Driving mishaps among individuals with type 1 diabetes: a prospective study

The association between diabetes and safe driving: A systematic search and review of the literature and cross-reference with the current guidelines

AIMS

We conducted this review to characterize the quality of evidence about associations between diabetes and safe driving and to evaluate how these findings are reflected within current guidelines available to support clinicians and their patients with diabetes.

METHODS

The first stage entailed a systematic search and review of the literature. Evidence surrounding harms associated with diabetes and driving was identified, screened, extracted and appraised for quality utilizing the Newcastle Ottawa Scales (NOS). Next, relevant guidelines regarding driving and diabetes were sourced and summarized. Finally, the identified guidelines were cross-referenced with the results of the systematic search and review.

RESULTS

The systematic search yielded 12,461 unique citations; 52 met the criteria for appraisal. Fourteen studies were rated as 'high', two as 'medium' and 36 as 'low'. Studies with ratings of 'high' or 'medium' were extracted, revealing a body of inconsistent methods and findings. These results, cross-referenced with the guidelines, suggest a lack of agreement and a limited evidence base to justify recommendations.

CONCLUSIONS

The results presented emphasize the need for a better understanding of the impacts of diabetes on safe driving to inform evidence-based guidelines.

[Diabetes mellitus and road traffic-a position paper of the Austrian Diabetes Association (update 2023)]

Public safety (prevention of accidents) is the primary objective in assessing fitness to drive a motor vehicle. However, general access to mobility should not be restricted if there is no particular risk to public safety. For people with diabetes mellitus, the Führerscheingesetz (Driving Licence Legislation) and the Führerscheingesetz-Gesundheitsverordnung (Driving Licence Legislation Health enactment) regulate important aspects of driving safety in connection with acute and chronic complications of the disease. Critical complications that may be relevant to road safety include severe hypoglycemia, pronounced hyperglycemia and hypoglycemia perception disorder as well as severe retinopathy and neuropathy, endstage renal disease and certain cardiovascular manifestations. If there is a suspicion of the presence of one of these complications, a detailed evaluation is required.In addition, the individual antihyperglycemic medication should be checked for existing potential for hypoglycemia. Sulfonylureas, glinides and insulin belong to this group and are therefore associated with the requirement of a 5-year limitation of the driver's license. Other antihyperglycemic drugs without potential for hypoglycemia such as Metformin, SGLT‑2 inhibitors (Sodium-dependent-glucose-transporter‑2 inhibitors, gliflozins), DPP-4-inhibitors (Dipeptidyl-Peptidase inhibitors, gliptins), and GLP‑1 analogues (GLP‑1 rezeptor agonists) are not associated with such a time limitation.The relevant laws which regulate driving safety give room for interpretation, so that specific topics on driving safety for people with diabetes mellitus are elaborated from a medical and traffic-relevant point of view. This position paper is intended to support people involved in this challenging matter.

Evaluation of motor vehicle crashes between scooter riders and car drivers after diagnosis of type 2 diabetes in Taiwan

BACKGROUND

Despite the plausibility that diabetes may increase the risk of motor vehicle crashes (MVCs) due to various diabetes related complications and co-morbidity, findings from epidemiological studies on the relationship between diabetes and MVCs remained inclusive mainly due to heterogeneity in the study design and failure to complete consideration of potential confounders. This study re-visited this putative association with an improved study design.

METHOD

This study employed a controlled before-after study design and included 1,264,280 people aged 18-75 years with T2D newly diagnosed from 2009-2014 and an equal number of age-, sex-, and time-matched controls. The rate ratios (RRs) of vehicle type-specific incidence rates of MVCs in the 1 and 2 years before and after diabetes diagnosis (or the matched dates) were compared between the individuals with type 2 diabetes (T2D) and their matched controls.

RESULTS

The rate of MVCs increased slightly among people with T2D over 1 and 2 years following diabetes diagnosis, with RRs of 1.04 (95% confidence interval [CI]=1.02-1.07) and 1.11 (95% CI=1.09-1.13), respectively. These RRs were comparable to those obtained for controls (1.06 and 1.12, respectively). By contrast, the RRs of scooter crashes were significantly higher in the T2D group than in the control group during the 1 year (1.28 vs. 1.08, p < 0.001) and 2 years (1.32 vs. 1.08, p < 0.001) following diabetes diagnosis.

CONCLUSION

T2D diagnosis was associated with a moderate but significant increase in the risk of MVCs among scooter drivers, but not among car drivers.

Sugar and stops in drivers with insulin-dependent type 1 diabetes

BACKGROUND

Diabetes is a major public health challenge, affecting millions of people worldwide. Abnormal physiology in diabetes, particularly hypoglycemia, can cause driver impairments that affect safe driving. While diabetes driver safety has been previously researched, few studies link real-time physiologic changes in drivers with diabetes to objective real-world driver safety, particularly at high-risk areas like intersections. To address this, we investigated the role of acute physiologic changes in drivers with type 1 diabetes mellitus (T1DM) on safe stopping at stop intersections.

METHODS

18 T1DM drivers (21-52 years, μ = 31.2 years) and 14 controls (21-55 years, μ = 33.4 years) participated in a 4-week naturalistic driving study. At induction, each participant's personal vehicle was instrumented with a camera and sensor system to collect driving data (e.g., GPS, video, speed). Video was processed with computer vision algorithms detecting traffic elements (e.g., traffic signals, stop signs). Stop intersections were geolocated with clustering methods, state intersection databases, and manual review. Videos showing driver stop intersection approaches were extracted and manually reviewed to classify stopping behavior (full, rolling, and no stop) and intersection traffic characteristics.

RESULTS

Mixed-effects logistic regression models determined how diabetes driver stopping safety (safe vs. unsafe stop) was affected by 1) disease and 2) at-risk, acute physiology (hypo- and hyperglycemia). Diabetes drivers who were acutely hyperglycemic (≥ 300 mg/dL) had 2.37 increased odds of unsafe stopping (95% CI: 1.26-4.47, p = 0.008) compared to those with normal physiology. Acute hypoglycemia did not associate with unsafe stopping (p = 0.537), however the lower frequency of hypoglycemia (vs. hyperglycemia) warrants a larger sample of drivers to investigate this effect. Critically, presence of diabetes alone did not associate with unsafe stopping, underscoring the need to evaluate driver physiology in licensing guidelines.

CONCLUSION

This study links acute, abnormal physiologic fluctuations in drivers with diabetes to driver safety based on unsafe stopping at stop-controlled intersections, providing recommendations for clinicians aimed at improving patient safety, fair licensing guidelines, and targets for developing advanced driver assistance systems.

