High blood pressure may be linked to greater overall disability in people with multiple sclerosis (MS), although the rate at which disability progresses might be slower than in patients without hypertension, a retrospective study concludes. The research, involving a large number of MS patients, helps to clarify a rather confusing range of views on how factors related to heart and metabolic disorders influence this disease’s course.
Studies investigating risk factors for disability progression in MS tend to come to rather different conclusions, as do those exploring risk factors for heart or metabolic disease (like obesity or diabetes) in relation to MS. In terms of hypertension, some studies report that MS patients develop high blood pressure at the same rate as other people, while others find high blood pressure is unusual in people with MS.
To get a clearer picture of how blood pressure might affect MS, and to identify potential links between heart and metabolic disease and MS, scientists at Chaim Sheba Medical Center and Tel Aviv University examined the medical records of 2,396 patients, most with relapsing-remitting disease.
The study, “Disability Progression in Multiple Sclerosis Is Affected by the Emergence of Comorbid Arterial Hypertension,“ published in the Journal of Clinical Neurology, used the Expanded Disability Status Scale (EDSS) for measuring disability, setting three values as measures of disease progression — EDSS scores of 4 (unaided walking and normal activities possible), 6 (assistance with walking needed), and 8 (bedridden, but use of arms).
Researchers also explored if patients had high blood pressure or a family history of hypertension, diabetes, or heart disease. In addition, they collect data about smoking habits.
Only 8.6% of patients studied had high blood pressure, but as a group they were more likely to progress in disability, with 62.3%, 51.2%, and 16.9% of them reaching EDSS 4, 6, and 8, respectively. Among patients without high blood pressure, the corresponding numbers were 43.2%, 27.9%, and 10.3%. The average time for disease progression to one of these three disability levels in all patients was, respectively, 123.5, 163.1, and 218.9 months.
Nevertheless, patients with high blood pressure took longer to progress between levels than those with normal pressure. On average, people with hypertension and MS took 51.6, 38.9, and 62.7 months longer to move to EDSS levels 4, 6, or 8, respectively, than those without elevated blood pressure who reached the same EDSS scores.
Smoking seemed to shorten the time for a patient to reach EDSS 4 and 8 disability levels (7.6 and 65.1 months earlier, respectively), while family history of heart and metabolic disease was not linked to progression.
Older age, in itself, is thought to be a risk factor for disease progression. The patients in this study were relatively young, with a mean age of 46.5, but taking age into account did not change the outcome of the analysis.
“Disability progression is more prevalent amongst hypertensive MS patients. However, they experience longer time intervals between the stages of disability progression,” the research team concluded.