Effect of immigration on multiple sclerosis sex ratio in Canada: the Canadian Collaborative Study.

BACKGROUND: The ratio of female to male (F:M) multiple sclerosis (MS) cases varies geographically, generally being greater in areas of high prevalence. In many regions, including Canada, rising MS incidence in women has been implied by the marked increase in F:M ratio. METHODS: We examined the F:M ratio over time in MS patients in the Canadian Collaborative Study born outside Canada, with onset postmigration (n = 2531). We compared the trends to native-born Canadians, by region of origin and age at migration. RESULTS: Regression analysis showed that year of birth (YOB) was a significant predictor of sex ratio in immigrants (chi(2) = 21.4, p<0.001 correlation r = 0.61). The rate of change in sex ratio was increasing in all migrant subgroups (by a factor of 1.16 per 10-year period, p<0.001), with the steepest increase observed in those from Southern Europe (1.27/10 years, p<0.001). The overall immigrant F:M ratio was 2.17, but varied by country of origin. It was significantly lower in migrants from Southern Europe compared with Northern Europe or USA (1.89 vs 2.14 and 2.86, p = 0.023 and p = 0.0003, respectively). Increasing age at immigration was associated with decreasing sex ratio (p = 0.041). The sex ratio of individuals migrating <21 was significantly higher than those migrating > or =21 (2.79 vs 1.96, p = 0.004). CONCLUSIONS: MS sex ratio in immigrants to Canada is increasing but variable by region of origin and influenced by age at migration. The findings highlight the importance of environmental effect(s) in MS risk, which are likely gender-specific.

Repeat instability in the 27-39 CAG range of the HD gene in the Venezuelan kindreds: Counseling implications.

The instability of the CAG repeat size of the HD gene when transmitted intergenerationally has critical implications for genetic counseling practices. In particular, CAG repeats between 27 and 35 have been the subject of debate based on small samples. To address this issue, we analyzed allelic instability in the Venezuelan HD kindreds, the largest and most informative families ascertained for HD. We identified 647 transmissions. Our results indicate that repeats in the 27-35 CAG range are highly stable. Out of 69 transmitted alleles in this range, none expand into any penetrant ranges. Contrastingly, 14% of alleles transmitted from the incompletely penetrant range (36-39 CAGs) expand into the completely penetrant range, characterized by alleles with 40 or more CAG repeats. At least 12 of the 534 transmissions from the completely penetrant range contract into the incompletely penetrant range of 36-39 CAG repeats. In these kindreds, none of the individuals with 27-39 CAGs were symptomatic, even though they ranged in age from 11 to 82 years. We expect these findings to be helpful in updating genetic counseling practices.

Replication of twelve association studies for Huntington's disease residual age of onset in large Venezuelan kindreds.

BACKGROUND: The major determinant of age of onset in Huntington's disease is the length of the causative triplet CAG repeat. Significant variance remains, however, in residual age of onset even after repeat length is factored out. Many genetic polymorphisms have previously shown evidence of association with age of onset of Huntington's disease in several different populations. OBJECTIVE: To replicate these genetic association tests in 443 affected people from a large set of kindreds from Venezuela. METHODS: Previously tested polymorphisms were analysed in the HD gene itself (HD), the GluR6 kainate glutamate receptor (GRIK2), apolipoprotein E (APOE), the transcriptional coactivator CA150 (TCERG1), the ubiquitin carboxy-terminal hydrolase L1 (UCHL1), p53 (TP53), caspase-activated DNase (DFFB), and the NR2A and NR2B glutamate receptor subunits (GRIN2A, GRIN2B). RESULTS: The GRIN2A single-nucleotide polymorphism explains a small but considerable amount of additional variance in residual age of onset in our sample. The TCERG1 microsatellite shows a trend towards association but does not reach statistical significance, perhaps because of the uninformative nature of the polymorphism caused by extreme allele frequencies. We did not replicate the genetic association of any of the other genes. CONCLUSIONS: GRIN2A and TCERG1 may show true association with residual age of onset for Huntington's disease. The most surprising negative result is for the GRIK2 (TAA)(n) polymorphism, which has previously shown association with age of onset in four independent populations with Huntington's disease. The lack of association in the Venezuelan kindreds may be due to the extremely low frequency of the key (TAA)(16) allele in this population.

