Demographics of the UK cystic fibrosis population: implications for neonatal screening

Decreased lung function in female but not male subjects with established cystic fibrosis-related diabetes

OBJECTIVE

Although cystic fibrosis-related diabetes (CFRD) is associated with decreased lung function, sex is not known to influence CFRD. However, compared with male subjects with cystic fibrosis, female subjects with cystic fibrosis have increased morbidity. This study examines the association between female subjects with CFRD and poor lung function relative to male subjects using the percent predicted forced expiratory volume in 1 s (FEV(1)) as a surrogate measure of morbidity.

RESEARCH DESIGN AND METHODS

We compared 323 patients with established CFRD with 489 cystic fibrosis control subjects with normal glucose tolerance (NGT) listed in the U.K. Cystic Fibrosis Database. Patients stratified by sex and chronic Pseudomonas aeruginosa infection were compared using binary logistic regression, and patients with new CFRD diagnoses were compared prospectively for the year 2002.

RESULTS

CFRD in female subjects (but not male subjects) without chronic P. aeruginosa infection had a 20% lower percent predicted FEV(1) compared with control subjects with NGT (95% CI -11.7 to -27.7; P < 0.0001). Genotype, age, treatment center, age at diagnosis of cystic fibrosis, pregnancy, liver function, or dose of pancreatic enzyme replacement therapy did not confound this female disadvantage. Comparison of female subjects with newly diagnosed CFRD free of chronic P. aeruginosa infection with matched control subjects with NGT showed no FEV(1) disadvantage in the 1st year after CFRD diagnosis.

CONCLUSIONS

Only female subjects with CFRD have significantly decreased lung function compared with sex-matched NGT control subjects. The absence of poor lung function in the first 12 months after diagnosis of diabetes suggests that an opportunity may exist to intervene and possibly prevent a decline in lung function, which can be as much as 20% in female subjects with CFRD.

Bacterial activity in cystic fibrosis lung infections

Background

Chronic lung infections are the primary cause of morbidity and mortality in Cystic Fibrosis (CF) patients. Recent molecular biological based studies have identified a surprisingly wide range of hitherto unreported bacterial species in the lungs of CF patients. The aim of this study was to determine whether the species present were active and, as such, worthy of further investigation as potential pathogens.

Methods

Terminal Restriction Fragment Length Polymorphism (T-RFLP) profiles were generated from PCR products amplified from 16S rDNA and Reverse Transcription Terminal Restriction Fragment Length Polymorphism (RT-T-RFLP) profiles, a marker of metabolic activity, were generated from PCR products amplified from 16S rRNA, both extracted from the same CF sputum sample. To test the level of activity of these bacteria, T-RFLP profiles were compared to RT-T-RFLP profiles.

Results

Samples from 17 individuals were studied. Parallel analyses identified a total of 706 individual T-RF and RT-T-RF bands in this sample set. 323 bands were detected by T-RFLP and 383 bands were detected by RT-T-RFLP (statistically significant; P ≤ 0.001). For the group as a whole, 145 bands were detected in a T-RFLP profile alone, suggesting metabolically inactive bacteria. 205 bands were detected in an RT-T-RFLP profile alone and 178 bands were detected in both, suggesting a significant degree of metabolic activity. Although Pseudomonas aeruginosa was present and active in many patients, a low occurrence of other species traditionally considered to be key CF pathogens was detected. T-RFLP profiles obtained for induced sputum samples provided by healthy individuals without CF formed a separate cluster indicating a low level of similarity to those from CF patients.

Conclusion

These results indicate that a high proportion of the bacterial species detected in the sputum from all of the CF patients in the study are active. The widespread activity of bacterial species in these samples emphasizes the potential importance of these previously unrecognized species within the CF lung.

Comparative analysis of Cystic Fibrosis Registry data from the UK with USA, France and Australasia

BACKGROUND

Using the UK Cystic Fibrosis Database, we analysed the health of the UK CF paediatric population (UKPP) in terms of their biographical, clinical and infection status and compared outcomes with the US, French and Australasian CF Registries.

METHODS

UKPP data were collected for 2,673 patients aged less than 18 years in 2001 and used as a reference base for comparison with the most recent equivalent CF Registry reports.

