Impact of Comorbidities on Cognition in Multiple Sclerosis Patients: A Multivariable Analysis

Introduction:

Cognitive Impairment (CI) is common in multiple sclerosis (MS), can have disabling consequences on quality of life, and is often prioritized among MS patients. Its causes are multifactorial. An association between cortical injury and CI is consistently demonstrated. Futhermore, clinical factors, such as comorbidities, seems to contribute for CI onset; however few studies have examined their impact on MS cognition.

Objective: To evaluate the association between comorbidities and CI in MS.

Methods:

MS patients underwented brain MRI, neuropsychological assessment (NP) and were screened for the comorbidities presence. Cortical lesions (CL) were identified by phase-sensitive inversion recovery (PSIR) MRI sequences. NP was performed using the Brief International Cognitive Assessment for Multiple Sclerosis (BICAMS), with z scores calculated  based on Brazilian normative values. Clinical data and results were compared between patients without comorbidities (C-) and patients with comorbidities (C+). The association between CL, comorbidities, and CI was assessed by a multivariable logistic regression (MLR) analysis.

Results:

Forty-eight individuals were included, 45.8% were C- and 54.2% C+. The C+ was older (48.5 vs. 41; p = .02) and had more individuals with CI (p = .009). The C-  had a higher number of CL (5 ± 5 vs. 2.5 ± 3.2; p = .04), however without higher number of individuals with CL (p = .31), and scored better than C+ in the SDMT (55.1 ± 16 vs. 45.6 ± 21, p = .04) and BVMT (24.4 ± 5.9 vs. 21.1 ± 7.4, p = .05). MLR analysis identified only comorbidities as significant (p = .018) for CI (B = 2.06; OR = 7.85; 95% C.I. 1.41 - 43.4, p = .02).

Conclusions:

Comorbidities increases the chances of CI. The association of the CL load with CI seems to depend on its interaction with cofactors. Strategies to optimize comorbidities management in MS are warranted.