Background/Purpose:

Survival rates of patients with systemic lupus erythematosus (SLE) have improved significantly over the last four decades. Mortality rates remain high, however, and are almost 4 times that of the general population. A bi-modal pattern of mortality in SLE has been described whereby death within the first year after diagnosis was associated with active lupus and infection, while death in later years was associated with atherosclerosis and corticosteroid use.

The aim of this study was to re-examine the causes of mortality in lupus patients followed prospectively at a large lupus clinic between 1970 and 2013.

Methods:

Causes of death were recorded and acquired from autopsy reports (n=48), discharge summaries (n=64), hospital notes (n=23), and death certificates (n=20). Causes were divided into 5 categories: active lupus, atherosclerosis-related, infection, malignancy and ‘other’, and designated as either a ‘primary’ or ‘secondary’ cause.  Atherosclerosis-related (AS) deaths were those attributable to acute myocardial infarction, congestive cardiac failure (as a direct result of coronary artery disease), or stroke, all in the absence of active SLE. ‘Other’ causes referred to those that were not attributable to active SLE, atherosclerosis, infection or malignancy.

Results:

Out of 264 patients known to have died, causes of death were established in 206 cases. Mean disease duration at time of death was 14.6 ± 11.8 years, with 47 (23%) dying within 5 years and 62 (30%) dying 20 or more years after diagnosis. Mean age at death was 52.6 ± 17.5 years, with 56 (27%) dying before the age of 40. Infection was responsible for the majority of deaths (n=71 (34.5%)), followed by active SLE (n=38 (18.4%)), AS (n=38 (18.4%)), malignancy (n=24 (11.7%)) and ‘other’ (n=60 (29.1%)). Renal failure in inactive SLE (n=6) and bowel perforation (n=5) were among ‘other’ causes.

There was a significant decline in the number of deaths attributable to infection and active SLE with increasing disease duration: 49% (n=23) and 34%(n=16) of deaths in those with SLE for less than 5 years were due to infection and active lupus, respectively, compared with 26% (n=16) and 15% (n=9) of deaths in those with SLE for 20 or more years (p=0.01). Atherosclerosis was increasingly responsible for death with increasing disease duration: 13% (n=5) with less than 5 years disease duration, compared with 23% (n=14) after 20 years of SLE (p=0.11). Malignancy also increased in prevalence as a cause of death with greater disease duration (p=0.13).

Conclusion:

Within the first 5 years of disease onset, infection and active SLE account for over 80% of deaths in lupus. Despite a significant reduction as a cause of death over time, infection remains the single biggest killer in those with disease over 20 years. The importance of atherosclerosis as a cause of death increases over time and replaces active SLE as the next most important cause of death in lupus patients with increasing disease duration.

ACR Meeting Abstracts - https://acrabstracts.org/abstract/causes-of-mortality-in-lupus-patients-followed-prospectively-at-a-large-single-centre-lupus-clinic/