Driving with Type 1 Diabetes: Real-World Evidence to Support Starting Glucose Level and Frequency of Monitoring During Journeys

There is limited evidence supporting the recommendation that drivers with insulin-treated diabetes need to start journeys with glucose >90 mg/dL. Glucose levels of drivers with type 1 diabetes were monitored for 3 weeks using masked continuous glucose monitoring (CGM). Eighteen drivers (median [IQR] age 40 [35, 51] years; 11 men) undertook 475 trips (duration 15 [13, 21] min). Hypoglycemia did not occur in any trip starting with glucose >90 mg/dL (92%; n = 436). Thirteen drivers recorded at least one trip (total n = 39) starting with glucose <90 mg/dL. Among these, driving glucose was <70 mg/dL in five drivers (38%) during 10 trips (26%). Among five drivers (28%), a ≥ 36 mg/dL drop was observed within 20 min of starting their journey. Journey duration was positively associated with maximum glucose change. These findings support current guidelines to start driving with glucose >90 mg/dL, and to be aware that glucose levels may change significantly within 20 min. A CGM-based, in-vehicle display could provide glucose information and alerts that are compatible with safe driving. Clinical Trial Registration number: ACTRN12617000520336.

Hypoglycemia While Driving in Insulin-Treated Patients: Incidence and Risk Factors

OBJECTIVES

This study aimed to investigate a potential daily-life concern for patients with diabetes hypoglycemia while driving by (1) estimating their incidence in insulin-treated drivers, (2) determining factors associated with their occurrence, and (3) analyzing patients' behavior regarding prevention of hypoglycemia.

METHODS

We conducted an observational study from November 2013 to May 2018 in the endocrinology-diabetology-nutrition department of our university hospital. All patients treated for diabetes older than 18 years admitted in the department were eligible. A specific questionnaire assessing attitudes, knowledge, and consequences of hypoglycemia was provided. In this study, only insulin-treated patients who regularly drive were analyzed.

RESULTS

On the 233 insulin-treated drivers included, 45 (19%) self-reported at least 1 hypoglycemia while driving in the preceding year. Two factors were significantly associated with their occurrence: type 1 diabetes (odds ratio [OR] = 3.19; 95% confidence interval [CI] = 1.55-6.57) and experiences of asymptomatic hypoglycemia (OR = 2.20; 95% CI = 1.05-4.63). Awareness of the treatment hypoglycemia risk because of information provided by a medical specialist was also but nonsignificantly associated with hypoglycemia while driving (OR = 2.61; 95% CI = 0.86-7.92). Forty-one patients (18%) combined those 3 variables, 20 (49%) of them self-reported hypoglycemia while driving. Thirty-four percent of the patients never carried carbohydrates for hypoglycemia correction. Seventy-six percent do not monitor blood glucose level before driving.

CONCLUSIONS

Our questionnaire allowed us to highlight that 19% our cohort of insulin-treated drivers declared experiencing hypoglycemia while driving. Risk factors identified and prevention data collected should help us better target patient education.

Diabetes and driving safety: A survey among health care professionals in Saudi Arabia

AIMS

Diabetes mellitus may impair an individual's fitness to drive. In this study, we explore health care providers' (HCPs) knowledge of problems associated with diabetes and driving, and evaluate the consistency of counseling on driving safety for patients with diabetes.

METHODS

We conducted a cross-sectional survey-based study among HCPs in Saudi Arabia. We designed a web-based questionnaire to collect demographic data, assess HCPs' knowledge of driving and diabetes and their compliance with driving safety regulations, and meet Diabetes Canada's and the British Driver and Vehicle Licensing Agency's recommendations. Data were analyzed using descriptive statistics and chi-square analysis.

RESULTS

We received 389 responses to the questionnaire. The majority of the respondents were consultants (38.8%), worked in governmental institutes (72.2%), and managed more than 30 patients weekly (34.4%). Only 5.7% of HCPs correctly answered all the driving safety questions. Diabetes educators and general practitioners had the fewest correct answers (p-value 0.03). About 12.6% of HCPs stated that they always counseled their patients about driving safety strategies.

CONCLUSION

HCPs' education in problems associated with diabetes and driving should be improved to ensure quality counseling for their patients.

Incidence of ocular and systemic diseases affecting visual function among state bus drivers

Purpose:

To evaluate the incidence of ocular and systemic disease affecting visual function among state transport corporation bus drivers in a south Indian district.

Methods:

This retrospective study analysed the records of all the drivers who presented to a south Indian tertiary-care eye hospital in 2019 for their mandatory annual ocular check-up. Details reviewed included demographic details; refraction; presence of systemic and ocular diseases with vision-threatening potential; presence of ocular conditions responsible for visual loss and the treatment administered.

Results:

3042 drivers (mean age, 47.0 ± 5.7 years) were evaluated. Visual function-threatening systemic diseases were present in 25.0% drivers, out of which diabetes mellitus (18.7%) was the most common pathology. The most common ocular problem was refractive error (45.0%). Visual function-threatening ocular diseases were present in 9.5% drivers. Diabetic retinopathy, visually-significant cataract, glaucoma and central serous chorioretinopathy were noted in 4.0%, 1.9%, 1.7% and 0.8% drivers. Surgical intervention was required in 2.2% drivers. Thirteen drivers were temporarily deemed unfit for driving heavy-weight vehicles.

Conclusion:

Several bus drivers suffer from vision-threatening systemic and ocular diseases. Some of them require surgical intervention to retain fitness. A complete ocular and systemic evaluation of diseases with vision-threatening potential should be performed at the time of renewal of the driving license. The drivers should be educated about the systemic diseases which can affect their driving skills and must be encouraged to seek medical help at an early stage.

Predictors of traffic events due to hypoglycemia in adults with type 1 diabetes: A Brazilian prospective cohort study

BACKGROUND

Individuals with type 1 diabetes (T1D) are exposed to an elevated risk of automobile accidents especially because of hypoglycemia that impairs physiological and defense responses.

OBJECTIVES

To assess local risk factors for traffic events in T1D adult Brazilian patients.

METHODS

This is a prospective study and 12-month follow-up to assess predictors for traffic events on a cohort of drivers with T1D (n = 168) in Brazil. The inclusion criteria for participants were Brazilian nationality, age ≥ 18 years-old, diagnosis of T1D for more than one year, driving license B, C or D categories (four-wheel vehicles), driving three-times per week or more, and checking blood glucose twice-daily or more. The primary outcome was hypoglycemia driving mishaps assessed by a seven-query questionnaire about the past 30 days. Secondary outcomes included driving mishaps not related to hypoglycemia. Statistical analysis was performed through Poisson regression models with robust variance estimarion, in which the measure of association is the relative risk.

