Disparities in multimorbidity and comorbidities in rheumatoid arthritis by sex across the lifespan

Abstract

Objectives: Multimorbidity is burdensome for people with RA. We investigated differences in multimorbidity and comorbidities by sex and age in the RA population.

Methods: This cross-sectional analysis used national administrative claims (OptumLabs® Data Warehouse) from people with RA and non-RA comparators (matched on age, sex, race, census region, index year and length of baseline insurance coverage) from 2010-2019. RA was determined using a validated algorithm. Multimorbidity was defined as ≥2 (MM2+) or ≥5 (MM5+) comorbidities from a validated set of 44 chronic conditions. We used logistic regression to assess associations between characteristics and multimorbidity.

Results: The sample included 154 391 RA patients and 154 391 non-RA comparators. For people aged 18-50 years, RA women (vs RA men) had 7.5 and 4.4 (vs 3.2 and 0.9 in non-RA women vs non-RA men) percentage point increases for MM2+ and MM5+, respectively. For people aged 51+ years, RA women (vs RA men) had 2.1 and 2.5 (vs 1.2 and 0.3 in non-RA women vs non-RA men) percentage point increases for MM2+ and MM5+, respectively. Interactions revealed that differences in multimorbidity between women and men were exacerbated by RA (vs non-RA) (P < 0.05), with more pronounced effects in people aged 18-50. Men had more cardiovascular-related conditions, whereas RA women had more psychological, neurological and general musculoskeletal conditions. Other comorbidities varied by sex and age.

Conclusion: Multimorbidity disproportionately impacts women with RA. Research, clinical and policy agendas for rheumatic diseases should acknowledge and support the variation in care needs by sex and gender across the lifespan.

Keywords: RA; comorbidity; disparities; multimorbidity; sex.

Figure 1.

Association between cohort characteristics and multimorbidity. Panel A: $\ge$2 morbidities. Association between cohort characteristics and multimorbidity. Panel B: $\ge$5 morbidities

Figure 2.

Adjusted absolute risk of multimorbidity in RA (vs non-RA) by sex and age group. Statistical significance of the absolute risk of MM2+ between males and females was tested with Wald tests based on adjusted logistic regression models for four groups: (i) Non-RA (ages 18–50); (ii) RA (ages 18–50); (iii) non-RA (Ages 51+); (iv) RA (ages 51+). Bars represent prevalence for MM2+ (Panes A) and MM5+ (Panel B). Capped lines are 95% Cis

Figure 3.

Adjusted absolute risk of multimorbidity in non-RA and RA by sex and age