From Reuters Health
- A short questionnaire can identify drivers with type 1 diabetes who are at high risk of future driving mishaps, and an online intervention can help them avoid these mishaps, according to a U.S. study.
“Like pilots who have to go through a pre-flight checklist to ensure all systems are a go, drivers with diabetes should go through a check list, asking themselves whether they have had more physical activity, taken more insulin, eaten fewer carbohydrates than usual, feel any unusual symptoms and judge whether they are low or likely to go low during the drive,” said lead author Dr. Daniel Cox from the University of Virginia Health System and Virginia Driving Safety Laboratory in Charlottesville.
“If the answer is yes, then they should take appropriate steps to avoid hypoglycemia while driving,” Cox said by email.
Drivers with type 1 diabetes have a greater risk of collisions than their spouses without diabetes, and those mishaps correspond to the use of insulin pumps, a history of collisions, severe low blood sugar (hypoglycemia) and previous hypoglycemia-related driving mishaps, the study team writes in Diabetes Care.
The researchers developed an 11-item questionnaire to screen drivers with type 1 diabetes for a high risk of driving mishaps and developed an online intervention intended to help high-risk individuals avoid future mishaps.
Their Risk Assessment of Diabetic Drivers (RADD) scale included questions about past experiences while driving, like “have you had an automobile accident or received a moving vehicle violation in the last 2 years?” and diabetes-specific questions like, “have you had low blood glucose in the past 6 months?” and “was it a hassle trying to hide dizziness or other symptoms of low blood glucose?”
Based on answers to 11 questions, around 35 percent of individuals with type 1 diabetes could be classified as high-risk drivers whose mishap rate was nearly three times higher than that of people in the low-risk group.
High-risk drivers who went on to participate in the online intervention at had a driving mishap rate of about 2.5 per year in the following 12 months, compared with about 4.25 mishaps per year among high-risk drivers who did not participate in the intervention. Still, the mishap rate of high-risk drivers who did the intervention remained higher than that of low-risk drivers.
“Driving is a privilege, not a right,” Cox said. “Whether we have type 1 diabetes, sleep apnea, narcolepsy, slowed reaction times due to aging, or some other chronic or acute condition (e.g., excessive sleepiness or intoxication), we all have a responsibility to ourselves, our families, and others on the road to ensure we are a safe driver.”
People with diabetes should realize they should never drive when their blood glucose is below 70, because it is too easy to slip from mild hypoglycemia to moderate hypoglycemia that impairs judgment, information processing speed, and general reaction time, Cox added. “As soon as hypoglycemia is detected or suspected, the driver should immediately safely pull off the road, treat it, and not resume driving until the hypoglycemia resolves.”
“Diabetic patients have a tendency not to disclose their driving mishaps or near miss events due to fear of losing their driving licenses," said Dr. Thinzar Min from Swansea University in the UK, who was not involved in the study.
In the UK, drivers are allowed only one severe hypoglycemic episode in 12 months to retain Group 1 license (cars and motorcycles) and no severe hypoglycemic episodes for Group 2 licenses (trucks and busses), Min noted.
“I think the RADD scale would be more accurate if the patients can use it to assess themselves if they are high-risk or not,” she said. “Online interventions should be aimed at all diabetic patients who are taking insulin.”
Dr. Eitaro Nakashima from Chubu Rosai Hospitalin Nagoya, Japan, wrote recently about the pitfalls of tightening driving regulations for diabetic patients in Japan and Europe. "In my opinion, each patient should understand the degree of risk of driving mishaps and prepare sugar in their car. For general public, education and individual customized treatment are important for good outcome instead of tightening of driving regulations,” he told Reuters Health by email.
SOURCE: Diabetes Care, online April 12, 2017.
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Predicting and Reducing Driving
Mishaps Among Drivers With
Type 1 Diabetes
Two aims of this study were to develop and validate 1) a metric to identify drivers
with type 1 diabetes at high risk of future driving mishaps and 2) an online intervention
to reduce mishaps among high-risk drivers.