RESULTS

Although differences exist between National CF Registries, all record similar demographic factors and key outcomes. Where plausible comparisons can be made, we report that the UKPP had the oldest median age (15.0 years), the Australasian population had the lowest median age at diagnosis (1.8 months). Approximately, double the expected number of UKPP patients (23% and 19%, respectively) fall below the 10th centile for height and weight with similar outcomes in Australasia. UKPP and French populations had similar proportions with FEV1 >80% predicted (53% and 54%, respectively).

CONCLUSION

Each Registry's data systems have developed independently providing a first step towards international comparisons. Standardisation of data collection criteria and definition for national CF Registries is required and we propose a standardised minimum data set, which would facilitate data integration as part of a global Registry for CF.

Update on newborn screening for cystic fibrosis

PURPOSE OF REVIEW

Cystic fibrosis (CF) is the most common lethal genetic disorder in the United States to be identified in childhood. In November 2003 the US Cystic Fibrosis Foundation and the Centers for Disease Control and Prevention convened an expert panel to review the indications for CF newborn screening. In this review we discuss the information during the year leading up to this meeting as well as publications since the meeting.

RECENT FINDINGS

During the past several years an increasing number of CF patients have been diagnosed with newborn screening. These patients have demonstrated several benefits to screening while also uncovering new challenges. Health benefits have included improved nutrition persisting for many years and the avoidance of nutritional complications. Early identification has also meant that these often clinically healthy infants are being followed in CF centers for care. This has added to the need for avoiding infection risks to which these patients might not have otherwise been exposed. Psychosocial benefits include the avoidance of stress due to delayed diagnosis as well as assistance with family planning. Psychosocial challenges include carrier identification and detection of patients with mild disease or without a clear diagnosis.

SUMMARY

Although no study has definitively shown reduced lung disease or prolonged survival in CF patients detected by newborn screening, the general consensus is that improved nutrition and cognitive potential, in addition to the reduced costs for hospitalization and intensive therapies, support the benefits of screening.

Fertility and pregnancy outcomes in men and women with cystic fibrosis in the United Kingdom

BACKGROUND

The survival of patients with cystic fibrosis (CF) now occurs into the fourth decade of life. Our aim was to evaluate the fertility and pregnancy outcomes of men and women with cystic fibrosis within a large British cohort.

METHODS

A population based cohort study of 4659 males and females registered with the UK Cystic Fibrosis Database in 2001.

RESULTS

Poor respiratory health (forced expiratory volume in 1 s FEV1 <50%) and CF-related diabetes increased significantly post-puberty compared with childhood. Few individuals with CF sought fertility treatment (1% men, 0.5% women) or achieved pregnancies (1.3% of partners of men, 5.7% women). However, the majority of pregnancies had a good outcome (67% live term birth among male partners, 74% among women). Women who achieved a pregnancy were less likely to suffer from poor respiratory health (FEV1 <50%), age adjusted Odds Ratio 0.6 (95% CI 0.3-0.9), less likely to be homozygous for the DF508 genotype OR 0.5 (95% CI 0.3-0.9) and had a significantly earlier median age at diagnosis (0 years vs 2 years, P=0.001).

CONCLUSIONS

Increasing numbers of males and females with cystic fibrosis are reaching reproductive age but currently very few have a child. Optimal adult health should improve the reproductive prognosis for both men and women.

Bronchiectasis: sex and gender considerations

Bronchiectasis in women may act more virulently. Identified gender and sex differences range from increased exposure risks to altered inflammatory responses. Common among the most well-documented examples is a differential immune response. There is sufficient evidence to suggest that chronic airway infection, most notably non-CF bronchiectasis, is a more common and more virulent disease in women. This is particularly evident in CF-and non-HIV-related environmental mycobacterial respiratory tract infections. Whether this represents an inflammatory-immune process, or environmental, anatomic, or other genetic difference remains to be detailed fully.

Early intervention and prevention of lung disease in cystic fibrosis: a European consensus

In patients with cystic fibrosis (CF), early intervention and prevention of lung disease is of paramount importance. Principles to achieve this aim include early diagnosis of CF, regular monitoring of the clinical status, various hygienic measures to prevent infection and cross-infection, early use of antibiotic courses in patients with recurrent or continuous bacterial colonisation and appropriate use of chest physiotherapy.