

The prevalence of inhaled antibiotic use in the North American CF population increased during 1996 through 2005 due to increased chronic use, while acute use to treat pulmonary exacerbations decreased. In 2005, 50% of CF patients used inhaled tobramycin and 9% used inhaled colistin chronically; most of the latter used both agents concurrently. Airway obstruction severity and airway infection status were predictors of inhaled antibiotic use.

CONCLUSIONS

Increased chronic use and decreased acute use of inhaled antibiotics presumably reflect a shift toward more proactive management of airway infections in the North American CF population. The effects of these usage patterns on long-term clinical outcomes and emergence of antibiotic-resistant Pseudomonas aeruginosa strains warrant further study.

Cystic fibrosis lung disease in adult patients

As the longevity of all patients with cystic fibrosis (CF) continues to increase (median 2005 survival=36.8 years), more adult patients will be receiving their medical care from nonpediatric adult-care providers. Cystic fibrosis remains a fatal disease, with more than 80% of patients dying after the age of 18 years, and most deaths resulting from pulmonary disease. The changing epidemiology requires adult-care providers to become knowledgeable and competent in the clinical management of adults with CF. Physicians must understand the influence of specific genotype on phenotypic disease presentation and severity, the pathogenic factors determining lung disease onset and progression, the impact of comorbid disease factors such as CF-related diabetes and malnutrition upon lung disease severity, and the currently approved or standard accepted therapies used for chronic management of CF lung disease. This knowledge is critical to help alleviate morbidity and improve mortality for the rapidly expanding population of adults with CF.

Modulation of cystic fibrosis lung disease by variants in interleukin-8

Cystic fibrosis pulmonary disease is characterized by excessive and prolonged inflammation. CF Pulmonary disease severity exhibits considerable variation that, to some extent, appears to be due to the presence of modifier genes. Several components of the inflammatory response are known to have altered regulation in the CF lung. Genetic variants in 52 inflammatory genes were tested for associations with lung disease indices in a CF patient population (n=737) homozygous for the DeltaF508 cystic fibrosis transmembrane conductance regulator mutation. Variants in three inflammatory genes showed significant genotypic associations with CF lung disease severity, including IL8 and previously reported TGFbeta1 (P< or =0.05). When analyzed by gender, it was apparent that IL8 variant associations were predominantly due to males. The IL8 variants were tested in an additional CF population (n=385) and the association in males verified (P< or =0.01). The IL8 variants were in strong linkage disequilibrium with each other (R2> or =0.82), while variants in neighboring genes CXCL6, RASSF6 and PF4V1 did not associate (P> or =0.26) and were in weaker LD with each other and with the IL8 variants (0.01< or =R2< or =0.49). Studies revealed differential expression between the IL8 promoter variant alleles (P<0.001). These results suggest that IL8 variants modify CF lung disease severity and have functional consequences.

Predictors of mucoid Pseudomonas colonization in cystic fibrosis patients

RATIONALE

Chronic mucoid Pseudomonas aeruginosa within the airway in cystic fibrosis (CF) patients can determine prognosis. Understanding the risk factors of mucoid P. aeruginosa acquisition may change how we deliver care. This study aims to evaluate whether presence of risk factors reported to predict disease severity including gender, CFTR genotype, bacterial organisms in airway cultures, and serum levels of vitamins A and E, albumin, C-reactive protein, alpha 1-antitrypsin, and immunoglobulins increased the risk of mucoid P. aeruginosa acquisition.

METHODS

Primary endpoint was age at first transition from negative to positive culture for mucoid P. aeruginosa. Cox proportional hazards regression with time-dependent covariates examined development of mucoid P. aeruginosa infection and its association with longitudinally measured serum biomarkers, pulmonary function, and culture results for other organisms.

RESULTS

Median ages at CF diagnosis and at first culture were 0.55 and 5.7 years, respectively. Median number of cultures/patient was 17. Of the 323 subjects, 150 developed mucoid P. aeruginosa during a median 8.1 years' follow-up. In multivariate analysis, gender (relative hazard [RH] 0.55 for male vs. female, P = 0.001), number of DF508 alleles (RH 1.66 for 1 or 2 vs. 0, P = 0.04), FEV(1) % (RH 1.16 for 10% decrease, P = 0.008), and most recent Staphylococcus aureus status (RH 0.24 for positive vs. negative, P < 0.0001) remained statistically significant.

CONCLUSION

Female gender, number of DF508 alleles, decreased lung function, and lack of S. aureus on recent sputum culture are important risk factors for early detection of mucoid P. aeruginosa.

