Cognitive Function Trajectories in Association With the Depressive Symptoms Trajectories in Systemic Lupus Erythematosus Over Time

Researchers in rheumatology should avoid categorization of continuous predictor variables

BACKGROUND

Rheumatology researchers often categorize continuous predictor variables. We aimed to show how this practice may alter results from observational studies in rheumatology.

METHODS

We conducted and compared the results of two analyses of the association between our predictor variable (percentage change in body mass index [BMI] from baseline to four years) and two outcome variable domains of structure and pain in knee and hip osteoarthritis. These two outcome variable domains covered 26 different outcomes for knee and hip combined. In the first analysis (categorical analysis), percentage change in BMI was categorized as ≥ 5% decrease in BMI, < 5% change in BMI, and ≥ 5% increase in BMI, while in the second analysis (continuous analysis), it was left as a continuous variable. In both analyses (categorical and continuous), we used generalized estimating equations with a logistic link function to investigate the association between the percentage change in BMI and the outcomes.

RESULTS

For eight of the 26 investigated outcomes (31%), the results from the categorical analyses were different from the results from the continuous analyses. These differences were of three types: 1) for six of these eight outcomes, while the continuous analyses revealed associations in both directions (i.e., a decrease in BMI had one effect, while an increase in BMI had the opposite effect), the categorical analyses showed associations only in one direction of BMI change, not both; 2) for another one of these eight outcomes, the categorical analyses suggested an association with change in BMI, while this association was not shown in the continuous analyses (this is potentially a false positive association); 3) for the last of the eight outcomes, the continuous analyses suggested an association of change in BMI, while this association was not shown in the categorical analyses (this is potentially a false negative association).

CONCLUSIONS

Categorization of continuous predictor variables alters the results of analyses and could lead to different conclusions; therefore, researchers in rheumatology should avoid it.

Intraindividual Change in Cognitive Function Among Adults With Systemic Lupus Erythematosus: A Markov Analysis Over 7 Years

OBJECTIVE

Cognitive impairment is prevalent in systemic lupus erythematosus (SLE). There remain gaps in understanding cognition and SLE longitudinally. We studied intraindividual change in cognition in SLE over time.

METHODS

Data were from the University of California, San Francisco Lupus Outcome Study, which included 1281 adults with SLE. The Hopkins Verbal Learning Test-Revised (HVLT-R) and the Controlled Oral Word Association Test (COWAT) were administered annually over 7 years. A two-state Markov analysis was used to model transition intensities for probabilities of change in cognition. Logistic regression examined the association between clinical variables and cognitive change.

RESULTS

Minimal transition between cognitive states was observed in the Markov analysis. Using the COWAT, higher levels of self-reported depression were associated with decreased likelihood of cognitive improvement (Relative Risk [RR]: 0.98; 95% confidence interval [CI]: 0.96-0.99), and higher self-reported disease severity was associated with cognitive decline (RR: 1.05; 95% CI: 1.02-1.09). Using the HVLT-R, increasing age (RR: 1.02; 95% CI: 1.01-1.03) and higher education level (RR: 1.82; 95% CI: 1.28-2.58) were associated with cognitive improvement, and higher self-reported disease severity (RR: 1.02; 95% CI: 1.01-1.03) and depression (RR: 1.05; 95% CI: 1.03-1.07) were associated with cognitive decline.

CONCLUSION

Most individuals with SLE did not transition between states of high (Z score ≥ -1.5) or low (Z score < -1.5) cognition in a Markov analysis over a 7-year assessment period, highlighting a degree of relative stability in cognition over time. Increasing age and higher education levels were associated with greater likelihood of cognitive improvement. Greater self-reported SLE disease severity and depression were associated with cognitive decline.

Trajectories of depressive symptoms in systemic lupus erythematosus over time

OBJECTIVES

The objectives of this study were to determine the trajectories of depressive symptoms in patients with SLE and to identify baseline characteristics that are associated with a patient's trajectory of depression.

