Patient characteristics (Table 1)A total of 429 patients were included: 203 received a mAb and 226 ETA (supplementary figure S1). At baseline, extra-articular symptoms, especially inflammatory bowel disease, were less frequent with ETA than mAb treatment. Other baseline characteristics did not differ between the two groups.
Uveitis occurrence:
Qualitative description: In total, 73 (6.3%) patients had a history of uveitis, 27 during the year before TNFi start; 19 of 396 (4.4%) patients with available data had at least one uveitis episode during the first year of treatment. With all TNFi lines, 52 (12.9%) patients had at least one uveitis episode (Table 2).
Quantitative description: During the first year of TNFi treatment, 43 uveitis episodes were reported. With all TNFi lines, 170 uveitis episodes were reported; 117 occurred with the first TNFi agent (Table 2).
Propensity score allocationThe variables selected for the propensity score were: occurrence of at least one uveitis in the whole period preceding the introduction of the first TNFi, age, sex, history of inflammatory bowel disease, delay between the diagnosis date and introduction of the first TNFi, and diagnosis of rheumatism (PsA or SpA) (supplementary table S1). This score balanced the population characteristics and probability of being assigned ETA as the first-line TNFi in both groups of patients (Supplementary figure S2, Supplementary figure S3)Qualitative analysis comparing uveitis incidence with ETA versus mAbs The crude incidence of at least one uveitis episode within 1 year after starting the first TNFi was numerically lower for patients with ETA than mAbs but not significantly (OR = 0.81 [0.32, 2.03], p = 0.65) and was still lower on adjustment for the propensity score but not significantly (OR = 0.94 [0.35, 2.54], p = 0.90) (Table 3). During the first-line TNFi treatment (Fig. 1b), the probability of at least one uveitis episode was higher with ETA than mAbs but not significantly (OR = 1.39 [0.71, 2.72], p = 0.3) and was higher on adjustment for the propensity score but still not significantly (OR = 1.89 [0.90, 4.01, p = 0.09) (Table 3).When considering all prescribed therapeutic lines of TNFi agents, the probability of at least one uveitis episode was numerically higher with ETA than mAbs but not significantly (OR = 1.57 [0.71, 3.46], p = 0.27) and was further increased on adjustment for the propensity score but still not significantly (OR = 1.98 [0.90, 4.37 ], p = 0.08) (Table 3). Quantitative analysis comparing uveitis incidence with ETA versus mAbsOn quantitative analysis, the risk of uveitis within 1 year after starting the first TNFi was lower with ETA than mAbs but not significantly (RR = 0.54 [0.24; 1.24], p = 0.15) and was still lower on adjustment for the propensity score but not significantly (RR = 0.62 [0.26, 1.46]) (p = 0.27) (Table 3). When considering the first-line TNFi treatment, risk of uveitis was reduced with ETA versus mAbs but not significantly (RR = 0.97 [0.66, 1.43], p = 0.89) and was increased on adjustment for the propensity score but not significantly (RR = 1.10 [0.70; 1.72], p = 0.68) (Table 3). When considering total TNFi treatment exposure (all prescribed therapeutic lines), risk of uveitis was higher with ETA than mAbs but not significantly (RR = 1.01 [0.61; 1.69], p = 0.96) and was further increased on adjustment for the propensity score but still not significantly (RR = 1.21 [0.68, 2.16], p = 0.53) (Table 3).
Uveitis occurrence before and during TNFi treatment
We found no significant decrease in number of participants with at least one uveitis episode when comparing the incidence of uveitis between the year before starting treatment and the first year of the first-line TNFi (p=0.17) (Fig. 1a, Table 4). When comparing the incidence of uveitis over the previous year and after the TNFi start, the main analysis did not find any significant difference between the two groups (0.0066 uveitis/patient-months in the previous year and 0.011 uveitis/patient-months in the first TNFi year, p=0.80; Table 5). As well, the sensitivity analysis (number of uveitis episodes set to 1) did not reveal a significant difference between the two incidences (p=0.69; Table 5).
We compared the incidence of uveitis with first-line TNFi treatment versus the incidence during the time between the diagnosis of SpA and the introduction of the first TNFi (Fig. 1b). The qualitative analysis showed a significant decrease in number of patients with at least one uveitis episode (p=0.0002) (supplementary table S2). The quantitative analysis as well as the sensitivity analysis revealed no significant difference in pre-treatment and treatment incidences (p= 0.19 and p= 0.16, respectively) (Supplementary table S3).
Finally, we compared the incidence of uveitis between the total period under TNF treatment, considering all therapeutic lines, and between the date of diagnosis and introduction of the first TNFi (Fig. 1c). The qualitative analysis revealed a significant decrease in incidence under treatment (p=0.049) (supplementary table S2), whereas the quantitative analysis revealed a significant increase in incidence under treatment (p=0.04 for the main analysis and p=0.03 for the sensitivity analysis; supplementary table S3).