Diabetes and Accident Insurance

We read with great interest the article by Mathiesen and Borch-Johnsen on the relationship between diabetes and accident involvement (1). What is not entirely clear from the paper is what types of accidents would be covered by "leisure-time insurance" and therefore be included as events by this study. It is interesting in this regard that the majority of accidents among diabetic individuals were falls and not traffic-related events, as would have been expected. The authors stated, "We found, however, no data to support the assumption that individuals with diabetes have an increased risk of accidents. " We suggest that the authors review several published studies in which diabetes was found to be associated with an increased risk of traffic crash involvement. For example, Waller (2) found that diabetic individuals known to the California Department of Motor Vehicles had almost twice as many traffic crashes on a per mile basis compared with a reference group of nondiabetic drivers. Similar studies conducted in Oklahoma and Washington State presented consistent results (3,10). More recently, Hansotia and Broste (4) reported that drivers with diabetes have a slightly increased risk of traffic accidents compared with unaffected individuals. Koepsell et al. (5) reported that older drivers involved in injurious traffic crashes were 2.6 times more likely to have a diagnosis of diabetes than control subjects, de Klerk and Armstrong (7) also reported an increased risk of hospital admissions for road trauma among young diabetic men. Songer et al. (8) found no overall association between IDDM and traffic crashes; however, women with IDDM were at increased risk. A number of other publications have, like Mathiesen and Borch-Johnsen, found no association between diabetes and crash involvement or found a reduced risk (6,9,11-13). With respect to non-traffic-related events, O'Loughlin et al. (14) found a positive association between diabetes and injurious falls among older adults, although Herndon et al. (15) reported no association. From the point of view of an insurance company, the results are clear. Over a particular period of time, those with diabetes are at no increased risk for leisure-time injury insurance claims. Despite this, it is still possible from an etiologic perspective that given exposure to a risk, those with diabetes would be more likely to have an injury. Mathiesen and Borch-Johnsen did not take into account person-time in leisure-time activities that would put diabetic subjects at risk. For example, in Table 2, the authors report the age range of the diabetic and control groups, the lower bounds being 3 and 0 years of age, respectively. Clearly, there are some subjects who are not a risk for traffic crashes (as operators) because they are too young to drive. Failure to account for individuals too young to drive and including nondrivers in the enumeration of person-time will reduce traffic crash rates. In addition, accounting for driving exposure (i.e., amount of time spent driving) may be important because those with diabetes may drive less than their counterparts without diabetes. A similar argument can be made for other accidents (e.g., athletic injuries); individuals with diabetes may spend less time in athletics in general or in higher-risk athletics in particular. The results of this study should not be interpreted as necessarily refuting the hypothesis that some aspect of diabetes or its sequelae is a causal factor in accident occurrence.