摘要：Objectives. We assessed the impact that possible veteran suicide misclassification biases (i.e., inaccuracy in ascertainment of veteran status on the death certificate and misclassification of suicide as other manner of death) have on veteran suicide rate estimates. Methods. We obtained suicide mortality data from the 2003–2010 National Violent Death Reporting System and the 2003–2010 Department of Defense Casualty Analysis System. We derived population estimates from the 2003–2010 American Community Survey and 2003–2010 Department of Veterans Affairs data. We computed veteran and nonveteran suicide rates. Results. The results showed that suicide rates were minimally affected by the adjustment for the misclassification of current military personnel suicides as veterans. Moreover, combining suicides and deaths by injury of undetermined intent did not alter the conclusions. Conclusions. The National Violent Death Reporting System is a valid surveillance system for veteran suicide. However, more than half of younger (< 25 years) male and female suicides, labeled as veterans, were likely to have been current military personnel at the time of their death and misclassified on the death certificate. Rapidly rising suicide rates among current and former US military personnel have generated nationwide concern. There is increasing evidence that veterans of both genders are at greater risk for suicide than their nonveteran counterparts. 1–5 Moreover, veterans who receive care through the Veterans Health Administration (VHA) have higher rates of suicide than non–VHA users 6–8 and nonveterans. 9 Furthermore, younger veterans (< 35 years) have the highest risk of suicide. 1,4,10,11 But some studies have found no connection between military service and suicide. 12–14 These conflicting findings have been attributed in part to misclassification biases. Previous research 15,16 and the Blue Ribbon Work Group’s report 17 have noted that suicide mortality estimates are often compromised by 2 main sources of misclassification: (1) inaccuracy in ascertainment of veteran status on the death certificate and (2) misclassification of suicides as other manners of death. The first bias refers to the designation of veteran status on the death certificate: “ever served in the armed forces.” The argument is that the item does not distinguish between military personnel currently serving on active duty, in the National Guard, or in the Reserves, and veterans who have separated from the service. However, recent evidence shows high correlation between death certificate and self-reported veteran status (agreement rate = 95% 18 ), proxy-derived information ( κ = 0.91 4 ), and VHA records (sensitivity = 95%; specificity = 91% 19 ). Nonetheless, the validity of the designation of veteran status on the death certificate may differ by age. 20 It is likely that the death certificate item would be accurate for older veterans but not necessarily for younger decedents. As a consequence, suicide rate estimates derived for younger veterans are likely to be more affected by this bias resulting in overestimation. This concern is particularly important because the relative risk for suicide is highest among younger veterans. The second bias refers to self-inflicted death misclassified as other manners of death such as injuries of undetermined intent. Previous studies have shown evidence that veterans’ deaths relative to nonveterans’ are less likely to be classified as injuries of undetermined intent. 5,17 Deceased veterans may be more likely than nonveterans to be classified as suicides for several reasons, including higher use of firearms (more likely to be classified as suicide than another method), greater availability of accurate information for death certificates among VHA users, and implicit societal beliefs that veterans are at elevated risk for suicide. In this case, misclassification bias (chiefly for nonveterans) may account for the apparently higher suicide rates found in the veteran population. Few, if any, studies have attempted to test for the effect of these misclassification biases on suicide rate estimation in the veteran and nonveteran populations. Yet this information is essential for surveillance efforts and suicide prevention among veterans. Therefore, the aims of this study were (1) to assess the effect of excluding current military personnel (listed as veterans on the death certificate) from veteran suicide rate estimates by age and gender and (2) to test the effect of including deaths by injury of undetermined intent as suicides on suicide rate estimates.