Duration of intravenous antibiotic therapy in people with cystic fibrosis

BACKGROUND

Respiratory disease is the major cause of mortality and morbidity in cystic fibrosis (CF). Life expectancy of people with CF has increased dramatically in the last 40 years. One of the major reasons for this increase is the mounting use of antibiotics to treat chest exacerbations caused by bacterial infections. The optimal duration of intravenous antibiotic therapy is not clearly defined. Individuals usually receive intravenous antibiotics for 14 days, but treatment may range from 10 to 21 days. A shorter duration of antibiotic treatment risks inadequate clearance of infection which could lead to further lung damage. Prolonged courses of intravenous antibiotics are expensive and inconvenient and the incidence of allergic reactions to antibiotics also increases with prolonged courses. The use of aminoglycosides requires frequent monitoring to avoid some of their side effects. However, some organisms which infect people with CF are known to be multi-resistant to antibiotics, and may require a longer course of treatment.

OBJECTIVES

To assess the optimal duration of intravenous antibiotic therapy for treating chest exacerbations in people with cystic fibrosis.

SEARCH STRATEGY

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Trials Register which comprises references identified from comprehensive electronic database searches, handsearches of relevant journals, abstract books and conference proceedings. Most recent search of the Group's Cystic Fibrosis Trials Register: February 2008.

SELECTION CRITERIA

Randomised and quasi-randomised controlled trials comparing different durations of intravenous antibiotic courses for acute respiratory exacerbations in people with CF, either with the same drugs at the same dosage, the same drugs at a different dosage or frequency or different antibiotics altogether, including studies with additional therapeutic agents.

DATA COLLECTION AND ANALYSIS

No eligible trials were identified.

MAIN RESULTS

No eligible trials were identified.

AUTHORS' CONCLUSIONS

There are no clear guidelines on the optimum duration of intravenous antibiotic treatment. Duration of treatment is currently based on unit policies and response to treatment. Shorter duration of treatment should improve quality of life and compliance; result in a reduced incidence of drug reactions; and be less costly. However, this may not be sufficient to clear a chest infection and may result in an early recurrence of an exacerbation. This systematic review identifies the need for a multicentre, randomised controlled trial comparing different durations of intravenous antibiotic treatment as it has important clinical and financial implications.

Airway epithelial control of Pseudomonas aeruginosa infection in cystic fibrosis

Defective expression or function of the cystic fibrosis transmembrane conductance regulator (CFTR) underlies the hypersusceptibility of cystic fibrosis (CF) patients to chronic airway infections, particularly with Pseudomonas aeruginosa. CFTR is involved in the specific recognition of P. aeruginosa, thereby contributing to effective innate immunity and proper hydration of the airway surface layer (ASL). In CF, the airway epithelium fails to initiate an appropriate innate immune response, allowing the microbe to bind to mucus plugs that are then not properly cleared because of the dehydrated ASL. Recent studies have identified numerous CFTR-dependent factors that are recruited to the epithelial plasma membrane in response to infection and that are needed for bacterial clearance, a process that is defective in CF patients hypersusceptible to infection with this organism.

Infections in chronic lung diseases

Chronic lung diseases are prevalent worldwide and cause significant mortality and suffering. This article discusses infections that occur in three chronic lung diseases: chronic obstructive pulmonary disease, bronchiectasis, and cystic fibrosis. Rather than discussing the role of infections as etiology of these diseases, this article focuses on infections that occur in the background of established chronic lung disease.

Approach to eradication of initial Pseudomonas aeruginosa infection in children with cystic fibrosis

The primary cause of morbidity and mortality in children with cystic fibrosis (CF) is the progression of obstructive lung disease secondary to chronic endobronchial infection, mainly caused by Pseudomonas aeruginosa (Pa). Initial Pa isolates are typically non-mucoid, usually susceptible to most anti-pseudomonal antibiotics, and potentially amenable to eradication. Preliminary studies of early intervention suggest a "window of opportunity" with anti-pseudomonal antibiotics to eradicate Pa from upper and lower airways. Several large trials in young children with CF are currently ongoing with the goals of (1) investigating if early intervention at the time of initial Pa acquisition is effective and safe and (2) identifying the least invasive and safest treatment regimen to achieve both microbiologic and clinical benefits.

