Exposure to high doses of topical corticosteroids has been shown to be associated with an increased risk of osteoporosis and major osteoporotic fractures.
A Danish registry study of more than 700,000 adults compared bone outcomes in patients with cumulative doses equivalent to 200-499 g (reference group), 500-999 g, 1000-1999 g, 2000-9999 g, and >10,000g of mometasone.
The study, published in JAMA Dermatology, found both the incidence rates of osteoporosis and major fractures increased with the cumulative dose of topical steroids.
A diagnosis of osteoporosis increased stepwise from 36.7 in the reference group to 43.1, 50.2, 55.2 and 58.7 per 10,000 person-years in the higher doses.
Major osteoprotic fractures (MOF), comprising fractures of the hip, forearm, vertebra and humerus, increased from 81.6 in the reference group to 88.7, 100.6, 113.1 and 122.3 per 10,000 person-years respectively.
The study said similar dose-dependent increases were seen for secondary end-points such as a filled prescription for osteoporosis medications or vertebral fractures.
The effect sizes were modest however, ranging from adjusted HRs of 1.06 to 1.24 for osteoporosis and HR 1.01 to 1.27 for MOF.
The population-attributable risk of any exposure ≥500 g compared with non-exposed individuals (200-499 g) was 4.3% for osteoporosis and 2.7% for MOF.
Results were similar for patients with psoriasis or other conditions.
Younger women (aged <50 years) had slightly higher risk estimates associated with topical steroids use than older women.
The study said the absolute risk for the individual user of topical corticosteroids (TCS) remains low.
“For people requiring potent treatment on large body surfaces for prolonged periods, other corticosteroid-sparing treatments for inflammatory dermatoses may be considered, although the benefit of such intervention, strictly speaking, has not been demonstrated for TCS users.”
“Alternatively, earlier evaluation of and prophylaxis for osteoporosis and prophylactic therapy may be considered in patients with extensive use of potent and very potent TCS.”
An editorial in the Journal said the osteoporosis risk associated with glucocorticoids was previously thought to be limited to systemic agents.
However evidence was building for a lesser but still significant impact on bone from cumulative doses of inhaled glucocorticoids and now topical steroids.
Professor Rebecca Jackson, from the division of endocrinology, diabetes and metabolism at Ohio State University, said dermatologists had few reasons to be concerned.
“First, although there is a modest association of TCS use with osteoporosis and fracture, it is critical to recognize that this study’s findings do not provide evidence that TCSs at conventional doses (prescribed for most dermatologic conditions) cause considerable harm.”
“Despite demonstrating a dose-response relationship of TCSs with osteoporosis outcomes, the number of patient-years of TCS use needed for 1 fracture is almost 4-fold lower than that reported for high-dose oral glucocorticoids (40 mg prednisolone for ≥30 days).”
She said the retrospective study was unable to take into consideration factors such as underlying disease, disease severity, location of use of steroids on the body, surface area exposed and skin integrity.
Commenting on the study endocrinologist Professor Peter Ebeling from Monash Health said the findings were useful for dermatologists, endocrinologists and GPs to know.
“It’s more of an effect at a population level. So the attributable risk for osteoporosis was 4.3% at the population level but … the lowest exposure needed for one additional patient to be harmed was at least 10,000 grams applied.”
“So that seems like a very high dose to me but in those groups I think they should be screened for bone health with a bone density test and that is probably not being done at the moment.”
“In people with severe atopic dermatitis who do require very high doses of potent steroids, they should have a screen of their bone health.”