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

State-of-the-Art Review of The Application and Development of Various Methods of Aerosol Therapy

Aerosol therapy is a rapidly developing field of science. Due to a number of advantages, the administration of drugs to the body with the use of aerosol therapy is becoming more and more popular. Spraying drugs into the patient's lungs has a significant advantage over other methods of administering drugs to the body, including injection and oral methods. In order to conduct proper and effective aerosol therapy, it is necessary to become familiar with the basic principles and applications of aerosol therapy under various conditions. The effectiveness of inhalation depends on many factors, but most of all on: the physicochemical properties of the sprayed system, the design of the medical inhaler and its correct application, the dynamics of inhalation (i.e. the frequency of breathing and the volume of inhaled air). It is worth emphasizing that respiratory system diseases are one of the most frequently occurring and fastest growing diseases in the world. Accordingly, in recent years, a significant increase in the number of new spraying devices and pharmaceutical drugs for spraying has appeared on the market. It should also be remembered that the process of spraying a liquid is a complicated and complex process, and its efficiency is very often characterized by the use of micro- and macro parameters (including average droplet diameters or the spectrum of droplet diameter distribution). In order to determine the effectiveness of the atomization process and in the delivery of drugs to the patient's respiratory tract, the analysis of the size of the generated aerosol droplets is most often performed. Based on the proposed literature review, it has been shown that many papers dealt with the issues related to aerosol therapy, the selection of an appropriate spraying device, the possibility of modifying the spraying devices in order to increase the effectiveness of inhalation, and the possibility of occurrence of certain discrepancies resulting from the use of various measurement methods to determine the characteristics of the generated aerosol. The literature review presented in the paper was prepared in order to better understand the spraying process. Moreover, it can be helpful in choosing the right medical inhaler for a given liquid with specific rheological properties. The experimental data contained in this study are of great cognitive importance and may be of interest to entities involved in pharmaceutical product engineering (in particular in the case of the production of drugs containing liquids with complex rheological properties).

Assessment of Educational Inhaler Technique Interventions Among Community Pharmacists: A Systematic Review

Objective

Community pharmacists are the last point of contact before patients are provided with an inhaled asthma device and are expected to adequately educate and train patients on its use. Evidence has shown that pharmacists lack the knowledge and skills required to appropriately counsel patients on these devices. The aim of this systematic review was to focus on evaluating the effects of educational interventions on community pharmacists knowledge of inhaler technique.

Methods

A literature search was conducted using the databases Pubmed and Embase with no applied time restrictions. The databases were searched from inception to December 2018. Articles were eligible for inclusion if they reported outcomes evaluating the improvement in pharmacists knowledge of inhaler technique after an educational intervention and provided details of the intervention. Pharmacists working in settings other than community pharmacies and inhaler devices used for conditions other than asthma were excluded.

Results

Five studies met the eligibility criteria. Workshops and one-on-one instruction were the main educational strategies used in these studies to augment the pharmacists knowledge of asthma inhaler devices. A checklist was utilized by all studies to evaluate the pharmacists improvement of inhaler technique after an educational intervention. All studies showed an improvement in inhaler technique of pharmacists post-intervention.

Conclusion

Studies identified in this systematic review have shown that an educational intervention produced positive outcomes related to the pharmacists knowledge on the steps involved in using asthma inhaler devices. However, the study findings focused on short-term retention of knowledge of inhaler technique and did not address the application of these results in clinical practice.

A review of standard pharmacological therapy for adult asthma – Steps 1 to 5

The aim of pharmacological therapy for asthma is to improve symptoms and lung function and minimize the risk of asthma attacks. The intensity of treatment is based on the level of asthma control and the potential risk of future deterioration. In the British asthma guidelines, treatments are divided into steps 1 to 5, with each step signifying a need for an increase in therapy in response to symptoms or to prevent exacerbations. Treatments comprise of inhaled or systemic medications. Inhaled therapy includes short-acting and long-acting medication to improve symptoms and inhaled corticosteroids that reduce airway inflammation. Systemic treatments include medications that act on specific biological pathways, such as the leukotriene or immunoglobulin E pathways, or systemic corticosteroids. In choosing a particular therapy, treatment benefits are balanced by the potential risks of medication-related adverse effects. This review will provide a practical guide to the key pharmacological therapies for adult asthma at steps 1 to 5 based on British guidelines and consider future options for new treatments.