METHODS

Data from the Lupus Outcomes Study at the University of California, San Francisco were analysed. Depressive symptomatology was assessed in years two through seven using the Center for Epidemiologic Studies Depression Scale (CES-D), with higher scores representing more severe depressive symptoms. Group-based trajectory modelling was used to determine latent classes of CES-D scores over time. Ordinal logistic regression analyses were performed to identify baseline characteristics associated with worse classes of depressive symptoms.

RESULTS

CES-D scores for 763 individuals with SLE over 6 years were mapped into four distinct classes. Class 1 (36%) and class 2 (32%) comprised the largest proportion of the cohort and were defined by the lowest and low CES-D scores (no depression), respectively. Class 3 (22%) and class 4 (10%) had high and the highest scores (depression), respectively. Greater age [odds ratio (OR): 0.97, 95% CI: 0.96, 0.99] and higher education level (OR: 0.79, 95% CI: 0.70, 0.89) at baseline were associated with lower odds of membership in worse classes of depressive symptoms. Conversely, lower income (OR: 1.73, 95% CI: 1.03, 2.92), worse SF-36 physical functioning scores (OR: 1.12, 95% CI: 1.12, 1.13) and worse SF-36 bodily pain scores (OR: 1.58, 95% CI: 1.55, 1.61) were positively associated with membership in worse classes of depressive symptoms.

CONCLUSION

Four classes of depressive symptoms were identified in patients with SLE. Understanding the trajectories of depressive symptoms and the associated risk factors can aid in the management of these symptoms in individuals living with SLE.

Disease trajectory of SLE clinical endpoints and covariates affecting disease severity and probability of response: Analysis of pooled patient-level placebo (Standard-of-Care) data to enable model-informed drug development

Systemic lupus erythematosus (SLE) is an autoimmune disease affecting multiple organ systems. Many investigational agents have failed or shown only modest effects when added to standard of care (SoC) therapy in placebo-controlled trials, and only two therapies have been approved for SLE in the last 60 years. Clinical trial outcomes have shown discordance in drug effects between clinical endpoints. Herein, we characterized longitudinal disease activity in the SLE population and the sources of variability by developing a latent disease trajectory model for SLE component endpoints (Systemic Lupus Erythematosus Disease Activity Index [SLEDAI], Physician's Global Assessment [PGA], British Isles Lupus Assessment Group Index [BILAG]) and composite endpoints (Systemic Lupus Erythematosus Responder Index [SRI], BILAG-based Composite Lupus Assessment [BICLA], and Lupus Low Disease Activity State [LLDAS]) using patient-level historical SoC data from nine phase II and III studies. Across all endpoints, in predictions up to 52 weeks from the final disease trajectory model, the following baseline covariates were associated with a greater decrease in SLE disease activity and higher response to placebo + SoC: Hispanic ethnicity from Central/South America, absence of hypocomplementemia, recent SLE diagnosis, and high baseline disease activity score using SLEDAI and BILAG separately. No discernible differences were observed in the trajectory of response to placebo + SoC across different SoC medications (antimalarial and immunosuppressant such as mycophenolate, methotrexate, and azathioprine). Across all endpoints, disease trajectory showed no difference in Asian versus non-Asian patients, supporting Asia-inclusive global SLE drug development. These results describe the first population approach to support a model-informed drug development framework in SLE.

Patient Experiences of Systemic Lupus Erythematosus: Findings From a Systematic Review, Meta-Summary, and Meta-Synthesis

OBJECTIVE

To explore the experience of patients with systemic lupus erythematosus (SLE).

METHODS

A systematic review of qualitative studies published in English in the past 10 years and identified through the PubMed, CINAHL, Scopus, and Web of Science databases was performed following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The methodologic quality of each included study was assessed using the Critical Appraisal Screening Programme tool. Study findings were then subjected to a meta-summary and meta-synthesis.