RESULTS

A total of 109 participants completed the 12-month follow-up. Most of them were men (66%) and 37 ± 11 years-old, and had a mean HbA1c of 8.2% (66 mmol/mol). In the follow up, the incidence of traffic events was high (70.6%); however, only a minority was attributed to hypoglycemia as the cause of the reported event (19.3%). The best predictors for new traffic events due to hypoglycemia were those related to driving characteristics. The best of them was a history of episodes of hypoglycemia while driving [RR 3.40 (1.22-9.43); p < 0.05].

CONCLUSIONS

We found that previous episodes of hypoglycemia while driving significantly increase the risk of new traffic events and are the best predictor for it. This highlights the need to assess the risks of traffic accidents especially in people who have had experienced episodes of hypoglycemia while driving.

Type 2 diabetes can undermine driving performance of middle-aged male drivers through its deterioration of perceptual and cognitive functions

It has been widely agreed that it is risky for patients with diabetes to drive during hypoglycemia. However, driving during non-hypoglycemia may also bring certain safety hazards for some patients with diabetes. Based on previous studies on diabetes-related to early aging effect, as well as gender differences in health belief and driving behavior, we have hypothesized that middle-aged male drivers with type 2 diabetes, compared with the control healthy ones, may experience a decline in driving performance without awareness. And the decline is caused by impaired perceptual and cognitive driving-related functions. To verify these hypotheses, we recruited 56 non-professional male drivers aged between 40 and 60 (27 patients with type 2 diabetes and 29 healthy controls) to perform a simulated car-following task and finish behavioral tests of proprioception, visual search, and working memory abilities during non-hypoglycemia. They also reported their hypoglycemia experience and perceived driving skills. We found that the patients had equal confidence in their driving skills but worse driving performance as shown in larger centerline deviation (t = 2.83, p = .006), longer brake reaction time (t = 3.77, p = .001) and shorter minimum time-to-collision (t = -3.27, p = .002). Such between-group differences in driving performance could be fully mediated by proprioception, visual search ability, and working memory capacity but not by hypoglycemia experience. Regarding the effect sizes of the mediation, the visual search ability played the most important role, and then followed the working memory and the proprioception. This initial study provides original and first-hand evidence demonstrating that the middle-aged male drivers with type 2 diabetes have deteriorated driving performance, but they are unaware of it. We will also discuss the possible measures to identify people of the highest risk and improve their safety awareness by using the findings of the current study.

Quantifying vehicle control from physiology in type 1 diabetes

Objective: Our goal is to measure real-world effects of at-risk driver physiology on safety-critical tasks like driving by monitoring driver behavior and physiology in real-time. Drivers with type 1 diabetes (T1D) have an elevated crash risk that is linked to abnormal blood glucose, particularly hypoglycemia. We tested the hypotheses that (1) T1D drivers would have overall impaired vehicle control behavior relative to control drivers without diabetes, (2) At-risk patterns of vehicle control in T1D drivers would be linked to at-risk, in-vehicle physiology, and (3) T1D drivers would show impaired vehicle control with more recent hypoglycemia prior to driving.Methods: Drivers (18 T1D, 14 control) were monitored continuously (4 weeks) using in-vehicle sensors (e.g., video, accelerometer, speed) and wearable continuous glucose monitors (CGMs) that measured each T1D driver's real-time blood glucose. Driver vehicle control was measured by vehicle acceleration variability (AV) across lateral (AV_Y, steering) and longitudinal (AV_X, braking/accelerating) axes in 45-second segments (N = 61,635). Average vehicle speed for each segment was modeled as a covariate of AV and mixed-effects linear regression models were used.Results: We analyzed 3,687 drives (21,231 miles). T1D drivers had significantly higher overall AV_{X, Y} compared to control drivers (B_X = 2.5 × 10^-2B_Y = 1.6 × 10^-2, p < 0.01)-which is linked to erratic steering or swerving and harsh braking/accelerating. At-risk vehicle control patterns were particularly associated with at-risk physiology, namely hypo- and hyperglycemia (higher overall AV_X,Y). Impairments from hypoglycemia persisted for hours after hypoglycemia resolved, with drivers who had hypoglycemia within 2-3 h of driving showing higher AV_X and AV_Y. State Department of Motor Vehicle records for the 3 years preceding the study showed that at-risk T1D drivers accounted for all crashes (N = 3) and 85% of citations (N = 13) observed.Conclusions: Our results show that T1D driver risk can be linked to real-time patterns of at-risk driver physiology, particularly hypoglycemia, and driver risk can be detected during and prior to driving. Such naturalistic studies monitoring driver vehicle controls can inform methods for early detection of hypoglycemia-related driving risks, fitness to drive assessments, thereby helping to preserve safety in at-risk drivers with diabetes.

Looking for an optimal pedal layout to improve the driving performance of patients with diabetic peripheral neuropathy

Diabetes can undermine people's ability to drive safely, but most previous studies have focused on its deterioration of the central nervous system. This study sought to investigate how diabetic peripheral neuropathy (DPN), a common complication of diabetes characterized by reduced sensitivity of the limbs, can influence people's braking behavior and other safety-related measures of driving. In addition, it also tested how such a deteriorating effect can be reduced by using certain pedal layout designs. In total, 29 healthy drivers and 31 drivers of type 2 diabetes matched in demographic variables were invited to participate in this study. The participants with type 2 diabetes (they are from here on out referred to as "patients")were then split into two subgroups based on the severity of DPN using the median of the Semmes-Weinstein monofilaments Examination (SWME) scores. All three groups of participants finished a series of vehicle-pedestrian conflict tasks in a driving simulator using nine different types of pedal layouts. These layouts varied in the lateral distance between the accelerator and the brake (45 mm, 60 mm, and 75 mm) and the width of brake pedals (50 mm, 70 mm, 90 mm). The results showed that patients with serious DPN had longer brake reaction times (BRT) and shorter minimum distance-to-collision (DTC) as compared to the other two groups. However, the effects of such a disadvantage varied across different pedal layouts. When the accelerator-brake distance was 45 mm, patients with serious DPN showed no compromised driving performance as compared to other two groups. In conclusion, we found the DPN could undermine driving performance of participants with type 2 diabetes, and a closer accelerator-brake lateral distance (45 mm) may be an optimal choice for them to counteract such a negative influence.