The Diskus: a review of its position among dry powder inhaler devices

The use of dry powder inhalers (DPIs) to administer treatments for respiratory diseases has increased significantly in recent years. There is now a wide range of DPIs available that vary considerably in design, required operational techniques, output characteristics and drug delivery across a range of inhalation patterns. Different patient populations may find individual types of DPI easier to use correctly than others and selecting the right DPI for particular patient requirements will improve compliance with therapy. For example, some DPIs offer a greater resistance against inspirational flow rate than others which affects the total emitted dose and also fine particle mass of the aerosol released. An individual patient may therefore receive different amounts of drug when inhaling from different DPIs. Therefore, it is important that the prescriber is fully aware of the characteristics of the different types of DPI, so that he or she can prescribe the device that is most appropriate to an individual patient's needs. This review explores the characteristics of currently available DPIs and evaluates their efficacy and patient acceptability. The differences in output characteristics, ease of use and patient preferences between available devices is shown to affect treatment efficacy and patient compliance with therapy. Changing the DPI prescribed to a patient to a cheaper or generic device may therefore adversely affect disease control and thereby increase the cost of treatment.

Evidence based guidelines--a step too far?

The growth of clinical guidelines has helped to improve the standard of patient care with the archetypal document being the British Thoracic Society's guidelines on asthma management. In recent years however the fashion has evolved to style guidelines according to the tenants of 'evidence based medicine'. We examine the evidence behind this fashion and conclude that there is a grave danger of bias and distortion of the data from this approach.

An evaluation of children's metered-dose inhaler technique for asthma medications

Regardless of the medication delivery system, health care providers need to teach accurate medication administration techniques to their patients, educate them about the particular nuances of the prescribed delivery system (eg, proper storage), and reinforce these issues at each health encounter. A single instruction session is not sufficient to maintain appropriate inhaler techniques for patients who require continued use. Providing written steps for the administration technique is helpful so that the patient can refer to them later when using the medication. The National Heart, Lung, and Blood Institute's "Practical Guide for the Diagnosis and Management of Asthma" recommends that practitioners follow these steps for effective inhaler technique training when first prescribing an inhaler: 1. Teach patients the steps and give written instruction handouts. 2. Demonstrate how to use the inhaler step-by-step. 3. Ask patients to demonstrate how to use the inhaler. Let the patient refer to the handout on the first training. Then use the handout asa checklist to assess the patient's future technique. 4. Provide feedback to patients about what they did right and what they need to improve. Have patients demonstrate their technique again, if necessary. The last two steps should be performed (ie, demonstration and providing feedback on what patients did right and what they need to improve) at every subsequent visit. If the patient makes multiple errors, it is advisable to focus on improving one or two key steps at a time. With improvements in drug delivery come challenges, necessitating that practitioners stay current with new medication administration techniques. Teaching and reinforcing accurate technique at each health care encounter are critical to help ensure medication efficacy for patients with asthma. Since one fifth of children in the study performed incorrect medication technique even after education, checklists of steps for the correct use of inhalation devices, such as those provided in this article, should be given to patients for home use and for use by clinicians to evaluate patient technique at each health encounter.

Effect of mouthpiece washing on aerosol performance of CFC-free Ventolin

The prescribing information for chlorofluorocarbon (CFC)-free salbutamol metered-dose inhalers carries a strongly-worded instruction to wash the mouthpiece weekly, but patients rarely carry this out. This study investigated the effect of washing/not washing the mouthpiece on CFC-free Ventolin aerosol performance. Twelve CFC-free Ventolin inhalers were actuated two puffs four times/day, and assessed by unit dose sampler and cascade impactor on Days 1, 7, 8, 14, 15, 21, and 22 ("throughlife," i.e., over the entire content of the inhaler). The mouthpieces of six inhalers were washed after the last actuation on Days 7, 14, and 21. A single priming maneuver, as recommended by the manufacturer, was sufficient for fine particle mass. There were no significant through-life differences in delivered dose between washed and unwashed inhalers. Without washing, fine particle mass fell from 47 microg to 33 microg (Friedman p=0.002). Fine particle mass increased significantly after washing (median change + 11.2 microg, p=0.019 cf. unwashed). Large particle mass showed no significant through-life trend for washed or unwashed inhalers, but was significantly reduced after washing (p=0.04 cf. unwashed). This study shows a progressive through-life reduction in fine particle mass from CFC-free Ventolin inhalers, which is prevented by weekly mouthpiece washing. However, in view of the steep bronchodilator dose-response curve for salbutamol, further studies are needed to determine whether such device care is clinically necessary.

