asthma comorbidities

4 min read Updated 2026-03-25
respirology asthma rhinitis GERD OSA
Contents
asthma comorbidities

The “unholy trinity” — rhinosinusitis, GERD, and OSA — drives treatment resistance in asthma. Addressing these before escalating asthma therapy is mandatory. Obesity deserves separate attention as both a comorbidity and an asthma mimic.

the unholy trinity

rhinosinusitis / allergic rhinitis

The most prevalent asthma comorbidity (~80% of asthmatics have concurrent rhinitis). “United airways” concept — nasal inflammation and lower airway inflammation are part of the same disease.

Impact on asthma:

  • Untreated rhinitis worsens asthma control and increases exacerbation risk
  • Post-nasal drip triggers cough and may be misattributed to uncontrolled asthma
  • Nasal polyposis — associated with AERD, eosinophilic phenotype, and more severe disease

Management:

  • Intranasal corticosteroids (first-line — mometasone, fluticasone)
  • Second-generation oral antihistamines for allergic symptoms
  • Nasal saline irrigation
  • Allergen avoidance where feasible
  • Dupilumab treats asthma + nasal polyposis simultaneously — see severe asthma
  • Referral for polypectomy if medical therapy fails
always examine the nose

In any patient with uncontrolled asthma, assess nasal symptoms systematically. An untreated nose is one of the most common reasons for apparent treatment failure.

gastro-oesophageal reflux disease (GERD)

Prevalence 2–3× higher in asthma than general population. The relationship is bidirectional — asthma medications (beta-agonists, theophylline) relax the lower oesophageal sphincter; hyperinflation increases transdiaphragmatic pressure.

Impact on asthma:

  • Micro-aspiration triggers bronchospasm and airway inflammation
  • Vagal reflex from oesophageal acid exposure → bronchoconstriction
  • Nocturnal symptoms may be GERD rather than asthma

Management:

  • PPI trial (standard dose × 8–12 weeks) — but evidence for improving asthma outcomes is mixed; treat only if symptomatic GERD is present
  • Lifestyle measures (elevation of head of bed, avoid late meals, weight loss)
  • Do not empirically escalate asthma therapy for what may be reflux-mediated cough
PPI for asthma without GERD symptoms — no benefit

Empirical PPI in asthma patients without reflux symptoms does not improve asthma control. Treat GERD when symptomatic; do not prescribe PPI as an “asthma add-on.”

obstructive sleep apnoea (OSA)

Prevalence in difficult-to-treat asthma: up to 50%.

Impact on asthma:

  • Nocturnal intermittent hypoxia promotes airway inflammation
  • Upper airway oedema worsens both OSA and laryngeal hyperresponsiveness
  • Shared risk factors: obesity, rhinitis, GERD

When to investigate:

  • Uncontrolled asthma + daytime somnolence, snoring, witnessed apnoeas
  • Obesity (BMI > 30) with nocturnal asthma symptoms
  • STOP-BANG score ≥ 3

Management:

  • Polysomnography for diagnosis
  • CPAP — may improve asthma control in those with confirmed OSA (reduces airway inflammation, improves nocturnal symptoms, and reduces moderate exacerbations with ≥ 6 months of therapy)
  • Weight loss

obesity

Obesity both mimics and worsens asthma — see asthma mimics for the diagnostic challenge.

Asthma in obesity:

  • Obese patients have more symptoms, more exacerbations, and poorer treatment response
  • Reduced corticosteroid responsiveness (neutrophilic inflammation more common)
  • Mechanical effects: reduced FRC and ERV → airway closure at tidal breathing → air trapping sensation perceived as “asthma”

Management:

  • Weight loss is the most effective intervention — 5–10% body weight loss improves asthma control, FEV1, and quality of life
  • Consider bariatric surgery referral if BMI > 40 (or > 35 with comorbidities)
  • Confirm asthma diagnosis objectively — methacholine challenge if uncertain

pregnancy

Rule of thirds: ~1/3 improve, ~1/3 worsen, ~1/3 unchanged during pregnancy. Uncontrolled asthma carries greater risk to the foetus (hypoxia, pre-eclampsia, preterm birth) than any asthma medication.

  • Do not stop ICS — budesonide has the most safety data in pregnancy and is preferred
  • Do not withhold OCS if exacerbating — untreated exacerbations are more dangerous than corticosteroids
  • Manage step-wise as for any other patient (GINA 2024)
  • LABA (formoterol, salmeterol): limited but reassuring data; continue if needed for control
  • SABA: safe in pregnancy
  • Methacholine challenge is contraindicated in pregnancy
  • Monitoring: spirometry each trimester; close follow-up in third trimester (when worsening peaks)

other comorbidities

ComorbidityImpactAction
Anxiety / depressionSymptom over-perception, poor adherence, ED over-useScreen with PHQ-9/GAD-7; treat; improve self-management education
Vocal cord dysfunctionCoexists in up to 40%; causes symptoms attributed to asthmaLaryngoscopy; speech pathology (subjective improvement, though objective scores may not change) — see asthma mimics
HormonalPerimenstrual asthma worsening (up to 40% of women)Consider OCP or LTRA peri-menstrually (limited evidence); document pattern
MedicationsBeta-blockers (non-selective), ASA/NSAIDs → bronchospasmCardioselective beta-blockers (bisoprolol) are usually safe; avoid non-selective. ASA/NSAID sensitivity → see eosinophilic lung disease

systematic approach to the “uncontrolled” asthmatic

  1. Confirm diagnosis — was variable airflow limitation documented?
  2. Confirm adherence and inhaler technique
  3. Screen for the unholy trinity: rhinitis, GERD, OSA
  4. Assess obesity contribution
  5. Check for VCD overlap
  6. Review medications (beta-blockers, NSAIDs)
  7. Assess psychosocial factors (anxiety, depression, health literacy)
  8. Only then consider treatment escalation — see severe asthma

Key references