Asthma and Elderly

Ageing does play an essential role in asthma pathogenesis and also has an implication on its diagnosis and management in the elderly. The following figure explains the effects of ageing on the respiratory system, immune system as well its manifestation on the pathophysiology of asthma in the elderly:

Despite increased morbidity and mortality in older patients with asthma, the pathogenesis in this age group is not well-characterized. Asthma in the elderly may result from the persistence of childhood asthma, the return in later life of childhood asthma that was quiescent in adulthood, or asthma that developed in later life (late-onset asthma). (Table 1).

As in childhood onset asthma, a family history of asthma is also a risk factor for late-onset asthma in the elderly, in addition to allergen sensitization. However, respiratory infections such as the respiratory syncytial virus (RSV) and Chlamydia pneumoniae may play a more important role than atopy in the development of such late-onset asthma (Table 1). Having a history of smoking is also an influential factor although it has been implicated more in the pathogenesis of chronic obstructive pulmonary disease (COPD).

Asthma in children and adults is primarily a clinical diagnosis. However, symptoms that suggest asthma, such as wheeze and a sensation of bronchospasm, may be absent in older asthmatic patients. Furthermore, even when present, typical respiratory symptoms of wheeze, breathlessness, chest tightness and cough have poor predictive value in old age.

The symptomatology in elderly asthmatics is relatively non-specific because of the presence of co-morbidities. However the 'hallmark' of asthma remains the same across all ages, i.e., symptoms tend to be variable, intermittent, worse at night and provoked by triggers, including exertion, and eliciting these features remains at the core of diagnosing asthma in older people.

Under-diagnosis of asthma in the elderly remains a major issue and the reasons for this are multifactorial and include reduced perception of symptoms, misattribution of symptoms to other causes and underuse of objective testing such as spirometry. The diagnosis of asthma is made by determining the symptoms by examining the medical history and obtaining an objective assessment of the variable airflow obstruction.

The typical symptoms of asthma such as dyspnoea, chest tightness, cough and wheezing are similar in both elderly and young patients. However, when considering the diagnosis of asthma in an older patient, there are a number of diseases that should be included in the differential diagnosis. But, it is important to rule out the conditions that mimic asthma. Hence, the following list of conditions can be considered for the differential diagnosis of asthma in older patients:

However, the diagnosis of these two distinct diseases is not always straightforward since many elderly individuals may present with an 'overlap syndrome'.

It is important to evaluate the clinical symptoms of asthma by office spirometry, which measures the FEV₁ and the FVC. If the spirometry results are consistent with airway obstruction, it is essential to perform the bronchodilator reversibility test; a 12% or 200 ml increase in the FEV₁ values is suggestive of reversible obstructive airway disease.

There is a misperception that reliable spirometry measurements cannot be obtained from elderly individuals. Several studies have demonstrated that between 82% and 93% of elderly patients are able to perform good spirometry.

Ageing is associated with a decline in the FVC and FEV₁ by 15-30 ml/year, and the decline in the FEV₁ often exceeds the reduction in the FVC, resulting in a decline in the predicted values and lower limit of normal. Using a fixed cutoff value (<70%), as is recommended by Global initiative for chronic Obstructive Lung Disease(GOLD), potentially results in overestimation and misclassification of obstructive lung disease in older adults.

Good quality testing from an elderly patient may require 20-30 minutes more than the time required for younger subjects. The minimum number of FVC manoeuvres needed to achieve consistent results is higher in older adults (up to 5-8 manoeuvres required). Older patients have difficulty in achieving end-of-test thresholds and using slow vital capacity manoeuvres or the measurement of FEV₁/FEV₆ (forced expiratory volume in 6 seconds) to detect airflow obstruction.

Alternative methods for examining significant airflow reversibility to the PEFR or FEV₁:

Investigations in suspected asthma at first presentation in older people are important to differentiate asthma from the various diseases that may present with wheeze or breathlessness. Investigations are also important in asthma in following the course of the disease, response to treatment and in the management of acute severe attacks.

Generally speaking, the principles of asthma management in the elderly remain the same as in the younger population, with special considerations for education and medication use. The goals of management revolve around the same components of asthma management as in the younger population, namely, assessment and monitoring, education, control of triggers and pharmacotherapy.

At the initial visit, the patient's asthma should be classified either according to the severity or the level of control as per the asthma guidelines, as is done in the younger adults.

When performing the initial assessment, it is critical to ask patients what triggers their asthma as these exposures may be modified. Common triggers include aeroallergens, infections (commonly viruses and sometimes bacteria), irritants and psychosocial factors, including depression and social isolation, and allergen avoidance measures should be applied. Since viral and pneumococcal infections are frequent risk factors for asthma as well asthma exacerbations in the elderly, it may be beneficial to administer the pneumococcal vaccination more frequently than every 5-10 years because, with ageing, IgG opsonophagocytic activity and response to polysaccharide vaccination diminish.