Device Selection and Outcomes of Aerosol Therapy: Evidence-Based Guidelines

BACKGROUND

The proliferation of inhaler devices has resulted in a confusing number of choices for clinicians who are selecting a delivery device for aerosol therapy. There are advantages and disadvantages associated with each device category. Evidence-based guidelines for the selection of the appropriate aerosol delivery device in specific clinical settings are needed.

AIM

(1) To compare the efficacy and adverse effects of treatment using nebulizers vs pressurized metered-dose inhalers (MDIs) with or without a spacer/holding chamber vs dry powder inhalers (DPIs) as delivery systems for beta-agonists, anticholinergic agents, and corticosteroids for several commonly encountered clinical settings and patient populations, and (2) to provide recommendations to clinicians to aid them in selecting a particular aerosol delivery device for their patients.

METHODS

A systematic review of pertinent randomized, controlled clinical trials (RCTs) was undertaken using MEDLINE, EmBase, and the Cochrane Library databases. A broad search strategy was chosen, combining terms related to aerosol devices or drugs with the diseases of interest in various patient groups and clinical settings. Only RCTs in which the same drug was administered with different devices were included. RCTs (394 trials) assessing inhaled corticosteroid, beta2-agonist, and anticholinergic agents delivered by an MDI, an MDI with a spacer/holding chamber, a nebulizer, or a DPI were identified for the years 1982 to 2001. A total of 254 outcomes were tabulated. Of the 131 studies that met the eligibility criteria, only 59 (primarily those that tested beta2-agonists) proved to have useable data.

RESULTS

None of the pooled metaanalyses showed a significant difference between devices in any efficacy outcome in any patient group for each of the clinical settings that was investigated. The adverse effects that were reported were minimal and were related to the increased drug dose that was delivered. Each of the delivery devices provided similar outcomes in patients using the correct technique for inhalation.

CONCLUSIONS

Devices used for the delivery of bronchodilators and steroids can be equally efficacious. When selecting an aerosol delivery device for patients with asthma and COPD, the following should be considered: device/drug availability; clinical setting; patient age and the ability to use the selected device correctly; device use with multiple medications; cost and reimbursement; drug administration time; convenience in both outpatient and inpatient settings; and physician and patient preference.

Lack of awareness of need to clean CFC-free metered-dose inhalers

BACKGROUND

Chlorofluorocarbon (CFC)-free metered-dose inhalers (MDIs) were introduced into Australia in 1999. Device care instructions were modified (e.g., CFC-free salbutamol inhalers to be washed weekly), but this information was not communicated directly to health care professionals.

OBJECTIVE

This pilot study aimed to assess the level of awareness of device care protocols for CFC-free MDIs by patients and their pharmacists.

SETTING AND DESIGN

Purchasers of CFC-free MDIs were recruited from four community pharmacies. They were interviewed regarding information sources, knowledge of propellant change, and awareness of and adherence to device care protocols. The dispensing pharmacists were interviewed for knowledge of CFC-free device care. The primary outcome variable was awareness of the relevant device care protocol.

RESULTS

Thirty-nine patients were interviewed. Most patients (77%) were aware of the change to CFC-free propellant. Only nine patients (23%) were aware of the need to wash the device holder, and four patients (10% of total) complied with the specified protocol. One of the ten dispensing pharmacists could describe correct device care protocols for the CFC-free MDIs.

CONCLUSIONS

Although most patients are aware that MDIs are now CFC-free, there is a low level of awareness of the device care required for these inhalers, and a very low rate of compliance with recommended practice. Although the clinical impact of failing to wash the device holder is unclear, this added instruction may have substantial implications for patient satisfaction and medication delivery. Pharmaceutical manufacturers need to highlight to health care professionals any clinically important changes in device care instructions, so that appropriate information may be passed on to patients.