Inhaler devices for the treatment of asthma and chronic obstructive airways disease (COPD).

The research evidence on the effectiveness of inhaler devices for the treatment of asthma and chronic obstructive pulmonary disease published in a recent issue of Effective Health Care is reviewed.

Pressurised metered-dose inhalers versus all other hand-held inhalers devices to deliver bronchodilators for chronic obstructive pulmonary disease.

BACKGROUND: Bronchodilator therapy for COPD may be delivered by a number of different inhaler devices. OBJECTIVES: To determine the efficacy of pressurised metered dose inhalers (pMDI) compared to any other handheld inhaler device for the delivery of bronchodilators in non-acute COPD. SEARCH STRATEGY: The Cochrane Collaboration, Asthma and Wheeze Randomised Controlled Clinical Trials register was searched for studies. The UK pharmaceutical companies who manufacture inhaled COPD medication were also contacted. SELECTION CRITERIA: Two reviewers independently reviewed the results of computerised search and any potentially relevant articles were obtained in full. DATA COLLECTION AND ANALYSIS: One reviewer extracted details of each trial and a second reviewer checked all extracted data. Dichotomous outcomes such as exacerbation rate were assessed using relative risk, with 95% confidence interval (CI). MAIN RESULTS: Fourteen studies appeared potentially relevant but only three studies (61 patients) met the entry criteria. Two studies compared a dry powder device (Turbuhaler or Rotahaler) with a pMDI for beta2-agonist delivery, and one (36 patients cross-over design) the Respimat (soft mist device for ipratropium) vs a pMDI. For the Turbuhaler and Rotahaler, none of the reported outcome measures were significantly different. The Rotahaler study used a high and low dose of medication with or without large volume spacer. The study using the Respimat showed significant increases in FEV1 when compared to a pMDI (difference in change from base line 70 ml, 95% CI 10, 130 ml). The effect on change in FVC was of similar size. There were no differences between these two devices for any other reported outcomes. Although none of the included studies required prior patient ability to use any of the inhalers (and no study mentioned device training), it was assumed that all patients randomised into the study would have undergone training in use of the study inhalers and were capable of using those devices. REVIEWER'S CONCLUSIONS: In patients with stable COPD, pMDI produced similar outcomes to a dry powder device for delivering beta2-agonists, but the very small number of studies and included patients does not permit firm conclusions to be drawn. The soft mist device for ipratropium was more effective than a pMDI, but the data come from one small study. There need to be further well designed randomised controlled trials to define the role of inhaler devices using bronchodilators in stable COPD.

Pressurised metered dose inhalers versus all other hand-held inhaler devices to deliver beta-2 agonist bronchodilators for non-acute asthma.

BACKGROUND: A number of different inhaler devices are available to deliver beta2-agonist bronchodilators in asthma. These include hydrofluoroalkane (HFA) or chlorofluorocarbon (CFC)-free propelled pressurised metered dose inhalers (pMDIs) and dry powder devices. OBJECTIVES: To determine the clinical effectiveness of pMDI compared with any other available handheld inhaler device for the delivery of short-acting beta-2 agonist bronchodilators in non-acute asthma in children and adults. SEARCH STRATEGY: The Cochrane Collaboration Clinical Trials register was searched for studies as well as separate additional searches carried out on MEDLINE, EMBASE, CINAHL and also on the Current Contents Index as well as the Science Citation Index. In addition, 17 individual online respiratory journals and 12 electronically available clinical trial databases were also searched. The UK pharmaceutical companies who manufacture inhaled asthma medication were contacted in order to obtain details of any published or unpublished studies. SELECTION CRITERIA: - The full texts of all potentially relevant articles were reviewed independently by two reviewers. DATA COLLECTION AND ANALYSIS: Fixed and random effect models were used. Dichotomous outcomes were assessed using Odds Ratios or Relative Risks (RR) with 95% Confidence Intervals (95%CI). MAIN RESULTS: Eighty-four randomised controlled trials were included in this review, but few could be combined to assess a specific outcome for a given delivery device comparison. Only two studies required demonstration of adequate pMDI technique as an entry requirement. There were no difference between a standard CFC containing pMDI and any other device for most outcomes. Regular use of HFA-pMDI containing salbutamol reduced the requirement for short courses of oral corticosteroids (3 trials, 519 patients: RR 0.67; 95% CI 0.49, 0.91); however the total number of exacerbations were unchanged (3 trials, 1271 patients: RR 1.0; 95% CI 0.75, 1.33). REVIEWER'S CONCLUSIONS: In patients with stable asthma, short-acting beta-2 bronchodilators in standard CFC-pMDI's are as effective as any other devices. The effect of HFA-pMDI on requirement for oral corticosteroid courses to treat acute exacerbations should be confirmed. Effectiveness studies that use an intention-to-treat analysis are required.