Driving Safety and Real-Time Glucose Monitoring in Insulin-Dependent Diabetes

Our goal is to address the need for driver-state detection using wearable and in-vehicle sensor measurements of driver physiology and health. To address this goal, we deployed in-vehicle systems, wearable sensors, and procedures capable of quantifying real-world driving behavior and performance in at-risk drivers with insulin-dependent type 1 diabetes mellitus (DM). We applied these methodologies over 4 weeks of continuous observation to quantify differences in real-world driver behavior profiles associated with physiologic changes in drivers with DM (N=19) and without DM (N=14). Results showed that DM driver behavior changed as a function of glycemic state, particularly hypoglycemia. DM drivers often drive during at-risk physiologic states, possibly due to unawareness of impairment, which in turn may relate to blunted physiologic responses (measurable heart rate) to hypoglycemia after repeated episodes of hypoglycemia. We found that this DM driver cohort has an elevated risk of crashes and citations, which our results suggest is linked to the DM driver's own momentary physiology. Overall, our findings demonstrate a clear link between at-risk driver physiology and real-world driving. By discovering key relationships between naturalistic driving and parameters of contemporaneous physiologic changes, like glucose control, this study directly advances the goal of driver-state detection through wearable physiologic sensors as well as efforts to develop "gold standard" metrics of driver safety and an individualized approach to driver health and wellness.

Safe driving practices and factors associated with motor-vehicle collisions among people with insulin-treated diabetes mellitus: Results from the Diabetes and Driving (DAD) study

INTRODUCTION

The aim of this study was to assess the prevalence of people with insulin-treated diabetes mellitus (ITDM) who have discussed issues related to diabetes and driving with their health care providers (HCPs). We also sought to determine the safe driving practices that are currently employed by this group. Finally, we investigated the factors that might increase the risk of motor-vehicle collisions (MVCs) among this group in Saudi Arabia.

METHOD

This cross-sectional study surveyed a representative sample of 429 current male drivers with ITDM using a structured questionnaire in Saudi Arabia.

RESULTS

Most of the participants (76.5%) never discussed topics regarding diabetes and driving with their HCPs. The majority of the participants (61.8%) reported at least never doing one of the following: (a) carrying a blood glucose testing kit while driving, (b) testing their blood glucose level before driving or during a journey, or (c) having thought of a specific threshold of blood glucose level that would preclude driving. Three factors were associated with a higher risk of MVCs among participants with ITDM: (a) being on a basal/boluses regimen, (b) never having a discussion regarding diabetes and driving with their HCPs, and (c) having experienced hypoglycemia during driving.

CONCLUSIONS

The majority of people with ITDM had not had a discussion regarding diabetes and driving with their HCPs, which was reflected by a lack of safe driving practices. People with ITDM should be encouraged to take precautions while driving in order to prevent future MVCs.

PRACTICAL APPLICATIONS

This research highlights the importance of investing more effort in educating drivers who have diabetes about safe driving practices by their health care providers. Also, it will attracts the attention of policymakers for an urgent need to establish clear policies and procedures for dealing with drivers who have diabetes.

Variability of Diabetes Alert Dog Accuracy in a Real-World Setting

BACKGROUND

Diabetes alert dogs (DADs) are growing in popularity as an alternative method of glucose monitoring for individuals with type 1 diabetes (T1D). Only a few empirical studies have assessed DAD accuracy, with inconsistent results. The present study examined DAD accuracy and variability in performance in real-world conditions using a convenience sample of owner-report diaries.

METHOD

Eighteen DAD owners (44.4% female; 77.8% youth) with T1D completed diaries of DAD alerts during the first year after placement. Diary entries included daily BG readings and DAD alerts. For each DAD, percentage hits (alert with BG ≤ 5.0 or ≥ 11.1 mmol/L; ≤90 or ≥200 mg/dl), percentage misses (no alert with BG out of range), and percentage false alarms (alert with BG in range) were computed. Sensitivity, specificity, positive likelihood ratio (PLR), and true positive rates were also calculated.

RESULTS

Overall comparison of DAD Hits to Misses yielded significantly more Hits for both low and high BG. Total sensitivity was 57.0%, with increased sensitivity to low BG (59.2%) compared to high BG (56.1%). Total specificity was 49.3% and PLR = 1.12. However, high variability in accuracy was observed across DADs, with low BG sensitivity ranging from 33% to 100%. Number of DADs achieving ≥ 60%, 65% and 70% true positive rates was 71%, 50% and 44%, respectively.

CONCLUSIONS

DADs may be able to detect out-of-range BG, but variability across DADs is evident. Larger trials are needed to further assess DAD accuracy and to identify factors influencing the complexity of DAD accuracy in BG detection.

Predicting and Reducing Driving Mishaps Among Drivers With Type 1 Diabetes

OBJECTIVE

Two aims of this study were to develop and validate A) a metric to identify drivers with type 1 diabetes at high risk of future driving mishaps and B) an online intervention to reduce mishaps among high-risk drivers.

RESEARCH DESIGN AND METHODS

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 "DiabetesDriving.com" (DD.com). 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.

RESULTS

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 DD.com and DD.com + MI groups were combined. DD.com 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.

CONCLUSIONS

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 DD.com.

An empirically derived short form of the Hypoglycaemia Fear Survey II

AIMS

To develop an empirically derived short version of the Hypoglycaemia Fear Survey II that still accurately measures fear of hypoglycaemia.

METHODS

Item response theory methods were used to generate an 11-item version of the Hypoglycaemia Fear Survey from a sample of 487 people with Type 1 or Type 2 diabetes mellitus. Subsequently, this scale was tested on a sample of 2718 people with Type 1 or insulin-treated Type 2 diabetes taking part in DIALOG, a large observational prospective study of hypoglycaemia in France.

RESULTS

The short form of the Hypoglycaemia Fear Survey II matched the factor structure of the long form for respondents with both Type 1 and Type 2 diabetes, while maintaining adequate internal reliability on the total scale and all three subscales. The two forms were highly correlated on both the total scale and each subscale (Pearson's R > 0.89).

CONCLUSIONS

The short form of the Hypoglycaemia Fear Survey II is an important first step in more efficiently measuring fear of hypoglycaemia. Future prospective studies are needed for further validity testing and exploring the survey's applicability to different populations.

Insulin degludec is associated with less frequent and milder hypoglycemia in insulin-deficient patients with type 1 diabetes compared with insulin glargine or detemir

Introduction

The aim of this study was to determine the efficacy of insulin degludec (IDeg) relative to insulin glargine (IGlar) or insulin detemir (IDet) in glycemic control, as evaluated by continuous glucose monitoring (CGM) in insulin-deficient patients with type 1 diabetes.

Methods

We studied 28 outpatients treated with IGlar or IDet (IGlar/IDet). Basal insulin was switched to IDeg when glycemic control was considered unstable, as judged by the dawn phenomenon or nocturnal hypoglycemia. Whole-day CGM data were also divided into daytime and nighttime data.

