One Such Example Is The Comorbidities Associated With Asthma. These Comorbid Conditions Pose Problems In Diagnostic Processes.
The term “comorbidity” refers to the co-occurrence of some disorders and diseases more frequently than what it would be expected by chance. A more cohesive definition would be, “two or more medical conditions existing simultaneously irrespective of their causal relationship” (Jakovljevic et al.,, 2013). Comorbid conditions can complicate the diagnosis and management of diseases as they may lead to patients experiencing increased healthcare costs, polypharmacy, under treatment, overtreatment and even misdiagnosis of the primary medical condition (Kaplan et al.,, 2020) . Although clinical research and data of comorbidities affecting primary health conditions is somewhat still not vastly explored and documented, their presence cannot be denied. One Such Example Is The Comorbidities Associated With Asthma. These Comorbid Conditions Pose Problems In Diagnostic Processes. They may mimic asthma symptoms leading to an increase in the severity of the illness and even interfere during the process of clinical treatment as asthma therapies may aggravate the comorbid conditions or vice versa. This makes looking into this avenue very important. Especially when in this age, asthmatic conditions are much prevalent in the general public.
The main comorbid conditions of asthma include rhinitis, vocal cord dysfunction (VCD), gastro-oesophageal reflux disease (GERD), psychiatric disorders, obesity and obstructive sleep apnoea (OSA). These conditions are common and often overlooked while treating asthma patients. If we take a look at some statistics, 54% asthmatics in the US (Patel et al.,, 2013) and 63% in the UK (Weatherburn et al.,, 2017) were reported to be suffering from more than one comorbid conditions associated with asthma. The severity and occurrence of comorbid conditions in asthmatics also varies with age and this poses an even greater concern for clinicians dealing with asthma patients. This article will mainly deal with a brief insight into what these comorbid conditions are and how can they affect the diagnosis, severity and treatment of asthma.
Rhinitis often regarded as allergic rhinitis is a common comorbid condition found in 6 to 95% of asthma patients (Togias, 2003). The common symptoms of rhinitis include nasal itching, sneezing, increased nasal secretions, nasal obstruction and cough. The diagnosis of this comorbid condition may be missed if the patient is not questioned thoroughly about daily experiences and any changes in health conditions. In the process of treating rhinitis by using nasal corticosteroids, no evidence was found for the treatment to have a direct impact on lung function and asthma severity. Rhinitis induced sleep disturbances can lead to tiredness and fatigue, memory loss and depression, reducing the quality of life. Nasal congestion, rhinorrhea (the free discharge of a thin nasal mucus fluid) and smell restrictions are common symptoms which may help in identifying this comorbid disorder.
VOCAL CORD DYSFUNCTION
Vocal cord dysfunction (VCD) is a dynamic, episodic condition characterized by chest tightness, wheezing, hoarseness, cough and globus pharyngeus (sensation of a lump in the throat). These symptoms cause difficulties in diagnosis and assessing the severity of asthma and can be triggered by respiratory irritants, physical exertion, anxiety and even by the frequent use of inhalers. A study involving proper treatment of VCD using a multidisciplinary approach showed a decline in symptoms in 82% of the asthma patients (Kramer et al.,, 2017). Improper diagnosis of VCD can lead to inappropriate and excessive intake of bronchodilators. Although it can be difficult to diagnose, but consistent wheezing even at rest is one of the major pointers of VCD.
GASTRO-OESOPHAGEAL REFLUX (GERD)
Gastro oesophageal reflux or GERD is defined by a sensation of heartburn or acidic regurgitation. Comorbid GERD is often experienced after the consumption of certain foods like chocolate, alcohol, acidic drinks, coffee or a heavy meal. Other symptoms associated with GERD are hoarseness, development of nocturnal routine and dental erosion. According to one study, 58% of asthma patients were found to have developed GERD as a comorbid condition (Havemann et al.,, 2007). Improvement in lung function and decrease in asthmatic symptoms have been observed as a result of treating GERD through the use of Proton Pump Inhibitors (PPIs). PPIs work by blocking and reducing the production of stomach acid. Although this treatment has been proved to be beneficial for asthmatics, further evidence still needs to be thoroughly examined to establish a significant link. One concerning point is the fact that some asthma therapies may in turn increase the severity of GERD. An example of this is the use of corticosteroids as inhalers which may cause increased acid production, aggravating GERD symptoms.