Comparison of the effectiveness of inhaler devices in asthma and chronic obstructive airways disease: a systematic review of the literature.

BACKGROUND: Asthma and chronic obstructive pulmonary disease (COPD) are common diseases of the airways and lungs that have a major impact on the health of the population. The mainstay of treatment is by inhalation of medication to the site of the disease process. This can be achieved by a number of different device types, which have wide variations in costs to the health service. A number of different inhalation devices are available. The pressurised metered-dose inhaler (pMDI) is the most commonly used and cheapest device, which may also be used in conjunction with a spacer device. Newer chlorofluorocarbons (CFC)-free inhaler devices using hydrofluoroalkanes (HFAs) have also been developed. The drug is dissolved or suspended in the propellant under pressure. When activated, a valve system releases a metered volume of drug and propellant. Other devices include breath-actuated pMDIs (BA-pMDI), such as Autohaler and Easi-Breathe. They incorporate a mechanism activated during inhalation that triggers the metered-dose inhaler. Dry powder inhalers (DPI), such as Turbohaler, Diskhaler, Accuhaler and Rotahaler, are activated by inspiration by the patient. The powdered drug is dispersed into particles by the inspiration. With nebulisers oxygen, compressed air, or ultrasonic power is used to break up solutions or suspensions of medication into droplets for inhalation. The aerosol is administered by mask or by a mouthpiece. There has been no previous systematic review of the evidence of clinical effectiveness and cost-effectiveness of these different inhaler devices. OBJECTIVES: To review systematically the clinical effectiveness and cost-effectiveness of inhaler devices in asthma and COPD. METHODS: The different aspects of inhaler devices were separated into the most clinically relevant comparisons. Methods involved systematic searching of electronic databases and bibliographies for randomised controlled trials (RCTs) and systematic reviews. Pharmaceutical companies and experts in the field were contacted for further information. Trials that met the inclusion criteria were appraised and data extraction was under-taken by one reviewer and checked by a second reviewer, with any discrepancies being resolved through agreement. RESULTS--IN VITRO CHARACTERISTICS VERSUS IN VIVO TESTING AND CLINICAL RESPONSE: There is evidence that when comparative testing is performed on inhaler devices using the same methods, there is some correlation between particle size measurements and clinical response. However, the measurements are dependent upon the methods used, and a single measure of a device in isolation is of limited value. Also, there is little data on comparing devices of different types. There is currently insufficient data to verify the ability of in vitro assessments to predict inhaler performance in vivo. RESULTS--EFFECTIVENESS OF METERED-DOSE INHALERS FOR THE DELIVERY OF CORTICOSTEROIDS IN ASTHMA: The review of three trials in children and 21 trials in adults demonstrated no evidence to suggest clinical benefits of any other inhaler device over a pMDI in corticosteroid delivery. RESULTS--EFFECTIVENESS OF METERED-DOSE INHALERS FOR THE DELIVERY OF BETA-AGONISTS IN STABLE ASTHMA: In children, 11 studies were reviewed, of which seven compared the Turbohaler with the pMDI. One study found a significant treatment difference in peak expiratory flow rate, although there were differences in the patients' baseline characteristics. In adults, a review of 70 studies found no demonstrable difference in the clinical bronchodilator effect of short-acting b2-agonists delivered by the standard pMDI compared with that produced by any other DPI, HFA-pMDI or the Autohaler device. The finding that HFA-pMDIs may reduce treatment failure and oral steroid requirement in beta-agonist delivery needs further confirmatory research in adequately randomised clinical trials. RESULTS--EFFECTIVENESS OF NEBULISERS VERSUS METERED-DOSE INHALERS FOR THE DELIVERY OF BRONCHODILATORS IN STABLE ASTHMA: In children, three included trials compared different devices with a nebuliser and demonstrated no evidence of clinical superiority of nebulisers over inhaler devices in bronchodilator delivery. A total of 23 studies in adults found no equivalence for the main pulmonary outcomes and no evidence of difference in other outcomes. RESULTS--EFFECTIVENESS OF METERED-DOSE INHALERS FOR THE DELIVERY OF BETA-AGONISTS IN COPD: Only two studies were included in this review. No evidence of clinical difference was found in beta-agonist delivery. RESULTS--EFFECTIVENESS OF NEBULISERS VERSUS METERED-DOSE INHALERS FOR THE DELIVERY OF BRONCHODILATORS IN COPD: Evidence from 14 trials demonstrated equivalence for the main outcomes of pulmonary function. For other outcomes there was no evidence of treatment difference in bronchodilator delivery. RESULTS--PATIENTS' ABILITY TO USE METERED-DOSE INHALERS: Differences among studies and the heterogeneity of the results make it difficult to draw conclusions about inhaler technique differences between device types. The review of technique after teaching the correct technique suggests that there is no difference in patients' ability to use DPI or pMDIs. RESULTS--ECONOMIC ANALYSIS: The total number of NHS prescriptions for inhaler therapy for asthma in 1998 was over 31 million, with a net ingredient cost in excess of 392 million GB pounds. This economic assessment uses decision analysis to estimate the relative cost-effectiveness of inhaler devices for the delivery of bronchodilator and corticosteroid inhaled therapy. Overall, there were no differences in patient outcomes among the devices. On the assumption that the devices were clinically equivalent, pMDIs were the most cost-effective devices for asthma treatment. CONCLUSIONS: This systematic review examined the evidence from clinical trials evaluating the clinical effectiveness of different inhaler devices in the delivery of inhaled corticosteroids and beta2-bronchodilators for patients with asthma and COPD. The evidence from the published clinical literature demonstrates no difference in clinical effectiveness between nebulisers and alternative inhaler devices compared to standard pMDI with or without a spacer device. The cost-effectiveness evidence therefore favours pMDIs (or the cheapest inhaler device) as first-line treatment in all patients with stable asthma unless other specific reasons are identified. Patients can use pMDIs as effectively as other inhaler devices as long as the correct inhalation technique is taught. CONCLUSIONS--RECOMMENDATIONS FOR RESEARCH: Further clinical trials are required to demonstrate any differences in the clinical effectiveness and cost-effectiveness of inhaler devices and nebulisers compared with pMDIs. These should be of sufficient statistical power and methodological rigour to demonstrate any clinical benefit. Trials should be undertaken in community settings to ensure the generalisability of results. Outcome measures should be more patient-centred and report adverse effects more completely. Reporting of data from trials should be improved.