To achieve aim A, in study 1, 371 drivers with type 1 diabetes from three U.S.
regions completed a series of established questionnaires about diabetes and
driving. They recorded their driving mishaps over the next 12 months. Questionnaire
items that uniquely discriminated drivers who did and did not have subsequent
driving mishaps were assembled into the Risk Assessment of Diabetic
Drivers (RADD) scale. In study 2, 1,737 drivers with type 1 diabetes from all
50 states completed the RADD online. Among these, 118 low-risk (LR) and
372 high-risk (HR) drivers qualified for and consented to participate in a
2-month treatment period followed by 12 monthly recordings of driving mishaps.
To address aim B, HR participants were randomized to receive either routine care
(RC) or the online intervention “” ( Half of the DD.
com participants received a motivational interview (MI) at the beginning and end
of the treatment period to boost participation and efficacy. All of the LR participants
were assigned to RC. In both studies, the primary outcome variable was
driving mishaps.
Related to aim A, in study 1, the RADD demonstrated 61% sensitivity and 75%
specificity. Participants in the upper third of the RADD distribution (HR), compared
with those in the lower third (LR), reported 3.03 vs. 0.87 mishaps/driver/
year, respectively (P < 0.001). In study 2, HR and LR participants receiving RC
reported 4.3 and 1.6 mishaps/driver/year, respectively (P < 0.001). Related to
aim B, in study 2, MIs did not enhance participation or efficacy, so the
and + MI groups were combined. participants reported fewer
hypoglycemia-related driving mishaps than HR participants receiving RC (P = 0.01),
but more than LR participants receiving RC, reducing the difference between the
HR and LR participants receiving RC by 63%. HR drivers differed from LR drivers at
baseline across a variety of hypoglycemia and driving parameters.
The RADD identified higher risk drivers, and identification seemed relatively stable
across time, samples, and procedures. This 11-item questionnaire could inform
patients at higher risk, and their clinicians, that they should take preventive steps
to reduce driving mishaps, which was accomplished in aim B using
From the article
Vehicular collisions are the eighth leading
cause of death worldwide, accounting
for 1.24 million deaths in 2010. They
are projected to be the fifth leading
cause of death by 2030 (1). In the U.S.,
35,092 fatalities and an estimated 2.44
million nonfatal injuries occurred in
2015, costing the U.S. economy more
than $99 billion (2). Compared with
spouses without diabetes, drivers with
type 1 diabetes have greater risk of vehicular
collisions (2), possibly because of
the acute disruptive effects on cognitivemotor
abilities during periods of extreme
blood glucose (BG) (3,4) and
chronic complications such as retinopathy
and neuropathy that can interfere
with safe motor vehicle operation (5).
However, not all drivers with type 1 diabetes
are at an elevated risk of driving
mishaps. Research demonstrates that
compared with those without driving
mishaps, drivers with two or more mishaps
in the previous 12 months had
greater insulin sensitivity, released less
epinephrine during hypoglycemia, had
fewer hypoglycemia-specific symptoms
(6,7), performed worse on neuropsychological
tests during hypoglycemia (8),
and drove more poorly in a driving simulator
during hypoglycemia (but not euglycemia)
When examining drivers
who documented driving mishaps prospectively
over 12 months, mishaps
were not related to age, sex, duration
of disease, HbA1c, or awareness of selfreported
hypoglycemia. Instead, future
mishaps corresponded to the use of
insulin pumps, a history of collisions,
severe hypoglycemia, and hypoglycemiarelated
driving mishaps (9).
In recognition of this increased rate of
mishaps among drivers with type 1 diabetes,
the American Diabetes Association
(ADA) released a position statement on
diabetes and driving (10), which recommends
that clinicians should screen for
elevated risk and intervene to reduce it.
However, no specific screening tool or intervention
is available. To address this
gap, we developed and tested a brief
questionnaire that would allow a clinician
to screen drivers with type 1 diabetes
for a high risk of driving mishaps (aim
A). Further, we developed an Internet intervention
( intended to assist
high-risk individuals to better anticipate,
prevent, detect, and treat hypoglycemia
while driving in order to avoid future driving
mishaps (aim B).
