Commercial Pilots on Insulin ?
Ries Simons, consultant Aerospace Medicine
Chairman Advisory Board - European Society of Aerospace Medicine
Ries Simons FEB 2014
I have no financial relationships to disclose.
Ries Simons, M.D.
I will not discuss off-label use and/or investigational use
in my presentation
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March 2012
www.esam.aero
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There is consensus on the need for insulin in T1 and T2DM treatment to prevent microvascular and macrovascular complications.
Hypoglycaemia represents a significant and unacceptable threat to flight safety.
Discussion Statements
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Hypoglycaemia should always be prevented (not only in pilots)
Hypoglycaemia → syndromes of defective glucose regulation
→ impaired awareness of hypoglycemia
→ reduction neuroendocrine/symptomatic responsesto hypoglycaemia
[Cryer, 1992 ; Heller & Cryer, 1991]
Vicious Circle of Hypoglycaemia
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Risk Factors for Hypoglycaemia
Use of insulin or sulfonylureas
Have a lower HbA1c
Prior hypoglycaemia
C-peptide negativity
Long duration of DM
Hypoglycaemia unawareness
Alcohol / β-blockers / ACE-inhibitors
Irregular eating habits / fasting / fear of hyperglycaemia
Exercise
Older people
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Type 2 diabetics on insulin can also become hypoglycaemic !
Risk of severe hypoglycaemia ≈ similar in T2 and T1 DM
when matched for disease duration
Risk of car crashes:
no clear relationship with type of diabetes[2nd EU Working Group on Diabetes and Driving, 2005]
[Leese et al., 2003; Swinnen et al., 2009]
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Factors preventing Hypoglycaemia in Pilots
Consider only stable cases
Frequent monitoring of blood glucose (SMBG/CGM)
Use of long-acting + rapid-acting insulin analogues
Training in absolute avoidance of hypoglycaemia
Identify hypoglycaemic unawareness by
hyperinsulinaemic-hypoglycaemic clamp tests ?
Being a professional pilot
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CGM may reduce overall hypoglycemic exposure in well-controlled type 1 diabetes [Juvenile Diabetes Research Foundation CGM Study Group, 2009]
Real-time CGM reduced severe hypoglycemia in hypo-unaware T1DM patients [Choudhary et al., Diabetes Care 2013]
Continuous Glucose Monitoring
Frequent monitoring of blood glucose (SMBG or CGM)
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[Jensen et al., 2013]
CGM may be inaccurate in the hypoglycemic range, with hypoglycemic events confirmed by SMBG but not CGM[Rebrin et al., 2010; Kovatchev et al., 2008; Bode et al., 2004]
CGM + model: optimises prediction [Jensen et al., 2013]
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Heller et al., Lancet 2012; 379:1489-97
Type 1 DM
Long acting analogues: Less Hypos ?
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Long acting analogues: Less Hypos ?
Type 2 DM
Garber et al., Lancet 2012; 379:1498-507
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Restoration of self-awareness of hypoglycemia in adults with long-standing type 1 diabetes: hyperinsulinemic-hypoglycemic clamp substudy results from the HypoCOMPaSS trial (Leelarathna et al., 2013)
After HypoCOMPaSS education, mean BG at which subjects first felt hypoglycemic increased: from 2.6 to 3.1 mmol/L and symptom and plasma metanephrine responses to hypoglycemia were higher.
18 subjects with T1D and IAH: mean age 50, T1D duration 35 yrs, HbA1c 8.1% [65 mmol/mol]
Training aimed at absolute avoidance of hypoglycaemia
Other training programmes: BGAT, HyPOS, DAFNE
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“Healthy” reaction: hyperinsulinaemic hypoglycaemia characterized by a significant increase in the plasma adrenaline concentration and by decreases in peripheral resistance and diastolic blood pressure.
Hyperinsulinaemic-hypoglycaemic clamp test when in doubt?
[Laitinen et al, 2003 – n=18]
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Identify hypoglycaemic unawareness:hyperinsulinaemic-hypoglycaemic clamp tests ?
