Polymyalgia rheumatica, giant cell arteritis associated with increased fracture risk
medwireNews: Patients with polymyalgia rheumatica (PMR) or giant cell arteritis (GCA) have an elevated risk for fracture compared with the general population, results of a UK database study suggest.
In an analysis of data from patients aged a mean of approximately 70 years using primary care electronic medical records, Zoe Paskins (University of Keele, UK) and study co-authors found that 13.92% of 12,136 patients with PMR and 13.88% of 2673 patients with GCA experienced fractures over a median 9 years of follow-up, giving corresponding incidence rates of 148 and 147 per 10,000 person–years.
By comparison, 11.19% of 46,238 controls matched to the PMR patients on age, sex, and clinical practice, and 10.96% of the 10,423 matched controls for the GCA group experienced fractures, translating into incidence rates of 116 and 110 per 10,000 person–years, respectively.
After adjustment for factors including age, sex, comorbidities, and smoking, PMR patients had a 63% increased risk for fracture, and GCA patients a 67% greater risk, compared with the matched controls.
Despite a “marked overlap” between the two diseases, the researchers note that this similar increase in fracture risk associated with the two conditions was “surprising” because “considerably lower dose glucocorticoids are recommended for PMR than for GCA.”
Glucocorticoids “are a well-established cause of osteoporosis and fragility fracture,” they add.
Patients with PMR received glucocorticoids for a median of 16 months, compared with 13 months for those with GCA. When comparing PMR patients in the highest (10.0–73.3 mg) versus lowest (1.0–4.9 mg) quintiles of average daily glucocorticoid dose, those taking the highest doses had a 1.85-fold increased risk for fracture. Similarly, GCA patients in the highest (13.5–83.9 mg) versus lowest (1.1–5.7 mg) glucocorticoid dose quintiles had a 2.09-fold increased risk.
“Relatively little is known about ‘real life’ steroid use in PMR and GCA; however, our findings demonstrate that, PMR is, in practice, treated for a longer duration than GCA,” write Paskins and colleagues in BMC Medicine.
They explain that clinical practice guidelines for PMR recommend bisphosphonate use for bone protection for all patients aged over 65 years, and for younger patients with elevated fracture risk, whereas GCA guidelines advocate “bone protection for all.”
However, of the PMR and GCA patients who received two or more glucocorticoid prescriptions over the study period, only 12.6% and 10.1%, respectively, were prescribed bisphosphonates.
These findings indicate that “[m]ore needs to be done to improve adherence to guidelines to co-prescribe bisphosphonates,” say the researchers.
And looking to the future, they call for additional research to establish appropriate glucocorticoid tapering regimens, to determine “whether lower starting doses and/or aggressive dose reduction reduces fracture risk,” and to investigate the efficacy and safety profiles of non-glucocorticoid treatments for PMR and GCA patients.
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