Clinical efficacy of inhaler devices containing beta(2)-agonist bronchodilators in the treatment of asthma: cochrane systematic review and meta-analysis of more than 100 randomized, controlled trials

BACKGROUND

A number of different inhaler devices are available to deliver beta(2)-adrenoceptor agonist (beta(2)-agonist) bronchodilators in asthma. These include hydrofluoroalkane or chlorofluorocarbon (CFC)-free propelled pressurized metered-dose inhalers (pMDIs), many dry powder inhalers and breath-actuated inhalers.

OBJECTIVE

To determine the clinical efficacy of all available hand-held inhaler devices compared with the standard CFC-containing pMDI for the delivery of short-acting beta(2)-agonist bronchodilators in nonacute asthma in both children and adults.

METHODOLOGY

A systematic review and meta-analysis was carried out of all available randomized, controlled trials (RCTs) using the standard pMDI compared with any other hand-held inhaler device, delivering short-acting beta(2)-agonist bronchodilators in patients with stable asthma.

RESULTS

One hundred and eighteen RCTs were included in this review. No clinical differences were found between the standard CFC-containing pMDI and 12 other hand-held inhaler devices for most outcome measures. We found no evidence of clinical differences between studies using either a 1 : 1 (pMDI: another inhaler) or a 2 : 1 dosing ratio.

CONCLUSIONS

In patients with stable asthma, short-acting beta(2)-agonist bronchodilators in standard CFC-pMDIs are as effective as any other hand-held inhaler device; therefore the cheapest available device that the patient is able to use should always be considered. Pharmaceutical companies should in future submit to regulatory authorities clinical outcome data (as opposed to in vitro data) in support of any dosing schedules greater than 1 : 1 when compared with the standard pMDI. Clinical effectiveness studies that use an intention-to-treat analysis and report more patient-centered outcomes are required.

Evaluation of changes in central airway dimensions, lung area and mean lung density at paired inspiratory/expiratory high-resolution computed tomography

The aim of this study was to improve the understanding of interdependencies of dynamic changes in central airway dimensions, lung area and lung density on HRCT. The HRCT scans of 156 patients obtained at full inspiratory and expiratory position were evaluated retrospectively. Patients were divided into four groups according to lung function tests: normal subjects ( n=47); obstructive ( n=74); restrictive ( n=19); or mixed ventilatory impairment ( n=16). Mean lung density (MLD) was correlated with cross-sectional area of the lung (CSA(L)), cross-sectional area of the trachea (CSA(T)) and diameter of main-stem bronchi (D(B)). The CSA(L) was correlated with CSA(T) and D(B). MLD correlated with CSA(L) in normal subjects ( r=-0.66, p<0.0001) and patients with obstructive ( r=-0.62, p<0.0001), restrictive ( r=-0.83, p<0.0001) and mixed ventilatory impairment ( r=-0.86, p<0.0001). The MLD correlated with CSA(T) in the control group ( r=-0.50, p<0.0001) and in patients with obstructive lung impairment ( r-0.27, p<0.05). In patients with normal lung function a correlation between MLD and D(B) was found ( r=-0.52, p<0.0001). CSA(L) and CSA(T) correlated in the control group ( r=0.67, p<0.0001) and in patients with obstructive lung disease ( r=0.51, p<0.0001). The CSA(L) and D(B) correlated in the control group ( r=0.42, p<0.0001) and in patients with obstructive lung disease ( r=0.24, p<0.05). Correlations for patients with restrictive and mixed lung disease were constantly lower. Dependencies between central and peripheral airway dimensions and lung parenchyma are demonstrated by HRCT. Best correlations are observed in normal subjects and patients with obstructive lung disease. Based on these findings we postulate that the dependencies are the result of air-flow and pressure patterns.

Does the inhalation device affect the bronchodilatory dose response curve of salbutamol in asthma and chronic obstructive pulmonary disease patients?

OBJECTIVE

This open randomized study examined differences between the effects of an equal dose of salbutamol administered via the Diskus, Turbuhaler, and pMDI plus Volumatic. Measurements included dose response curves, dynamic and static lung volumes, respiratory muscle strength, and systemic effects.

