Baseline and follow-up data from a prospective, multinational cohort of more than 3,000 patients with clinically isolated events allowed researchers to develop an accurate prognostic nomogram to calculate an individual’s risk for conversion to clinically definite multiple sclerosis at 12 months.

“Identification of patient, disease, and examination factors associated with higher probability of second attack in clinical practice may enable clinicians to flag patients that could benefit from more intensive follow-up and consideration of early DMD [disease-modifying drug] treatment intervention, facilitating more favorable patient outcomes,” wrote Tim Spelman, PhD, and his associates.

The investigators followed 3,296 patients for a median of 2 years after they had been diagnosed with clinically isolated syndrome, and 1,953 experienced a second attack and moved to clinically definite multiple sclerosis. Patients who did not receive DMDs during the follow-up period were just over three times more likely to experience a relapse than were patients who received DMDs.

Risk of relapse was decreased when clinically isolated syndrome was diagnosed later, with an adjusted hazard ratio of 0.9 for every 5 additional years of age. Other risk factors for earlier relapse include higher Expanded Disability Status Scale score at the onset of the first demyelinating event, DMD exposure prior to the first attack, multiple brain and spinal MRI criteria, and oligoclonal bands.

“These results corroborate and extend prior, albeit smaller, studies observing similar sets of predictors of clinical conversion probability,” Dr. Spelman and his coauthors wrote.

The predictive nomogram had a concordance index of 0.81 between the 12-month estimated and observed conversion probabilities.

“While our own internal validation suggested good performance, both an additional training-validation approach and an external validation through the application of the nomogram to a separate MS data set or population are required to confirm the generalizability of the nomogram,” they wrote.

Read the full study in Multiple Sclerosis Journal (2016 Nov 24. doi: 10.1177/1352458516679893 ).