NARCOMS Report-Patient Determined Disease Steps (PDDS)
This issue of the North American Research Committee on Multiple Sclerosis (NARCOMS) Report focuses on two questions: 1. How a sample of NARCOMS registrants with different disease duration rate their own level of disability (if any) and 2. How this disability level may differ between men and women and different racial/ethnic groups.
In each NARCOMS update survey, our registrants provide a self-assessment of their disability status by completing the Patient Determined Disease Step (PDDS) scale. The PDDS was adapted from a physician administered scale call Disease Steps (Hohol, Orav, & Weiner, 1995) to be used as a patient-reported measure of disability. This NARCOMS Report reviews data on 9,642 participants who responded to the spring 2008 update survey. Table 1 summarizes the demographic information describing the responders. As typical in MS, most of the participants in this sample are female, Non-Hispanic white and over 40 years of age.
As a first step to a better understanding of how MS affects people throughout the world, the NARCOMS team has launched an investigation on how MS affects the Latino population. To accomplish this goal we are currently engaged in several projects aimed at recruiting Spanish speaking patients with MS to the Registry. As a preview, Table 2 provides a break down of PDDS levels for three different ethnic/racial groups in the NARCOMS Registry. Although the groups in this sample appear relatively similar, please note that the results have not been adjusted for differences in age and disease duration. Furthermore, the size of the Latino and AA groups in this sample is still quite small. Dr. Marrie et al. have published a detailed analysis on a larger set of NARCOMS data and demonstrated that African Americans experience more disability than Non-Hispanic whites through-out the course of their MS regardless of age (Marrie et al., 2006).
Figure 1 shows the PDDS levels for men and women based on how long they have experienced MS symptoms. On the average, the level of self-reported disability increased with disease duration. On average, men reported higher PDDS levels (which means more disability) than women regardless of disease duration. Men also reported higher average PDDS scores (more disability) than women regardless of the age of symptom onset (see Figure 2).
Figure 3 summarizes the average PDDS level reported in spring 2008 by Non-Hispanic whites vs. all other responders based on time since MS diagnosis. Among those who have had the disease the longest (diagnosis in 1940s or 1950s) Non-Hispanic whites report lower average disability than others, consistent with our previously published work (Marrie et al. 2006; 2008).
The data summarized in this NARCOMS Report support the concept that MS is a disease that progresses with age. As we age, the repair mechanisms in our bodies may become less effective, which may contribute to accumulating disability over time. As published earlier, Non-Hispanic whites tend to report less disability than other groups, including African Americans. Additional data will be needed to fully investigate this phenomenon. Lastly, men report more disability throughout the course of their MS than women, a finding that may be attributed to a higher prevalence of primary progressive MS among males. Much more research, however, will be needed to understand how MS affects us over time. We are curious to find out how the use of approved medications to treat MS may impact the disability progression and whether the current treatments yield an improved clinical outcome over the course of the disease. Does treating MS aggressively from the first diagnosis provide a better prognosis of improved health and reduced exacerbations and decreased disability? Your continued dedication to NARCOMS research will give us an opportunity to revisit these questions in the near future.
Hohol, M., Orav, E., & Weiner, H.. (1995). Disease Steps in Multiple Sclerosis: A Simple Approach to Evaluate Disease Progression. Neurology, 45(2), 251-5.
Marrie, R. A., Cutter, G., Tyry, T, Vollmer, T., & Campagnolo, D. (2006). Does multiple sclerosis-associated disability differ between races? Neurology, 66, 1235-1240.
Marrie, R. A., Horwitz, R., Cutter G., Tyry, T., Campagnolo, D., & Vollmer, T. (2008). Co-morbidity, Socioeconomic Status and Multiple Sclerosis. Multiple Sclerosis, 14(8), 1091-8.