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Diabetes type II

Considerations

The increasing prevalance of diabetes type II is raising alarm bells from a population health perspective. Unfortunately pilots and Air Traffic Controllers are not immune to this trend. Immobility, excessive food intake, soft drinks and alcohol consumption in more than small amounts contribute to the development of obesity.

In type II diabetes endogenous Insulin is present, frequently with hyperinsulinaemia, but also frequently with a degree of insulin deficiency. There is insulin resistance.

Diabetes type II is an insidious desease that can progress with few of no symtoms, leading eventually to microangiopathy and serious complications. Regular General Examination for the purpose of certification and the associated blood investigations required under the General Directions should identify applicants with diabetes early, well before safety relevant complications arise.

The aviation safety risks relate to:

  • Intrinsic risks from the diabetes mellitus. These are possible visual and congitive symptoms, including fatigue whereby poor glycaemic control results in severe hyperglycaemia; and
  • Long term intrinsic risks from diabetes, with end organ damage to the heart, kidneys, eyes and nerves; and
  • Iatrogenic risks due to medication. The main concern being the risk of hypoglycaemia resutling in cognitive impairment, and possibly coma.

The diagnosis of diabetes in NZ is made according to the New Zealand Society for the Study of Diabetes (NZSSD)(external link).

The NZSSD guidelines are reproduced here:

  • HbA1c ≤ 40 mmol/mol and, if measured, fasting glucose ≤6 mmol/L is normal
  • In symptomatic individuals an HbA1c ≥50 mmol/mol and, if measured, a fasting blood glucose ≥7.0 mmol/l or a random glucose ≥ 11.1 mmol/l, is sufficient to establish the diagnosis of diabetes. Diabetes confirmed.
  • In asymptomatic individuals the same criteria apply but, to confirm the diagnosis of diabetes, a confirmatory test (preferably HbA1c) is needed on a separate occasion. Two results above the diagnostic cutoffs, on separate occasions are required for the diagnosis of diabetes.
  • Those with an HbA1c of 41-49 mmol/mol and , if measured, a fasting glucose concentration of 6.1 - 6.9 mmol/l, are categorized as ‘pre-diabetes’ or impaired fasting glucose (also called ‘dysglycaemia’ or ‘borderline diabetes’). Patients with values in this range should be advised on diet and lifestyle modification (and from the age of 35 have a full cardiovascular risk assessment and appropriate management). HbA1c measurement should be repeated after 6-12 months.

Meeting these diagnostic criteria should result in a clear diagnosis of diabetes. A full cardiovascular risk assessment and appropriate CV and glycaemic management should follow. Additionally entry into microvascular screening programmes (retinal photography, microalbuminuria, eGFR, foot checks) should be commenced.

The American Diabetes Association (ADA) also recommended abolishing the use of the oral glucose tolerance test. The WHO has so far retained the glucose tolerance test.

Information to be provided

  • A recent HbA1c determination result;
  • Recent pre and post prandial capillary glucose determination results through the day (5 results) on three different days, if the applicant is treated with a Sulphonylurea, or other oral agents capable of inducing hypoglycaemia;
  • Download and statistical analysis of glucometer data, if treated with Insulin or if using such a device;
  • Renal function, electrolytes, blood lipids, urinary Albumin and Albumin/Creatintine ratio determination results, undertaken within the last 12 months, or more recent results if considered reasonably necessary by the ME;
  • Blood lipids determination udertaken in accordance with the GD Timetable for Routine Examination [PDF 500 KB];
  • A special report – Diabetes;
  • A specialist report if using Insulin, Sulphonylurea or other agents capable of inducing hypoglycaemia;
  • A retinal screening result, undertaken within the past two years;
  • GP notes for the past 12 months unless treated by diet and/or or Metfomin only.

Disposition

  • An applicant with diabetes type II, controlled by the use of any agent capable of inducing hypoglycaemia, (i.e. Sulphonylurea, Insulin), should be considered as having a condition that is of aeromedical significance;
  • An applicant with diabetes type II, that is not well controlled or resulting in end organ damage, should be considered as having a condition that is of aeromedical significance;
  • An applicant with diabetes type II, well controlled by the use of a Biguanide only (i.e. Metformin), may be considered as having a condition that is not of aeromedical significance if there is no evidence of end organ damage and provided conditions of surveillance are imposed (refer Part 67). The applicant must be compliant with medication. The cardiovascular risk should be assessed in accordance with the applicable General Direction;
  • An applicant with diabetes type II, well controlled by diet, may be considered as having a condition that is not of aeromedical significance if there is no evidence of end organ damage. The cardiovascular risk should be assessed in accordance with the applicable General Direction.
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