[Septic sacroiliitis: early diagnosis due to specific physical examination]. / Septische sacroiliitis.

BACKGROUND: Septic sacroiliitis is an uncommon disease which represents approximately 1-4% of all joint infections, therefore it is difficult to make the right diagnosis and to start early treatment. CASE REPORT: A 18 year old woman was admitted to the emergency room with a fever and pain in the left gluteal region. The patient was considered healthy and had no risk factors for septic arthritis. Edema and a small abscess was found in and around the left sacroiliac joint on pelvic MRI. The patient had positive blood cultures with Staphylococcus Aureus. Antibiotic treatment was initiated and lasted 7 weeks. She recovered completely and had no remaining complaints. CONCLUSION: Physical exam and clinical suspicion are important to consider the diagnosis of septic sacroiliitis. In addition a MRI of the pelvic is the best radiographic exam to conform the diagnosis.

Under what conditions is the intra-articular steroid injection superior to nonsteroidal anti-inflammatory drugs for treating sacroiliac joint pain?

OBJECTIVE: The purpose of this prospective study was to determine the conditions under which intra-articular injection therapy may be superior to nonsteroidal anti-inflammatory drugs (NSAIDs) in patients with sacroiliac joint pain in the outpatient setting at our hospital. PATIENTS AND METHODS: Patients with sacroiliac pain were divided into two groups: NSAID and the sacroiliac injection group. The NSAID group received 25 mg of indometacin orally once a day and 750 mg of naproxen orally once a day. In the sacroiliac injection group, 5 mg of betamethasone were injected into the sacroiliac joint. The patients' history of lumbar surgery, whether they had sacroiliitis, and the duration of pain were recorded. The patients' VAS (Visual analogue scale) scores at week 1 and month 1 were evaluated. RESULTS: VAS scores were decreased after the first week and first month in the sacroiliac injection group compared to the NSAID group (p<0.001). Sacroiliac steroid injection was found to be superior to NSAIDs in reducing VAS scores in patients with sacroiliitis, a history of lumbar surgery, and pain lasting more than 30 days (p<0.001). In patients without sacroiliitis, without a history of lumbar surgery, and with less than 30 days of pain, no difference was observed between the groups in reducing VAS scores at the end of the first month. CONCLUSIONS: In patients with sacroiliac joint pain, sacroiliac joint injection is superior to NSAIDs in pain relief in patients with pain for more than 30 days, those with MRI-diagnosed sacroiliitis, and those who have undergone lumbar surgery.

Colchicine-resistant sacroiliitis in a Japanese patient with familial Mediterranean fever.

The articular involvement in patients with familial Mediterranean fever (FMF) represents a clinical characteristic of acute monoarthritis with pain and hydrarthrosis, which always resolves spontaneously. Colchicine prevents painful arthritis attacks in most FMF cases. Spondyloarthritis is rarely associated with Japanese patients with FMF. Here, we report a Japanese male patient with FMF-related axial joint involvement. A 43-year-old male Japanese patient who presented with recurrent febrile episodes with hip joint and back pain was referred to our hospital. He carried heterozygous variants in exon 2 (L110P/E148Q) of the MEFV gene. FMF was suspected, and oral administration of colchicine (1 mg/day) was initiated. Colchicine treatment improved his febrile attack with hip joint pain. He was diagnosed as having FMF based on the Tel-Hashomer diagnostic criteria for FMF since he fulfilled one major criterion (repeated febrile attack accompanied by hip joint pain) and one minor criterion (improvement with colchicine treatment). Although the human leucocyte antigen-B27 allele was not detected, sacroiliitis-related symptoms progressed despite the ongoing colchicine treatment. Salazosulphapyridine and methotrexate were administered in addition to colchicine; however, these treatments were not effective. Canakinumab treatment successfully resolved this unique aspect of sacroiliitis, and the patient was finally diagnosed with FMF-associated axial joint involvement.