RESULTS

Twenty-six studies with a good overall methodologic quality were included, documenting the experience of 565 adult patients (95% women). A total of 17 codes emerged, summarizing the life experience of SLE patients; the most and least frequent codes in the meta-summary were "feeling not as I usually do" (69.2%) and "having wishes" (7.7%). The codes were then categorized into 5 main themes, summarizing the experience of living with SLE: 1) "experiencing waves of emotions due to the unpredictable nature of the disease," 2) "trying to live an ordinary life," 3) "listening to and obeying the body's limitations," 4) "reviewing my life projects," and 5) "dealing with future uncertainties."

CONCLUSION

Several qualitative studies have been published to date using good methodologic approaches. According to the findings, SLE negatively impacts patient experiences by affecting multiple dimensions of their daily lives, with fatigue and pain as the most frequent symptoms.

Depression-, Pain-, and Health-Related Quality of Life in Patients with Systemic Lupus Erythematosus

Objectives. A significant number of patients with systemic lupus erythematosus (SLE) have depression, and many are untreated. We aim to assess the frequency of moderate to severe depression (MSD) in a multiethnic group of SLE patients with different sociodemographic backgrounds, identify modifiable factors associated with depression, and determine the impact of depression, disease activity, damage, cognitive function, and pain severity on health-related quality of life (HRQoL). Methods. Ninety-nine patients with SLE were evaluated in a cross-sectional study. Sociodemographic data, Beck Depression Inventory (BDI II), SLE disease activity index (SLEDAI-2K), SLICC Damage Index (SLICC-DI), pain severity (10 cm visual analogue scale), cognitive function (Automated Neuropsychologic Assessment Metrics (ANAM)), and the physical (PCS) and mental (MCS) component scores of the Short Form Health Survey (SF-36) were recorded. Bivariate analysis identified potential associations of relevant variables with BDI II and SF-36. Regression analysis determined independent correlates with MSD, PCS, and MCS. Results. Over 50% of subjects (50.5%) were African-American, 37.1% had a family income of ≤$20,000, and 31.3% had MSD. In the bivariate analysis, family income, SLEDAI-2K, cognitive function, and pain severity were associated with MSD. Using binary logistic regression, SLEDAI-2K and pain severity remained independently correlated with MSD ( $p=0.004$ ). In the multiple linear regression analysis, pain severity was the only independent correlate of PCS ( $p<0.0001$ ), while cognitive function and BDI II were the main factors associated with MCS ( $p=0.020$ and $p<0.0001$ , respectively). Conclusion. Pain severity and disease activity are associated with MSD in our unique population, are potentially modifiable, and deserve further attention in the clinic. Depression and pain significantly affect HRQoL and should be aggressively managed.

Fibromyalgia, mood disorders, cognitive test results, cognitive symptoms and quality of life in systemic lupus erythematosus

OBJECTIVES

Cognitive dysfunction, and comorbidities such as mood disorder and fibromyalgia, are common in SLE. This study aims to explore the associations between fibromyalgia, mood disorders, cognitive symptoms and cognitive dysfunction in SLE patients, and their impact on quality of life.

METHODS

We tested cognition in SLE patients and healthy controls, and evaluated cognitive symptoms, mood disorder, fibromyalgia, fatigue and quality of life using patient-reported outcome measures. We examined associations of these comorbidities with both patient-reported cognitive symptoms and cognitive test performance.

RESULTS

High fibromyalgia symptom score and history of depression or anxiety were associated with cognitive dysfunction. There were no significant associations between current depression, anxiety symptoms or fatigue score and objective cognitive dysfunction. In contrast, mood disorder symptoms, history of mood disorder, fibromyalgia symptoms and fatigue all had significant associations with patient-reported cognitive symptoms. There were no significant associations between patient-reported cognitive symptoms and objective cognitive dysfunction. Objective cognitive dysfunction, patient-reported cognitive symptoms, history of mood disorder and fibromyalgia symptoms all had significant associations with poorer quality of life; fibromyalgia had the biggest impact.