The principles of pharmacologic treatment are similar for all ages. The medications used to treat older patients with asthma are not significantly different from those used in younger patients. However, there are several important considerations when prescribing these medications in older patients, including dosage adjustments for metabolic rates, drug interaction adverse effects, costs and delivery.

Since it is highly likely that asthma and COPD converge in the elderly individuals, the pharmacological management should take this fact into account while treating this population. Inhaled corticosteroids (ICS) have been a cornerstone of asthma treatment and, in combination with long-acting beta₂-agonists (LABAs), have proven their efficacy in COPD. Additionally, patients with asthma and COPD should be advised to stop smoking.

Corticosteroid therapy is the most effective form of anti-inflammatory medication for asthma; however, whether they inhibit the development of long-term structural changes in the airways is not known. To determine if ICS will have clinical benefit, patients may be given a 2-week trial of oral corticosteroids at a dose of 0.3-0.5 mg/kg (a dose lower than used in younger patients), after which the lung function test can be repeated to determine if the airways hyper-responsiveness is reversible.

Inhalational Device Selection in the Elderly

Drug delivery by the inhaled route offers the best efficacy-to-safety ratio for many asthma therapies. However, an ineffective inhalation technique remains a substantial problem that contributes to poor symptom control. The error rate increases with both age and the extent of airflow obstruction. It has been reported that up to 82% of the elderly (older than 70 years) patients do not have an adequate pressurized MDI (pMDI) technique.

Older people with asthma can acquire and retain an appropriate technique after specific instructions, but these instructions need to be repeated and reinforced to ensure continuous good inhaler technique. Nebulized treatment can be replaced by the more efficient pressurized inhaler devices or, if not, then home nebulization can be recommended for daily use.

Specific factors leading to impaired inhaler technique in older people are learning difficulties from impaired cognitive function, impaired vision and fine motor skills and decreased generation of inspiratory flow. The following chart may be considered when selecting an inhalation device for the elderly (Table 6).

The prevalence of co-morbidity from chronic disease increases with age. More than 50% of older people, aged 65 years or more, have at least three co-morbidities and a substantial portion have five or more, which are often unrecognized and untreated. Co-morbidity both compounds and confounds the management of asthma in older adults. Drug interactions and polypharmacy are important complications that accompany co-morbidity and ageing. Some of the common co-morbid disorders that complicate asthma and ageing are shown in the following table.

Other than the above-mentioned co-morbidities, it is also essential to manage others such as psychiatric co-morbidities (depression, panic attacks and general anxiety) as well as cardiovascular co-morbidities, all of which complicate asthma management.

Non-asthma drugs that may affect asthma:

The management of acute severe asthma is no different in the elderly than in the young, but co-existing diseases and medications can make diagnosis and management very challenging, and complications more likely. Objective measures of disease severity are particularly important in the management of acute asthma in the elderly. Older asthmatics patients often have an impaired perception of acute bronchoconstriction; doctors tend to underestimate the severity of their symptoms and older patients take, on average, three times as long to present to a hospital, compared with younger patients.

Healthcare professionals need to make sure elderly patients understand how to monitor symptoms and identify signs (such as awakening at night due to asthma; an increased need for inhaled beta₂-agonists to relieve symptoms or diminished response to inhaled beta₂-agonists) or changes in the PEFR (if PEFR monitoring is used) that indicate their asthma is worsening.

Each patient should be given a management plan (in the form of a printed handout) that includes clear information on what to do and this action plan should also take into account the co-morbidities that the patient may suffer from.

For emergency care, hospital management and intensive care:

Good communication and rapport between healthcare professionals and the patient has long been recognized as crucial to asthma management. This entails an individualized approach, tailored to each patient's age, level of education, wishes for autonomy and social and psychological status, to educate patients and/or their caregivers to take charge of their disease. Adherence can be a complex issue in older people with chronic respiratory disease, which can also be improved by applying patient education and self-management strategies.

Asthma education in elderly patients centres on several key issues such as the need for assistance with medication administration, assessment of inhaler technique, cognitive and/ or physical impairment, etc.

It has been suggested that a multidimensional strategy for the management of asthma in older people might be appropriate

This approach allows for personalized interventions that can be applied to manage the biological, clinical, functional and behavioural characteristics of the elderly asthmatics. A model of this approach places the patient in the centre of their own care and recognizes the many and divergent management issues that affect the health status and morbidity in older people with asthma.

Hence, although highly prevalent, asthma in the elderly can be managed successfully with the help of correct diagnosis, addressing co-morbidities as well as following an individualized and multidisciplinary approach to therapy.