Paraneoplastic sacroiliitis.

A man in his early 70s presented with stiffness and aching in the shoulder and pelvic girdles. His C reactive protein level was elevated at 116 mg/L, leading to an initial diagnosis of polymyalgia rheumatica. Treatment with prednisone at 20 mg/day provided limited improvement and relapses recurred despite concomitant immunosuppressive agents. Extensive investigations failed to reveal an underlying aetiology.Five years later, gross painless haematuria led to the detection of an invasive papillary urothelial carcinoma. A review of the staging CT scan revealed findings compatible with bilateral erosive sacroiliitis, which had developed since his initial presentation. Radical cystoprostatectomy provided temporary relief but after a further 9 months, symptoms relapsed, and metastatic spread was discovered.Paraneoplastic sacroiliitis is a rare clinical entity; and to the best of our knowledge, this is the first reported case associated with a solid tumour.

Axial spondylarthritis following COVID-19 infection.

Although SARS-CoV-2 syndrome primarily affects the lungs, systemic manifestations have been reported. New rheumatic immune-mediated inflammatory diseases have been reported following SARS-CoV-2 infection. We present a case of a woman in her mid-30s who developed inflammatory back pain due to bilateral sacroiliitis with erosions after contracting SARS-CoV-2 infection. Her inflammatory markers on presentation were normal. MRI of the sacroiliac joints demonstrated bone marrow oedema and erosive changes in both sacroiliac joints. As the patient was intolerant to non-steroidal anti-inflammatory drugs, adalimumab 40 mg subcutaneous (SC) injection was administered, which improved her symptoms in 8 weeks. However, due to the drug's side effects, SC adalimumab was switched to intravenous infliximab. The patient is currently tolerating her intravenous infliximab well and has experienced significant improvement in her symptoms. We reviewed the current literature on the prevalence of axial spondyloarthropathy after SARS-CoV-2 infection.

Vitamin D Status and Psoriatic Arthritis: Association with the Risk for Sacroiliitis and Influence on the Retention Rate of Methotrexate Monotherapy and First Biological Drug Survival-A Retrospective Study.

A growing body of evidence on the importance of vitamin D in immune modulation has increased the interest in its possible impact on the course of rheumatological diseases. The scope of our study is to assess if the presence of different statuses of vitamin D could interfere in the clinical subsets, in methotrexate monotherapy discontinuation, and biological drug (b-DMARDs) survival in psoriatic arthritis patients (PsA). We conducted a retrospective study on PsA patients and split them into three groups based on their vitamin D status: the group with 25(OH)D ≤ 20 ng/mL, the group with levels of 25(OH)D between 20 and 30 ng/mL, and the group with serum levels of 25(OH)D ≥ 30 ng/mL. All patients were required to fulfill the CASPAR criteria for psoriatic arthritis and to have the evaluation of vitamin D serum levels at baseline visit and at clinical follow-up visits. The exclusion criteria were ages less than 18 years old, the presence of HLA B27, and satisfaction of rheumatoid arthritis classification criteria (during the study time). Statistical significance was set at p ≤ 0.05. Furthermore, 570 patients with PsA were screened and 233 were recruited. A level of 25(OH)D ≤ 20 ng/mL was present in 39% of patients; levels of 25(OH)D between 20 and 30 ng/mL presented in 25% of patients; 65% of patients with sacroiliitis presented 25 (OH)D ≤ 20 ng/mL. Methotrexate monotherapy discontinuation for failure was higher in the group with 25 (OH)D ≤ 20 ng/mL (survival time: 92 ± 10.3 weeks vs. 141.9 ± 24.1 weeks vs. 160.1 ± 23.6 weeks; p = 0.02) with higher discontinuation risk (HR = 2.168, 95% CI 1.334, 3.522; p = 0.002) than those with 25(OH)D between 20 and 30 ng/mL and those with 25(OH)D ≥ 30 ng/mL. Significantly shorter survival of first b-DMARDs was assessed in the group with 25 (OH)D ≤ 20 ng/mL versus the other groups (133.6 ± 11 weeks vs. 204.8 ± 35.8 weeks vs. 298.9 ± 35.4; p = 0.028) (discontinuation risk 2.129, 95% CI 1.186, 3.821; p = 0.011). This study highlights significant differences in clinical presentation, in particular sacroiliac involvement and on drug survival (methotrexate and b-DMARDs) in PsA patients with vitamin D deficiency. Further prospective studies, including a larger sample of patients, are needed to validate these data and to assess if the supplementation of vitamin D could improve the b-DMARDs response in PsA patients.