CONCLUSIONS

Cognitive symptoms are common in SLE, but there were no associations between cognitive symptoms and objective cognitive dysfunction. Depression, anxiety and fibromyalgia were more consistently associated with patient-reported cognitive symptoms than with objective cognitive dysfunction. These factors all have a significant impact on quality of life. Understanding the discrepancy between patient-reported cognitive symptoms and cognitive test performance is essential to advance care in this area of unmet need.

The effects of disease activity, inflammation, depression and cognitive fatigue on resting state fMRI in systemic lupus erythematosus

OBJECTIVES

Cognitive dysfunction (CD) and depression are interlinked comorbidities of SLE. They may be the result of altered brain mechanisms. This study aimed to examine SLE effects on functional connectivity (FC) within the default mode network (DMN) using resting state fMRI-and how depression may impact this.

METHODS

Demographic, clinical and psychiatric data were collected from 19 SLE-active, 23 SLE-stable and 30 healthy controls (HC) participants. A T2*-weighted rsfMR scan was acquired and analysed using independent component analysis (ICA). Group z-scores for nodes associated with the DMN were tested. Significant nodes were entered into a factor analysis. The combined factor was used in correlations with factors of interest. Significant variables were used in a mediation analysis.

RESULTS

14 DMN nodes were defined using ICA. In five nodes, the SLE groups had significantly reduced FC compared with the HC group (p < 0.01). Factor analysis generated one factor that only depression score correlated with for both the HC group (rs=-0.510) and SLE groups combined (rs=-0.390). Mediation analysis revealed depression score accounted for 22% of the altered FC in the DMN. Disease state accounted for the remaining 78%.

CONCLUSIONS

Altered FC was evident in DMN nodes for SLE groups irrespective of disease activity. Depression accounts for some of this effect but SLE directly accounted for more. Further studies are needed to assess if these changes may be a precursor to CD in SLE. If so, rs-fMRI could be an early marker for CD in SLE and help in future CD in SLE treatment trials.

Cognitive Dysfunction in Systemic Lupus Erythematosus: Immunopathology, Clinical Manifestations, Neuroimaging and Management

Cognitive dysfunction (CD) is a common yet often clinically subtle manifestation that considerably impacts the health-related quality of life in patients with systemic lupus erythaematosus (SLE). Given the inconsistencies in CD assessment and challenges in its attribution to SLE, the reported prevalence of CD differs widely, ranging from 3 to 88%. The clinical presentation of CD in SLE is non-specific and may manifest concurrently with overt neuropsychiatric illness such as psychosis or mood disorders or as isolated impairment of attention, working memory, executive dysfunction or processing speed. Despite the lack of standardized and sensitive neuropsychological tests and validated diagnostic biomarkers of CD in SLE, significant progress has been made in identifying pathogenic neural pathways and neuroimaging. Furthermore, several autoantibodies, cytokines, pro-inflammatory mediators and metabolic factors have been implicated in the pathogenesis of CD in SLE. Abrogation of the integrity of the blood-brain barrier (BBB) and ensuing autoantibody-mediated neurotoxicity, complement and microglial activation remains the widely accepted mechanism of SLE-related CD. Although several functional neuroimaging modalities have consistently demonstrated abnormalities that correlate with CD in SLE patients, a consensus remains to be reached as to their clinical utility in diagnosing CD. Given the multifactorial aetiology of CD, a multi-domain interventional approach that addresses the risk factors and disease mechanisms of CD in a concurrent fashion is the favourable therapeutic direction. While cognitive rehabilitation and exercise training remain important, specific pharmacological agents that target microglial activation and maintain the BBB integrity are potential candidates for the treatment of SLE-related CD.