Comorbid psychiatric diseases mainly include depression, panic attacks and anxiety. A survey conducted by World Health Organization reported the prevalence of depressive symptoms in 2-26% of the patients observed (Scott et al.,, 2007). Anxiety and panic attacks often lead to excessive breathing which in turn may worsen asthmatic control. The trends of comorbid mental disorders associated with asthmatics also increase with age, owing to changes in behavior and higher rates of depression. Treating the psychiatric comorbidities with antidepressants does result in reduction in depressive symptoms which in turn leads to improvement in asthma symptoms (Brown et al.,, 2005). However, more evidence is required to establish a concrete link between the two. Just like the treatment therapies for the aforementioned asthma comorbidities, the medications associated with asthma therapy may prove to be having adverse mental effects such as mood swings and behavioral changes. This has been observed in the case of consuming large quantities of oral corticosteroids which led to manic and depressive states, as reported by the National Asthma Council of Australia in their Asthma Handbook (Australia, 2019). Another crucial point is the relationship between psychiatric comorbidities and asthma management as depression can alter medication effects and anxiety induced hyperventilation may lead to misinterpretation of the symptoms.
Obesity is defined as having a body mass index (BMI) ≥ 30 kg/m2. Obesity is a common comorbid condition in both children and adults with asthma, and it is present in 21–48% of patients with severe asthma (Gibeon et al.,, 2013). Obesity itself is a major health problem and poses equally concerning threats as a comorbid disease. Obesity can aggravate asthma conditions as more than normal BMI causes obstruction of airways. Breathlessness after physical exertion common in obese patients may be misinterpreted as asthma and this creates problems during diagnosis. Obstructive sleep apnoea and GERD in obese patients may also worsen asthmatic symptoms (Boulet et al.,, 2011), giving evidence that comorbidities may occur together creating mulitmorbid scenarios. Weight controlling therapies have shown convincing evidence to link weight loss in patients having comorbid obesity with improvements in asthma control and quality of life. Furthermore, obese patients show a varied response to inhaled corticosteroids (ICS) used for asthma control. This is due to continued breathing at low lung volumes which creates a very specific phenotype of asthma in obese patients (Boulet et al.,, 2007).
OBSTRUCTIVE SLEEP APNOEA
Obstructive sleep apnoea (OSA) is a common disorder characterized by repetitive episodes of nocturnal breathing cessation due to upper airway collapse. Its symptoms often include poor quality of sleep, nocturnal dyspnea (severe shortness of breath while sleeping), daytime sleepiness, depression and memory loss. The prevalence of OSA in children with asthma ranges from 35 to 66% (Ginis et al.,, 2017); in adults, prevalence is reported to be 40–50% (Auckley et al.,, 2008). The development of OSA in asthmatic patients varies with age, gender, behavioral and dietary habits. OSA and asthma may interfere during diagnostic procedures as both of them are marked with causing obstruction in airways. Continuous Positive Airway Pressure (CPAP) is one of the treatment therapies used for OSA. It involves the patient wearing a face or nasal mask while sleeping which ensures positive flow of air into the nasal passages to keep the airways open. Using this therapy to treat comorbid OSA in asthmatics has proved to reduce asthma severity and improve their quality of life (Kauppi et al.,, 2016), although more evidence is needed to establish a concrete link.
The main aim of this writing has been to highlight the presence of some of the comorbid conditions found in asthma patients as these can complicate disease management and clinical therapies. Many comorbidities can aggravate asthma symptoms while paradoxically, the treatment of asthmatic symptoms can worsen the severity of the prevalent comorbid disorders. At the end, it all comes down to measuring out the benefits of treatment for one condition against the potential risks of the associated comorbidities. Understanding the trends and patterns involved in this interconnection of pathophysiological processes may help clinicians and patients to better understand the ways of treating asthma more efficiently.