Application of vaccine technology to prevention of Pseudomonas aeruginosa infections

Development of an effective vaccine against the multiple presentations of Pseudomonas aeruginosa infection, including nosocomial pneumonia, bloodstream infections, chronic lung infections in cystic fibrosis patients and potentially sight-threatening keratitis in users of contact lenses, is a high priority. As with vaccine development for any pathogen, key information about the most effective immunologic effectors of immunity and target antigens needs to be established. For P. aeruginosa, although there is a role for cell-mediated immunity in animals following active vaccination, the bulk of the data indicate that opsonically-active antibodies provide the most effective mediators of acquired immunity. Major target antigens include the lipopolysaccharide O-polysaccharides, cell-surface alginate, flagella, components of the Type III secretion apparatus and outer membrane proteins with a potentially additive effect achieved by including immune effectors to toxins and proteases. A variety of active vaccination approaches have the potential for efficacy such as vaccination with purified or recombinant antigens incorporating multiple epitopes, conjugate vaccines incorporating proteins and carbohydrate antigens, and live attenuated vaccines, including heterologous antigen delivery systems expressing immunogenic P. aeruginosa antigens. A diverse range of passive immunotherapeutic approaches are also candidates for effective immunity, with a variety of human monoclonal antibodies described over the years with good preclinical efficacy and some early Phase I and II studies in humans. Finding an effective active and/or passive vaccination strategy for P. aeruginosa infections could be realized in the next 5 to 10 years, but will require that advances are made in the understanding of antigen expression and immune effectors that work in different human tissues and clinical settings, and also require a means to validate that clinical outcomes achieved in Phase III trials represent meaningful advances in management and treatment of P. aeruginosa infections.

Advancing outcome measures for the new era of drug development in cystic fibrosis

The growing pipeline of candidate drugs for cystic fibrosis (CF) is challenging clinical trial research. There has been a shift from evaluating drugs aimed at treating the secondary manifestations of CF to evaluating drugs targeted toward the primary prevention of chronic lung disease. As CF is an orphan disease, there is a fundamental need to assess new therapies efficiently and accurately by mechanisms that best use the number of available patients. This need can be addressed with the continued advancement and refinement of CF outcome measures. We begin by presenting an overview of the outcome measures currently used in CF clinical studies, defined and categorized in terms of one of the three main classes of endpoints: clinical efficacy measures, surrogate endpoints, and biomarkers. To move forward efficiently, clinical research in CF is dependent on the development of new outcomes able to capture biologic and clinical response to novel therapeutic approaches. We conclude with a discussion of the criteria by which all new outcome measures should be evaluated. A systematic, rigorous approach to outcome measure development is needed to provide the tools necessary for evaluating new therapies and moving drugs out of the pipeline and into the CF clinic.

Risk factors for rate of decline in forced expiratory volume in one second in children and adolescents with cystic fibrosis

OBJECTIVES

To characterize the rate of decline of forced expiratory volume in 1 second (FEV(1)) in children and adolescents with cystic fibrosis and to identify and compare risk factors associated with FEV(1) decline.

STUDY DESIGN

The rate of decline in FEV(1)% predicted over 3 to 6 years in 3 different age groups was determined. Risk factors for decline were identified and compared among and within age groups as a function of disease severity with repeated-measures, mixed-model regression.

RESULTS

Mean (+/-SD) baseline FEV(1)% predicted was 88.4% +/- 20.5% for 6- to 8-year-olds (n = 1811), 85.3% +/- 20.8% for 9- to 12-year-olds (n = 1696), and 78.4% +/- 22.0% for 13- to 17-year-olds (n = 1359). Decline in FEV(1)% predicted/year was -1.12, -2.39, and -2.34, respectively. High baseline FEV(1) and persistent crackles were significant independent risk factors for decline across all age groups. Female sex, Pseudomonas aeruginosa infection, low weight-for-age, sputum, wheezing, sinusitis, pulmonary exacerbations treated with intravenous antibiotics, elevated liver test results, and pancreatic insufficiency were also identified as independent risk factors in some age groups.

CONCLUSIONS

This study identifies risk factors for FEV(1) decline in children and adolescents with cystic fibrosis. Clinicians should not be reassured by high lung function, particularly in young children, because this factor, among others, is independently associated with steeper decline in FEV(1).

Évolution des épreuves fonctionnelles respiratoires (EFR) chez des enfants atteints de mucoviscidose et dépistés à la naissance. Lien avec l'infection pulmonaire. Étude sur 40 enfants et 744 EFR

OBJECTIVES

To report longitudinal assessment of pulmonary function in children with neonatal screening for cystic fibrosis and its relationships with Pseudomonas aeruginosa (PA) chronic infection, nutritional status, sex, age and genotype.