METHODS

The cumulative dose-response study compared the biological effects (pulmonary function, respiratory muscle function, systemic effects) of an equal dose of salbutamol delivered via four different devices in 23 patients with asthma and 21 patients with moderate or severe chronic obstructive pulmonary disease (COPD).

RESULTS

Salbutamol via Volumatic showed significantly better bronchodilation than via pMDI or Turbuhaler in both patient groups. No significant difference was found between salbutamol via Volumatic and Diskus. However, the advantage of Volumatic is of marginal clinical relevance since the additional bronchodilation was a maximum of 140 ml FEV(1) and did not exceed the minimal patient-perceivable improvement. In the asthma group a more evident plasma K(+) decrease was found after salbutamol delivered via pMDI and pMDI plus Volumatic. Furthermore, especially in the COPD patients a significant decrease was observed in hyperinflation and consequently an improvement in maximal inspiratory pressure as a result of salbutamol via all devices.

CONCLUSIONS

Bronchodilation by salbutamol was slightly more effective via Volumatic than via pMDI or Turbuhaler. No significant difference in bronchodilation was found between salbutamol via Volumatic and Diskus. The advantage of Volumatic is not of clinical relevance.

The inhalers of the future? A review of dry powder devices on the market today

International agreements to ban the use of environmentally damaging chlorofluorocarbons (CFCs) have signalled an end to the traditional CFC-propelled pressurised metered dose inhaler (pMDI) which has long been the mainstay of topical asthma therapy. The need for acceptable and cost-effective replacement inhalers, combined with opportunities to develop generic formulations of patent-expired drugs, has fueled a lively response from the pharmaceutical industry. Improvements in pMDI design and reformulation with propellants such as hydrofluoroalkanes may offer significant advantages over CFC-pMDIs and prolong the widespread use of pressurised drug delivery systems for many years to come. In the longer term, however, another likely candidate for success in providing economical, efficient and acceptable inhaled therapies is the breath-actuated, multiple-dose dry powder inhaler (DPI). This review concentrates on the multiple-dose DPIs available within Europe today.

Improvement of asthma control with a breath-actuated pressurised metred dose inhaler (BAI): a prescribing claims study of 5556 patients using a traditional pressurised metred dose inhaler (MDI) or a breath-actuated device

A relationship has been reported between sub-optimal inhaler technique and control of asthma symptoms. Randomised controlled trials and systematic reviews may fail to accurately represent this relationship, by excluding patients who are unable to correctly use the reviewed devices. Breath actuated inhalers (BAIs) are reported to be easier to use than metered dose inhalers (MDIs). This study uses a large primary care medical record database (DIN-LINK) to examine the 'real-life' clinical effectiveness of a BAI vs. traditional MDIs. A comparison is made between the quantity of asthma-related medication (beta2 agonist, oral steroids and antibiotics) and healthcare resource use required by children (0-12 years) and adults (13+ years) using either the BAI or an MDI over a 12-month period. Out of 5556 new asthma patients who met the inclusion criteria, 306 used a BAI and 5250 used a traditional MDI. Children and adults using the BAI received fewer prescriptions for all three medication types than those using a traditional MDI (children: beta2 agonists -18% P=0.036, oral steroids -88% P<0.05, antibiotics -68% P<0.05 and adults: beta2 agonists -10.9% P=0.179, oral steroids -51.2% P<0.05, antibiotics -19.5% P=0.276). All prescription results reached statistical significance, with the exception of beta2 agonist and antibiotic prescription numbers for adult patients. Children and adults using the BAI required less GP consultations for asthma (children -30.3%, P<0.05 and adults -22.9%, P<0.05) and less GP consultations for respiratory infections than those using a traditional MDI (children -35.2%, P=0.001 and adults -10.4%, P=0.236). Adults using the BAI required less outpatient appointments than adults using an MDI (-43.7%, P=0.166). All non-prescription resource results reached statistical significance with the exception of GP consultations for respiratory infections and outpatient visits in the adult group. In conclusion, children and adults using the BAI appear to have better asthma control than children and adults using an MDI as evidenced by fewer relief medication prescriptions and less healthcare resource use.

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.