Cognitive Impairment Common in SLE, Has Limited Impact on Quality of Life

Objective cognitive impairment (CI) is common among patients with systemic lupus erythematosus (SLE) with neuropsychiatric (NP) symptoms; however, CI may have a limited impact on health-related quality of life (HRQOL), according to study results published in Arthritis Care & Research (Hoboken).

Researchers identified the type and severity of objective cognitive dysfunction in patients with SLE and NP symptoms of different origins. They also explored the relationship between objective cognitive functioning and HRQOL.

The 4 phenotypes described in the study were minor/non-NPSLE, inflammatory NPSLE, ischemic NPSLE, and combined NPSLE. All the NPSLE syndromes were assigned based on 1999 American College of Rheumatology (ACR) case definitions for NPSLE.

A multidisciplinary assessment was conducted among all patients with a clinical diagnosis of SLE who visited the Leiden University Medical Center (LUMC) NPSLE tertiary referral center between 2007 and 2019. Patients with a suspected diagnosis of SLE who presented with NP symptoms were referred to the LUMC NPSLE clinic and were evaluated by a multidisciplinary team, including a rheumatologist, a neurologist, a clinical neuropsychologist, a psychiatrist, a neuroradiologist, and a vascular internist.

Among a total of 371 eligible patients, 357 underwent a neuropsychologic evaluation and were included in the study. The mean participant age was 44 years; 86% of the patients were women. The neuropsychological tests included in the assessment were Mini-Mental State Exam total score (for global cognitive function [GCF], score of 0-30); Wechsler Memory Scale (WMS) T-score (for learning and memory [L&M]); STROOP3 and Trail-Making Test-B (TMT-B) T-scores (for executive function and complex attention [EF&CA]); and STROOP 1 and STROOP2 time, and TMA-A T-score (for psychomotor speed [PS]). Mental/physical component scores were used to establish HRQOL.

Moderate CI was defined as a score of 25/30 or less and severe CI was defined as a score of 20/30 or less. In the other 3 cognitive domains, moderate CI was defined as a score of at least 1 SD lower than that of the general Dutch population and severe CI as a score of at least 2 SDs lower than that of the general Dutch population. Among the 357 study patients, 169 had a follow-up visit with a median follow-up time of 11 months.

The study results showed that impairment in GCF was observed in 8% of the patients, whereas GCF was reported in ±50% of individuals in all of the other cognitive domains. The most severe CI (all domains) was reported in patients with a combined NPSLE phenotype. The presence of diffuse CI (ie, L&M, EF&CA, and PS) was most common and occurred more frequently in patients with an inflammatory phenotype.

A weak association was observed between cognition and HRQOL, which was reported both longitudinally and cross-sectionally. The researchers noted, “Generally, 1 SD lower scores on the cognitive domains were associated with at most 1/5 SD lower [HRQOL].”

Limitations of the study included the fact that some data were missing from the analysis, which might have impacted the results. Patients who had the most severe NP presentations, and therefore not able to undergo cognitive evaluations, were excluded from this study. Subjective cognition was not measured, which may have led to missing more subtle CI that was not registered with the cognitive assessment.

The study authors concluded that to improve the QOL of patients with SLE, future investigations should focus on the underlying processes that determine a lower QOL, such as depression and anxiety, instead of on objective CI.

Reference

Monahan RC, Middelkoop HAM, Beaart-van de Voorde LJJ, et al. High prevalence but low impact of cognitive dysfunction on quality of life in patients with lupus and neuropsychiatric symptoms. Arthritis Care Res (Hoboken). Published online April 26, 2022. doi:10.1002/acr.24904