POPULATION AND METHODS

Children benefited systematically of 3 visits a year with pulmonary function tests (PFT) and bacteriological examination. Forty children and 744 PFTs were analysed, with 38 children during at least 4 years.

RESULTS

We reported a decrease of pulmonary function tests with chronic PA infection and the genotype DeltaF508/DeltaF508. The decline was gradual and not different between not infected and recently infected children. The PFTs of children infected for a long times were very deteriorate, probably due to the fact that they were infected with multiresistant strains of PA.

CONCLUSION

We think that it is important to survey pulmonary function before 5 years old in these early infected children. We should determinate if the important decrease of PFT in these early infected children is due to infection by PA mucoid.

Predictors of mortality in adults with cystic fibrosis

Assessment of prognostic indicators in patients with cystic fibrosis (CF) is important. The study's aim was to assess the relative contribution of gender, genetics and microbiology on survival in adults with CF. Adult patients were studied from 1995 to 2005 and data collected included FEV(1) (%predicted), body mass index (BMI), genetics, and microbiology. Data was available on 183 patients in 1995. Forty-five patients died in the subsequent 10 years. Patients who died during the study had lower mean (SD) FEV(1) %predicted in 1995 when compared to those remaining alive, 41.5 (15.2)% versus 69.8 (23.2)% predicted, respectively, P<0.001 and they had lower mean (SD) BMI in 1995, 19.2 (3.3) kg/m(2) in comparison to those remaining alive, 20.7 (3.4) kg/m(2), P=0.008. The proportion of patients infected with Pseudomonas aeruginosa and Burkholderia cepacia complex was higher in the group who died during the study compared to those remaining alive, odds ratio 20.9 P<0.0001 and 7.1 P<0.0001, respectively. The presence of the Delta F508 homozygous mutation did not alter survival, P=0.3. Patients infected with either P.aeruginosa or B.cepacia complex had reduced survival compared to those without infection, P=0.01 and P<0.0001, respectively. FEV(1)% (P<0.0001), infection with P.aeruginosa (P=0.005) or B.cepacia complex (P=0.03) were the only significant predictors of mortality. This study demonstrates adults who died were more likely to have worse lung function and be infected with either P.aeruginosa or B.cepacia complex. FEV(1)% and infection with P.aeruginosa or B.cepacia complex were the most significant predictors of survival in adults with CF.

Exacerbations in cystic fibrosis. 1: Epidemiology and pathogenesis

With the improving survival of patients with cystic fibrosis (CF), the clinical spectrum of this complex multisystem disease continues to evolve. One of the most important clinical events for patients with CF in the course of this disease is an acute pulmonary exacerbation. Clinical and microbial epidemiology studies of CF pulmonary exacerbations continue to provide important insight into the course, prognosis and complications of the disease. This review provides a summary of the pathophysiology, clinical epidemiology and microbial epidemiology of a CF pulmonary exacerbation.

Novel tobramycin inhalation powder in cystic fibrosis subjects: pharmacokinetics and safety

Aerosolized antibiotics are associated with a high treatment burden that can result in non-adherence to chronic therapy. We evaluated the pharmacokinetics (PK) and safety of tobramycin inhalation powder (TIP), a novel dry-powder formulation designed to deliver a high payload of tobramycin topically to the lungs for management of chronic Pseudomonas aeruginosa infections. This was a multi-center, open-label, sequential-cohort, single-dose, dose-escalation study using the standard 300 mg dose of tobramycin solution for inhalation (TSI) as an active control. Subjects were randomized to TIP or TSI in a 3:1 ratio in each of five cohorts. Measurements included serum and sputum tobramycin concentrations, administration time, serum chemistries, acute change in lung function, and adverse events (AEs). Out of 90 randomized subjects, 86 had data for safety analysis; and 84 had data for PK analysis. Serum tobramycin PK profiles were similar for TIP and TSI. Four capsules of 28 mg TIP (total tobramycin dose 112 mg) produced comparable systemic exposure to 300 mg TSI, in less than one-third the administration time. The most common AEs associated with TIP were cough (20%) and dysgeusia (17%). TIP allows for faster and more efficient pulmonary delivery of tobramycin than TSI and has a safety profile that supports continued clinical investigation. The increased rate of local respiratory tract irritation noted with TIP is not unexpected with a high-payload powder formulation. The development of dry powder inhaled antibiotics may represent an important advance in the treatment of chronic lung infections.