Clues for inflammatory diseases in the differential diagnosis of a child with sacroiliitis.

BACKGROUND: The purpose of this study was to compare the demographic, clinical and laboratory characteristics of patients with enthesitis-related arthritis (ERA), familial Mediterranean fever (FMF) and inflammatory bowel disease (IBD), which are inflammatory diseases that may develop sacroiliitis. Thus, it was aimed to reveal various findings that may indicate primary disease in patients with sacroiliitis. METHODS: Pediatric patients aged 6-18 years, who were being followed with a diagnosis of ERA (n = 62), FMF (n = 590), and IBD (n = 56) over the period 2013-2021 were included in the study. Sacroiliitis (n = 55) was diagnosed by magnetic resonance imaging of the sacroiliac joint, obtained from clinically suspected patients. RESULTS: Sacroiliitis was detected in 54.8% of ERA patients, 2.3% of FMF patients, and 12.5% of IBD patients. The mean follow-up period was 4.1 ± 2.8 years (10 months-8 years) for the entire study group. The most common MRI finding for sacroiliitis was bone marrow edema. Peripheral joint involvement (73.5%) and HLA B27 positivity (64.7%) was significantly higher in ERA patients, and ERA was diagnosed more frequently in patients presenting with sacroiliitis. Non-steroidal anti-inflammatory drugs (NSAIDs) were the first choice of treatment agent when sacroiliitis developed in all three patient groups. CONCLUSIONS: The clinical and laboratory findings of ERA, FMF and IBD can sometimes be intertwined or can even coexist. Treatment may differ depending on the disease associated with sacroiliitis, although NSAIDs may be used in the first-line treatment of all three diseases. Sacroiliitis patients with HLA B27 positivity and peripheral arthritis may need to be addressed as ERA.

Ultrasound guided corticosteroids sacroiliac joint injections (SIJIs) in the management of active sacroiliitis: a real-life prospective experience.

INTRODUCTION: Active sacroiliitis represents the hallmark of axial spondyloarthritis (axSpA) and manifests as inflammatory low back pain associated with morning stiffness (MS). Sometimes, the combination of non-steroidal anti-inflammatory drugs (NSAIDs) and biological disease modifying drugs (bDMARDs) proves unsatisfactory in achieving a remission. MATERIALS AND METHODS: We enrolled patients affected with active sacroiliitis confirmed via magnetic resonance imaging (MRI) and treated with a corticosteroid sacroiliac joint injection (SIJI) via ultrasound guidance. After SIJI, we evaluated visual-analogue scale (VAS) and MS pain changes. As controls, we selected axSpA patients starting bDMARDs. RESULTS: We enrolled 26 patients (mean age 55 ± 14 years; 25 females and 1 male; > 95% treated with NSAIDs; 46% on bDMARDs; 75.82 ± 123 months) and examined a total of 47 treated joints. We detected a 48% reduction in VAS pain after 24 h. Moreover, we observed a significant reduction (p < 0.0001) of VAS pain between the baseline and every subsequent follow-up visit. Further, a significant difference in VAS pain compared to the baseline in the controls was observed starting from week 12. There was a significant reduction in MS after 1 week due to SIJIs, while in the controls the first significant change from the baseline in MS was detected after 12 weeks. The efficacy of infiltrative therapy lasted up to 6 months: persistent VAS as well as MS pain reduction was observed. CONCLUSIONS: US-guided SIJI represents an effective and safe technique for patients who have active sacroiliitis yet are ineligible for biologic treatment or who experience unsatisfactory disease control despite receiving therapy.

