Inadequate or poor adherence to treatment not only has a negative effect on clinical outcomes and quality of life but may also lead to greater health-related expense [21]; therefore, adequate adherence is an important factor for improving clinical outcomes and quality of life in patients with SpA. Data from local registries provide invaluable information about treatment patterns and adherence in patients with SpA and offer a knowledge base specific to the disease landscape in the geographical region. Real-world data on adherence to TNFα inhibitors in patients with SpA, including information on factors that affect adherence and reasons for discontinuation, are limited [22], particularly in the Middle East. The current study evaluated 1- and 7-year adherence to etanercept treatment among patients with SpA from Iraq using real-world data from a local registry. The primary outcome was percentage of patients with 7-year adherence on etanercept. The study also compared treatment effectiveness between adherent and non-adherent groups of patients.

In this analysis, data from 964 patients with SpA entered in the National Center of Rheumatology (Baghdad teaching hospital) database from May 2012 to August 2019 were assessed. This cohort of 964 patients was the total number of patients with SpA treated with biologic therapies who were managed within the rheumatology department of the hospital during this period. Of these 964 patients, 763 were included in the analysis. Demographic and other baseline characteristics, including age, sex, disease duration, and concomitant medications, were recorded. As anticipated, most patients were male, with a mean age less than 40 years; these values are consistent with previously reported global estimates [3]. There was a high rate of concomitant steroid use at baseline (84%) and a low rate (31.7%) of HLA-B27-positive tests (thought to be low because not all patients were tested for HLA-B27). Around one-third of patients had started treatment with etanercept within a year of diagnosis.

Disease activity and functional status were assessed using the BASDAI and BASFI scores, respectively [23, 24]; both are validated tests that allow physicians to assess the effectiveness of drug therapies for SpA by observing changes in disease activity and functional limitation of patients.

In the current analysis, baseline scores were 8.06 and 7.75 for BASDAI and BASFI, respectively, and disease activity and functional impairment decreased significantly after 1 year of treatment with etanercept. Initiating etanercept within a year of diagnosis appeared to have a beneficial effect, with significantly greater BASDAI and BASFI score improvements achieved in this subgroup compared with patients who initiated treatment after 1 year of diagnosis, highlighting the benefits of initiating treatment at an early stage following diagnosis.

Adherence to treatment was high (more than 90% of patients) after 1 year but was 60% after 7 years. The difference in effectiveness of treatment between adherent and non-adherent groups was assessed by change in BASDAI and BASFI scores from baseline to last visit. Patients with SpA appeared to benefit from long-term adherence to etanercept treatment, but additional analyses are needed to further assess the reasons for treatment discontinuation, which may include disease remission.

The data from the current analysis are similar to those reported in other real-world analyses. In a prospective study using data collected from a multiple-disease registry of US veterans with SpA, 255 patients treated with 731 courses of TNFα inhibitor therapy over a 10-year period were assessed for persistence of treatment [22]. Most patients (85%) showed treatment persistence at 12 months; this declined over time (64% and 47% at 24 and 36 months, respectively). In a real-world analysis from Turkey, 269 patients with SpA received treatment with the TNFα inhibitor golimumab over 2 years [25]. Retention rates at 24 months were 75% and 80% for anti-TNFα-naive and anti-TNFα-experienced patients with SpA, respectively, with no significant differences in retention observed between groups. An observational study of patients with SpA from January 2014 to June 2017, from registries in five Nordic countries, comprised 1319 patients starting infliximab (24% originator, 76% biosimilar) and 1015 patients starting etanercept (49% originator, 51% biosimilar) [26]. Retention rates were similar for the originator and biosimilars in each instance [infliximab: originator 44%, biosimilar 46% (after 2 years); etanercept: originator 66%, biosimilar 73% (after 1 year)].

Relatively few studies have been published from the Middle East region. Region-specific analyses are important owing to genetic differences across populations, such that data cannot be extrapolated from one geographical region to another [27]. Specifically, more studies are needed in Iraq to examine the prevalence of SpA alongside demographic data, information about comorbidities, and observations about the association of SpA with HLA-B27, and there is a need for improvements in patient registries. Treatment strategies for SpA in Iraq as well as patient attitudes to treatment warrant further investigation, and clinical studies of new treatments for SpA should include patients from the Middle East [27]. Education and training of healthcare professionals, including primary care physicians, emergency physicians, and orthopedists, is needed to improve the differential diagnosis of lower back pain, increase awareness of inflammatory back pain, and know when further evaluation is needed. Early diagnosis and intervention for patients with SpA has the potential to improve clinical outcomes and quality of life. This can be achieved in the Middle East through a clear understanding of the disease in this region, and appropriate use of diagnostic tools and region-specific treatment guidelines, ensuring that the most cost-effective treatments are used appropriately for the benefit of patients [27].

These results suggest that Iraqi patients with SpA may benefit from adhering to etanercept treatment long term; however, additional analyses are required to determine a causal relationship between SpA disease activity and non-adherence in this population. Furthermore, additional studies are needed to further assess the reasons for treatment discontinuation, which may include disease remission.

Limitations of this analysis include bias due to missing and incomplete data, which can have a substantial effect on the precision of registry data. In addition, adherence to biologics may have been limited by the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) pandemic (2019–2020).