Newborn screening for cystic fibrosis.

BACKGROUND: This review was performed to test the hypothesis that presymptomatic diagnosis, for example by newborn screening, and early treatment may prevent or reduce irreversible organ damage and thereby improve outcome and quality of life in patients with cystic fibrosis. OBJECTIVES: To determine whether there is evidence that early diagnosis of cystic fibrosis by means of neonatal screening, followed by current treatment, improves survival and long term morbidity, without unacceptable adverse effects. SEARCH STRATEGY: We searched the Cochrane Cystic Fibrosis and Genetic Disorders Trials Register. Additional studies were identified by one of the reviewers from handsearching conference proceedings not included in the Cochrane Register. Pharmaceutical companies manufacturing screening tests for cystic fibrosis were also contacted to identify any trials of neonatal screening for cystic fibrosis. Date of the most recent search of the Group's specialised register: January 2001. SELECTION CRITERIA: All randomised or pseudorandomised controlled trials, published and unpublished, comparing screening followed by early treatment to clinical diagnosis and later treatment in patients with cystic fibrosis. DATA COLLECTION AND ANALYSIS: Four reviewers independently assessed trial eligibility and methodological quality and two of these reviewers independently extracted data. MAIN RESULTS: Two trials involving a total of 1,124,483 neonates met inclusion criteria. A total of 210 patients with cystic fibrosis aged from zero to 11 years with a maximum follow-up of eleven years are included. Concealment of allocation was unclear in both studies. Sequence generation was adequate in one study and unclear in the other. Method to ascertain cases was similar in one study and not similar in the other. An intention-to-screen-analysis was possible in one study, but could not be made due to lack of data and was not performed in the other. Differences in study design, variation in outcomes reported and their summary measures precluded calculation of pooled screening estimates. Only data from one study could be analysed in this review. This study reported a reduced risk of weight and height below the fifth percentile among screened patients (odds ratio control compared with screened group for: weight 6.16, 95% CI 2.44, 15.57 and height 5.03, 95% CI 1.63, 15.63). Adverse effects among parents in the screened and control populations were examined, but it is difficult to assess how meaningful these results are as the timing of the administration of the questionnaire to each group was not clear. Estimation of direct medical costs of screening suggested it was cheaper to diagnose cystic fibrosis by screening rather than other methods. The costing methods used however were not fully described and costs have not been related to effect. REVIEWER'S CONCLUSIONS: There are few randomised controlled trials assessing the effectiveness of neonatal screening in cystic fibrosis. From the data available at this time, there is little evidence suggesting benefit from screening for cystic fibrosis in the neonatal period, although there is similarly little evidence of harm. This systematic review has identified the need for individual patient data from both included studies. Although we have not been able to perform a meta-analysis, this review provides a summary of all the information currently available from randomised controlled trials on the effectiveness of neonatal screening for cystic fibrosis.

The current management of cystic fibrosis.

Cystic fibrosis (CF) is one of the commonest lethal inherited conditions among Caucasians. It affects multiple organ systems and exhibits a range of clinical problems of varying severity. Life expectancy has improved in recent years as treatment regimes have become more intensive, but current treatments are expensive, often time consuming and may affect quality of life. This review summarises the treatments currently used in the management of patients with CF, and the evidence for these.

Newborn screening for cystic fibrosis.

BACKGROUND: This review was performed to test the hypothesis that presymptomatic diagnosis, for example by newborn screening, and early treatment may prevent or reduce irreversible organ damage and thereby improve outcome and quality of life in patients with cystic fibrosis. OBJECTIVES: To determine whether there is evidence that early diagnosis of cystic fibrosis by means of neonatal screening, followed by current treatment, improves survival and long term morbidity, without unacceptable adverse effects. SEARCH STRATEGY: We searched the Cochrane Cystic Fibrosis and Genetic Disorders Trials Register. Additional studies were identified by one of the reviewers from handsearching conference proceedings not included in the Cochrane Register. Pharmaceutical companies manufacturing screening tests for cystic fibrosis were also contacted to identify any trials of neonatal screening for cystic fibrosis. Date of the most recent search of the Group's specialised register: November 1999. SELECTION CRITERIA: All randomised or pseudorandomised controlled trials, published and unpublished, comparing screening followed by early treatment to clinical diagnosis and later treatment in patients with cystic fibrosis. DATA COLLECTION AND ANALYSIS: Four reviewers independently assessed trial eligibility and methodological quality and two of these reviewers independently extracted data. MAIN RESULTS: Two trials involving a total of 1,124,483 neonates met inclusion criteria. A total of 210 patients with cystic fibrosis aged from zero to 11 years with a maximum follow-up of eleven years are included. Concealment of allocation was unclear in both studies. Sequence generation was adequate in one study and unclear in the other. Method to ascertain cases was similar in one study and not similar in the other. An intention-to-screen-analysis was possible in one study, but could not be made due to lack of data and was not performed in the other. Differences in study design, variation in outcomes reported and their summary measures precluded calculation of pooled screening estimates. Only data from one study could be analysed in this review. This study reported a reduced risk of weight and height below the fifth percentile among screened patients (odds ratio control compared with screened group for: weight 6.16, 95% Confidence Interval (CI) 2.44, 15.57 and height 5.03, 95% CI 1. 63, 15.63). Adverse effects among parents in the screened and control populations were examined, but it is difficult to assess how meaningful these results are as the timing of the administration of the questionnaire to each group was not clear. Estimation of direct medical costs of screening suggested it was cheaper to diagnose cystic fibrosis by screening rather than other methods. The costing methods used however were not fully described and costs have not been related to effect. REVIEWER'S CONCLUSIONS: There are few randomised controlled trials assessing the effectiveness of neonatal screening in cystic fibrosis. From the data available at this time, there is little evidence suggesting benefit from screening for cystic fibrosis in the neonatal period, although there is similarly little evidence of harm. This systematic review has identified the need for individual patient data from both included studies. Although we have not been able to perform a meta-analysis, this review provides a summary of all the information currently available from randomised controlled trials on the effectiveness of neonatal screening for cystic fibrosis.