Etanercept Withdrawal and Retreatment in Nonradiographic Axial Spondyloarthritis: Results of RE-EMBARK, an Open-Label Phase IV Trial.

OBJECTIVE: RE-EMBARK investigated etanercept (ETN) withdrawal and retreatment in patients with nonradiographic axial spondyloarthritis (nr-axSpA) achieving inactive disease. METHODS: Patients received ETN and a background nonsteroidal antiinflammatory drug for 24 weeks in period 1 (P1); those achieving inactive disease (Ankylosing Spondylitis Disease Activity Score [ASDAS] with C-reactive protein [CRP] < 1.3) discontinued ETN for 40 weeks or less (period 2 [P2]). Patients who flared (ASDAS with erythrocyte sedimentation rate [ESR] ≥ 2.1) were retreated for 12 weeks in period 3 (P3). The primary endpoint was the proportion of patients with inactive disease who flared within 40 weeks of ETN withdrawal. Baseline characteristics were analyzed post hoc as predictors of maintenance and regaining of inactive disease, respectively, using univariate logistic and stepwise multivariable logistic regression models. RESULTS: The proportion of patients experiencing flare following ETN withdrawal (P2) increased from 22.3% (25/112) after 4 weeks to 67% (77/115) after 40 weeks; 74.8% (86/115) experienced flare at any time during P2. Median time to flare was 16.1 weeks. Most patients (54/87, 62.1%) who were retreated with ETN in P3 reachieved inactive disease. Absence of both sacroiliitis detected on magnetic resonance imaging (MRI) and high-sensitivity CRP (hs-CRP) > 3 mg/L at baseline predicted inactive disease maintenance in P2 following ETN withdrawal in multivariable analysis; male sex and age younger than 40 years predicted regaining of inactive disease in P3 after flare/retreatment. There were no unexpected safety signals. CONCLUSION: Approximately 25% of patients maintained inactive disease for 40 weeks after discontinuing ETN. Absence of both MRI sacroiliitis and high hs-CRP at baseline predicted response maintenance after ETN withdrawal. (ClinicalTrials.gov: NCT02509026).

Response to netakimab in radiographic axial spondyloarthritis patients with different baseline C-reactive protein, sacroiliitis evaluated by MRI and peripheral joint involvement status: a post-hoc analysis of the ASTERA study.

OBJECTIVES: Netakimab is a humanised camelid-derived monoclonal antibody targeting interleukin-17A. Here, we report the results of post-hoc analysis of the ASTERA phase 3 study (NCT03447704, February 27, 2018) in patients with active radiographic axial spondyloarthritis (r-axSpA) grouped by baseline C-reactive protein (CRP), baseline sacroiliac joint (SIJ) inflammation through magnetic resonance imaging (MRI) or presence of peripheral arthritis (PA). METHODS: In this double-blinded, multicentre, randomised, placebo-controlled, phase 3 ASTERA study, 228 adult patients with active r-axSpA received 120 mg of subcutaneous netakimab or placebo at weeks 0, 1, 2, and thereafter every other week. For the subanalysis, 16-week data of 114 netakimab-treated patients with the available baseline CRP and SIJ MRI were grouped by normal (<5 mg/L) or abnormal (≥5 mg/L) CRP, by the grade of sacroiliitis (SI) based on the SPARCC MRI score <2 (MRI-SI-) or ≥2 (MRI-SI+), or by the presence of PA. ASAS-recommended activity, spinal mobility, and function endpoints for r-axSpA were analysed. RESULTS: At week 16, an improvement in all the outcomes was similar for MRI-SI- and MRI-SI+ patients, except for a change in ASspi-MRI-a which was significantly greater in MRI-SI+. Netakimab was effective regardless of baseline CRP and PA. For patients with CRP ≥5 mg/L, a more pronounced decline in r-axSpA activity was observed with a trend towards the most prominent improvement in ASDAS-CRP and BASDAI for patients with CRP >20 mg/L. CONCLUSIONS: Subcutaneous netakimab is effective in patients with r-axSpA irrespective of baseline CRP and inflammation on SIJ MRI. The benefit in patients with high CRP (>20 mg/L) was more pronounced.

