Shingles Increases the Risk of Giant Cell Arteritis

Complicated and uncomplicated herpes zoster are associated with a higher risk of giant cell arteritis (GCA) among patients older than 50 years, according to a recent study.

Previous histopathological studies have indicated that herpes zoster may often precede GCA.
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To explore this relationship further, the researchers assessed 16,686,345 patients older than 50 years in the Medicare 5% and Truven MarketScan datasets. All patients included in the study had received 12 months of continuous coverage and had no history of GCA or polymyalgia rheumatica.

ICD-9 codes from physician visits and/or hospital discharges were used to identify complicated and uncomplicated herpes zoster and GCA events. Prescription claims and drug codes were used to identify antiviral therapies and vaccinations. Multivariable Cox proportional hazards regression was used to determine risk of incident GCA.

Ultimately, the researchers found that unadjusted incidence rates of GCA were highest among those with complicated and uncomplicated herpes zoster. Among patients with preceding herpes zoster events, 5942 cases of GCA had occurred in 3.1% of patients in MarketScan and 6% of patients in Medicare. Following multivariable adjustment, complicated herpes zoster (MarketScan hazard ratio [HR] 2.16 vs Medicare HR 1.99) and uncomplicated herpes zoster (MarketScan HR 1.45 vs Medicare HR 1.42) were both associated with an increased risk of GCA.

Vaccination and antiviral treatment were not consistently associated with the risk of GCA. However, antivirals were marginally associated with a lower risk of GCA among patients in Medicare (HR 0.67).

“[Herpes zoster] is associated with increased GCA risk,” the researchers concluded. “The infrequency of [herpes zoster] in GCA patients suggests it is only one potential trigger for GCA. Antivirals and vaccination did not consistently mitigate this risk.”

—Christina Vogt

Reference:

England BR, Mikuls TR, Xie F, Yang S, Chen L, Curtis JR. Herpes zoster as a risk factor for incident giant cell arteritis [Published online August 29, 2017]. Arthritis Rheumatol. doi: 10.1002/art.40236.