Systematic review of clinical effectiveness of pressurised metered dose inhalers versus other hand held inhaler devices for delivering corticosteroids in asthma.

OBJECTIVE: To determine the clinical effectiveness of pressurised metered dose inhalers (with or without spacer) compared with other hand held inhaler devices for the delivery of corticosteroids in stable asthma. DESIGN: Systematic review of randomised controlled trials. DATA SOURCES: Cochrane Airways Group trials database (Medline, Embase, Cochrane controlled clinical trials register, and hand searching of 18 relevant journals), pharmaceutical companies, and bibliographies of included trials. TRIALS: All trials in children or adults with stable asthma that compared a pressurised metered dose inhaler with any other hand held inhaler device delivering the same inhaled corticosteroid. RESULTS: 24 randomised controlled trials were included. Significant differences were found for forced expiratory volume in one second, morning peak expiratory flow rate, and use of drugs for additional relief with dry powder inhalers. However, either these were within clinically equivalent limits or the differences were not apparent once baseline characteristics had been taken into account. No significant differences were found between pressurised metered dose inhalers and any other hand held inhaler device for the following outcomes: lung function, symptoms, bronchial hyper-reactivity, systemic bioavailability, and use of additional relief bronchodilators. CONCLUSIONS: No evidence was found that alternative inhaler devices (dry powder inhalers, breath actuated pressurised metered dose inhalers, or hydrofluoroalkane pressurised metered dose inhalers) are more effective than the pressurised metered dose inhalers for delivery of inhaled corticosteroids. Pressurised metered dose inhalers remain the most cost effective first line delivery devices.

