Comment on: Tselios K, Gladman DD, Sheane BJ, Su J, Urowitz M. All-cause, cause-specific and age-specific standardised mortality ratios of patients with systemic lupus erythematosus in Ontario, Canada over 43 years (1971-2013). Annals of the Rheumatic Diseases 2019; 78 (6): 802-806.
Commented by: Luís Inês, MD, PhD. Rheumatologist, CHUC Lupus Clinic, Rheumatology Dpt., Centro Hospitalar Universitário de Coimbra, Portugal. SLEuro general secretary.
Survival of patients with systemic lupus erythematosus (SLE) has progressively improved over the last 50 years. The 5-year survival rate was estimated at 50% in 1955, while it reached 95% over the last decade in developed countries. However, as the life expectancy has also greatly improved in the general population during the same period, there is a need to analyse standardized mortality ratios (SMR) to better understand the real trends in SLE mortality. The SMR represents the ratios of the number of deaths observed in a given cohort, such as a cohort of patients with SLE, divided by the deaths reported in the general population in the same geographic area and time period.
The aim of this study by Tselios et al was to assess the evolution of all-cause, cause-specific and age-specific SMRs of patients with SLE from 1971 to 2013 in Ontario, Canada.
The authors analysed 1732 patients with SLE followed in the Toronto Lupus Clinic from 1971 to 2013. Deaths and causes of death were identified in this SLE cohort. As a comparator, data from the general population of Ontario, Canada, was used for the calculation of the SMRs. The authors estimated the all-cause, atherosclerosis, infection and malignancy-related SMRs
Major findings of this study were:
- All-cause and cause-specific SMRs for SLE patients decreased progressively over time
- All-cause SMR decreased from 13.5 (8.6-18.5) in the ‘70s to 2.2 (1.4-3.1) in 2010-2013
- The all-cause age-specific SMR was much higher in younger (19-39 years) SLE patients – 12.4 (9.7-15.1) as compared to older (over 40 years) patients – 3.1 (2.6-3.6) over the 43 year period.
- Comparing the mean age at death of patient with SLE and in the general population, in 2010-2013 the potential years of life lost were 23.6 years in patients with SLE.
The authors highlight that the all-cause and cause-specific mortality (SMR) of patient with SLE is particularly high for younger patients (<40 years). This is still the case in recent years (2010-2013).
These findings underline the need to optimise the management of the disease and its major comorbidities, particularly in the younger age groups.
Commentator’s viewpoint: These results extend findings from other recent studies, that despite major improvements in long- term outcomes of patients with SLE, there remains a large loss in potential years of life. This present study, coming from a reference centre providing excellent care in a developed country, probably represents a best-case scenario. Other recent study suggests that relative survival of SLE patients may be stagnating or even worsening as compared to more accelerated improvements in the general population . The survival gap is particularly striking in younger patients, possibly due to unmet needs for improving management of lupus disease activity and/or for avoiding infections related to treatments. It is of paramount importance to optimise quality of care, both regarding disease management and comorbidities, to all patients with SLE in the general population beyond excellence centres.
- Yen EY, Shaheen M, Woo JMP, Mercer N, Li N, McCurdy DK, Karlamangla A, Singh RR. 46-Year Trends in Systemic Lupus Erythematosus Mortality in the United States, 1968 to 2013: A Nationwide Population-Based Study. Ann Intern Med 2017; 167(11):777-785.