Results

The dawn phenomenon or nocturnal hypoglycemia under IGlar/IDet treatment was observed in all patients. Among 26 patients who completed the study, there were no significant differences in parameters representing glycemic variability, hyperglycemia, mean glycemic control, and HbA1c or insulin therapy-related quality of life at the night score. Measures of hypoglycemia [whole-day %Low and area under the curve (AUC) below 70] were significantly lower under IDeg treatment than under IGlar/IDet treatment (%Low, 9.6 ± 11.5 vs. 14.7 ± 14.9%, p = 0.045; AUC below 70, 85.5 ± 126.0 vs. 145.0 ± 178.6 mg/dl h, p = 0.030). Dividing patients into two groups according to percentage or degree of hypoglycemia under IGlar/IDet treatment, the whole-day, daytime and nighttime %Low in the high-percentage groups and AUC below 70 in the high-degree groups were significantly ameliorated, respectively (p < 0.05).

Conclusion

Patients with unstable glycemic control under IGlar/IDet treatment did not improve glycemic control upon switching to IDeg, but the frequency and the degree of hypoglycemia was reduced in insulin-deficient outpatients with type 1 diabetes, especially in those suffering from severe hypoglycemia.

Diabetes and collision risk. A meta-analysis and meta-regression

AIMS

The main objective of this study was to see whether diabetes is associated with an increased collision risk and to test the effect of age and gender on the overall collision risk for diabetes drivers.

MATERIALS AND METHODS

Twenty-eight studies were included in meta-analysis, using mean age, gender, continent and the prevalence of fatal road incidents as covariates.

RESULTS

The collision risk for diabetes drivers was small and not statistically significant - RR = 1.11 (1.01-1.23) with a prediction interval (PI) or 0.77-1.65. Age and gender were not associated with an increased overall risk. Insulin-dependent diabetes patients had a slightly increased effect size compared with the overall diabetes population, but the effect was not statistically significant. European diabetes drivers had a lower collision risk compared with their North American counterparts, the main cause being the difference of collision risk in the countries in which the studies were performed.

CONCLUSIONS

Overall, diabetes patients do not have a statistically significant increased risk for unfavourable traffic events. Old age and insulin-dependent patients tend to have a higher risk. Advances in diabetes care, associated with advances in road safety regulations, and automotive industry have not decreased significantly the collision risk in the last 50 years for drivers with diabetes.

Traumatic injuries in patients with diabetes mellitus

Diabetes mellitus (DM) is associated with increased in-hospital morbidity and mortality in patients sustained traumatic injuries. Identification of risk factors of traumatic injuries that lead to hospital admissions and death in DM patients is crucial to set effective preventive strategies. We aimed to conduct a traditional narrative literature review to describe the role of hypoglycemia as a risk factor of driving and fall-related traumatic injuries. DM poses significant burden as a risk factor and predictor of worse outcomes in traumatic injuries. Although there is no consensus on the impact and clear hazards of hyperglycemia in comparison to the hypoglycemia, both extremes of DM need to be carefully addressed and taken into consideration for proper management. Moreover, physicians, patients, and concerned authorities should be aware of all these potential hazards to share and establish the right management plans.

Driving and diabetes: problems, licensing restrictions and recommendations for safe driving

Driving is a complex process that places considerable demands on cognitive and physical functions. Many complications of diabetes can potentially impair driving performance, including those affecting vision, cognition and peripheral neural function. Hypoglycemia is a common side-effect of insulin and sulfonylurea therapy, impairing many cognitive domains necessary for safe driving performance. Driving simulator studies have demonstrated how driving performance deteriorates during hypoglycemia. Driving behavior that may predispose to hypoglycemia while driving is examined. Studies examining the risk of road traffic accidents in people with insulin-treated diabetes have produced conflicting results, but the potential risk of hypoglycemia-related road traffic accidents has led to many countries imposing restrictions on the type and duration of driving licenses that can be issued to drivers with diabetes. Guidance that promotes safe driving practice has been provided for drivers with insulin-treated diabetes, which is the group principally addressed in this review.

Hypoglycaemia and automatism

Cognitive impairment unattended by subjective symptoms or objective signs is an uncommon but important consequence of hypoglycaemia. It can lead to a condition in which a patient behaves as an automaton in a manner totally alien to their usual personality and of which they have no recollection when their blood glucose level is restored to normal. It can cause a wide range of criminal behaviour, although the commonest offences relate to a loss of control, for example driving offences. Determination of criminal responsibility is extremely difficult and relies very heavily upon the quality of the medical evidence and interpretation of the law, which is out of step with current medical science.

Individual and societal consequences of hypoglycemia: A cross-sectional survey

BACKGROUND

Hypoglycemia and fear of hypoglycemia threaten individuals' ability to work and drive. We studied the effect of hypoglycemia on the individual and society, with a focus on possible implications of new European union legislation on patients' continued ability to drive.

METHODS

A cross-sectional survey of Danish Diabetes Association members was conducted to investigate individual and societal consequences of hypoglycemia.

RESULTS

A total of 3117/9951 individuals with type 1 diabetes (T1DM) (32.2%) or type 2 diabetes (T2DM) (67.8%) completed the survey. The calculated incidence rates of self-reported severe and mild hypoglycemia were 2.9, 0.6 and 0.1 events per patient year (ppy) in patients with T1DM, insulin using T2DM and non-insulin using T2DM, respectively; and incidence rates of self-reported mild hypoglycemia were 99.0, 23.2 and 10.9 events ppy, respectively. Self-care strategies to avoid hypoglycemia include maintaining higher blood glucose levels (45.7%) and reducing physical activity (15.7%). Few people take sick leave as a result of hypoglycemia, but prolonged mental recovery ≥4 h following an episode of mild or severe hypoglycemia was reported by 8.7 and 31.0%, respectively. 26.5% of patients holding a valid driving license reported having ever had at least one episode of severe hypoglycemia. Patients considering underreporting of hypoglycemia to maintain their driving license were more likely to have experienced severe hypoglycemia (odds ratio [OR]: 3.03; 95% CI: 2.42-3.79; p < 0.0001).

CONCLUSION

A high proportion of insulin-treated patients experience hypoglycemia resulting in fear of hypoglycemia and changes in self-care behavior that may compromise glycemic control. Many patients with a history of severe hypoglycemia consider underreporting hypoglycemic events through concern over retaining their driving license.

Fear of driving license withdrawal in patients with insulin-treated diabetes mellitus negatively influences their decision to report severe hypoglycemic events to physicians

BACKGROUND

Under current European Union legislation, two severe hypoglycemic events within 12 months is grounds for driving license withdrawal. The aim of the study reported here was to determine whether fear of such a withdrawal could lead to patients concealing severe hypoglycemia from physicians, which could negatively impact further treatment decisions.