Neonatal screening for sickle cell disease.

BACKGROUND: Sickle cell disease is an inherited disorder that occurs throughout the world with its highest incidence in areas of Africa where malaria is endemic. It affects up to one in 60 infants born in some areas of Africa. There are a number of potentially serious complications associated with the condition, and it is suggested that early treatment (before symptoms develop) can improve both morbidity and mortality. Screening for the condition in the neonatal period would enable early diagnosis and therefore early treatment. OBJECTIVES: To assess whether there is evidence that neonatal screening for sickle cell disease rather than symptomatic diagnosis reduces adverse short and long term outcomes for those in whom the disease is detected, without adverse outcomes in the population screened. SEARCH STRATEGY: We searched the Controlled Trials Register of the Cochrane Cystic Fibrosis and Genetic Disorders Group (See Group search strategy). Contact was made with experts in the field for any work as yet unpublished and reference lists of published studies were also searched. Date of the most recent search of the Group's specialised register: November 1999. SELECTION CRITERIA: Any randomised or pseudorandomised trial, published or unpublished comparing diagnosis by screening to clinical diagnosis would have been considered eligible for inclusion. DATA COLLECTION AND ANALYSIS: No trials of neonatal screening for sickle cell disease were found. MAIN RESULTS: No trials of neonatal screening for sickle cell disease were found. REVIEWER'S CONCLUSIONS: There is a lack of evidence from trials of neonatal screening for sickle cell disease. There is evidence of benefit from early treatment which is made possible by screening and there are a number of reviews and economic analyses of non-trial literature suggesting that screening is appropriate. Health care providers must therefore assess whether the information provided by these documents is relevant to their practice and situation when making decisions regarding neonatal screening for sickle cell disease. Systematic reviews of early treatments/interventions, including penicillin prophylaxis, pneumococcal vaccine and parental education should be considered.

The characterisation of thrombus development in an improved model of arterio-venous shunt thrombosis in the rat and the effects of recombinant desulphatohirudin (CGP 39393), heparin, and iloprost.

An existing arterio-venous shunt thrombosis model in the rat has been modified to increase its usefulness for the testing of anti-thrombotic agents and characterised using morphological and radiometric techniques. The thrombus formed on the cotton thread held in the shunt was found to be composed of platelet aggregates surrounded by red thrombus. After 30 min of blood flow there was a 15-fold increase in the platelet content of the thrombus and a 4-fold increase in the fibrin(ogen) content compared with an equivalent weight of whole blood. Use of the anticoagulants recombinant desulphatohirudin (CGP 39393, 4 mg/kg, s.c.) and unfractionated heparin (800 IU/kg, s.c.) showed that approx. 90% inhibition of thrombus weight and approx. 80% inhibition of fibrin(ogen) content could be achieved without significant effect on the platelet content. Conversely, using the platelet inhibitor Iloprost (1 microgram kg-1 min-1), a reduction in thrombus weight of 50% was associated with 75% inhibition of platelet content and only 20% inhibition of fibrin(ogen). These observations suggest that the growth of this type of thrombus is largely the result of continued fibrin formation rather than continued platelet recruitment and activation.

The effects of recombinant desulphatohirudin on arterial thrombosis in rats.

The role of thrombin in the formation of arterial thrombi is poorly understood. With the new availability of the specific thrombin inhibitor, recombinant desulphatohirudin, in large quantities this is now under investigation. A new model of arterial thrombosis in rats is described where a thrombus is formed on a mechanically injured vessel in vivo. Both platelet and fibrin deposition is inhibited by a recombinant hirudin (CGP 39393) at doses which prolong the activated partial thromboplastin time (APTT) to no more than 3-4 times the control level. In contrast, both unfractionated heparin and Fragmin only inhibit thrombosis when the APTT is excessively prolonged (i.e. to greater than 15 times the control value). It is concluded that CGP 39393 is an effective antithrombotic in arterial thrombosis at lower levels of anticoagulation than either heparin or Fragmin.