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

A PRESPOND Study

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

Disclosures

J Clin Rheumatol. 2019;25(2):59-64. 

In This Article

Results

In total, data of 251 patients were collected in the registry, among which 62 patients were excluded because of incomplete demographic and clinical data. Therefore, 189 patients were included in the statistical analysis. Although approximately a quarter of the patients were excluded from the statistical analysis, the demographic profile of the patients included in the analysis were largely similar with those who were excluded.

There were 30 patients (15.9%) started on biologics during the course of follow-up. As shown in Table 1, the mean duration of disease was 6.1 ± 8.3 years. At baseline, patients had a mean age of 37.7 ± 13.3 years, 144 (76.2%) were male, and 160 (84.7%) were Chinese. There were 14 patients (7.4%) in the low-education group (i.e., education up to secondary school), and 106 (56.1%) in the intermediate-education group (i.e., education up to high school, diploma, or equivalent), whereas the rest of the 69 patients (36.5%) were in the high-education group (i.e., at least a university degree). One hundred forty-eight patients (78.3%) stayed in public housing, and the remaining 41 (21.7%) stayed in private housing. One hundred twenty-one patients (64.0%) were employed, whereas the remaining 68 patients (36.0%) were unemployed. One hundred fifteen patients (61.2%) had elevated CRP at baseline, and mean ESR at baseline was 25.7 ± 23.6 mm/h. There were 72 patients (38.1%) with high BASDAI score of greater than or equal to 4. There were 42 patients (22.2%) and 39 patients (20.6%) with high PCS and MCS scores of greater than 50, respectively. One hundred forty-five patients (76.7%) reported they had good response to NSAIDs. Common comorbidities included hyperlipidemia (15.3%), hypertension (11.6%), PUD (6.9%), and skin symptoms including eczema and vitiligo (4.2%). Fifty patients (26.5%) had past surgeries.

Patients who were subsequently initiated on biologics during the study had a significantly lower mean age (32.8 ± 11.4 years) compared with those who were not initiated on biologics (38.6 ± 13.5 years). Erythrocyte sedimentation rate level at baseline had significantly higher mean value (35.4 ± 28.9 mm/h) in patients who were subsequently initiated on biologics during the study than in those who were not (23.9 ± 22.0 mm/h). There was a significantly smaller percentage of patients who had high MCS scores and good response to NSAIDs at baseline who were subsequently initiated on biologics as compared with patients who were not initiated on biologics. There was also a significantly higher percentage of patients who had presence of PUD who were subsequently initiated on biologics as compared with patients who were not initiated on biologics (Table 1).

Table 2 shows the univariable and multivariable associations of the final model, whereas Supplementary Table 1, http://links.lww.com/RHU/A95, shows the univariable associations of the initial model, which included all the variables before backward modeling was conducted. In the univariable model using baseline variables, age (OR, 0.96; 95% CI, 0.93–1.00; p = 0.03), ESR (OR, 1.02; 95% CI, 1.00–1.03; p = 0.02), presence of PUD (OR, 3.78; 95% CI, 1.14–12.5; p = 0.03), and lack of good response to NSAIDs (OR, 3.15; 95% CI, 1.39–7.18; p < 0.01) were significant independent factors associated with biologics initiation. Higher ESR and presence of PUD were associated with higher odds of biologics initiation. On the other hand, older age and good response to NSAIDs were associated with lower odds of biologics initiation. Duration of disease, employment status, BASDAI, PCS and MCS of SF-36, and presence of skin symptoms did not register significant association in the univariable analysis (Table 2).

In the multivariable logistics regression analyses, duration of disease, age, employment status, BASDAI, PCS and MCS of SF-36, ESR, presence of PUD and skin symptoms, and responsiveness to NSAIDs were included in the final model. Of these variables, older age (OR, 0.93; 95% CI 0.89–0.98; p < 0.01), high MCS (OR, 0.18; 95% CI, 0.03–0.89; p = 0.04), higher ESR (OR, 1.02; 95% CI, 1.00–1.04; p = 0.02), presence of PUD in patients (OR, 10.4; 95% CI, 2.21–48.8; p < 0.01), and lack of good response to NSAIDs (OR, 4.44; 95% CI, 1.63–12.1; p < 0.01) were found to be factors associated with biologics initiation (Table 2).

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