Gouty sacroiliitis: A case report of an often-overlooked cause of inflammatory back pain.

Gout is a chronic disease caused by monosodium urate crystal deposition, typically affecting the big toe, midfoot, and ankle. As it rarely involves the sacroiliac joints, it could be easily misdiagnosed as spondylarthritis. Here, we report the case of a patient with a long history of gout with recurrent low back pain. Computed tomography of the sacroiliac joint suggested sacroiliac arthritis, puncture biopsy indicated gout granuloma, and polarized light microscopy confirmed monosodium urate crystal deposits.

Enthesitis-related arthritis: the clinical characteristics and factors related to MRI remission of sacroiliitis.

BACKGROUND: To describe the clinical characteristics and explore the factors related to the MRI remission of sacroiliitis in patients with enthesitis-related arthritis (ERA). METHODS: Patients with ERA from 2018-2022 in our medical center were retrospectively reviewed, which identified according to Pediatric Rheumatology International Trials Organization (PRINTO) criteria. Demographics, clinical characteristics, examinations, and treatments were described. Univariate and multivariate logistic regression models were used to analyze the factors related to MRI remission of sacroiliitis in ERA. RESULTS: This retrospective study included 160 ERA patients (51.9% male) with a mean onset age of 9.2 ± 3.0 years. There were 144 cases (81.9%) with peripheral arthritis, and the hip, knee, and ankle joints were the most commonly involved joints. Enthesitis occurred in 48 cases (30.0%), and sacroiliitis occurred in 142 cases (88.5%) at diagnosis. Human leukocyte antigen (HLA)-B27 was positive in 33 cases (17.1%), and acute uveitis occurred in 3 cases (1.9%). The majority of patients (93.7%) were treated with disease-modifying anti-rheumatic drugs (DMARDs), and 60% with biologics. Among 62 patients with MRI-defined sacroiliitis, 27 (43.5%) cases showed improvement in the sacroiliac joint lesion after treatment. Multivariate logistic regression analysis showed that duration from onset to diagnosis of less than 3 months (OR = 3.609, 95% CI: 1.068-12.192) and active joints of more than 4 (OR = 4.916, 95% CI: 1.006-24.037) were independent factors. CONCLUSION: We highlighted differences in ERA clinical characteristics. Patients with a shorter diagnosis time and more joint involvement improved more significantly in sacroiliac joint lesions after treatment.

Gluteus maximus abscess revealing a tuberculous arthritis: A case report and review of the literature.

Although tuberculosis is a widespread disease in Morocco, musculoskeletal form is relatively rare and even rarer when affects the sacroiliac joint. Tuberculous sacroiliitis remains a challenge for orthopedists owing to its insidious onset and non-specific clinical presentation. Herein, we report the case of a 23-year-old male with a growing mass in his left gluteal area, diagnosed with tuberculous sacroiliitis, based on bacteriological and histological findings. The aim of our work is to draw attention to the importance of continued awareness for early detection and adequate treatment of this very rare entity.

Evaluation of active inflammation, chronic structural damage, and response to treatment of sacroiliitis in axial spondyloarthritis using the Spondyloarthritis research consortium of Canada scoring system.

