Study: Cognitive Impairment Has Little Effect on QOL in SLE

Patients with systemic lupus erythematosus (SLE) and neuropsychiatric (NP) symptoms have a high rate of cognitive impairment, according to a new study, but the deficits do not appear to have a major impact on their healthcare-related quality of life (HRQOL).

The report was published in Arthritis Care & Research and based on patients who sought care at Leiden University Medical Center’s Neuropsychiatric SLE Clinic, in the Netherlands, between 2007 and 2019.

The authors wrote that cognitive dysfunction is a common feature of SLE, but its prevalence is unclear given the wide range of rates reported in the scientific literature. The mechanism of the association between SLE and cognitive dysfunction is also unclear, but they do say it may be related to central nervous system inflammation, among other potential causes.

In the new study, the authors wanted to answer 2 questions: What percentage of people with SLE and neuropsychiatric symptoms have cognitive dysfunction? How does cognitive impairment affect those patients’ HRQOL?

The investigators analyzed the cases of 357 patients who were treated at their clinic for SLE with NP symptoms. Eighty-six percent were female, and the mean age was 44 years. The patients were examined based on 4 cognitive domains: global cognitive function, learning and memory, executive function and complex attention, and psychomotor speed.

Just 8% of patients had global cognitive function impairment (including just 2% with severe impairment). However, 49% had learning and memory impairment, 43% had impairment of executive function and complex attention, and 51%, psychomotor speed impairment. The high rates of impairment were seen across neuropsychiatric SLE phenotypes, but impairment was most severe in patients with a combined inflammatory/ischemic phenotype. Diffuse cognitive impairment, covering multiple cognitive domains, had the strongest association with the inflammatory phenotype.

The investigators then used the mental and physical component scores of the Short Form-36 assessment to understand the patients’ HRQOL. However, the authors found that the associations between cognitive impairment and QOL tended to be weak.

“In general, 1 SD (standard deviation) lower scores on the cognitive domains were associated with at most 1/5 SD lower HRQOL,” they wrote.

The weak association held true even among a subset of patients who received assessments at a median follow-up of 11 months.

The investigators said their inability to find a link between cognitive impairment and QOL differs from some previous research, which has suggested a stronger impact of the former on the latter.

They said the difference may be due to different methodologies, including how cognitive deficits were assessed and how the association between cognition and QOL was calculated. One previous study, for instance, used subjective measures of cognitive decline rather than objective tools.

“It seems likely that an individual’s perceived limitations in cognition associated (more) strongly with self-assessed HRQOL, and experienced cognitive dysfunction is known to differ strongly from objective cognitive dysfunction in patients with SLE,” they noted.

They said it may be more useful in future studies to focus on patient-reported cognition measures.

Reference

Monahan RC, Middelkoop HA, Beaart-van de Voorde LJ, 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