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Trial registered on ANZCTR

Registration number
Ethics application status
Date submitted
Date registered
Date last updated
Type of registration
Prospectively registered

Titles & IDs
Public title
The validity and reliability of a portable device for the diagnosis of Obstructive Sleep Apnoea in patients with Atrial Fibrillation: SAFARI
Scientific title
The validity and reliability of a portable device for the diagnosis of Obstructive Sleep Apnoea in patients with Atrial Fibrillation.
Secondary ID [1] 289599 0
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Obstructive Sleep Apnoea 299373 0
Atrial Fibrillation 299374 0
Condition category
Condition code
Cardiovascular 299358 299358 0 0
Other cardiovascular diseases
Respiratory 299359 299359 0 0
Sleep apnoea

Study type
Description of intervention(s) / exposure
This will be a prospective observational diagnostic accuracy study to compare the test characteristics of the index test (ApneaLink) to the gold standard polysomnography (PSG) for the diagnosis of OSA in patients with AF. Additionally, the epidemiology of OSA in this patient group will be examined.
ApneaLink, is a portable, limited channel sleep study device, which will be worn at home by the patient for one night. This device includes overnight oximetry (worn on the finger), nasal airflow signal detected via a nasal cannula as well as respiratory effort signal detected via a band worn around the chest. It generates an Apnoea Hypopnoea index (AHI) using total recording time as the denominator.
ApneaLink and in-laboratory sleep study (PSG) will be performed within one week of one another. All patients will undergo both of these diagnostic tests, though the order will be randomised. Interpreting physicians of each study will be blinded to the results of the other.
The Index test (ApneaLink) will be compared to in-laboratory sleep study as the gold standard, and the validity examined.
The epidemiology of OSA in the AF population examined as per the secondary aims.

Intervention code [1] 295390 0
Early detection / Screening
Comparator / control treatment
In-hospital polysomnography (PSG) is the gold-standard test for obstructive sleep apnoea. This is a multi-channel test requiring the patient to stay overnight in hospital. Various leads are attached to the patient including EEG (electroencephalogram) leads, EMG (electro-myelogram) leads on the chin muscles, a thermistor and nasal cannula for airflow and abdominal and thoracic bands to assess respiratory effort, as well as limb leads. Patients will undergo this test overnight in a dedicated hospital sleep laboratory.
Control group

Primary outcome [1] 298827 0
To determine the validityof a portable device as a screening tool for OSA in AF patients. This includes sensitivity, specificity, receiver operating characteristic (ROC), positive and negative predictive values, as compared with the gold standard of PSG.
Timepoint [1] 298827 0
Following both ApneaLink and PSG assessments
Secondary outcome [1] 325320 0
Utility of phenotypic characteristics for the prediction of OSA in an AF cohort. These include: body mass index (BMI), neck circumference, craniofacial photogrammetry, co-morbidities including hypertension and diabetes, respiratory illness, sleep questionnaires (viz. Epworth Sleepiness Score, Berlin Questionnaire), AF characteristics (ie. paroxysmal vs chronic, and treatments received), echocardiographic parameters, plasma biomarkers (CRP, BNP, others), This outcome will be assessed by correlation of these characteristics obtained by patient interview, clinical assessment, photography, blood tests and medical records with PSG findings.
Timepoint [1] 325320 0
Following both ApneaLink and PSG assessments.
Secondary outcome [2] 325321 0
Prevalence of OSA in an AF cohort as per PSG findings
Timepoint [2] 325321 0
Following PSG assessment.

Key inclusion criteria
* Sequential subjects with paroxysmal or persistent AF referred for Pulmonary Vein Isolation (PVI) at a tertiary referral institution OR Sequential subjects presenting with AF at a tertiary referral institution emergency department.
* Willingness and capacity to give written informed consent and willingness to comply with the study.
Minimum age
18 Years
Maximum age
No limit
Both males and females
Can healthy volunteers participate?
Key exclusion criteria
* Age < 18.
* Pregnant women.
* People highly dependent on medical care (eg intubated, intensive care patients, GCS < 15).
* Life expectancy < 12 months.
* Patients with a history of psychological illness such as to interfere with the patient’s ability to understand the requirements of the study.
* Those otherwise unable to give their own written informed consent.
* Previous formal PSG diagnosis of OSA.

