Poster Presentation ANZOS-Breakthrough Discoveries Joint Annual Scientific Meeting 2018

Assessing for Obstructive Sleep Apnoea in a severely obese population in the ACT (#304)

Louise Brightman 1 , Hsin-Chia Carol Huang 1 2
  1. Obesity Management Service, ACT Health, Canberra, ACT, Australia
  2. Respiratory and Sleep Medicine Department, The Canberra Hospital, Canberra, ACT, Australia

 

Background 

Obesity is the main driver for Obstructive Sleep Apnoea (OSA), with the incidence of OSA in severely obese patients reported to be as high as 78%.1 OSA can negatively impact health therefore timely diagnosis and appropriate management are crucial. The ACT Health Obesity Management Service (OMS) routinely assess for sleep-related symptoms and refer for polysomnography (PSG) when medically indicated. This study quantifies PSG referrals and new OSA diagnoses, reviews Epworth Sleepiness Scale (ESS) scores and compares with previous OMS data.2

  

Methodology

A retrospective chart audit was performed on new patients who attended OMS from July 2016 to June 2017. Pre-existing OMS patients were excluded. Demographic and anthropometric data were collated along with PSG referrals and OSA diagnoses. Periodic ESS scores were reviewed and descriptive analyses were performed.

 

Results

Of 162 patients, 43 (26.5%) had pre-existing OSA. 60 patients (37.0%) were referred for PSG based on clinical suspicion. 7/60 (11.7%) declined PSG. 46/60 (77.0%) were diagnosed with OSA (13=mild, 15=moderate, 18=severe). Concomitant Obesity Hypoventilation Syndrome (OHS) was detected in 8/46 (17.4%). Ventilation therapy was commenced in 36/46 (78.3%) including 5 patients who dis-engaged from OMS but continued OSA treatment. Despite clinical recommendation, 10 patients subsequently ceased ventilation therapy. Median ESS score pre-PSG was 7/24 (IQR 4-11) and at 12 months was 6/24 (IQR 4-9). Compared to previous data, PSG referrals increased (11.0% to 37.0%) whilst OSA diagnoses slightly decreased (86.4% to 77.0%).

 

Conclusions

The increased number of PSG referrals suggests that OMS now has a higher level of suspicion for co-morbid OSA. The high incidence of OSA diagnoses following referral to OMS suggests that severely obese patients should be screened for sleep-related symptoms in other healthcare settings. Future studies should focus on PSG referral thresholds and cost-effectiveness, and correlations between ESS scores, OSA treatment and concurrent weight loss.

 

  1. Lopez PP et al. Prevalence of OSA in morbidly obese patients who presented for weight loss surgery evaluation: more evidence for routine screening for obstructive sleep apnoea before weight loss surgery. The American Surgeon 2008; 74:834-838.
  2. Kojima C, Huang H-C C. Diagnostic polysomnography in the ACT Obesity Management Service patient cohort. Internal Medicine Journal (RACP Congress Abstract) 2017:47:13.