Background/Purpose: In patients with rheumatic and musculoskeletal diseases (RMDs) and infected with Covid – 19, a) we want to assess the mortality rate (MR) related to COVID-19; and b) to analyze the role of RMDs in mortality risk.

Methods: An observational longitudinal study was conducted during the epidemic peak in Madrid (1stMar to 20thMay2020). All patients attended at the rheumatology outpatient clinic of a tertiary hospital with a diagnosis of RMDs and SARS – CoV 2 infection were included (according to a medical diagnosis or confirmed with a positive SARS-CoV-2 PCR diagnostic test). Main outcome: death related to COVID-19 infection. Independent variable: type of RMDs including: autoimmune (systemic autoimmune conditions (SAC) and inflammatory joint disease (IJD)) and non–autoimmune (mechanical diseases and inflammatory diseases (microcrystalline arthritis and tendonitis)). Covariates: sociodemographic, comorbidities, treatment for the RMDs.

Survival techniques were used to estimate the MR related to COVID-19, given per 1,000 persons-month with a 95% confidence interval [CI]. The time of observation comprised the elapsed time between the date of COVID-19 diagnosis of infection until the date of patient’s death, or end of study. Cox multiple regression analysis was run to examine the effect of autoimmune RMDs compared to non-autoimmune RMDs on mortality risk adjusted by sex, age and comorbidities. Results were expressed by Hazard Ratio (HR) and [CI].

Results: 405 patients were included with RMD and COVID – 19 infection with a total follow-up 642.57 patients-month. 69.14 % were women with a mean age at diagnosis of 59.37 ± 15.26 years. The evolution time from the diagnosis of rheumatic disease was 7.62 ± 8.39 years. Of the 405 patients, 243 (60%) had non-autoimmune RMD and 162 (39.9%) (106 (65.43%) IJD, 56 (34.56%) systemic condition) had autoimmune RMD. Of the 405 patients, 44 (11%) died during the follow-up, being 12± 14 days the mean time from infection to death (P50: 6[2-12] and a maximum of 60 days). MR was estimated in 68.48 [50.96-92.01] per 1,000 persons-month. CMR was higher for men (MR 105.45 [68.03-163.45]) than for women (MR 52.99 [35.52-79.06]) and in older people (MR < 60: 4.47, [0.67-31.70]; MR 60-75 years: 32.28 [13.44-77.55]; MR >75Years: 487.18 [354.49-669.53]). The HR of mortality in autoimmune RMDs compared to non-autoimmune RMDs did not achieved statistical significance (HR: 1.39 [0.77-2.5], p=0.27). After adjusting for confounders, we did not find higher risk of mortality among the different types of RMDs (HR autoimmune vs non-autoinmunes: HR: 1.12 [0.6-2.02], p=0.7; HR IJD vs SAC; 1.42 [0.58-3.48], p=0.441; HR non-autoimmune vs SAC: 1.19 [0.52-2.68], P=0.677). Age (HR: 1.13; [1.10-1.15], p< 0.001), and the presence of comorbidities (HR: 2.43; [1.16-4.15], p=0.015) increased the Mortality risk.

Conclusion: In patients with RMD and COVID-19 infection, we found a mortality rate of 68.5 per 1000 persons-month. This study shows that the mortality risk related to COVID-19 is similar between autoimmune and non-autoimmune diseases after adjusting by confounders. We also found that age and comorbidities are risk factors for mortality related to COVID-19 infection.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/mortality-rate-related-to-covid-19-in-rheumatic-and-musculoskeletal-diseases-rmds/