Study design
Purpose of the study
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Masking / blinding
Open (masking not used)
Who is / are masked / blinded?

Intervention assignment
Other design features
Not Applicable
Type of endpoint(s)
Statistical methods / analysis
We used a conservatively estimated prevalence of 50%, based on a previous reported prevalence of 65% for OSA in an Australian AF population. Sensitivity and specificity for the ApneaLink device for the detection of moderate or severe OSA (AHI > 15) have been documented at 0.947 and 1.0 respectively in a different population.

Sample size estimates for the derivation study were obtained by the method of evaluating confidence intervals for likelihood ratios. We hypothesise that ApneaLink will be clinically useful as a screening tool if the upper limit of the confidence interval for the negative likelihood ratio is no greater than 0.4. Therefore we would require at least 17 patients with OSA and 17 patients without OSA to complete the final analysis, in each of the PVI and ED referral groups, totalling 68 patients. To offset an expected withdrawal rate of 10% we will aim to recruit a total of 74 patients for the derivation phase.

To allow prospective validation of the performance of ApneaLink as a predictor of OSA, we will recruit a total of 99 patients to allow a one third split of the sample (25 patients) to be used to validate the model. The validity of the prediction model for predicting treatment outcome will be assessed by measuring its test characteristics (eg sensitivity, specificity, likelihood ratios etc. in this new sample).

Recruitment status
Date of first participant enrolment
Date of last participant enrolment
Date of last data collection
Sample size
Accrual to date
Recruitment in Australia
Recruitment state(s)
Recruitment hospital [1] 6090 0
Royal North Shore Hospital - St Leonards
Recruitment postcode(s) [1] 13551 0
2065 - Royal North Shore Hospital

Funding & Sponsors
Funding source category [1] 293984 0
Government body
Name [1] 293984 0
Northern Sydney Local Health District
Address [1] 293984 0
Dr Anna Mohammadieh (PI)
Level 8
Pacific Highway St Leonards
NSW 2065
Country [1] 293984 0
Primary sponsor type
Department of Respiratory and Sleep Medicine, Royal North Shore Hospital, NSLHD
Royal North Shore Hospital
Level 8
Pacific Highway, St Leonards
NSW 2065
Secondary sponsor category [1] 292802 0
Name [1] 292802 0
Address [1] 292802 0
Country [1] 292802 0

Ethics approval
Ethics application status
Ethics committee name [1] 295402 0
Northern Sydney Local Health District HREC
Ethics committee address [1] 295402 0
Research Office
Kolling Building
Royal North Shore Hospital
Reserve Road
St Leonards NSW 2065
Ethics committee country [1] 295402 0
Date submitted for ethics approval [1] 295402 0
Approval date [1] 295402 0
Ethics approval number [1] 295402 0

Brief summary
Mounting evidence highlights the importance of screening for obstructive sleep apnoea in patients with atrial fibrillation. Treating obstructive sleep apnoea in these patients may improve outcomes, such as improving the risk of recurrence of atrial fibrillation after Pulmonary Vein Isolation procedures. We will examine the validity of a portable sleep study device (ApneaLink) for the diagnosis of Obstructive Sleep Apnoea in patients with Atrial Fibrillation.

Trial website
Trial related presentations / publications
Public notes

Principal investigator
Name 67154 0
Dr Anna Mohammadieh
Address 67154 0
Department of Respiratory and Sleep Medicine
Level 8
Royal North Shore Hospital
Reserve Road
St Leonards NSW 2065
Country 67154 0
Phone 67154 0
+612 9926 7111
Fax 67154 0
+612 9463 2099
Email 67154 0
Contact person for public queries
Name 67155 0
Dr Anna Mohammadieh
Address 67155 0
Department of Respiratory and Sleep Medicine
Level 8
Royal North Shore Hospital
Reserve Road
St Leonards NSW 2065
Country 67155 0
Phone 67155 0
+612 9926 7111
Fax 67155 0
Email 67155 0
Contact person for scientific queries
Name 67156 0
Dr Anna Mohammadieh
Address 67156 0
Department of Respiratory and Sleep Medicine
Level 8
Royal North Shore Hospital
Reserve Road
St Leonards NSW 2065
Country 67156 0
Phone 67156 0
+612 9926 7111
Fax 67156 0
Email 67156 0

No information has been provided regarding IPD availability
Summary results
No Results