#apaperaday: Different bone health progression patterns and early-stage risk marker in glucocorticoid-treated ambulatory Duchenne muscular dystrophy

In today’s #apaperaday, Prof. Aartsma-Rus reads and comments on the paper titled:  Different bone health progression patterns and early-stage risk marker in glucocorticoid-treated ambulatory Duchenne muscular dystrophy

Today’s pick is from a confetti-worthy paper as deemed by Yuzu. It is Duchenne themed as I will be attending the 21st @Parent_Project conference in Rome. DOI: 10.1007/s00198-024-07018-3

Duchenne patients progressively lose muscle mass and muscle function. Chronic treatment with glucocorticosteroids slows down disease progression, but results in loss of bone mass (amongst other side effects). This leads to an increased risk for fractures.

The biggest risk factor for a future fracture is a fracture. However, authors argue that ideally you would also know the risk factor for the first fracture and to have a more individualized management of osteoporosis. Therefore they wanted to make a predictive model.

In order to achieve this, they collected longitudinal data on bone mineral density in a cohort of 153 Chinese Duchenne patients. For 71 patients there were at least 3 separate measurements of bone density. All patients were ambulant and on steroids.

Patients were on average 8 years old at baseline and on steroids for ~2 years (mean start age 7.9). Authors identified different trajectories for bone mineral density loss. Some patients had a low baseline and then declined slowly (27%), most had a middle trajectory (60%)

13% of patients had a high baseline. Both the high and middle trajectories declined more than the low baseline trajectory. However, authors discuss this is likely a floor effect (there is not much lower they can go).

Predictors for low bone density in this cohort were baseline density and the starting age for steroids. For the low density trajectory patients 50% had osteoporosis within 2 years, while this was 5.3 years for the middle trajectory.

Authors discuss that making their model was challenging as the patients all had both Duchenne and steroids, which both have an individual impact on bone density (Duchenne patients are less active so there is less weight bearing, which leads to loss of bone mass).

Also Duchenne patients have a different growth trajectory than individuals without Duchenne. Clearly the natural history for bone density is different in Duchenne (maximum bone density in healthy individuals is around age 27).

Authors outline that their cohort appears to have more loss of bone density than a published cohort from the UK. However, this may be due to differences between Chinese and Caucasian patients and underlines why it is important to not only have studies from white individuals.

Authors outline that with the information they have now, they aim to have a more individualized management protocol for bone preservation (more proactive in low trajectory patients and less rigorous for high trajectory patients).

Authors outline that there are limitations: this involved only ambulant patients from age 5 years to 17 years. More studies are needed (as always). However, it is good that authors started to provide information from non-Caucasians so we have a less limited dataset.