Blood glucose monitoring by insulin-treated pilots of commercial and private aircraft: An analysis of out-of-range values

AIM

To examine blood glucose measurements recorded as part of the diabetes protocol operated by the UK, Ireland and Austria, which allows commercial airline pilots with insulin-treated diabetes to fly.

METHODS

An observational study was conducted in pilots with insulin-treated diabetes, granted medical certification to fly commercial or noncommercial aircraft, who recorded pre-flight and hourly in-flight blood glucose measurements. These values were correlated to a traffic light system (green 5.0 to 15.0 mmol/L; amber 4.0 to 4.9 mmol/L and 15.1 to 20.0 mmol/L; and red <4.0 mmol/L or >20.0 mmol/L) and studied for trends in glucose concentrations, time course within flight and any consequences. Pilot demographics were also analysed.

RESULTS

Forty-four pilots (90%) recorded one or more blood glucose value outside the green range during the 7 years of the study. Pilot age, diabetes type and duration, and follow-up period were comparable among subgroups, and mean glycated haemoglobin did not differ before and after certification in a way which would indicate poorer glycaemic control in any subgroup. A total of 892 blood glucose values (2.31%) were outside the green range, with half reported in-flight at various time intervals. There were 48 (0.12%) low red range values recorded, 14 (0.04%) of which occurred in-flight; all but four were restored to within the green range by the time of the next measurement. Appropriate corrective action was taken for all out-of-range values, with no reports of pilot incapacitation from any cause.

CONCLUSIONS

The traffic light system appears effective in identifying and reducing the frequency and severity of out-of-range values.

An Evaluation of the Safety of Pilots With Insulin-Treated Diabetes in Europe Flying Commercial and Noncommercial Aircraft

OBJECTIVE

The risk of hypoglycemia in people with insulin-treated diabetes has debarred them from certain "safety-critical" occupations, including flying commercial aircraft. This report evaluates the effectiveness of a protocol enabling a large cohort of insulin-treated pilots to fly commercially.

RESEARCH DESIGN AND METHODS

This was an observational study of pilots with insulin-treated diabetes who were granted medical certification to fly commercial and noncommercial aircraft. Clinical details, pre- and in-flight (hourly and 30 min before landing) blood glucose values were correlated against the protocol-specified ranges: green (5-15 mmol/L), amber (low, 4-4.9 mmol/L; high, 15.1-20 mmol/L), and red (low, <4 mmol/L; high, >20 mmol/L).

RESULTS

A total of 49 pilots with type 1 (84%) or type 2 (16%) diabetes who had been issued class 1 or class 2 certificates were studied. Median diabetes duration was 10.9 years. Mean HbA_1c was 7.2% (55.0 mmol/mol) before certification and 7.2% (55.1 mmol/mol) after certification (P = 0.97). Blood glucose values (n = 38,621) were recorded during 22,078 flying hours. Overall, 97.69% of measurements were within the green range, 1.42% within the low amber range, and 0.75% within the high amber range. Only 0.12% of readings were within the low red range and 0.02% within the high red range. Out-of-range readings declined from 5.7% in 2013 to 1.2% in 2019. No episodes of pilot incapacitation occurred, and glycemic control did not deteriorate.

CONCLUSIONS

The protocol is practical to implement, and no events compromising safety were reported. This study represents what is, to our knowledge, the most extensive data set from people with insulin-treated diabetes working in a "safety-critical" occupation, which may be relevant when estimating risk in other safety-critical occupations.