Factors Associated With Initiation of Biologics in Patients With Axial Spondyloarthritis in an Urban Asian City


Wan Yu Png, BSc (Pharm)(Hons); Yu Heng Kwan, BSc (Pharm)(Hons); Yi Xuan Lee, BSc (Pharm)(Hons); Ka Keat Lim, MPharm, MSc; Eng Hui Chew, BSc (Pharm)(Hons), PhD (Pharm); Nai Lee Lui, MBBS, MMed, MRCP, FAMS; Chuen Seng Tan, BSc, MSc, PhD; Julian Thumboo, MBBS, MMed, MRCP, FAMS, FRCP; Truls Østbye, MD, MPH, MBA, PhD, FFPH; Warren Fong, MBBS, MRCP, FAMS


J Clin Rheumatol. 2019;25(2):59-64. 

In This Article

Abstract and Introduction


Objective: The aim of this study was to examine if patients' sociodemographic, clinical characteristics, and patient-reported outcomes were associated with biologics initiation in patients with axial spondyloarthritis in Singapore.

Methods: Data from a dedicated registry from a tertiary referral center in Singapore from January 2011 to July 2016 were used. Initiation of first biologics was the main outcome of interest. Logistic regression analyses were used to explore the association of various factors on biologics initiation.

Results: Of 189 eligible patients (aged 37.7 ± 13.3 years; 76.2% were males), 30 (15.9 %) were started on biologics during follow-up. In the multivariable analysis model, age (odds ratio [OR]; 0.93; 95% confidence interval [CI], 0.89–0.98; p < 0.01), mental component summary score of Short-Form 36 Health Survey (OR, 0.18; 95% CI, 0.03–0.89; p = 0.04), erythrocyte sedimentation rate (OR, 1.02; 95% CI, 1.00–1.04; p = 0.02), presence of peptic ulcer disease (OR, 10.4; 95% CI, 2.21–48.8; p < 0.01), and lack of good response to nonsteroidal anti-inflammatory drugs (OR, 4.44; 95% CI, 1.63–12.1; p < 0.01) were found to be associated with biologics initiation.

Conclusions: Age, erythrocyte sedimentation rate, mental component summary score, comorbidities of peptic ulcer disease, and responsiveness to nonsteroidal anti-inflammatory drugs were associated with biologics initiation. It is essential that clinicians recognize these factors in order to optimize therapy.


Axial spondyloarthritis (AxSpA) is a type of inflammatory rheumatic disease that is chronic in nature and can cause severe disability. It includes patients with both nonradiographic and radiographic spondyloarthritis, which is also termed ankylosing spondylitis.[1] Patients with AxSpA typically present with chronic back pain and stiffness of any part of the spine.[1]

Nonsteroidal anti-inflammatory drugs (NSAIDs) are effective in reducing pain and stiffness in patients with AxSpA and are recommended for first-line treatment.[2,3] There have been some recent therapeutic advances that have resulted in the development of biologics, such as tumor necrosis factor α antagonists infliximab and adalimumab.[4] Biologics are genetically engineered protein drugs derived from human genes given parenterally, and they have demonstrated effectiveness in reducing inflammation and joint damage.[4] It has been shown to improve disease activity and functional capacity in several randomized controlled trials in both ankylosing spondylitis and nonradiographic AxSpA patients.[5] Other benefits include improvement in health-related quality of life, fatigue, sleep disturbance, and absenteeism from work.[6–8] The Assessment of SpondyloArthritis International Society/European League Against Rheumatism guideline recommends that biologics be initiated in patients having persistently high disease activity, not responding to NSAIDs, having contraindications to NSAID therapy, or experiencing NSAID-related adverse effect.[2] Despite the implementation of guidelines, there could be other factors associated with biologics initiation. It is essential that clinicians recognize these factors in order to achieve optimal therapy for patients. Doing so shall contribute to the advancement of care and management of AxSpA that ultimately will benefit the patients.

We had conducted a systematic review of factors affecting initiation of biologics in patients with rheumatologic conditions prior to this study.[9] A total of 42 factors from 24 articles were identified to have influenced initiation of biologics in various countries. The factors were categorized into patient factors (e.g., age, sex, race/ethnicity, education level, household income), disease-related factors (e.g., disease activity, quality of life, comorbidities), therapy-related factors (e.g., response to nonbiologics, use of corticosteroids and pain medications), health care team–related factors (e.g., physician preference, care by a rheumatologist), and system in place–related factors (e.g., greater countries' socioeconomic welfare and region of residence).

From the systematic review, we found that there were limited studies on AxSpA when compared with other rheumatologic conditions such as rheumatoid arthritis (RA). In addition, studies related to AxSpA and RA are usually conducted in countries from Europe and North America, which have different health care systems and patient demographics from other regions. Thus, factors resulting in initiation of biologics in these Western countries may not be readily generalizable to, for example, the Asia context, as factors could be influenced by social and economic issues. Hence, we aimed to examine the factors associated with the initiation of biologics in patients with AxSpA in Singapore, an urban city state in Asia.