Effect of Diabetes Mellitus on Giant Cell Arteritis

Abstract

Objective To determine if type 2 diabetes mellitus (DM) is protective against giant cell arteritis (GCA) and to estimate the incidence of GCA diagnosis in the Medicare population. Methods Medicare 5% claims files from 1991-2011 were used to identify beneficiaries diagnosed with DM, but not GCA, within a three-year ascertainment period. Propensity score matching was used to define a control group of non-diabetics with comparable demographic covariates. Competing-risk regression was then used to assess the impact of DM diagnosis on GCA diagnosis. To allow for a three-year ascertainment period, the analysis sample was limited to beneficiaries over 68 years old at baseline. Results A total of 151,041 beneficiaries diagnosed with DM were matched to an equal number of controls. Mean study follow-up was 67.75 months. GCA was diagnosed among 1,116 beneficiaries with DM (0.73%) versus 465 (0.30%) controls. The risk of receiving a GCA diagnosis among patients with DM was increased by 100% (sub hazard ratio (SHR): 2.00; 95% confidence interval (CI): 1.78 2.25). The annual incidence of GCA diagnosis among U.S. Medicare beneficiaries over 68 was 93 in 100,000. Conclusion A DM diagnosis is not protective against a GCA diagnosis in the Medicare population. Our data suggests that a DM diagnosis increases the risk of GCA diagnosis within 5.7 years for Medicare beneficiaries over 68.

Ophthalmic presentation of giant cell arteritis in African-Americans

“…Other published studies, including a recent report using Medicare, claims file data have suggested that GCA occurs less commonly in African-American populations, including areas where the population is composed of significant numbers of African-Americans. 1,7,37,38 Our findings are consistent with these reports.…”

“…3 Since then a few studies have reported on the occurrence of GCA in minority groups. The incidence in African-Americans is believed to be lower than in Caucasians, 1,[4][5][6][7] but there is no clear consensus on the nature of disease presentation in this population, as the majority of studies of GCA in African-Americans are case reports or small case series. [8][9][10][11][12][13][14][15][16][17] One study did not find a difference in the presentation of GCA in African-Americans compared with Caucasians, 17 another reported higher rates of vision loss and jaw claudication, 15 and a third noted higher rates of male patients, vision loss, and anemia, and lower rates of constitutional symptoms.…”

Negative associations for fasting blood glucose, cholesterol and triglyceride levels with the development of giant cell arteritis

“…Among the cases who subsequently developed GCA, not a single individual had a history of diabetes at baseline, compared with 2.3% of the controls. This is in line with studies suggesting that GCA cases at the time of diagnosis have a lower prevalence of diabetes compared with controls [ 12 ], although there are conflicting results [ 13 ]. Methodological differences in diabetes ascertainment and possibly age-related effects of diabetes on the risk of GCA may explain such discrepancies.…”

“…A meta-analysis of observational studies demonstrated that patients with GCA have a significantly reduced prevalence of diabetes at the time of diagnosis compared with the general population [ 12 ], but a subsequently published large register-based study came to the opposite conclusion [ 13 ]. It has been shown that during the first 2 years after GCA diagnosis, the incidence of diabetes is increased, most likely due to treatment with high doses of glucocorticoids [ 14 ].…”

Herpes Zoster as a Risk Factor for Incident Giant Cell Arteritis

“…Since an optimal approach to identifying GCA using administrative data is unknown, we attempted to control for the misclassification of GCA by limiting eligible subjects to those >50 years of age and requiring at least 2 outpatient encounters with the diagnostic code or the inclusion on the hospital discharge form. Other investigators have used similar GCA definitions . In sensitivity analyses, we also made our GCA definition more specific in several ways: by requiring a CPT code for temporal artery biopsy, by requiring at least 2 steroid prescriptions, or by requiring at least 1 outpatient diagnostic code for GCA to have been assigned by a rheumatologist.…”