Excess GCA deaths mainly occur early in disease course
medwireNews: People with giant cell arteritis (GCA) have an elevated risk for all-cause mortality relative to the general population, particularly within the first year following diagnosis, researchers report.
The Danish registry study included 9908 patients aged at least 50 years (average 73 years) who were diagnosed with GCA between 1996 and 2018 and redeemed at least three prednisolone prescriptions within 6 months; these individuals were matched based on age, sex, and calendar time to 98,204 people without a history of GCA.
As reported in Rheumatology, 6.4% of the GCA cohort died within 1 year of diagnosis, while 45.0% died during 10 years of follow-up.
Philip Therkildsen (Aarhus University Hospital, Denmark) and team report that the adjusted relative risk (RR) for mortality in people with GCA versus the control participants “was highest within the first years following diagnosis,” with a significant RR of 1.49 at 1 year, and then “decreased over time as the cumulative incidence of deaths increased,” with an RR of 1.03 at 10 years.
On the other hand, they say that the risk difference (RD) for mortality “increased within the first years following diagnosis and remained relatively constant over time,” with adjusted RD values of 2.2% at 1 year and 2.1% at 10 years.
“This demonstrates that GCA is associated with an increased mortality and that the excess number of deaths primarily occurs within the first years following the diagnosis,” a time period corresponding to “the highest disease activity and administration of the highest prednisolone doses,” write the researchers.
Moreover, analysis of cause-specific death rates supports the hypothesis that the elevated mortality risk in GCA “may in part be due to glucocorticoid-related complications,” they add.
Specifically, GCA patients had a significantly higher risk than controls for infectious (RR=2.58), endocrine (RR=2.67), cardiovascular (RR=1.48), and gastrointestinal (RR=3.03) diseases at 1 year, and these risks were attenuated, but still statistically significant at 10 years (RRs=1.29, 1.38, 1.08, and 1.40, respectively). The risk for respiratory disease was significantly elevated in the GCA group at 1 year (RR=1.46), but not at 10 years.
The team also categorized GCA patients based on temporal artery biopsy (TAB) results, finding that TAB-positive individuals had a lower mortality risk relative to controls than TAB-negative individuals and those who did not undergo TAB, with RRs of 1.19, 1.49, and 1.78, respectively, at 1 year.
“This indicates that studies focusing on biopsy-positive GCA patients only, may not be generalizable to the full GCA population as they would likely underestimate the overall mortality,” say Therkildsen et al.
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