In support of previously published case reports, in a dose-response relationship.
In a stepwise manner, the hazard ratios for major osteoporotic fracture (MOF) were found to start climbing incrementally for those with a cumulative topical steroid dose equivalent of more than 500 g of mometasone furoate when compared with exposure of 200-499 g, according to the team of investigators from the University of Copenhagen.
“Use of these drugs is very common, and we found an estimated population-attributable risk of as much as 4.3%,” the investigators reported in the study, published in JAMA Dermatology.
The retrospective cohort study drew data from the Danish National Patient Registry, which covers 99% of the country’s population. It was linked to the Danish National Prescription Registry, which captures data on pharmacy-dispensed medications. Data collected from the beginning of 2003 to the end of 2017 were evaluated.
Exposures to potent or very potent topical corticosteroids were converted into a single standard with potency equivalent to 1 mg/g of mometasone furoate. Four strata of exposure were compared to a reference exposure of 200-499 g. These were 500-999 g, 1,000-1,999 g, 2,000-9,999 g, and 10,000 g or greater.
For the first strata, the small increased risk for MOF did not reach significance (HR, 1.01; 95% confidence interval, 0.99-1.03), but each of the others did. These climbed from a 5% greater risk (HR 1.05 95% CI 1.02-1.08) for a cumulative exposure of 1,000 to 1,999 g, to a 10% greater risk (HR, 1.10; 95% CI, 1.07-1.13) for a cumulative exposure of 2,000-9,999 g, and finally to a 27% greater risk (HR, 1.27; 95% CI, 1.19-1.35) for a cumulative exposure of 10,000 g or higher.
The study included more than 700,000 individuals exposed to topical mometasone at a potency equivalent of 200 g or more over the study period. The reference group (200-499 g) was the largest (317,907 individuals). The first strata (500-999 g) included 186,359 patients; the second (1,000-1,999 g), 111,203 patients; the third (2,000-9,999 g), 94,334 patients; and the fifth (10,000 g or more), 13,448 patients.
“A 3% increase in the relative risk of osteoporosis and MOF was observed per doubling of the TCS dose,” according to the investigators.
Patients exposed to doses of high-potency topical steroids that put them at risk of MOF is limited but substantial, according to the senior author, Alexander Egeberg, MD, PhD, of the department of dermatology and allergy at Herlev and Gentofte Hospital, Copenhagen.
“It is true that the risk is modest for the average user of topical steroids,” Dr. Egeberg said in an interview. However, despite the fact that topical steroids are intended for short-term use, “2% of all our users had been exposed to the equivalent of 10,000 g of mometasone, which mean 100 tubes of 100 g.”
If the other two strata at significantly increased risk of MOF (greater than 1,000 g) are included, an additional 28% of all users are facing the potential for clinically significant osteoporosis, according to the Danish data.
The adverse effect of steroids on bone metabolism has been established previously, and several studies have linked systemic corticosteroid exposure, including inhaled corticosteroids, with increased risk of osteoporotic fracture. For example, one study showed that patients with chronic obstructive pulmonary disease on daily inhaled doses of the equivalent of fluticasone at or above 1,000 mcg for more than 4 years had about a 10% increased risk of MOF relative to those not exposed.
The data associate topical steroids with increased risk of osteoporotic fracture, but Dr. Egeberg said osteoporosis is not the only reason to use topical steroids prudently.
“It is important to keep in mind that osteoporosis and fractures are at the extreme end of the side-effect profile and that other side effects, such as striae formation, skin thinning, and dysregulated diabetes, can occur with much lower quantities of topical steroids,” Dr. Egeberg said
For avoiding this risk, “there are no specific cutoffs” recommended for topical steroids in current guidelines, but dermatologists should be aware that many of the indications for topical steroids, such as psoriasis and atopic dermatitis, involve skin with an impaired barrier function, exposing patients to an increased likelihood of absorption, according to Dr. Egeberg.
“A general rule of thumb that we use is that, if a patient with persistent disease activity requires a new prescription of the equivalent of 100 g mometasone every 1-2 months, it might be worth considering if there is a suitable alternative,” Dr. Egeberg said.
In an accompanying editorial, Rebecca D. Jackson, MD, of the division of endocrinology, diabetes, and metabolism in the department of internal medicine at Ohio State University, Columbus, agreed that no guidelines specific to avoiding the risks of topical corticosteroids are currently available, but she advised clinicians to be considering these risks nonetheless. In general, she suggested that topical steroids, like oral steroids, should be used at “the lowest dose for the shortest duration necessary to manage the underlying medical condition.”
The correlation between topical corticosteroids and increased risk of osteoporotic fracture, although not established previously in a large study, is not surprising, according to Victoria Werth, MD, chief of dermatology at the Philadelphia Veterans Affairs Hospital and professor of dermatology at the University of Pennsylvania, also in Philadelphia.
“Systemic absorption of potent topical steroids has previously been demonstrated with a rapid decrease in serum cortisol levels,” Dr. Werth said in an interview. She indicated that concern about the risk of osteoporosis imposed by use of potent steroids over large body surface areas is appropriate.
To minimize this risk, “it is reasonable to use the lowest dose of steroid possible and to try to substitute other medications when possible,” she said.
Dr. Egeberg reported financial relationships with Abbvie, Almirall, Bristol-Myers Squibb, Dermavant Sciences, Galderma, Janssen Pharmaceuticals, Eli Lilly, Novartis, Pfizer, Samsung, Bioepis, and UCB. Five authors had disclosures related to some of those pharmaceutical companies and/or others. Dr. Jackson had no disclosures.