30. Lower frequency of comorbidities prior to onset of giant cell arteritis; a population-based study
Creators: name: Mohanad Elfishawi1
name: Jigisha Rakholiya1
name: Gunderson2, Tina
name: Cynthia Crowson1, 2
name: Kaymakci1, Mahmut
name: Matteson1, Eric
name: Turesson3, Carl
name: Wadstrom3, Karin
name: Weyand1, Cornelia
name: Koster1, Matthew
name: Warrington1, Kenneth
Publisher: name: Zenodo
Year: 2022
Subjects: Vasculitis
ANCA
Abstracts
Giant Cell Arthritis
MPA
GPA
EGPA
Takayasu
IgA vasculitis

description: <strong>Background:</strong> Advancing age, female sex and white race are risk factors for development of giant cell arteritis (GCA). Recently metabolic features such as lower fasting blood glucose (FBG) were thought to predispose to GCA. However, the risk factors for development of GCA remain incompletely understood. We aimed to assess the frequency of comorbidities and metabolic risk factors at, and prior to, onset of GCA. <strong>Methods:</strong> We conducted a retrospective case-control study of patients diagnosed with incident GCA in a geographically defined population from 01/01/2000 till 12/31/2019. Two age- and sex-matched controls were identified for every GCA case and assigned an index date corresponding to the incidence date of GCA. Twenty-five chronic conditions from either the Charlson, Elixhauser, or Rheumatic Disease Comorbidity Index were identified using ICD-9 diagnosis codes within a two-year lookback period; 2 or more codes ≥30 days apart were used to define a comorbidity. Prevalence of comorbidities, clinical and laboratory data among cases and controls were compared at incidence date and 5 years prior. Subjects with less than one year of diagnosis history were excluded from each analysis. Medical records of all subjects were manually abstracted for comorbidities and laboratory data at incidence date, at 5 years, and at 10 years prior to incidence date. Comparisons were performed using Chi square, Fisher exact, or rank-sum tests. Additional analyses for association between lab outcomes and GCA were performed using logistic regression models, adjusted for age, sex, smoking status (ever/never), and BMI. <strong>Results:</strong> The cohort included 129 patients with GCA (74% female, mean age at diagnosis 77 years) and 253 controls. At GCA incidence/index date, the prevalence of diabetes mellitus (DM) was lower in patients with GCA (5% vs 17%; p=0.001). At 5 years prior to incidence/index date, cases had a lower prevalence of DM (2% vs 13%; p&lt;0.001) and hypertension (HTN) (27% vs 45%; p=0.002) as compared to controls. The mean number (SD) of comorbidities at 5 years prior to incidence/index date was lower [0.7 (1.0)] in cases than controls [1.3 (1.4)] (p&lt;0.001) (Table 1). Moreover, at 5 years prior to incidence/index date, cases had a significantly lower median Fasting Blood Glucose (FBG) (96 vs 104 mg/dL; p &lt;0.001) and BMI (25.8 vs 27.7 kg/m<sup>2</sup>; p-value=0.018) as compared to controls. At 10 years prior to the incidence/index date, the median FBG among cases was also lower (93 vs 98 mg/dL; p&lt;0.001), although BMI was not significantly different at that time point. Total cholesterol (median 211 vs 201 mg/dL; p=0.029), low-density lipoprotein (LDL) (123 vs 112 mg/dL; p=0.056), and high-density lipoprotein (HDL) (62 vs 57 mg/dL; p=0.013) were higher among cases compared with controls at 5 years prior to incidence/index date, and no different at 10 years prior. Logistic regression analysis at 5-years and 10-years prior to GCA diagnosis/incident date showed a significant association between GCA and lower FBG, OR 0.965 (95%CI 0.944-0.983) for 5-years prior and OR 0.975 (95%CI 0.952-0.993) for 10-years prior to GCA diagnosis. Higher total cholesterol and LDL were also significantly associated with GCA at 5 years prior OR 1.008 (95%CI 1.001-1.016) and OR 1.009 (95%CI 1.001-1.019) respectively, but this was not at found at 10-years prior to diagnosis. <strong>Conclusions:</strong> Development of GCA was associated with a lower prevalence of DM and HTN, and lower total number of comorbidities, at 5 years prior to incidence date. FBG and BMI were also lower among individuals who later developed GCA, suggesting that metabolic factors influence the risk of GCA. Future studies to elucidate the patho-mechanisms underlying these observations are warranted. <strong>Disclosures:</strong> E. Matteson, Boehringer Ingelheim, Gilead Sciences; C. Turesson, Bristol-Myers Squibb, Roche, Abbvie, Bristol-Myers Squibb, Nordic Drugs, Pfizer, Roche; K. Warrington, Eli Lilly, Kiniksa.