Analysing and reporting of observational data: a systematic review informing the EULAR points to consider when analysing and reporting comparative effectiveness research with observational data in rheumatology

Health Equity Implications of Missing Data Among Youths With Childhood-Onset Systemic Lupus Erythematosus: A Proof-of-Concept Study in the Childhood Arthritis and Rheumatology Research Alliance Registry

OBJECTIVE

Health disparities in childhood-onset systemic lupus erythematosus (SLE) disproportionately impact marginalized populations. Socioeconomically patterned missing data can magnify existing health inequities by supporting inferences that may misrepresent populations of interest. Our objective was to assess missing data and subsequent health equity implications among participants with childhood-onset SLE enrolled in a large pediatric rheumatology registry.

METHODS

We evaluated co-missingness of 12 variables representing demographics, socioeconomic position, and clinical factors (e.g., disease-related indices) using Childhood Arthritis and Rheumatology Research Alliance Registry childhood-onset SLE enrollment data (2015-2022; n = 766). We performed logistic regression to calculate odds ratios (ORs) and 95% confidence intervals (95% CIs) for missing disease-related indices at enrollment (Systemic Lupus Erythematosus Disease Activity Index 2000 [SLEDAI-2K] and/or Systemic Lupus International Collaborating Clinics/American College of Rheumatology Damage Index [SDI]) associated with data missingness. We used linear regression to assess the association between socioeconomic factors and SLEDAI-2K at enrollment using 3 analytic methods for missing data: complete case analysis, multiple imputation, and nonprobabilistic bias analyses, with missing values imputed to represent extreme low or high disadvantage.

RESULTS

On average, participants were missing 6.2% of data, with over 50% of participants missing at least 1 variable. Missing data correlated most closely with variables within data categories (i.e., demographic). Government-assisted health insurance was associated with missing SLEDAI-2K and/or SDI scores compared to private health insurance (OR 2.04 [95% CI 1.22, 3.41]). The different analytic approaches resulted in varying analytic sample sizes and fundamentally conflicting estimated associations.

CONCLUSION

Our results support intentional evaluation of missing data to inform effect estimate interpretation and critical assessment of causal statements that might otherwise misrepresent health inequities.

Comparative effectiveness of treatments for rheumatoid arthritis in clinical practice: A systematic review

OBJECTIVE

To assess real-world comparative effectiveness studies of biologic (b) and targeted synthetic (ts) disease-modifying antirheumatic drugs (DMARDs) in adults with rheumatoid arthritis (RA) through a systematic review.

METHODS

We searched Medline for journal articles (2001-2021) and Embase® for abstracts presented at the European Alliance of Associations for Rheumatology and American College of Rheumatology (ACR) 2020 and 2021 annual meetings on non-randomized studies comparing the effectiveness of b/tsDMARDs using ACR-recommended disease activity measures, measures of functional status, and patient-reported outcomes (HAQ, PROMIS PF, patient pain, Patient and Physician Global Assessment of disease activity). Methodological heterogeneity between studies precluded meta-analyses. Risk of bias was assessed using the Cochrane Risk Of Bias In Non-randomized Studies of Interventions-I tool.

RESULTS

Of 1283 records screened, 68 were selected for data extraction, of which 1 was excluded due to critical risk of bias. Most studies were multicenter observational cohort/registry studies (n = 60) and were published between 2011 and 2021 (n = 60). Mean or median reported RA duration was between 6 and 15 years. Disease Activity Score in 28 joints (46 studies), Clinical Disease Activity Index (37 studies), and Health Assessment Questionnaire-Disability Index (32 studies) were the most common outcomes used in clinical practice, with regional differences identified. The most common comparison was between tumor necrosis factor inhibitors (TNFis) and non-TNFi bDMARDs (35 studies). There were no evident differences between b/tsDMARDs in clinical effectiveness.

CONCLUSION

This systematic review summarizing real-world evidence from a very large number of global studies found there are many effective options for the treatment of RA, but relatively less evidence to support the use of any one b/tsDMARD or drug class over another. Treatment for patients with RA should be tailored to suit individual clinical profiles. Further research is needed to identify whether specific patient subgroups may benefit from specific drug classes.

EULAR points to consider when analysing and reporting comparative effectiveness research using observational data in rheumatology

Background

Comparing treatment effectiveness over time in observational settings is hampered by several major threats, among them confounding and attrition bias.

Objectives

To develop European Alliance of Associations for Rheumatology (EULAR) points to consider (PtC) when analysing and reporting comparative effectiveness research using observational data in rheumatology.

Methods

The PtC were developed using a three-step process according to the EULAR Standard Operating Procedures. Based on a systematic review of methods currently used in comparative effectiveness studies, the PtC were formulated through two in-person meetings of a multidisciplinary task force and a two-round online Delphi, using expert opinion and a simulation study. Finally, feedback from a larger audience was used to refine the PtC. Mean levels of agreement among the task force were calculated.

Results

Three overarching principles and 10 PtC were formulated, addressing, in particular, potential biases relating to attrition or confounding by indication. Building on Strengthening the Reporting of Observational Studies in Epidemiology guidelines, these PtC insist on the definition of the baseline for analysis and treatment effectiveness. They also focus on the reasons for stopping treatment as an important consideration when assessing effectiveness. Finally, the PtC recommend providing key information on missingness patterns.

Conclusion

To improve the reliability of an increasing number of real-world comparative effectiveness studies in rheumatology, special attention is required to reduce potential biases. Adherence to clear recommendations for the analysis and reporting of observational comparative effectiveness studies will improve the trustworthiness of their results.