METHODS

A total of 663 patients with insulin-treated diabetes were anonymously surveyed about whether they would conceal severe hypoglycemic events from their physicians, if revealing them could result in driving license withdrawal. This investigation utilized an adapted and expanded questionnaire by Graveling et al.

RESULTS

Of all diabetic patients surveyed, 26.17% would most likely not report hypoglycemia, and 25.86% were undecided. In a group of patients with type 1 diabetes, 31.83% would likely not report hypoglycemic events, and 25.06% were undecided. The patients least likely to report severe hypoglycemic events were those who indicated that vehicles were partly essential for work, and who also had more than two hypoglycemic events monthly.

CONCLUSION

A considerable percentage of diabetic patients would likely conceal severe hypoglycemic events from their physicians due to fear of driving license withdrawal. Patient failure to report severe hypoglycemic events can potentially lead to physicians being misinformed regarding the patient's condition, which could lead to inadequate monitoring and treatment.

Hypoglycemia from a cardiologist's perspective

Hypoglycemia in people with diabetes mellitus (DM) has been potentially linked to cardiovascular morbidity and mortality. Pathophysiologically, hypoglycemia triggers activation of the sympathoadrenal system, leading to an increase in counter-regulatory hormones and, consequently, increased myocardial workload and oxygen demand. Additionally, hypoglycemia triggers proinflammatory and hematologic changes that provide the substrate for possible myocardial ischemia in the already-diseased diabetic cardiovascular system. Hypoglycemia creates electrophysiologic alterations causing P-R-interval shortening, ST-segment depression, T-wave flattening, reduction of T-wave area, and QTc-interval prolongation. Patients who experience hypoglycemia are at an increased risk of silent ischemia as well as QTc prolongation and consequent arrhythmias. The Action to Control Cardiovascular Risk in Diabetes (ACCORD) trial showed an increase in all-cause mortality with intensive glycemic control, whereas the Action in Diabetes and Vascular Disease: Preterax and Diamicron Modified Release Controlled Evaluation (ADVANCE) study and Veteran's Affairs Diabetes Trial (VADT) showed no benefit with aggressive glycemic control. Women, elderly patients, and those with renal insufficiency are more vulnerable to hypoglycemic events. In fact, hypoglycemia is the most common metabolic complication experienced by older patients with DM in the United States. The concurrent use of medications like β-blockers warrants caution in DM because they can mask warning signs of hypoglycemia. Here we aim to elucidate the pathophysiology, review the electrocardiographic changes, analyze the current clinical literature, and consider the safety considerations of hypoglycemia as it relates to the cardiovascular system. In conclusion, in the current era of DM and its vascular ramifications, hypoglycemia from a cardiologist's perspective deserves due attention.

Medications and impaired driving

OBJECTIVE

To describe the association of specific medication classes with driving outcomes and provide clinical recommendations.

DATA SOURCES

The MEDLINE and EMBASE databases were searched for articles published from January 1973 to June 2013 on classes of medications associated with driving impairment. The search included outcome terms such as automobile driving, motor vehicle crash, driving simulator, and road tests.

STUDY SELECTION AND DATA EXTRACTION

Only English-language articles that contained findings from observational or interventional designs with ≥ 10 participants were included in this review. Cross-sectional studies, case series, and case reports were excluded.

DATA SYNTHESIS

Driving is an important task and activity for the majority of adults. Some commonly prescribed medications have been associated with driving impairment measured by road performance, driving simulation, and/or motor vehicle crashes. This review of 30 studies identified findings with barbiturates, benzodiazepines, hypnotics, antidepressants, opioid and nonsteroidal analgesics, anticonvulsants, antipsychotics, antiparkinsonian agents, skeletal muscle relaxants, antihistamines, anticholinergic medications, and hypoglycemic agents. Additional studies of medication impact on sedation, sleep latency, and psychomotor function, as well as the role of alcohol, are also discussed.

CONCLUSIONS

Psychotropic agents and those with central nervous system side effects were associated with measures of impaired driving performance. It is difficult to determine if such associations are actually a result of medication use or the medical diagnosis itself. Regardless, clinicians should be aware of the increased risk of impaired driving with specific classes of medications, educate their patients, and/or consider safer alternatives.

Diabetes and driving

The principal safety concern for driving for people treated with insulin or insulin secretagogues is hypoglycaemia, which impairs driving performance. Other complications, such as those causing visual impairment and peripheral neuropathy, are also relevant to medical fitness to drive. Case control studies have suggested that drivers with diabetes pose a modestly increased but acceptable and measurable risk of motor vehicle accidents compared to non-diabetic drivers, but many studies are limited and of poor quality. Factors which have been shown to increase driving risk include previous episodes of severe hypoglycaemia, previous hypoglycaemia while driving, strict glycaemic control (lower HbA1c) and absence of blood glucose monitoring before driving. Impaired awareness of hypoglycaemia may be counteracted by frequent blood glucose testing. The European Union Third directive on driving (2006) has necessitated changes in statutory regulations for driving licences for people with diabetes in all European States, including the UK. Stricter criteria have been introduced for Group 1 vehicle licences while those for Group 2 licences have been relaxed. Insulin-treated drivers can now apply to drive Group 2 vehicles, but in the UK must meet very strict criteria and be assessed by an independent specialist to be issued with a 1-year licence.

Diabetes and driving safety: science, ethics, legality and practice

Diabetes affects over 25 million people in the United States, most of whom are over the age of 16 and many of whom are licensed to drive a motor vehicle. Safe operation of a motor vehicle requires complex interactions of cognitive and motor functions and medical conditions that affect these functions often will increase the risk of motor vehicle accidents (MVA). In the case of diabetes, hypoglycemia is the most common factor that has been shown to increase MVA rates. When people with diabetes are compared with nondiabetic controls, systematic analyses show that the relative risk of MVA is increased by between 12% and 19% (Relative Risk Ratio 1.12-1.19). In comparison, the RRR for attention deficit hyperactivity disorder is 4.4 and for sleep apnea is 2.4. Epidemiologic research suggests that patients at risk for hypoglycemia-related MVAs may have some characteristics in common, including a history of severe hypoglycemia or of hypoglycemia-related driving mishaps. Experimental studies also have shown that people with a history of hypoglycemia-related driving mishaps have abnormal counter-regulatory responses to hypoglycemia and greater cognitive impairments during moderate hypoglycemia.

Implications of new European Union driving regulations on patients with Type 1 diabetes who participated in the Diabetes Control and Complications Trial

AIMS

Recurrent severe hypoglycaemia in a patient with diabetes is strongly associated with a crash risk while driving. To help ensure road safety, recent changes were made to European Union driving regulations for patients with diabetes. These included the recommendation that more than one episode of severe hypoglycaemia within 12 months would lead to the loss of a driving licence. This study has assessed the impact of this regulation if applied to patients who participated in the Diabetes Control and Complications Trial.

