Suicide kills far more Americans than homicide, its twin and much higher profile cause of fatal intentional injury. For 1999–2003, the observation period for this study, the annualized suicide rate for the United States was almost double the homicide rate – 11 versus 6 per 100,000 population [1
]. Suicide ranked fourth as a cause of potential years of life lost before age 65 years for (non-Hispanic) whites, seventh for Hispanics, and ninth for (non-Hispanic) blacks. Suicide is avoidable mortality [2
], and the proximate mental and physical health of decedents is salient to its understanding. To better comprehend the relationship between proximate health and suicide, we accessed national vital statistics data to describe and evaluate comorbidity in white, black, and Hispanic suicides. Untenable as biological constructs, race and ethnicity are social constructs with important implications for health disparities and healthcare delivery [4
]. Questions about the reliability and validity of multiple cause-of-death data added impetus to our research.
Although we assume that black and Hispanic suicides experienced at least as much proximate mental and physical illness as white suicides, we expect that medicolegal authorities record less comorbidity on their death certificates. This assumption and expectation stem primarily from comparative survey research on the general US population. A study utilizing the Sample Adult component of the 1998–2003 National Health Interview Surveys showed that blacks and Hispanics report being in worse health, having more physical limitations and annual bed days, less health insurance coverage, fewer physician visits, and more unmet mental healthcare needs than whites [5
]. These groups also compare unfavorably on objective measures of healthcare access and management [6
]. With the focus more specifically on mental health, an analysis of the 2005–2006 National and Nutrition Examination Survey showed that blacks had a higher prevalence of depression than whites and Hispanics [7
]. An analysis of the 2001–2004 National Health Interview Survey indicated no difference in the prevalence of serious psychological distress between blacks and whites [8
]. While the prevalence was equivalent between Hispanics and whites at ages 18 through 64 years, it was almost three times higher for Hispanics at ages 65 and older. Limited to a comparison between blacks and whites, the National Survey of American Life revealed 45% excess chronicity in major depressive disorder among blacks [9
]. Turning back to racial-ethnic treatment disparities, an analysis of the Collaborative Psychiatric Epidemiology Surveys found that 36% of Latinos and 41% of African-Americans with a past-year depressive disorder had received mental health treatment compared to 60% of non-Latino whites [10
Our expectation of relative underdocumentation of comorbidity on the death certificates of the minority suicides is partially supported by a records-based study [11
]. Subjects were adult enrollees in TennCare, Tennessee's Medicaid-waiver managed care program, a public assistance program which offers equal financial access to all low-income groups [12
]. This study found that only 29% of African-American suicides and possible suicides, as compared to 51% of white opposites, used prescribed antidepressants in the year prior to their deaths [11
]. The authors interpreted this differential as indirect evidence that serious mood disorders are underdiagnosed or undertreated in African-Americans. However, they acknowledged that African-Americans may have been more likely to receive nonpharmacological therapy than whites, and thus could have been less likely to have antidepressant prescriptions filled. They operationalized their possible suicides as decedents whose deaths were officially classified under injury of undetermined intent, and no subjects had a record of chronic psychosis or serious medical illness.
Meta-analyses which combine studies of predominantly patient samples affirm that both comorbid psychopathology and physical disease are suicide determinants [13
]. Reinforcement comes from two national multiple cause-of-death (MCOD) analyses, an Australian suicide study [17
] and a US replication [18
]. Implying high bi-national reliability of MCOD data, comparison of their multivariate results revealed identical suicide-associated comorbidities: depression and mood disorders, schizophrenia, and cancer. By contrast, gender-specific prevalences of comorbid psychopathology were almost three times as high in Australian suicides. Moreover, the prevalence of comorbid physical disease was twice as high in Australian as US male suicides, and there was 78% excess prevalence among Australian female suicides compared to US counterparts. The magnitude of these prevalence gaps was surprising, as was the revelation that only among Australian suicides was comorbid psychopathology more prevalent than comorbid physical disease. While both nations are economically and technologically sophisticated democracies, with a shared suicide rate of 11 per 100,000 population [1
], life expectancy and healthy life expectancy at birth in Australia exceed US expectancies by approximately three years [20
]. Indeed, the prevalence gaps and differential weight of comorbid psychopathology indicate that Australian death certificates surpass those of the United States in documenting true comorbidity among suicides. We subsequently ascertained that Australian death investigations are more standardized than those in the United States, and that US coders have less capacity than Australian counterparts to access medicolegal records to help resolve outstanding questions [[22
]; personal communication, Robert N. Anderson, National Center for Health Statistics, September 22, 2008].
Death certificates are essential for conducting epidemiologic surveillance, planning and prioritizing healthcare expenditures and services, and formulating policy for preventing traumatic deaths at state and national levels. Moreover, mortality data from the National Vital Statistics System are more universal, standardized, and timely than data from other major health databases [23
]. Nevertheless, critics cite persuasive empirical evidence from validation studies to charge that death certificates are seriously deficient [24
], In the mid-1990s, a survey of over 700 medical examiners and coroners showed that few had received any formal training in death certification in their medical school training or residencies [28
]. Death certification still receives scant attention in medical school and hospital training [29
]. An additional complicating factor is the declining adult autopsy rate, from 18% in 1955 to just 8% by 2003 [32
]. Both a low autopsy rate and training deficits will impede ascertainment and recording of comorbidity on the death certificates of suicides. We are motivated by these factors and the US-Australian prevalence gaps, as well as by the healthcare utilization literature, to assess whether comorbidity is underdocumented in black and Hispanic suicides relative to white suicides.