Resistance to Pseudomonas aeruginosa chronic lung infection requires cystic fibrosis transmembrane conductance regulator-modulated interleukin-1 (IL-1) release and signaling through the IL-1 receptor

Innate immunity is critical for clearing Pseudomonas aeruginosa from the lungs. In response to P. aeruginosa infection, a central transcriptional regulator of innate immunity-NF-kappaB-is translocated within 15 min to the nuclei of respiratory epithelial cells expressing wild-type (WT) cystic fibrosis (CF) transmembrane conductance regulator (CFTR). P. aeruginosa clearance from lungs is impaired in CF, and rapid NF-kappaB nuclear translocation is defective in cells with mutant or missing CFTR. We used WT and mutant P. aeruginosa and strains of transgenic mice lacking molecules involved in innate immunity to identify additional mediators required for P. aeruginosa-induced rapid NF-kappaB nuclear translocation in lung epithelia. We found neither Toll-like receptor 2 (TLR2) nor TLR4 nor TLR5 were required for this response. However, both MyD88-deficient mice and interleukin-1 receptor (IL-1R)-deficient mice failed to rapidly translocate NF-kappaB to the nuclei of respiratory epithelial cells in response to P. aeruginosa. Cultured human bronchial epithelial cells rapidly released IL-1beta in response to P. aeruginosa; this process was maximized by expression of WT-CFTR and dramatically muted in cells with DeltaF508-CFTR. The IL-1R antagonist blocked P. aeruginosa-induced NF-kappaB nuclear translocation. Oral inoculation via drinking water of IL-1R knockout mice resulted in higher rates of lung colonization and elevated P. aeruginosa-specific antibody titers in a manner analogous to that of CFTR-deficient mice. Overall, rapid IL-1 release and signaling through IL-1R represent key steps in the innate immune response to P. aeruginosa infection, and this process is deficient in cells lacking functional CFTR.

Association between pulmonary function and sputum biomarkers in cystic fibrosis

RATIONALE

Sputum biomarkers of infection and inflammation are noninvasive measures that enable quantification of the complex pathophysiology of cystic fibrosis (CF) lung disease. Validation of these biomarkers as correlates of disease severity is a key step for their application.

OBJECTIVES

We constructed a large database from four multicenter studies to quantify the strength of association between expectorated sputum biomarkers and FEV(1.)

METHODS

FEV(1) (range, 25-120% predicted) and quantitative data on expectorated sputum biomarkers including free neutrophil elastase, IL-8, neutrophils, Pseudomonas aeruginosa, and Staphylococcus aureus were obtained from 269 participants (ages, 9-54 years) from 33 centers. Cross-sectional and longitudinal statistical analyses were performed to estimate associations between the markers and FEV(1), including the use of multivariable analyses.

RESULTS

Elastase was negatively correlated with FEV(1) (correlation [r] = -0.35; 95% confidence interval [CI]: -0.46, -0.22). On average, patients with CF who differed in their elastase measurements by 0.5 log differed in their FEV(1) values by -7.3% (95% CI: -9.7, -4.6). Neutrophil counts and IL-8 were also each negatively correlated. In a multivariable regression, elastase and neutrophil counts were able to explain the majority of variation in FEV(1). Elastase was further shown to have a significant longitudinal association with FEV(1), specifically a -2.9% decline in FEV(1) (95% CI: -5.0, -0.9) per 1-log increase in elastase. Although correlated with FEV(1), bacterial densities were unable to explain clinically meaningful differences in FEV(1) within and across patients.

CONCLUSIONS

These data support the role of sputum biomarkers as correlates of disease severity in a diverse CF population.

Advances in cystic fibrosis therapies

PURPOSE OF REVIEW

Over the past four decades, outcomes for patients with cystic fibrosis have improved dramatically. Major contributors to this improvement are a better understanding of disease pathogenesis and the systematic conduct of clinical trials evaluating new therapies designed to address these defects. This review describes recent developments in cystic fibrosis pulmonary therapies intended to treat various facets of the disease, including several treatments currently in development.

RECENT FINDINGS

The mainstays of therapy for cystic fibrosis, such as nutritional support and mechanical mucus clearance, are now supplemented with aggressive antibiotic regimens intended to suppress or eradicate bacterial colonization, anti-inflammatory agents, and new approaches that improve mucociliary clearance. Therapies in development address the underlying ion transport defect found in cystic fibrosis airways and also include small-molecule agents that restore function to the mutant cystic fibrosis transmembrane conductance regulator.

SUMMARY

Recent advances in therapies for cystic fibrosis offer the promise of improved outcomes and longer lives for patients with cystic fibrosis.

