In "Socioeconomic status and disability progression in multiple sclerosis: a multinational study," Dr. Katharine Harding 1 and her colleagues considered whether people's income, education, and social standing affected how quickly their multiple sclerosis (MS) worsened. The rate at which MS causes worsening of cognitive and physical functioning can vary. The reasons for these differences are not clear but are interesting because they may lead to better treatment for MS. How was the study done? To see if socioeconomic status (SES) affected MS-related disability, the authors reviewed 2 databases containing information on patients with MS. One was from British Columbia, Canada, and the other from Cardiff, Wales, United Kingdom. These databases have been kept since the 1980s and have patient information. This includes date of diagnosis and disability scores over time. In Canada, the database information was linked to records from the provincial health system. In Wales, it was linked to National Health Service records. The data were used to estimate each patient's SES based on where the patient lived. The patients were divided into 5 groups based on their SES. Group 1 were those with the lowest SES and group 5 were those with the highest SES. The authors used statistics to analyze the relationship between SES and worsening of disability scores. The influence of SES on the time it took patients to change from relapsing-remitting MS to secondary progressive multiple sclerosis (SPMS) was also studied. This is important because patients with SPMS become disabled more quickly and do not respond well to treatment. The authors also made changes to account for differences such as age and sex among their study populations so that any findings could be attributed to differences in SES and not these other factors.