Influence of national socioeconomic status on treatment retention and disease activity in psoriatic arthritis and axial spondyloarthritis: evidence over 2 years in 13 European countries.

OBJECTIVES

To explore the association between national socioeconomic indicators, and (i) 6/12/24-month retention of biologic/targeted synthetic disease-modifying antirheumatic drugs (b/tsDMARD), and (ii) disease activity at treatment start, in patients with psoriatic arthritis (PsA) or axial spondyloarthritis (axSpA).

METHODS

Longitudinal data from 13 European countries, including 38,911 patients with spondyloarthritis (17,296 PsA and 21,615 axSpA) initiating b/tsDMARDs in 2015-2021, were collected by the European Spondyloarthritis Research Collaboration Network. Kaplan-Meier, mixed-effects Cox regression, linear regression, and mixed models were used for comparisons across countries with low/medium/high national socioeconomic indicators (gross domestic product [GDP], Human Development Index [HDI], gross national income, current health expenditure, out-of-pocket expenditure), stratified by disease/b/tsDMARD number/sex.

RESULTS

Drug retention was significantly lower in both men and women with PsA/axSpA from countries with high vs medium/low GDP per capita after 6/12/24 months' treatment with 1st/≥2nd b/tsDMARD (log rank P < .001). For all socioeconomic indicators, higher wealth was associated with earlier discontinuation of 1st b/tsDMARD both in PsA and axSpA men and women. The strength of associations varied across indicators, treatment lines, and sex. The strongest associations between socioeconomic measures and b/tsDMARD retention were seen with GDP per capita and HDI, and most prominently in women with axSpA. At the country level, most disease activity measures at the start of 1st/≥2nd b/tsDMARD were significantly worse with lower GDP, particularly for PsA.

CONCLUSIONS

Treatment retention varies with countries' socioeconomic status. Clinicians and health policy makers should be aware of later discontinuation/switching of b/tsDMARDs and a tendency to higher country-level disease activity at b/tsDMARD initiation in lower-income countries.