Worse outcomes linked to ethnicity for early inflammatory arthritis in England and Wales: a national cohort study

Abstract

Objective: To assess variability in care quality and treatment outcomes across ethnicities in early inflammatory arthritis (EIA).

Methods: We conducted an observational cohort study in England and Wales from May 2018 to March 2020, including patients with a suspected/confirmed EIA diagnosis. Care quality was assessed against six metrics defined by national guidelines. Clinical outcomes were measured using DAS28. Outcomes between ethnic groups ('White', 'Black', 'Asian', 'Mixed', 'Other') were compared, and adjusted for confounders.

Results: A total of 35 807 eligible patients were analysed. Of those, 30 643 (85.6%) were White and 5164 (14.6%) were from ethnic minorities: 1035 (2.8%) Black; 2617 (7.3%) Asian; 238 (0.6%) Mixed; 1274 (3.5%) Other. In total, 12 955 patients had confirmed EIA, of whom 11 315 were White and 1640 were from ethnic minorities: 314 (2.4%) Black; 927 (7.1%) Asian; 70 (0.5%) Mixed; 329 (2.5%) Other. A total of 14 803 patients were assessed by rheumatology within three weeks, and 5642 started treatment within six weeks of referral. There were no significant differences by ethnicity. Ethnic minority patients had lower odds of disease remission at three months [adjusted odds ratio 0.79 (95% CI: 0.65, 0.96)] relative to White patients. Ethnic minorities were significantly less likely to receive initial treatment withMTX[0.68 (0.52, 0.90)] or with glucocorticoids [0.63 (0.49, 0.80)].

Conclusion: We demonstrate that some ethnic minorities are less likely to achieve disease remission in three months following EIA diagnosis. This is not explained by delays in referral or time to treatment. Our data highlight the need for investigation into the possible drivers of these inequitable outcomes and reappraisal of EIA management pathways.

Keywords: Asian; Black; DAS28; DMARD; Mixed; Other; care quality; disease outcome; early inflammatory arthritis; ethnic minorities.

Fig. 1

Population flow chart EIA: early inflammatory arthritis; NEIAA: national early inflammatory arthritis audit.

Fig. 2

Association between ethnicity and performance in quality metrics at three months (A) Quality metric 1 and 2; (B) Quality metrics 3–6. Logistic regression coefficient plots demonstrating the relationship between ethnicity and performance in care quality metrics 1–6 at three months in patients with confirmed EIA diagnoses. Metric 1: primary care provider to a rheumatologist within 3 working days; metric 2: seen within Rheumatology services within 3 weeks; metric 3: started treatment within 6 weeks of referral; metric 4: providing education; metric 5: having a treatment target set; accessing emergency rheumatology services. White patients were used as the reference group. All models were clustered by England and Wales Hospital Trust codes (clustered standard errors were estimated to account for within-centre correlations). The confounder-adjusted model was adjusted for age, gender, smoking, comorbidities, DAS28 at baseline, seropositivity for RF or CCP. Data are presented as odds ratios and 95% CIs. CCP: anti-citrullinated c-peptide antibody; DAS28: disease activity score for 28 joints; EIA: early inflammatory arthritis; M: metric.

Fig. 3

Associations between ethnicity and disease remission at three months Logistic regression coefficient plots demonstrating the relationship between ethnicity and disease remission (based on DAS28) in three months in patients with confirmed EIA diagnoses. White patients were used as the reference group. All models were clustered by England and Wales Hospital Trust codes (clustered standard errors were estimated to account for within-centre correlations). The confounder-adjusted model was adjusted for age, gender, smoking, comorbidities, DAS28 at baseline, seropositivity for RF or CCP. Data are presented as odds ratios and 95% CIs. CCP: anti-citrullinated c-peptide antibody; DAS28: disease activity score for 28 joints; EIA: early inflammatory arthritis.