Trends in mortality in patients with systemic autoimmune rheumatic diseases (SARD) during the COVID-19 pandemic in Mexico

The study aimed to analyze the influence of the COVID-19 pandemic on mortality rates in patients with systemic autoimmune rheumatic diseases (SARD) in Mexico. We selected SARD-related deaths using National Open Data and Information from the Ministry of Health, Mexico, and ICD-10 codes. We assessed the observed compared to the predicted mortality values for 2020 and 2021, employing trends from 2010 to 2019 with joinpoint and prediction modelling analyses. Among 12,742 deaths due to SARD between 2010 and 2021, the age-standardized mortality rate (ASMR) increased significantly between 2010 and 2019 (pre-pandemic) (annual percentage change [APC] 1.1%; 95% CI 0.2-2.1), followed by a non-significant decrease during the pandemic period (APC 13.9%; 95% CI 13.9-5.3). In addition, the observed ASMR of 1.19 for 2020 for SARD and of 1.14 for 2021 were lower than the predicted values of 1.25 (95% CI 1.22-1.28) for 2020 and 1.25 (95% CI 1.20-1.30) for 2021. Similar findings were identified for specific SARD, mainly systemic lupus erythematosus (SLE), or by sex or age group. Interestingly, the observed mortality rates for SLE in the Southern region of 1.00 in 2020 and 1.01 in 2021 were both significantly greater than the predicted values of 0.71 (95% CI 0.65-0.77) in 2020 and 0.71 (95% CI 0.63-0.79). In Mexico, the observed SARD mortality rates were not higher than the expected values during the pandemic, except for SLE in the Southern region. No differences by sex or age group were identified.