The higher the cumulative dose, and the longer the period of treatment, the greater the risk of a possible detrimental effect of steroids on bone health in patients with asthma, according to the findings of a study published in the journal Thorax.
'Both [oral] and [inhaled] steroids are associated with an increased risk of osteoporosis and [fragility fracture] in people with asthma. The use of [these drugs] should be kept to the minimum necessary to treat symptoms and should be stepped down if symptoms and exacerbations are well managed,' say the researchers.
They add that doctors should also consider prescribing bisphosphonate treatment to protect patients’ bone health.
The team, from the University of Nottingham, used the Clinical Practice Research Datalink (CPRD) GOLD database and Hospital Episode Statistics (HES) data for July 2018, to identify all adults with asthma diagnosed between April 2004 and December 2017, who also had either osteoporosis or fragility fractures.
These patients were matched with at least four control patients of the same age and gender from the same general practice, but who did not have osteoporosis or fragility fractures.
The results showed a clear association between both cumulative dose and number of courses of inhaled or oral steroids and the risk of osteoporosis or fragility fractures.
Two to three steroid tablet prescriptions in the preceding 12 months were linked with larger odds of osteoporosis: patients given 9 or more prescriptions and cumulative doses of 2.5g or more had more than 4 times the risk of those who were not prescribed these drugs, after accounting for other factors likely to affect bone density, such as smoking, weight, and alcohol intake. They were also more than twice as likely to experience a fragility fracture.
Similarly, those given 11 or more prescriptions for inhaled steroids were 60% more likely to have osteoporosis and 31% more likely to have fragility fractures than those not prescribed these drugs.
Patients given cumulative steroid doses of more than 120mg in the preceding year were 20% more likely to experience a fragility fracture.
Only around half of patients prescribed steroid tablets and even fewer prescribed steroid inhalers were prescribed bisphosphonates in the year leading up to a diagnosis of osteoporosis or fragility fracture, a finding the researchers call 'disappointing'.
'Current guidelines on asthma do not fully cover the management of bone comorbidities and no specific bone protection guidance is given,' they say. 'Our results suggest that risk and prevention of osteoporosis and [fragility fractures] should be addressed explicitly in future guideline updates.'
As an observational study, the analysis cannot establish cause and the researchers note that inhalers can be difficult to use correctly, so potentially underestimating the actual dose taken. Their analysis also relied on prescription data rather than confirmed treatment.