Neonatal screening for cystic fibrosis does not affect time to first infection with Pseudomonas aeruginosa

OBJECTIVE

Newborn screening for cystic fibrosis was introduced in the Piedmont region of Italy in the year 2000. Our aim with this study was to estimate the effect of newborn screening on the risk of Pseudomonas aeruginosa infection at the regional cystic fibrosis pediatric reference center.

METHODS

The time to first infection with P aeruginosa within the historical cohort of cystic fibrosis children diagnosed between January 1, 1997, and June 30, 2004, was investigated, comparing survival functions and the adjusted hazard ratio of children diagnosed before and after newborn screening introduction. The role of pancreatic insufficiency was also concurrently investigated.

RESULTS

Overall, 71 children diagnosed with cystic fibrosis were identified, 27 cases were clinically diagnosed before newborn screening introduction, and 5 of them presented with meconium ileus, whereas 44 were identified by newborn screening. Among them 35 needed pancreatic enzyme supplementation, whereas 34 children were infected with P aeruginosa. Both the nonparametric and semiparametric survival estimates failed to show any significant increase in the risk of P aeruginosa infection among screened children compared with historical controls. However, the median time from cystic fibrosis diagnosis to P aeruginosa infection among screened children was significantly shorter (183 vs 448 days). Children with impaired pancreatic function were at high risk of P aeruginosa infection.

CONCLUSIONS

The results of the study suggest that health authorities should regard newborn screening for cystic fibrosis as an opportunity to improve care and outcomes among affected children and shift the focus from whether it is appropriate to screen to how to optimize biomedical and psychosocial outcomes of screening.

Attitudes toward physical activity in adolescents with cystic fibrosis: sex differences after training: a pilot study

This study compared the attitudes of 16 adolescents (8 males and 8 females) with cystic fibrosis (CF) toward exercise and physical activity (PA) before and after a 6-week exercise program. Although the boys and girls had similar ages (12-18 years), the boys were fitter and leaner and had higher pulmonary function. Subjects reported both positive exercise attitudes of self and perceived attitudes of parents/friends that remained essentially unchanged after strenuous training. Boys reported higher vigorous activities at baseline than girls, but all subjects increased participation in very hard PAs after training. Girls had small but nonsignificant increases in PA at each (mild-vigorous) level. Results emphasize that adolescents with a mild to moderate lung disease can significantly increase PA in a nursing intervention.

Composition of nasal airway surface liquid in cystic fibrosis and other airway diseases determined by X-ray microanalysis

The ionic composition of the airway surface liquid (ASL) in healthy individuals and in patients with cystic fibrosis (CF) has been debated. Ion transport properties of the upper airway epithelium are similar to those of the lower airways and it is easier to collect nasal ASL from the nose. ASL was collected with ion exchange beads, and the elemental composition of nasal fluid was determined by X-ray microanalysis in healthy subjects, CF patients, CF heterozygotes, patients with rhinitis, and with primary ciliary dyskinesia (PCD). In healthy subjects, the ionic concentrations were approximately isotonic. In CF patients, CF heterozygotes, rhinitis, and PCD patients, [Na] and [Cl] were significantly higher compared when compared with those in controls. [K] was significantly higher in CF and PCD patients compared with that in controls. Severely affected CF patients had higher ionic concentrations in their nasal ASL than in patients with mild or moderate symptoms. Female CF patients had higher levels of Na, Cl, and K than male patients. As higher salt concentrations in the ASL are also found in other patients with airway diseases involving chronic inflammation, it appears likely that inflammation-induced epithelial damage is important in determining the ionic composition of the ASL.

Delayed diagnosis of females with respiratory presentation of cystic fibrosis did not segregate with poorer clinical outcome

OBJECTIVE

Does a delay in diagnosis exist in females with cystic fibrosis (CF) presenting with respiratory symptoms alone. Does it segregate with poorer clinical outcomes?

STUDY DESIGN AND SETTING

A set of 3,851 patients registered with the UK CF Database (diagnosed 1986-2003) were divided into four mutually exclusive categories by mode of presentation: meconium ileus or distal intestinal obstruction syndrome (MI/DIOS); positive family history; newborn screening; and symptoms excluding MI/DIOS. The last symptom category was subdivided to create a group for respiratory symptoms alone.