Hyperinsulinemic hypoglycemic clamp: insulin is infused at a constant rate but blood glucose is allowed to fall and is fixed at a hypoglycemic level.
The hypoglycemic clamp can be used to test hypoglycemic counterregulation.
Antecedent hypoglycemia blunted the counterregulatory responses (epinephrine and sympathetic nerve activity) in type 2 and type 1 diabetics (compared with healthy controls) [Davis et al., 2009]
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The only method to exclude impaired performance due to
in-flight hypoglycaemia will be to ensure that BG levels are
≥5 mmol/l (≥91 mg/dl) during the entire flight operation [Warren & Frier, 2005]
Discussion Statement
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ESAM Recommendation
ITDM applicants may be considered for aeromedical certification:
on a case by case basis
using a protocol based on the principles developed by
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Important entry criteria to the protocol:
Evidence of stable glycaemic control
HbA1c between 6.5 and 8.0% (42–64 mmol/mol) blood glucose analysis over 3 months before application:
≤5% of readings <4.0 mmol/L80% of readings 5 - 15 mmol/L)
no recurrent (≤ 2) severe hypoglycaemia in past 5 years no severe hypoglycaemia in the preceding 1 year
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Pre- and In-Flight Requirements
5-15 mmol/l (91 - 273 mg/dl)
>6 mmol/l (110 mg/dl)
5.5-16.5 mmol/l (100-300 mg/dl)
5-15 mmol/l (91 - 273 mg/dl)
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ADA/EASD recommendations
HbA1c concentration of between 6 and 7% (42–53 mmol/mol)
This enables pilots to have safe in-flight blood glucose, because in stable patients these HbA1c values are associated with average estimated glucose concentrations of between
7.0 mmol/L and 8.6 mmol/L (126 -154 mg/dL)
(eAG [mg/dl] = 28.7 x HbA1c – 46.7)[American Diabetes Association, 2011; Nathan et al., 2008]
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Commercial pilots: more complicated?
Pro: Multi-pilot OPS: in-flight BG management easy to do
Con: Circadian problems
Con: Irregular rosters
Con: Delays
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Commercial pilots: more complicated?
Con: Circadian problems
Con: Irregular rosters
Con: Delays
Problems may be overcome by:
tailor-made training
self-management BG
long acting insulin analogue + ‘on demand’ short acting analogues
long-haul simulator ‘try-outs’ at circadian difficult times of day + delays
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Avoid to come near upper limit of 15 mmol/L (273 mg/dL):
seems safe for cognitive-motor function* [Cox et al. 2005]
may allow too high BG during big part of professional life high BG during long-haul flight may cause dehydration (?)
Considerations regarding Commercial Pilots:
Flying is their job: 8-11 hrs / 4-5 days a week
* Would this also apply to slightly hypoxic pilots?
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King et al. (2011). Changes in Altitude Cause Unintended Insulin Delivery From Insulin Pumps: Mechanisms and implications.
Diabetes Care 34:1932–1933, 2011
In-flight: + 1.37 U of 5 Animas Pumps (0.685% of cartridge volume)
+ 1.01 U of 5 Medtronic Pumps (0.561% of cartridge volume)
Rapid Decompression: + >8 Units All Pumps
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We will confidently fly with an insulin-treated pilot who has astable glycaemic control, has no substantial disease complications, and is compliant with self measurement and management of pre-flight and in-flight blood glucose.
Civil aviation authorities should continue to aim for consistency in guidelines between international authorities and consider individual cases of insulin-treated pilots for certification.
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Data of all pilots flying with insulin should be systematically collected to assess the usefulness and safety of the
recommendations
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Insulin treated ATCOs
Should be considered on a case by case basis
Same principles as for pilots, but easier to replace in case of symptoms
When started on insulin treatment, ATCO must be reassigned to non-safety related duties for 3 months or until criteria for acceptableblood glucose regulations are met.
ITDM ATCOs should identify themselves to supervisors/colleagues,who should be informed about symptoms of hypoglycemia.
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A huge challenge both for the applicant
and the examiner . . . . . .
The art of medicine is to give the best individual guidance,
based on science and individual clinical considerations . . .
But it is satisfying, because