Factors predicting incomplete recovery from relapses in multiple sclerosis: a prospective study

Objective To prospectively evaluate predictors of incomplete recovery after the first attacks in a cohort of patients with clinically isolated syndrome or relapsing-remitting multiple sclerosis. Methods Seventy-two consecutive patients recruited from January 2001 to December 2003, evaluated every six months or at any relapse up to 31 July 2005. Relapse intervals were calculated from the date of onset, nadir, onset of improvement and maximum improvement. Predictive factors analysed were relapse-related (age at relapse onset, season and severity of the relapse, type of symptoms, speed of onset, plateau and total duration, number of affected Functional systems, preceding infections) and individual-related (gender, age at first attack, season of birth and first attack, characteristics of first brain MRI and cerebrospinal fluid oligoclonal bands, Link Index, IgG). Results We counted 209 attacks: 44 (21%) left mild sequelae, and 27 (13%) severe. The highest probability of sequelae was associated with sphincteric symptoms (9120; 45%), followed by sensitive (38/113; 34%), motor (20/84; 24%), visual (13/61; 21%), cerebellar (4/24; 17%), brainstern (5/44; 11%) and others (0/6) (P < 0.005). Four variables were still relevant to predict sequelae after multivariate analysis: mild, moderate or severe relapses versus very mild (Odds ratio = 17.2, 95% confidence limits = 2.2-136.4), intermediate or long relapses versus short (3.2, 1.5-6.9), age >= 30 at relapse onset (2.9, 1.5-5.7) and bi-polysymptomatic versus monosymptomatic (2.2, 1.1-4.3). Conclusions Factors predicting incomplete recovery are more closely linked to the characteristics of the single relapse (extension and duration of tissue damage) than to the patient's genetic and environmental background.