METHODS

All patients in the Diabetes Control and Complications Trial were assumed to be drivers. Repeated hypoglycaemic episodes within a year were determined during the mean 6.5 years of the study.

RESULTS

Of the 1441 patients in the Diabetes Control and Complications Trial, 439 (30%) had more than one severe hypoglycaemic episode during a 12-month period of their study participation. Amongst the study groups, 312/711 (44%) of intensively treated and 127/730 (17%) of conventionally treated patients would have lost their licence at some point during the trial. The risk of licence loss increased with lower mean HbA1c , longer duration of diabetes and younger age (all P < 0.001).

CONCLUSIONS

More than one episode of severe hypoglycaemia within a year was a frequent event in subjects in the Diabetes Control and Complications Trial, especially in intensively treated patients. If applied to current practice, improving road safety through these changes to European Union regulations could have a substantial impact on drivers who have Type 1 diabetes. This emphasizes the need to take into account the potential effects of severe hypoglycaemia in those who rely on a driving licence.

Long-term results of laparoscopic Roux-en-Y Gastric bypass: evaluation after 9 years

This retrospective study aimed to evaluate the long-term results of the laparoscopic Roux-en-Y gastric bypass (LRYGB) procedure performed at our department of bariatric surgery. The 126 consecutive patients treated by LRYGB between January 1, 2001 and December 31, 2002 were analyzed in August 2011. Seventy-seven patients (61.1 %), including 18 who had had previous bariatric surgery, were available for evaluation after 9.4 ± 0.6 years (range, 8.7-10.9 years). Eight patients (10.4 %) suffered from type 2 diabetes mellitus (DMII) at the time of surgery. Initial body mass index (BMI) was 40.3 ± 7.5 kg/m(2) (range, 24.5-66.1 kg/m(2)). There was no postoperative mortality, but two patients died of causes unrelated to the surgery. Some 9 % of the patients suffered from internal herniation, despite the closure of potential hernia sites. With time, the patients had the tendency to experience weight regain: percentage of excess BMI lost was 56.2 ± 29.3 % (range, -78.8 to 117.9 %), down from a maximum of 88.0 ± 29.6 % (range, -19.7 to 197.1 %), that had been obtained after a median of 2.0 years (range, 1-8 years). LRYGB was effective for diabetes control in 85.7 % of the affected patients, but, surprisingly, 27.9 % developed new-onset diabetes. The weight regain in this latter patient group was statistically not different from the nondiabetic group. Conversely, four patients required hospitalization for hypoglycemic syndrome. Two patients underwent reversal of their bypass for problems linked to glucose metabolism (one hypoglycemia, one DMII). Patient quality of life was fair. The patient satisfaction remained good in 76 % of the cases.

Harvesting experiential expertise to support safe driving for people with diabetes mellitus: a qualitative study evaluated by peers in a survey

BACKGROUND

Hypoglycemia is a frequent phenomenon in people being treated for diabetes mellitus, which can acutely disrupt driving performance. For the benefit of personal and public traffic safety, we decided to identify successful diabetes-related (SDR) behaviors to support safe driving for people with diabetes, from the perspective of experiential experts with diabetes mellitus. Experiential experts are people who can manage their own illness and conditions by developing expertise relevant to maintaining health and countering illness, and who are able to use this expertise to the benefit of peers.

OBJECTIVE

The aim of our study was to objectify and systematize experiential expertise in terms of SDR behaviors, based on reports by experiential experts, to support safe driving for people with type 1 and type 2 diabetes mellitus. The emphasis was on preventing hypoglycemia as a short-term complication during driving.

METHODS

We performed a mixed-methods study involving (i) semi-structured in-depth interviews with 33 experiential experts with diabetes mellitus from the Dutch Diabetes Association (DVN; Diabetesvereniging Nederland), in order to identify SDR behaviors regarding safe driving, and (ii) a validation study by means of a survey among a panel of 98 experiential experts (peers) from the DVN, to determine the extent to which they agreed with the communicability, importance, and feasibility of these behaviors for drivers with diabetes mellitus.

RESULTS

We identified a comprehensive set of 11 SDR behaviors, differentiated into seven general and four specific behaviors, to support safe driving. The general behaviors concern the following topics: (i) acquiring knowledge and information; (ii) acquiring and using self-measuring of blood glucose (SMBG) equipment; (iii) knowing one's physical response pattern; (iv) obtaining knowledge about the medication used; (v) preventing long-term eye complications; (vi) influencing factors that can affect blood glucose; and (vii) renewal procedure for driving license. The four specific behaviors refer to the following topics: (i) measures to be taken before driving; (ii) responding effectively to hypoglycemia while driving; (iii) informing and instructing passengers; and (iv) preventing hypoglycemia in drivers with type 2 diabetes mellitus not using SMBG equipment. Key factors for safe driving proved to be the ability of drivers to anticipate and respond effectively to hypoglycemia while driving and to inform and instruct fellow passengers. Participants of the validation survey agreed to a considerable degree with the communicability, importance, and feasibility of these behaviors to support safe driving for people with diabetes mellitus.

CONCLUSIONS

This study resulted in the identification and description of SDR behaviors to support safe driving. It proved possible to operationalize experiential expertise in terms of such behaviors. The next step is to have these behaviors validated by professional care providers in the field of diabetes, followed by translation into recommendations in self-management programs.

Acute consequences of hypoglycaemia in diabetic patients

Strict glycaemic control is a major concern in many people with diabetes, hypoglycaemia being the most limiting factor in the daily management of patients with diabetes. Acute consequences of hypoglycaemic attacks are not precisely evaluated. Acute cardiovascular (CV) complications as myocardial ischaemia or stroke seem to be rare, but possibly ignored mainly in older frail patients. Recent large trials in type 2 diabetic patients have not shown the anticipated mortality benefits of strict glycaemic control, and reported a higher frequency of severe hypoglycaemia in the intensive treatment arms with an excess of CV deaths. The authors of these trials persist to deny a direct link between CV deaths and hypoglycaemia. In young type 1 diabetics "dead in bed" syndrome represents a rare but devastating consequence probably due to arrhythmia and prolonged QTc interval. Driving mishaps represent another complication but with a controversial frequency. Neurologic syndromes are frequent during severe hypoglycaemia but usually reversible. Major brain damages are scarce, but cognitive defects or dementia should be underestimated in older and frail type 2 diabetics. Thus, iatrogenic hypoglycaemia due to insulin or sulphonylureas may cause recurrent morbidity in type 1 and type 2 diabetic subjects, and should be prevented by a reevaluation of glycaemic targets in some patients, patient education and the use of new antidiabetic drugs without hypoglycaemic risk.