The Internet program,, which
focuses on the anticipation, prevention,
detection, and treatment of hypoglycemia
while driving, was effective at reducing
hypoglycemia-related driving
mishaps among HR drivers with type 1
diabetes. Beyond its efficacy, an advantage
of this intervention is the online
format, which made it immediately
available to participants (regardless of
their geographic location) in the privacy
and convenience of their own homes,
and did not require any clinic visits.
The improvement in hypoglycemiarelated
driving mishaps cannot be attributed
to changes in general attitudes and
self-reported behaviors involving driving
and hypoglycemia, as these improved
equally in participants in the DD.comAll
group and the HR group receiving RC. It
is also important to note that
only affected hypoglycemia-related driving
mishaps, not hyperglycemia- or nondiabetes-
related mishaps. Together,
these data suggest that had the
specific effect intended: reducing the occurrence
of hypoglycemia-related driving
mishaps. The results also suggest that the
HR group receiving RC derived some psychological
and behavioral benefits from
participating in this study, perhaps by
completing questionnaires that raised
their level of awareness regarding their
own driving risk.
Like the Diabetes Control and Complications
Trial, which relied on participant
self-report of severe hypoglycemia (33),
this randomized clinical trial relied on
self-report of driving mishaps and causal
attributions. Concern about participant
response bias is lessened by the fact that
HR participants receiving RC reported a
higher incidence of driving mishaps than
LR participants receiving RC, and that all
groups reported a similar number of
hyperglycemia- and non-diabetes-related
driving mishaps. It may be that individuals
who devoted the time and effort to
complete this program had a differential
bias in not reporting drivingmishaps. This
seems unlikely, however, given that the
number of driving mishaps in the two groups was similar, whereas the
number of mishaps reported in the two
RC groups differed.
Other methodological limitations exist,
which should be noted. 1) This design
did not allow us to determine
whether a simpler, shorter intervention
could have been as effective as this fiveunit
program. It may be that just giving
HR drivers the tool kit and simple instructions
concerning how to anticipate,
prevent, detect, and treat hypoglycemia
would have yielded similar results. 2)
Because we did not test with
LR or intermediate-risk drivers, we cannot
determine the effect of the intervention
on those samples of drivers. 3)
Because DD.comAll participants attributed
25% of their driving mishaps to hyperglycemia,
this intervention could
possibly be enhanced by also focusing
on anticipating, preventing, detecting,
and treating driving-related hyperglycemia.
4) Given that the participant sample
was recruited via the Internet,
results from this selective sample may
not generalize to all drivers with type 1
diabetes. 5) An additional limitation is
that only 70% of the participants eventually
completed the intervention, regardless
of whether they received MIs.
This is unlikely to be a consequence of
the online study format, since both RC
groups had a higher rate of monthly diary
completion (96%) than either of the
intervention groups. Noteworthy is that
the highest dropout rate coincided
with the completion of unit 3, in which
there was the highest demand for
“homework” activities (i.e., extensive
reporting of driving diary activities).
Nonetheless, in this large-scale, national,
8 Predicting and Reducing Driving Mishaps Diabetes Care
randomized trial with a 12-month followup, significantly reduced the
risk of future driving mishaps among
HR drivers with type 1 diabetes. This
demonstrates that driving risk can be
reduced in those drivers who are more
vulnerable to hypoglycemia-related
driving mishaps.
This series of studies demonstrates that
some drivers with type 1 diabetes are
at greater risk of driving mishaps. These
HR drivers can be identified using the
RADD, a brief, psychometrically sound
questionnaire that the ADA will soon
host on their website. Finally, the incidence
of future driving mishaps among
HR drivers can be reduced via the DD.
com Internet intervention, which helps
drivers with type 1 diabetes to better
anticipate, prevent, detect, and treat
hypoglycemia while driving.
www red DiabetologNytt