Metanephrines in Obstructive Sleep Apnoea

Study Overview
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Brief Summary
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Although most patients have essential (unexplained) hypertension, some patients have a treatable underlying condition. One such condition is phaeochromocytoma, a tumour that produces excessive stress hormones. Left undiagnosed, patients may develop a hypertensive crisis that can be fatal. Measurements of stress hormones (both 24-hour urine collection and morning blood tests) are highly sensitive for detecting these tumours. However, these stress hormones may also be elevated in obstructive sleep apnoea (OSA) which affects 1 in 5 adults. The investigators hypothesize that in patients with OSA, blood tests will be better than 24-hr urine tests at ruling out a tumour. If this is confirmed, then OSA patients with suspected phaeochromocytoma could be investigated with a morning blood test instead of a traditional urine test, reducing unnecessary additional tests and patient anxiety. In this single site study, the investigators plan to recruit 70 patients undergoing polysomnography. 24hr urine and bloods will be measured. Patients with elevated hormone levels will undergo imaging to rule out a tumour. The primary outcome will be the accuracy of each test in ruling out a tumour. The secondary outcomes will be the relationship between stress hormone level and severity of OSA, which may help to explain the increased cardiovascular risk in patients with OSA, and the change in stress hormone level with treatment for OSA

Official Title
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Utility of Plasma and Urine Metanephrines in the Diagnosis of Phaeochromocytoma in Patients With Obstructive Sleep Apnoea

Conditions
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Pheochromocytoma, Obstructive Sleep Apnea, Catecholamine; Secretion

Intervention / Treatment
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* Diagnostic Test: Measurement of Urine and plasma metanephrines


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients aged 21-70 years attending for a sleep study to evaluate for OSA Exclusion Criteria: Medications that can cause changes in metanephrine levels Other factors that can cause changes in metanephrine levels Renal impairment (eGFR < 60ml/min) Other serious medical conditions

Ages Eligible for Study
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Minimum Age: 21 Years
Maximum Age: 70 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Obstructive Sleep Apnoea (OSA)<br>Subjects with OSA | Diagnostic Test: Measurement of Urine and plasma metanephrines<br>* Measurement of Urine and plasma metanephrines<br>|
| Elevated Urine Metanephrines<br>Subjects with elevated metanephrines | Diagnostic Test: Measurement of Urine and plasma metanephrines<br>* Measurement of Urine and plasma metanephrines<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Urine and plasma metanephrines | Measurement of 24 hours urine metanephrines | 1 year | 
| Urine and plasma metanephrines | Measurement of plasma metanephrines | 1 year | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Relationship between metanephrine level and severity of OSA | comparison of metanephrine level and severity of OSA as dertermined by sleep study | 1 year | 
| Change in metanephrine levels with treatment for OSA | Change in plasma and urine metanephrine levels during treatment for OSA | 1 year |