Systematic review of clinical effectiveness of pressurised metered dose inhalers versus other hand held inhaler devices for delivering beta (2 )agonists bronchodilators in asthma.

OBJECTIVES: To determine the clinical effectiveness of pressurised metered dose inhalers compared with other hand held inhaler devices for delivering short acting beta(2) agonists in stable asthma. DESIGN: Systematic review of randomised controlled trials. DATA SOURCES: Cochrane Airways Group specialised trials database (which includes hand searching of 20 relevant journals), Medline, Embase, Cochrane controlled clinical trials register, pharmaceutical companies, and bibliographies of included trials. TRIALS: All trials in children or adults with stable asthma that compared the pressurised metered dose inhaler (with or without a spacer device) against any other hand held inhaler device containing the same beta(2) agonist. RESULTS: 84 randomised controlled trials were included. No differences were found between the pressurised metered dose inhaler and any other hand held inhaler device for lung function, blood pressure, symptoms, bronchial hyperreactivity, systemic bioavailability, inhaled steroid requirement, serum potassium concentration, and use of additional relief bronchodilators. In adults, pulse rate was lower in those using the pressurised metered dose inhaler compared with those using Turbohaler (standardised mean difference 0.44, 95% confidence interval 0.05 to 0.84); patients preferred the pressurised metered dose inhaler to the Rotahaler (relative risk 0.53, 95% confidence interval 0.36 to 0.78); hydrofluoroalkane pressurised metered dose inhalers reduced the requirement for rescue short course oral steroids (relative risk 0.67, 0.49 to 0.91). CONCLUSIONS: No evidence was found to show that alternative inhaler devices are more effective than standard pressurised metered dose inhalers for delivering acting beta(2 )agonist bronchodilators in asthma. Pressurised metered dose inhalers remain the most cost effective delivery devices.

Lansoprazole versus ranitidine for the treatment of reflux oesophagitis. UK Lansoprazole Clinical Research Group.

BACKGROUND: Lansoprazole is a H+.K(+)-ATPase (proton pump) inhibitor with an anti-secretory action and is therefore potentially useful in the treatment of gastro-oesophageal reflux. METHODS: This study was conducted to determine the efficacy and short-term safety of lansoprazole at doses of 30 mg or 60 mg once daily, compared with ranitidine 150 mg twice daily, in the treatment of patients with reflux oesophagitis. This was a double-blind, stratified, randomized, comparative, parallel group study conducted in five centres in the UK. A total of 229 patients (155 men) aged 18-79 years with endoscopically-confirmed oesophagitis were randomized to receive lansoprazole 30 mg p.o. daily, lansoprazole 60 mg p.o. daily, or ranitidine 150 mg p.o. b.d. Efficacy was assessed by endoscopic examination at 4 weeks and 8 weeks, together with symptom relief and antacid usage. RESULTS: Lansoprazole 30 mg and 60 mg were superior at 4 and 8 weeks (P < 0.01) to ranitidine in healing reflux oesophagitis: respective healing rates being 84%, 72% and 39% after 4 weeks and 92%, 91% and 53% after 8 weeks. Relief of heartburn with lansoprazole 30 mg and 60 mg was superior to that achieved with ranitidine at both week 4 (P < 0.01) and week 8 (P < 0.02). Sixty-four patients experienced a total of 85 adverse events, one-third of which were considered drug-related. The incidence and severity were similar in the three groups. CONCLUSION: Lansoprazole 30 mg and 60 mg once daily are more effective than ranitidine 150 mg twice daily in the short-term treatment of reflux oesophagitis.