RESULTS

Females presenting with respiratory symptoms alone were diagnosed 9 months later than males (median age of diagnosis in males 22 months, n = 325; females, 31 months, n = 322; P = .028). No gender differences were observed for anthropometric, lung function, microbiological, supplemental feeding, or time since diagnosis using discriminant analysis applied to all patients (n = 461, Wilks' lambda = .97, P = .15) or to patients divided by genotype: DeltaF508/DeltaF508 (n = 168, Wilks' lambda = .97, P = .69), class I-III genotype (n = 251, Wilks' lambda = .96, P = .41), or class IV-V genotype (n = 73, Wilks' lambda = .90, P = .50) presenting with respiratory symptoms alone.

CONCLUSIONS

A relative delay in diagnosis exists in female patients presenting with respiratory symptoms alone compared with males. This does not, however, segregate with a significantly poorer clinical phenotype in the UK.

Gender differences in health-related quality of life of adolescents with cystic fibrosis

Background

Female patients with cystic fibrosis (CF) have consistently poorer survival rates than males across all ages. To determine if gender differences exist in health-related quality of life (HRQOL) of adolescent patients with CF, we performed a cross-section analysis of CF patients recruited from 2 medical centers in 2 cities during 1997–2001.

Methods

We used the 87-item child self-report form of the Child Health Questionnaire to measure 12 health domains. Data was also collected on age and forced expiratory volume in 1 second (FEV₁). We analyzed data from 98 subjects and performed univariate analyses and linear regression or ordinal logistic regression for multivariable analyses.

Results

The mean (SD) age was 14.6 (2.5) years; 50 (51.0%) were female; and mean FEV₁ was 71.6% (25.6%) of predicted. There were no statistically significant gender differences in age or FEV₁. In univariate analyses, females reported significantly poorer HRQOL in 5 of the 12 domains. In multivariable analyses controlling for FEV₁ and age, we found that female gender was associated with significantly lower global health (p < 0.05), mental health (p < 0.01), and general health perceptions (p < 0.05) scores.

Conclusion

Further research will need to focus on the causes of these differences in HRQOL and on potential interventions to improve HRQOL of adolescent patients with CF.

Risk factors for death of patients with cystic fibrosis awaiting lung transplantation

RATIONALE

The optimal timing for listing of cystic fibrosis patients for lung transplantation is controversial.

OBJECTIVES

We conducted a retrospective cohort study of 343 patients listed for lung transplantation at four academic medical centers to identify risk factors for death while awaiting transplantation.

METHODS

Data on possible risk factors were abstracted from medical records.

MEASUREMENTS

Time to death, patient demographic characteristics, and risk factors for death while awaiting transplantation were assessed. Univariate and multivariate survival analyses were performed using Cox regression.

RESULTS

By univariate analyses, FEV1 < or = 30% predicted (HR, 3.8; 95% CI, 2.0-7.5), Pa(CO2) > or = 50 mm Hg (HR, 1.85; 95% CI, 1.1-3.0), and shorter height (HR, 1.8; 95% CI, 1.1-3.0) were associated with a higher risk of death. Referral from an accredited cystic fibrosis center was associated with a lower risk (HR, 0.53; 95% CI, 0.30-0.92). The final multivariate model included referral from an accredited cystic fibrosis center (HR, 0.5; 95% CI, 0.3-1.0) and listing year after 1996 (HR, 0.4; 95% CI, 0.2-0.7); both were associated with a lower risk of death. FEV1 < or = 30% predicted (HR, 6.8; 95% CI, 2.4-19.3), Pa(CO2) > or = 50 mm Hg (HR, 6.9; 95% CI, 1.5-32.1), and use of a nutritional intervention (HR, 2.3; 95% CI, 1.3-4.1) were associated with increased risk. Patients with FEV1 > 30% predicted had a higher risk of death only when their Pa(CO2) was > or = 50 mm Hg (HR, 7.0; 95% CI, 1.5-32), while the increased risk of death with FEV1 < or = 30% was not further influenced by the presence of hypercapnia.

CONCLUSIONS

We identified risk factors for waiting list mortality that could impact on transplant listing and allocation guidelines.

Modifier genetics: cystic fibrosis

Cystic fibrosis (CF) is the most common lethal autosomal recessive disorder in the Caucasian population, affecting about 30,000 individuals in the United States. The gene responsible for CF, the CF transmembrane conductance regulator (CFTR), was identified 15 years ago. Substantial variation in the many aspects of the CF phenotype among individuals with the same CFTR genotype demonstrates that factors independent of CFTR exert considerable influence on outcome in CF. To date, the majority of published studies investigating the cause of disease variability in CF report associations between candidate genes and some aspect of the CF phenotype. However, a definitive modifier gene for CF remains to be identified. Despite the challenges posed by searches for modifier effects, studies of affected twins and siblings indicate that genetic factors play a substantial role in intestinal manifestations. Identifying the factors contributing to variation in pulmonary disease, the primary cause of mortality, remains a challenge for CF research.

