Table 1.

Prevalence, symptoms, diagnosis and associated asthma phenotypes of common comorbid conditions in children and adults with asthma.

Comorbid condition	Prevalence in children with asthma (%)	Prevalence in adults with asthma (%)	Symptoms	Diagnosis	Associated asthma phenotypes
(1) Rhinitis	59–781,2	82–903,4	• Nasal itching, sneezing, increased nasal secretions and nasal obstruction5 • General symptoms such as lassitude, cough and sleepiness may also occur5 as a consequence of sleep disturbances	• History and physical examination • Further testing for allergen-specific IgE antibodies and allergen skin prick testing • Validated questionnaires, such as Total Nasal Symptom Score and Sinonasal Questionnaire6,7	• Most commonly associated with early-onset allergic asthma phenotype8
(2) VCD	Not known	19–509,10	• Chest tightness, wheezing (may be high pitched and musical or stridulous), hoarseness, dysphonia, cough and globus pharyngeus11	• Endoscopic examination12 • Spirometry13 • Pittsburgh VCD Index13	• Not associated with an asthma phenotype8
(3) GERD	43–8714	58 (includes patients aged 15–75 years)15	• Asthma symptoms worsen after consuming certain foods16 • Cough or wheezing after consuming acidic drinks or food or after a large meal11,16 • Hoarseness, predominance of nocturnal symptoms, symptom (heartburn, regurgitation) occurrence when changing position, unexplained dental decay11,16	• Trialling PPI8 • Specific examinations assessing GERD, such as impedance–pH monitoring and/or gastro-oesophageal endoscopy12	• Not associated with any asthma phenotype8
(4) Psychiatric diseases	Anxiety or depressive disorders: 1617	Any anxiety disorder: 34 (panic attacks, 25%; panic disorder, 12%; agoraphobia, 12%; generalised anxiety disorder, 9%)18	• Varies according to individual conditions	• Hospital Anxiety and Depression Scale questionnaire and psychiatric assessment19 • Patient Health Questionnaire (PHQ-9) for depression20 • Generalised Anxiety Disorder Questionnaire (GAD-7) for anxiety21	• Not associated with an asthma phenotype8
(5) Obesity	8–1622	21–48 (in severe asthma)23–26	• BMI ≥ 30 kg/m227	• Measure weight and height to determine body mass index27	• At least two distinct phenotypes of asthma in obesity. Obese state can both alter early-onset allergic asthma and lead to the development of late-onset asthma28
(6) OSA	35–6629,30	40–5031,32	• Brief paroxysmal nocturnal dyspnoea, choking during sleep and poor sleep quality • Daytime sleepiness • Depression and memory loss13,19,33	• Polysomnography (gold standard)19 • Validated questionnaires, such as the Epworth Sleepiness Score, STOP-BANG or the Berlin Questionnaire are also available for screening19	• Not associated with an asthma phenotype8