Gaissmaier, W.,Giese, H.,Galesic, M.,Garcia-Retamero, R.,Kasper, J.,Kleiter, I.,Meuth, S. G.,Kopke, S.,Heesen, C.

Objective: A shared decision-making approach is suggested for multiple sclerosis (MS) patients. To properly evaluate benefits and risks of different treatment options accordingly, MS patients require sufficient numeracy - the ability to understand quantitative information. It is unknown whether MS affects numeracy. Therefore, we investigated whether patients' numeracy was impaired compared to a probabilistic national sample. Methods: As part of the larger prospective, observational, multicenter study PERCEPT, we assessed numeracy for a clinical study sample of German MS patients (N = 725) with a standard test and compared them to a German probabilistic sample (N = 1001), controlling for age, sex, and education. Within patients, we assessed whether disease variables (disease duration, disability, annual relapse rate, cognitive impairment) predicted numeracy beyond these demographics. Results: MS patients showed a comparable level of numeracy as the probabilistic national sample (68.9% vs. 68.5% correct answers, P = 0.831). In both samples, numeracy was higher for men and the highly educated. Disease variables did not predict numeracy beyond demographics within patients, and predictability was generally low. Conclusion: This sample of MS patients understood quantitative information on the same level as the general population. Practice implications: There is no reason to withhold quantitative information from MS patients.