Objectives To study the relationship between damage in different organ systems and mortality in patients with SLE.
Methods 679 patients who fulfilled at least 4 of the ACR criteria for SLE between 1995 and 2011 were prospectively followed. The cumulative rate of survival was studied by Kaplan-Meier’s plot. For those who died during the disease course, data were censored at the time of death. For other patients, including those who were lost follow-up, data were censored at the time of last clinic visits. Organ damage was assessed by the ACR SLICC damage scores (SDI). Cox regression models were established to study the association between damage in individual systems and mortality in this cohort of patients.
Results 679 SLE patients were studied (623 women, 92%). All were ethnic Chinese. The mean age of onset of SLE was 32.5±13.6 years and the mean follow-up time of the entire cohort of patients was 117±89 months. 67 (9.9%) patients died during the course of illness and 33 (4.9%) patients were lost to follow-up. 23 (3.4%) patients developed end stage renal failure (ESRF). The main contributing causes of death were: infection (51%), cardiovascular events (12%), cerebrovascular events (16%), cancer (9%), suicide (3%) and others (8%). Infective complications were the commonest causes of death both in patients with disease duration of less (55%) and more than 5 years (47%). In patients with SLE for less than 5 years, 19% of all deaths were caused by vascular events, which was lower than those with disease for more than 5 years (36%). The cumulative survival rate of the patients was 94.8% at 5 years, 91.3% at 10 years and 88% at 15 years. 301 (44%) patients had organ damage (SDI score ≥1). Among patients who had organ damage, the frequency of damage in individual systems was, in decreasing order: neuropsychiatric (N=102, 15%), musculoskeletal (N=93, 14%), renal (N=78, 11%), ocular (N=46, 6.8%), cardiovascular (N=38, 5.6%), pulmonary (N=36, 5.3%), gonadal (N=32, 4.7%), endocrine (N=23, 3.4%), peripheral vascular (N=22, 3.2%), malignancy (N=19, 2.8%) and gastrointestinal (N=8, 1.1%). Within the first 5 years of onset of SLE, neuropsychiatric damage was most frequent (10%), followed by renal (7.9%) and dermatological (7%) damage. In patients with SLE duration of more than 5 years, the commonest cause of damage was in the musculoskeletal system (18.4%), followed by neuropsychiatric (17%) and renal damage (13.3%). The presence of any organ damage was strongly and significantly associated with mortality (HR 6.42[3.05-13.5]; p<0.001). Cox regression analysis revealed that damage in the neuropsychiatric system (HR 1.74[1.31-2.32]; p<0.001), renal (HR 1.97 [1.61-2.42]; p<0.001), cardiovascular (HR 1.75 [1.21-2.53]; p=0.03) and pulmonary (HR 2.63 [1.50-4.62]; p=0.001) systems was significantly associated with mortality.
Conclusions In patients with SLE, organ damage predicts mortality, in particular damage in the renal, nervous, cardiovascular and pulmonary systems. Neuropsychiatric damage is most common in early disease while musculoskeletal damage is most frequent in long-standing disease. Prevention of infective and cardiovascular complications, and minimization of renal damage is important in improving the survival of SLE.
Disclosure of Interest None Declared
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