In the constantly evolving field of MS, personalized medicine is still one of the most important unmet need that requires further attention
We aimed to develop a dynamic risk calculator to predict the long-term prognosis of MS in the context of a large MS Centre in Catalonia
This is an observational study based on data prospectively acquired from a deeply phenotyped CIS cohort from Barcelona. We first built a natural history baseline risk score (BRS) for predicting moderate disability, integrating baseline prognostic factors: Sex, age at CIS, CIS topography, number of T2 lesions, contrast-enhancing lesions (CEL) and oligoclonal bands. This BRS was designed as follows: For untreated patients, we built a Weibull model to estimate the median time to confirmed EDSS 3.0 and with these estimates we identified risk groups based on the median of the cut-offs of 2000 survival trees. Then we obtained the BRS of the full cohort. In patients with more than ten years of follow-up, we performed an inverse probability weighting to balance patients during their follow up for the propensity of being treated or lost to follow-up. The weights were estimated via a proportional hazards (PH) Cox model considering both baseline information (CIS year, BRS) and time-dependent (diagnosis status, new T2 lesions, CEL and cumulative number of relapses). Finally, a weighted PH Cox model was built to estimate the time to confirmed EDSS 3.0 considering the BRS and time-dependent events (new T2 lesions, cumulative number of relapses and first or second-line treatment use). Sensitivity analyses using other disability outcomes and different follow-ups were conducted.
Of 956 patients, 577 (60.4%) were untreated before confirmed EDSS 3.0. Two BRS were obtained: low and high-BRS. Of 400 patients followed for more than ten years, 226 (56.5%) were low-BRS and 174 (43.5%) were high-BRS. High-BRS showed a HR=2.16 95%CI (1.16,4.02). Each new T2 lesion presented HR=1.04 95%CI (1.00,1.08) and each new relapse HR=1.46 95%CI (1.23,1.74). Being on second-line treatment showed a protective effect (HR=0.23 95%CI (0.06,0.94)) but no association was found for first-line treatments (HR=1.32 95%CI (0.67,2.60). Sensitivity analyses confirmed the association between BRS, new T2 lesions and the accumulation of relapses with the prognosis. However, treatment results were inconclusive.
Presenting a high-BRS doubles the risk of reaching moderate disability. Each new lesion and new relapse increses the risk by 4% and 46%, respectively; and second-line treatments seem to be protective. If validated, this risk calculator could be a crucial step to personalized medicine.