It can be challenging to directly apply individual noninvasive biomarkers to monitor the progression of Duchenne muscular dystrophy (DMD) and detect the effect of treatments in the clinic, according to a new study published in the journal Muscle and Nerve. However, “trends over time may complement functional measures in the assessment of individuals with DMD.”

With the development of novel therapies to treat patients with DMD, trackable noninvasive biomarkers gain even more importance.

In order to measure changes in certain noninvasive biomarkers and assess their relationship to the patient’s age and motor function, a team of researchers led by Cuixia Tian, MD, from the Division of Neurology, University of Cincinnati College of Medicine and Cincinnati Children’s Hospital Medical Center, Cincinnati, OH retrospectively analyzed 555 DMD patients who have been treated with glucocorticoids for at least a year and were not enrolled in any clinical trial testing disease-modifying therapies for DMD.

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The researchers reviewed the patients’ serum creatine kinase, serum creatinine, and urine creatinine levels as well as the ratio of urine creatinine over urine osmolality. They also extracted information from their medical records about the age at which they lost the ability to walk and Functional Motor Scale (FMS) values.

They found that the levels of serum creatine kinase, serum, and urine creatinine as well as urine creatinine over urine osmolality values all decreased with declining motor function. 

Serum creatine kinase consistently decreased and FMS scores consistently worsened with age. However, there were no clear inflection points. 

Finally, the researchers noted an increased odds ratio for loss of ambulation with lower serum creatine kinase and serum and urine creatinine, levels and urine creatinine over urine osmolality ratio. The most notable of these was the level of urine creatinine.

“Future studies could elucidate predictive utility of these biomarkers in assessing motor function changes in DMD,” the researchers concluded. 


Zygmunt AM, Wong BL, Horn PS, et al. A longitudinal study of creatine kinase and creatinine levels in Duchenne muscular dystrophy. Muscle Nerve. Published online November 28, 2022. doi:10.1002/mus.27760