BACKGROUND: Axial spondyloarthritis (axSpA) is a chronic inflammatory rheumatic disease affecting the spine and sacroiliac joints. To investigate whether there are differences in inflammatory and chronic structural damages, as assessed by a semiquantitative MRI scoring method, between non-radiographic axial spondyloarthritis (nr-axSpA) and ankylosing spondylitis (AS) patients with active inflammation at baseline, and to evaluate the treatment response in these patients after 3 months of tumor necrosis factor-alpha (TNF-α) inhibitor treatment. METHODS: Fifty-eight axSpA patients with active inflammation were included in the study. The patients were divided into nr-axSpA group and AS group. MRI examinations of the sacroiliac joints were performed before and after treatment. Inflammatory and structural damages in these patients were assessed using the established Spondyloarthritis Research Consortium of Canada (SPARCC) inflammation and sacroiliac joint structural (SSS) scoring methods, which are two MRI-based scoring methods. The SPARCC score, SSS score, erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP) level were compared between the two groups. RESULTS: At baseline, SPARCC scores for patients in the nr-axSpA and AS groups did not differ significantly (P > 0.05); however, SSS scores for fat metaplasia, erosion, and backfill for patients in the AS group were significantly higher (P < 0.001). Compared with baseline, SPARCC scores were significantly decreased in both groups after treatment (P < 0.001); however, after treatment, no statistically significant difference was found regarding SPARCC scores between the AS and nr-axSpA groups. Compared with baseline, a significant increase in the SSS scores for fat metaplasia and backfill (P < 0.001) and a significant decrease in the SSS scores for erosion (P < 0.001) were observed in all axSpA patients. Changes in the SPARCC score was inversely correlated with the changes in the SSS score for fat metaplasia (r = - 0.634, P < 0.001). Changes in the SSS score for backfill were positively correlated with the changes in the SSS score for fat metaplasia (r = 0.277, P < 0.05) and inversely correlated with those for erosion (r = - 0.443, P < 0.001). CONCLUSION: The SPARCC and SSS scoring systems can be used to assess inflammatory and chronic structural damages as well as treatment responses in patients with axSpA. More severe structural damages were seen in AS patients. TNF-α inhibitor treatment for 3 months could effectively reduce inflammation in axSpA patients.

Sacroiliitis at diagnosis as a protective predictor against disease flare after stopping medication: outcomes of a Southeast Asian enthesitis-related arthritis (ERA) longitudinal cohort.

OBJECTIVES: To assess short- and long-term outcomes of ERA in a large monocentric cohort in Singapore. METHODS: Children diagnosed with ERA according to ILAR criteria from 2002 to 2021 were recruited. Nonparametric statistics were used to describe the data. Outcomes were defined according to modified Wallace criteria, and probabilities and predictors were determined using Kaplan-Meier survival and logistic regression analyses. RESULTS: One hundred fifty-one ERA patients (male 86%; Chinese 81%) were included. The median age at onset was 11.9 years (IQR: 9.4-13.9), and disease duration was 5.3 years (IQR: 2.9-8.4). At diagnosis, 39% of the patients had sacroiliitis. HLA-B27 was positive in 83%, and biologics were used in 72% of the patients. Clinical inactive disease (CID) was achieved in 92% of the patients, of which 27% achieved within 6 months. Sacroiliitis at diagnosis is an unfavorable predictor of early CID at 6 months. Medication was discontinued in one-third of the patients. Favorable predictor of medication withdrawal includes male gender, while unfavorable predictors include positive HLA-B27 and ANA. Two-thirds of the patients with CID had at least one disease flare. Sacroiliitis at diagnosis is a protective predictor of flare after stopping medication. CONCLUSION: Despite a high proportion of ERA patients achieving CID, only one-third could stop medication with high rates of disease flare. Unfavorable predictors include older age at onset, HLA-B27, and ANA positivity. While sacroiliitis at diagnosis is a negative predictor of CID at 6 months, it is associated with less disease flare after discontinuing medication.