Psychometric properties of the hypoglycemia fear survey-ii for adults with type 1 diabetes

OBJECTIVE

To perform the first comprehensive psychometric evaluation of the Hypoglycemia Fear Survey-II (HFS-II), a measure of the behavioral and affective dimensions of fear of hypoglycemia, using modern test-theory methods, including item-response theory (IRT).

RESEARCH DESIGN AND METHODS

Surveys completed in four previous studies by 777 adults with type 1 diabetes were aggregated for analysis, with 289 subjects completing both subscales of the HFS-II and 488 subjects completing only the Worry subscale. The aggregated sample (53.3% female, 44.4% using insulin pumps) had a mean age of 41.9 years, diabetes duration of 23.8 years, HbA(1c) value of 7.7%, and 1.4 severe hypoglycemic episodes in the past year. Data analysis included exploratory factor analysis using polychoric correlations and IRT. Factors were analyzed for fit, trait-level locations, point-measure correlations, and separation values.

RESULTS

Internal and test-retest reliability was good, as well as convergent validity, as demonstrated by significant correlations with other measures of psychological distress. Scores were significantly higher in subjects who had experienced severe hypoglycemia in the past year. Factor analyses validated the two subscales of the HFS-II. Item analyses showed that 12 of 15 items on the Behavior subscale, and all of the items on the Worry subscale had good-fit statistics.

CONCLUSIONS

The HFS-II is a reliable and valid measure of the fear of hypoglycemia in adults with type 1 diabetes, and factor analyses and IRT support the two separate subscales of the survey.

Impaired driving from medical conditions: a 70-year-old man trying to decide if he should continue driving

Some medical disorders can impair performance, increasing the risk of driving safety errors that can lead to vehicle crashes. The causal pathway often involves a concatenation of factors or events, some of which can be prevented or controlled. Effective interventions can operate before, during, or after a crash occurs at the levels of driver capacity, vehicle and road design, and public policy. A variety of systemic, neurological, psychiatric, and developmental disorders put drivers at potential increased risk of a car crash in the short or long term. Medical diagnosis and age alone are usually insufficient criteria for determining fitness to drive. Strategies are needed for determining what types and levels of reduced function provide a threshold for disqualification in drivers with medical disorders. Evidence of decreased mileage, self-restriction to driving in certain situations, collisions, moving violations, aggressive driving, sleepiness, alcohol abuse, metabolic disorders, and multiple medications may trigger considerations of driver safety. A general framework for evaluating driver fitness relies on a functional evaluation of multiple domains (cognitive, motor, perceptual, and psychiatric) that are important for safe driving and can be applied across many disorders, including conditions that have rarely been studied with respect to driving, and in patients with multiple conditions and medications. Neurocognitive tests, driving simulation, and road tests provide complementary sources of evidence to evaluate driver safety. No single test is sufficient to determine who should drive and who should not.

Effect of automated bio-behavioral feedback on the control of type 1 diabetes

OBJECTIVE

To test the effect of an automated system providing real-time estimates of HbA(1c), glucose variability, and risk for hypoglycemia.

RESEARCH DESIGN AND METHODS

For 1 year, 120 adults with type 1 diabetes (69 female/51 male, age = 39.1 [14.3] years, duration of diabetes 20.3 [12.9] years, HbA(1c) = 8.0 [1.5]), performed self-monitoring of blood glucose (SMBG) and received feedback at three increasingly complex levels, each continuing for 3 months: level 1--routine SMBG; level 2--adding estimated HbA(1c), hypoglycemia risk, and glucose variability; and level 3--adding estimates of symptoms potentially related to hypoglycemia. The subjects were randomized to feedback sequences of either levels 1-2-3 or levels 2-3-1. HbA(1c), symptomatic hypoglycemia, and blood glucose awareness were evaluated at baseline and at the end of each level.

RESULTS

For all subjects, HbA(1c) was reduced from 8.0 to 7.6 from baseline to the end of study (P = 0.001). This effect was confined to subjects with baseline HbA(1c) >8.0 (from 9.3 to 8.5, P < 0.001). Incidence of symptomatic moderate/severe hypoglycemia was reduced from 5.72 to 3.74 episodes/person/month (P = 0.019), more prominently for subjects with a history of severe hypoglycemia (from 7.20 to 4.00 episodes, P = 0.008) and for those who were hypoglycemia unaware (from 6.44 to 3.71 episodes, P = 0.045). The subjects' ratings of the feedback were positive, with up to 89% approval of the provided features.

CONCLUSIONS

Feedback of SMBG data and summary SMBG-based measures resulted in improvement in average glycemic control and reduction in moderate/severe hypoglycemia. These effects were most prominent in subjects who were at highest risk at the baseline.

Type 1 diabetic drivers with and without a history of recurrent hypoglycemia-related driving mishaps: physiological and performance differences during euglycemia and the induction of hypoglycemia

OBJECTIVE

Collisions are more common among drivers with type 1 diabetes than among their nondiabetic spouses. This increased risk appears to be attributable to a subgroup of drivers with type 1 diabetes. The hypothesis tested is that this vulnerable subgroup is more at risk for hypoglycemia and its disruptive effects on driving.

RESEARCH DESIGN AND METHODS

Thirty-eight drivers with type 1 diabetes, 16 with (+history) and 22 without (-history) a recent history of recurrent hypoglycemia-related driving mishaps, drove a virtual reality driving simulator and watched a videotape of someone driving a simulator for 30-min periods. Driving and video testing occurred in a double-blind, randomized, crossover manner during euglycemia (5.5 mmol/l) and progressive hypoglycemia (3.9-2.5 mmol/l). Examiners were blind to which subjects were +/-history, whereas subjects were blind to their blood glucose levels and targets.

RESULTS

During euglycemia, +history participants reported more autonomic and neuroglycopenic symptoms (P≤0.01) and tended to require more dextrose infusion to maintain euglycemia with the same insulin infusion (P<0.09). During progressive hypoglycemia, these subjects demonstrated less epinephrine release (P=0.02) and greater driving impairments (P=0.03).

CONCLUSIONS

Findings support the speculation that there is a subgroup of type 1 diabetic drivers more vulnerable to experiencing hypoglycemia-related driving mishaps. This increased vulnerability may be due to more symptom "noise" (more symptoms during euglycemia), making it harder to detect hypoglycemia while driving; possibly greater carbohydrate utilization, rendering them more vulnerable to experiencing hypoglycemia; less hormonal counterregulation, leading to more profound hypoglycemia; and more neuroglycopenia, rendering them more vulnerable to impaired driving.