New-Onset Diabetes Risk in Giant Cell Arteritis With Prednisone

Patients with either giant cell arteritis (GCA) or granulomatosis with polyangiitis (GPA) who are prescribed prednisolone or prednisone have a significantly increased risk of developing new-onset diabetes early during treatment course, according to research published in the Journal of Rheumatology.

Mikkel Faurschou, MD, PhD, of the Copenhagen Lupus and Vasculitis Clinic, Center for Rheumatology and Spine Diseases at Copenhagen University Hospital in Denmark, and colleagues used the Danish National Hospital Register (NHR) to identify 2024 patients with a diagnosis of either GCA (n=1682) or GPA (n=342) and determine their medication exposure.

Patients who had been prescribed antidiabetic drugs 2 years prior to the date of study inclusion were excluded from the analysis. The Danish Civil Registration System was used to identify 9 randomly selected, age- and sex-matched population controls. In total, the comparison cohort included 15,138 individuals as GCA population controls and 3078 individuals as GPA population controls.

Median time between diagnostic biopsy and GCA diagnosis was 0.1 month (interquartile range [IQR]: 0.03-0.2); median time from first GPA hospitalization to date of study inclusion was 1.1 month (IQR: 0.5-2.3).

In the GCA and GPA cohorts, 99% and 87% of patients, respectively, had a prescription for prednisolone or prednisone within the first year of follow up; that number dropped to 37% and 46%, respectively, during the tenth year of follow-up. 

In both cohorts, median cumulative prednisolone/prednisone dose was ≥5.6 g within the first year, and ≤2.5 g per year during each subsequent year.

Across both cohorts, 177 patients met the criteria for new-onset diabetes during follow-up. Within the GCA cohort, the risk was increased 7-fold; the risk was higher in the CPA cohort with a 10.4x increased risk.

Incidence rates for diabetes were not significantly increased in either cohort when set against the comparison cohort. However, the adjusted odds ratio (OR) for diabetes was 1.6 (95% confidence interval [CI], 1.02-2.5) among patients who had been prescribed the median cumulative dose of prednisolone or prednisone during the first year of follow up. Adjusted OR for diabetes per 10 mg increase was 1.3 (95% CI, 1.01-1.8) during the same time period. 

Summary and Clinical Applicability

“Our present cohort study demonstrates a markedly increased risk of diabetes during initial treatment phases among patients diagnosed with GCA or GPA,” wrote Dr Faurschou and colleagues. “We observed statistically significant associations between exposures to high cumulative doses of prednisolone/[prednisone] and new-onset diabetes among patients with vasculitis.”

Dr Faurschou and colleagues noted that, among all cohorts, a patient’s likelihood of being diagnosed with diabetes was higher among patients with GCA or GPA vs the population control groups due to the “clinical attention paid to persons undergoing therapy for systemic vasculitis.”

Additional studies should be performed to determine the predictive factors of diabetes in patients with a GCA or GPA diagnosis. 

Limitations and Disclosures

• Data did not include information on traditional risk factors for type 2 diabetes, which prevented the researchers from studying the diabetes risk in conjunction with predisposed factors like weight and glucose tolerance

• Researchers were unable to investigate whether the diabetes risk in patients with biopsy-proven GCA differed from the risk in patients with biospsy-negative or nonbiopsied patients

Reference

Faurschou M, Ahlström MG, Lindhardsen J, Obel N, Baslund B. Risk of diabetes mellitus among patients diagnosed with giant cell arteritis or granulomatosis with polyangiitis: comparison with the general population. J Rheumatol. 2016 Oct 15. doi: 10.3899/jrheum.160797  [Epub ahead of print]

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