Objective: To determine to what extent the diagnosis of systemic lupus erythematosus (SLE) in deceased lupus patients is under-reported in death certificates, and the patient characteristics associated with such an occurrence.
Methods: The death certificates of 76 of the 81 deceased SLE patients from two US lupus cohorts (LUMINA for Lupus in Minorities: Nature vs Nurture and CLU for Carolina Lupus Study), including 570 and 265 patients, respectively, were obtained from the Offices of Vital Statistics of the states where the patients died (Alabama, Georgia, North Carolina, South Carolina, Tennessee and Texas). Both cohorts included patients with SLE as per the American College of Rheumatology criteria, aged > or =16 yr, and disease duration at enrolment of < or =5 yr. The median duration of follow-up in each cohort at the time of these analyses ranged from 38.1 to 53.0 months. Standard univariable analyses were performed comparing patients with SLE recorded anywhere in the death certificate and those without it. A multivariable logistic regression model was performed to identify the variables independently associated with not recording SLE in death certificates.
Results: In 30 (40%) death certificates, SLE was not recorded anywhere in the death certificate. In univariable analyses, older age was associated with lack of recording of SLE in death certificates [mean age (standard deviation) 50.9 (15.6) years and 39.1 (18.6) yr among those for whom SLE was omitted and included on the death certificates, respectively, P = 0.005]. Patients without health insurance, those dying of a cardiovascular event and those of Caucasian ethnicity were also more likely to be in the non-recorded group. In the multivariable analysis, variables independently associated with not recording SLE as cause of death were older age [odds ratio = (95% confidence interval) 1.043 (1.005-1.083 per yr increase); P = 0.023] and lack of health insurance [4.649 (1.152-18.768); P = 0.031].
Conclusions: A high proportion of SLE diagnoses are not recorded in death certificates. Older patients and those without health insurance are more prone to have SLE not recorded. These findings do have implications for the assessment of the impact of this disease in epidemiological studies conducted using vital statistics records.