Clinical characteristics, treatment and outcomes of acute postpartum inflammatory sacroiliitis: a retrospective study.

PURPOSE: We performed this research to report the clinical characteristics and clinical therapeutic strategies of acute postpartum inflammatory sacroiliitis. METHODS: We retrospectively analyzed the data of patients diagnosed with acute postpartum inflammatory sacroiliitis from 2014 to 2020. All their clinical details including clinical symptoms and signs, laboratory tests, radiologic examination, diagnosis and treatment process and clinical outcomes were obtained and analyzed in this retrospective analysis. RESULTS: Eleven patients diagnosed with acute postpartum inflammatory sacroiliitis complain of low back pain. Magnetic resonance imaging (MRI) is useful in diagnosing acute postpartum inflammatory sacroiliitis. The systemic non-steroidal anti-inflammatory drugs (NSAIDs) administration, sacroiliac joint injection, and physical therapy effectively alleviated the pain with symptoms disappearing, and the abnormal signal reduced in MRI. CONCLUSION: Acute postpartum inflammatory sacroiliitis is an uncommon disease with atypical symptoms. MRI examination may be the best diagnostic method. General NSAIDs and sacroiliac joint injections of local anesthetic plus corticosteroid under the guidance of fluoroscopy or ultrasound can achieve safe and effective treatment. This retrospective study was approved by the Committee on the Ethics of our hospital (No. 202101023). TRIAL REGISTRY: Trial registration was performed in the Chinese Clinical Trial Registry ( http://www.chictr.org.cn , No. ChiCTR2100045656).

Treatment With Tumor Necrosis Factor Inhibitors Is Associated With a Time-Shifted Retardation of Radiographic Sacroiliitis Progression in Patients With Axial Spondyloarthritis: 10-Year Results From the German Spondyloarthritis Inception Cohort.

OBJECTIVE: To investigate the longitudinal association between radiographic sacroiliitis progression and treatment with tumor necrosis factor inhibitors (TNFi) in patients with early axial spondyloarthritis (SpA) in a long-term inception cohort. METHODS: We included patients from the German Spondyloarthritis Inception Cohort who underwent radiographic assessment of the sacroiliac joints at baseline and at least once more during the 10-year follow-up. Two central readers scored the radiographs according to the modified New York criteria for ankylosing spondylitis. The sacroiliac sum score was calculated as a mean of the scores determined by both readers. TNFi use was assessed according to exposure in the current and/or previous 2-year radiographic interval. The association between TNFi use and radiographic sacroiliitis progression was examined by longitudinal generalized estimating equation analysis with adjustment for potential confounders. RESULTS: In this long-term inception cohort, 10-year follow-up data on 737 radiographic intervals assessed in 301 patients with axial SpA (166 patients with nonradiographic axial SpA and 135 patients with radiographic axial SpA) were obtained. Having received ≥12 months of treatment with TNFi in the previous 2-year radiographic interval was associated with a significant decrease in the sacroiliitis sum score (ß = -0.09 [95% confidence interval (95% CI) -0.18, -0.003]; analyses adjusted for age, sex, symptom duration, HLA-B27 status, Bath Ankylosing Spondylitis Disease Activity Index score, C-reactive protein, and nonsteroidal antiinflammatory drug intake). In contrast, among patients receiving TNFi in the current radiographic interval, there was no significant association with change in the sacroiliitis sum score (ß = 0.05 [95% CI -0.05, 0.14]). This effect of having received ≥12 months of treatment with TNFi in the previous 2-year radiographic interval was stronger in patients with nonradiographic axial SpA as compared to patients with radiographic axial SpA (ß = -0.16 [95% CI -0.28, -0.03] versus ß = -0.04 [95% CI -0.15, 0.07]). CONCLUSION: Treatment with TNFi was associated with the reduction in radiographic sacroiliitis progression in patients with axial SpA. This effect became evident between 2 and 4 years after treatment was initiated.