Growth and lung function in Asian patients with cystic fibrosis

BACKGROUND

The incidence of cystic fibrosis (CF) in Asians is rare. How these patients fare in terms of morbidity and mortality in the UK compared to their non-Asian peers is not well documented.

AIMS

To retrospectively study annual reviews of 31 Asian CF patients from three London paediatric CF centres.

METHODS

Disease severity was assessed by lung function, age at first infection with Pseudomonas aeruginosa, and body mass index (BMI). The Asian children were compared with 143 matched non-Asian patients with CF. Matching criteria used were same sex and treatment centre as the Asian index patient. In addition, the controls were matched so that their date of birth, date of diagnosis, and date at annual review were within 12 months of the index patient.

RESULTS

There was no significant difference in age at diagnosis or age at annual review between the Asian and non-Asian children. Mean Z-scores for FEV1 and FVC were significantly lower for the Asian girls. There was no significant difference in Z-scores for BMI between the Asian children and their controls. Age at first isolation of Pseudomonas aeruginosa in Asian girls was significantly later than for their controls (8.3 years compared to 5.6 years for non-Asian girls).

CONCLUSIONS

While the Asian boys' lung function seems comparable with that of their non-Asian peers, the Asian girls emerge as a potentially vulnerable group and more work is required to discover why this is the case.

Cystic fibrosis since 1938

Cystic fibrosis (CF) was distinguished from celiac disease in 1938. Then, it was a pathologic diagnosis, life expectancy was approximately 6 months, and the autosomal recessive disease was believed to arise from abnormal mucus plugging exocrine ducts. Death often occurred from lung infection. Discovery of the sweat electrolyte defect in 1953 and standardization of the sweat test in 1959 allowed identification of milder cases, and CF was no longer considered only a disorder of mucus. In 1955, establishment of centers with programs of aggressive, comprehensive care initiated striking improvement in longevity. The pillars of care established then (attention to nutrition, airway clearance, treatment of lung infection) remain today. In 1983, chloride transport was identified as the basic physiologic CF defect, accompanied by increased sodium reabsorption. In 1980, we learned that inflammation contributes independently to lung disease and constitutes an independent therapeutic target. In 1989, the discovery of the CF gene demonstrated the basic defect to be in a cAMP-regulated chloride channel. This afforded new diagnostic tests, opportunities for research, and prospects for using the gene as therapy. Since then, substantial advances in basic and clinical research catalyzed therapeutic improvements: median survival age now exceeds 30 years. The Cystic Fibrosis Foundation center network provides not only opportunity to conduct clinical trials but also means to disseminate new therapies. In the future, treatments directed at the basic defect can be expected, with concomitant improvements in morbidity and mortality.

Gender-sensitive association of CFTR gene mutations and 5T allele emerging from a large survey on infertility

Human infertility in relation to mutations affecting the cystic fibrosis transmembrane regulator (CFTR) gene has been investigated by different authors. The role of additional variants, such as the possible forms of the thymidine allele (5T, 7T and 9T) of the acceptor splice site of intron 8, has in some instances been considered. However, a large-scale analysis of the CFTR gene and number of thymidine residues, alone and in combination, in the two sexes had not yet been addressed. This was the aim of this study. Two groups were compared, a control group of 20,532 subjects being screened for perspective reproduction, and the patient group represented by 1854 idiopathically infertile cases. Analyses involved PCR-based CFTR mutations assessment, reverse dot-blot IVS8-T polymorphism analyses, denaturing gradient gel electrophoresis (DGGE) and DNA sequencing. The expected 5T increase in infertile men was predominantly owing to the 5/9 genotypic class. The intrinsic rate of 5T fluctuated only slightly among groups, but some gender-related differences arose when comparing their association. Infertile men showed a significantly enriched 5T + CFTR mutation co-presence, distributed in the 5/9 and 5/7 classes. In contrast, females, from both the control and the infertile groups, showed a trend towards a pronounced reduction of such association. The statistical significance of the difference between expected and observed double occurrence of 5T + CFTR traits in women suggests, in line with other reports in the literature, a possible survival-hampering effect. Moreover, regardless of the 5T status, CFTR mutations appear not to be involved in female infertility. These results underline the importance of (i) assessing large sample populations and (ii) considering separately the two genders, whose genotypically opposite correlations with these phenomena may otherwise tend to mask each other.