Axial spondyloarthritis may protect against poor outcomes in COVID-19: propensity score matched analysis of 9766 patients from a nationwide multi-centric research network

Introduction: 

The outcomes of COVID-19 in patients with axial spondyloarthritis (ax-SpA) have not been explored in detail. Tumour necrosis factor inhibitors (TNFi) are commonly used for ax-SpA patients, and how they influence outcomes may have implications on COVID-19 management. 

Methods:

A nationwide multi-centric research network was queried for patients with ax-SpA, including ankylosing spondylitis (AS) and non-radiographic SpA (nr-SpA) who had developed COVID-19. An equal number of propensity score(PS) matched controls were extracted from the database amongst patients with COVID-19 who did not have any inflammatory arthritis. Outcomes included mortality and others including hospitalization, intensive care unit, ventilation, acute kidney injury (AKI), renal replacement therapy, acute respiratory distress syndrome, cerebral infarction, venous thromboembolism (VTE), and sepsis. 

Results: 

We identified 9766 patients with ax-SpA (924 AS and 8842 nr-SpA) and 691,862 without SpA who had COVID-19. In the unmatched comparison, patients with ax-SpA had higher risk ratios (RR) for all outcomes. After matching for demographics and comorbidities, patients with ax-SpA had lower RR for mortality [RR: 0.707 (95% CI: 0.598–0.836), p < 0.0001], severe COVID-19 [RR: 0.791 (0.69–0.906), p = 0.0007], hospitalization [RR: 0.872 (0.826–0.921), p < 0.0001], and AKI [RR: 0.902 (0.816–0.997), p = 0.044]. Only the risk of VTE was higher in ax-SpA patients [RR: 1.219 (1.037–1.433), p = 0.016]. Amongst the ax-SpA group, males had worse outcomes in 9 out of the 11 domains except for VTE and cerebral infarction, while blacks had worse outcomes in all except for mortality and the need for renal replacement therapy. AS had similar risk ratios for all outcomes compared with nr-SpA except hospitalization [RR: 1.457 (1.03–2.06), p = 0.0318]. There was no difference in outcomes in patients who had received TNFi in the year previous to COVID-19 infection. Ax-SpA patients who had been prescribed non-steroidal anti-inflammatory drugs in the 3 months prior to COVID-19 had poorer outcomes. 

Conclusion: 

In conclusion, COVID-19 outcomes were better in patients with ax-SpA as compared with PS matched controls except for increased risk for VTE. The use of TNFi is not associated with better or worse outcomes. These apparently protective effects observed need to be validated and explored further.