To our knowledge, this is the first study to identify what matters to Jordanian living with MS and to assess the psychometric properties of the Arabic version of the PGI. In this study, individuals with MS in Jordan were interviewed using an individualized measure (PGI) to identify areas that affected their QOL due to MS disease. Approximately, 88% of our study sample were able to complete the PGI, thus PGI is a feasible and acceptable tool among Jordanian living with MS. These results are consistent with previous studies [13, 14, 20, 33, 34].
In the current study, a total of 36 areas of QOL concerns were identified using the PGI with the top 11 are emotional function, involuntary movement reaction functions, walking, seeing function (vision), socializing, sleep functions, doing housework, work, muscle power functions, fatigue and moving around. When mapping those top areas to the study measures (EQ-5D, and PDDS), we found that only five areas (Emotional function, walking, doing housework, work and moving around) out of the top 11 were found in the EQ-5D and only two areas (walking and moving around) were included in the PDDS. Our results are supported by previous studies that found PGI captures more important areas to people with chronic conditions including MS than standard measures [13, 20, 34].
Several well-known and common symptoms among people with MS were not captured by the current study measures (EQ-5D and PDDS). For example, sleep function, which affects 50%- 70% of individuals with MS [35-37] was not included in the EQ-5 D or the PDDS. Fatigue, which is one of the most common symptoms of multiple sclerosis (MS) [38-40], reported to affect between 50% and 80% of MS patients at some point in the disease course, has been identified in the PGI but not the other tools (EQ-5D and PDDS). Other areas such as involuntary movement reaction functions, vision, socializing, functions, and muscle power functions were not included in the EQ-5D and PDDS.
These results suggest that PGI captures what matters to people with MS and provides an accurate description of their current health status and QOL. On the other hand, standard measures could not capture all the important areas to people with MS and that might affect the extent to which patients can accurately describe their individual experiences with MS disease. The suggested explanation could be that standard measures (EQ-5D and PDDS) having fixed questions that may not be of importance to people with MS. Therefore, limited item content could restrict addressing and evaluating what matters to people with MS which subsequently impact negatively their QOL. As a result, it is clear that the standard measures were either having not relevant items or missing one’s that might affect the QOL in people with MS. Giving patients the opportunity to choose what matters to them would minimize threats to the content validity [41-44] and this was supported by using PGI, not standard measures.
This study also found that the average global score of the PGI was lower than the global score of the EQ-5D and the PDDS. This finding is consistent with the previous studies using a similar methodology in people with MS [34] and cancer [13]. This result could be explained by the nature of the PGI, where PGI allows people with MS to nominate areas that affected by their disease, rate, and weights them according to their importance which subsequently could affect the global score of the PGI. Therefore, the global score of the PGI may reflect the reality about the current health status of people with MS while the global score from the standard measures overestimate the current health status of people with MS. Furthermore, lower PGI score as compared to the standard measures would highlight the areas that need to be considered in the health-care professional treatment programs and gives a room for improvement when treatment is applied. All of the aforementioned reasons make PGI an interesting measure to be used in both the clinical setting and the research field to evaluate QOL and guide health-care decisions in people with MS.
This study also found a moderate correlation between the PGI and the study measures (EQ-5D and PPDS), indicating good construct validity. This result supports the idea that PGI measures different aspects of QOL than standard measures as the patients' voices are heard by allowing them to nominate, rate, and weights important areas to them.
This study has some limitations that need to be considered in future research. First, the sample size is relatively small. Second, only one generic measure and one disease-specific measure was administered and compared to the PGI. However, the reason was to decrease the burden on people with MS as many of the common standard measures used in the MS population take a long time to complete.