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Obstructive Sleep Apnoea

Comorbidities & Complications

The comorbidities of OSA are diverse and may require individual management. OSA is associated with hypertension and increased cardiovascular disease.

The comorbidities of OSA are diverse and may require individual management. OSA is associated with hypertension and increased cardiovascular disease.

As well as excessive daytime sleepiness, OSA can be associated with other symptoms of cognitive dysfunction including disruption of concentration, memory and executive functions, depressed mood, decreasing work performance and quality of life, and increasing absenteeism and the risk of work and motor vehicle accidents (See Assessment – History; Assessment – Fitness to Drive).1, 2

Table. Comorbidities associated with OSA

  • Hypertension
  • Mood disorders, depression
  • Cognitive dysfunction
  • Coronary artery disease
  • Heart failure
  • Atrial fibrillation
  • Cerebrovascular accident (CVA)
  • Diabetes mellitus type 2
  • Insomnia

OSA is associated with hypertension (approximately 50% of OSA patients have hypertension, and between 20-40% of patients with hypertension have OSA) and cardiovascular events ( acute myocardial infarction, cerebrovascular accident, congestive cardiac failure) as well as other conditions (increased prevalence of insulin resistance and type 2 diabetes, and increased risk of impotence).

OSA may cause hypertension and increased cardiovascular risk via a number of pathways. Intermittent hypoxia, nocturnal arousals and swings in intrathoracic pressure lead to autonomic imbalance, endothelial dysfunction and direct cardiac effects.3 A large longitudinal study 4 demonstrated a doubling of mortality, which was linked to coronary artery disease 5 over an 8-year period in middle-aged men with untreated severe OSA compared to those without OSA, when adjusted for confounders including body mass index (BMI).

Patients with hypertension (particularly those with resistant hypertension) should be questioned about symptoms of OSA as a possible underlying cause. Continuous positive airway pressure (CPAP) may assist in reducing blood pressure in patients with hypertension, however treatment effects are modest (~2-3 mm Hg reduction) and randomised controlled trials have thus far been unable to show a benefit of CPAP therapy on other CV risk factors such as diabetes or the incidence of cardiovascular events.6, 7 Thus, CPAP should not be seen as a replacement for pharmacological therapies or lifestyle advice for hypertension and other CV risk factors.

Figure. Proposed mechanistic pathways linking OSA with hypertension and increased cardiovascular risk8


AHI - Apnoea-Hypopnoea Index
BBTi - Brief Behavioural Therapy for Insomnia
BMI - Body Mass Index (kg/m2)
BQ - Berlin Questionnaire
CBTi - Cognitive Behavioural Therapy for Insomnia
CELL - Coblation Endoscopic Lingual Lightening
COPD - Chronic Obstructive Pulmonary Disease
CVA - Cerebrovascular Accident
CPAP - Continuous Positive Airway Pressure
CSA - Central Sleep Apnoea
DASS - Depression Anxiety Stress Scale
DBAS - Dysfunctional Beliefs and Attitudes about Sleep
DBP - Diastolic Blood Pressure
DIMS - Difficulties Initiating and/or Maintaining Sleep
DISE - Drug-Induced Sleep Endoscopy
DISS - Daytime Insomnia Symptom Scale
ENT - Ear Nose and Throat
ESS - Epworth Sleepiness Scale
FOSQ - Functional Outcomes of Sleep Questionnaire
FSH - Follicle-Stimulating Hormone
FTP - Friedman Tong Position
GP - General Practitioner
HANDI - RACGP Handbook of Non-Drug Interventions
HGNS - Hypoglossal Herve Htimulation
ISI - Insomnia Severity Index
K10 - Kessler Psychological Distress Scale
MAD - Mandibular Advancement Device
MAS - Mandibular Advancement Rplint
MBS - Medicare Benefits Schedule
MMA - Maxillomandibular Advancement Surgery
MRA - Mandibular Repositioning Appliance
ODI - Oxygenation Desaturation Index
OSA - Obstructive Sleep Apnoea
PLMD - Periodic Limb Movement Disorder
PT - Positional Therapy
PTSD - Post-Traumatic Stress Disorder
PSG - Polysomnography
QSQ - Quebec Sleep Questionnaire
REM - Rapid Eye Movement
RFTB - Radiofrequency Thermotherapy of the Tongue Base
SBP - Systolic Blood Pressure
SCI - Sleep Condition Indicator
SE - Sleep Efficiency
SF36 - Short-Form (36) Health Survey
SMILE - Submucosal Minimally Invasive Lingual Excision
SNRIs - Serotonin-Norepinephrine Reuptake Inhibitors
SOL - Sleep Onset Latency
SSRI - Selective Serotonin Reuptake Inhibitors
TFTs - Thyroid Function Tests
TIB - Time In Bed
TORS - Transoral Robotic Surgery
TST - Total Sleep Time
UPPP - Uvulopalatopharyngoplasty
WASO - Wake After Sleep Onset

Quick links


  1. Zheng D, et al. Effects of continuous positive airway pressure on depression and anxiety symptoms in patients with obstructive sleep apnoea: results from the sleep apnoea cardiovascular Endpoint randomised trial and meta-analysis. EClinicalMedicine 2019;11:89-96
  2. Vaessen TJ, et al. Cognitive complaints in obstructive sleep apnea. Sleep Med Rev 2015;19:51-8
  3. Bradley DT, et al. Obstructive sleep apnoea and its cardiovascular consequences. The Lancet 2009;373:82-93
  4. Quan SF, et al. The sleep heart health study: design, rationale, and methods. Sleep 1997;20:1077-85
  5. Punjabi NM, et al. Sleep-Disordered Breathing and Mortality: A Prospective Cohort Study. PLOS Med 2009;6:1-9
  6. Loffler KA, et al. SAVE Substudy Investigators. Continuous Positive Airway Pressure Treatment, Glycemia, and Diabetes Risk in Obstructive Sleep Apnea and Comorbid Cardiovascular Disease. Diabetes Care 2020
  7. Yu J, et al. Association of positive airway pressure with cardiovascular events and death in adults with sleep apnea: a systematic review and meta-analysis. JAMA 2017;318(2):156-6
  8. RACGP gplearning ‘Obstructive Sleep Apnoea'