The ASAS Health Index and Environmental Factors Item Set: validity and reliability of the Swedish translations in Swedish patients with ankylosing spondylitis

OBJECTIVES

To translate the Assessment of SpondyloArthritis international Society (ASAS) Health Index (HI) Environmental Factors Item Set (EFIS) into Swedish and culturally adapt it for a Swedish context, and to assess the construct validity of the Swedish version of the ASAS HI and test-retest reliability in ASAS HI and EFIS in Swedish patients with ankylosing spondylitis (AS).

METHOD

Translation and cross-cultural adaptation of the EFIS were carried out according to a forward-backward procedure consisting of five steps. The construct validity of the ASAS HI was tested using Spearman correlation with standard health outcomes for axial spondyloarthritis (axSpA). Reliability was analysed by internal consistency with the Cronbach's alpha coefficient for ASAS HI, and test-retest reliability with intraclass correlation coefficients (ICCs) for ASAS HI and kappa agreement for the individual items of EFIS.

RESULTS

The translation of EFIS showed acceptable face and content validity. ASAS HI showed an acceptable internal consistency (Cronbach's alpha 0.79), and excellent test-retest reliability (ICC 0.87). Test-retest reliability for EFIS showed varied results, with kappa agreement for the individual items ranging from poor (-0.027) to good (0.80).

CONCLUSIONS

The Swedish version of ASAS HI proved to be valid and reliable and is recommended for assessing the impact of AS on global functioning and health. A Swedish version of EFIS has been produced and uploaded on the ASAS website. The EFIS proved to have acceptable face and content validity, and may contribute to the contextual interpretation of the ASAS HI.

Physical function and sex differences in radiographic axial spondyloarthritis: a cross-sectional analysis on Bath Ankylosing Spondylitis Functional Index

BACKGROUND

Physical function is an important determinant of health-related quality of life in radiographic axial spondyloarthritis patients (r-axSpA). To improve the basis of effective healthcare efforts, we aimed to investigate which demographic and disease-related factors that influence Bath Ankylosing Spondylitis Functional Index (BASFI) in r-axSpA patients overall and stratified by sex. Furthermore, we sought to explore differences between sexes regarding separate BASFI questions and also to explore which factors that may contribute to these differences.

METHODS

This observational cross-sectional study included patients fulfilling the modified New York criteria for Ankylosing Spondylitis. Patients were assessed with 66/68 joint count and Bath Ankylosing Spondylitis Metrology Index (BASMI) measurements. Lateral X-rays were performed for Modified Stoke Ankylosing Spondylitis Spinal Score (mSASSS). Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), Ankylosing Spondylitis Disease Activity Score (ASDAS)-C-Reactive Protein (CRP), and BASFI were registered. Multivariable linear regression analyses were used to investigate which factors that associate with BASFI.

RESULTS

A total of 353 r-axSpA patients were included, mean age 52.2 ± 12.7 years, 62.3% males. No significant sex difference was seen in BASFI scores (2.7 ± 2.0 in males vs 2.9 ± 2.1 in females). Age, body mass index, ASDAS-CRP, BASMI or mSASSS, fatigue, and tenderness were found to associate independently with BASFI in different models (R2 0.53-0.63). Investigation of separate BASFI questions revealed that the ability to look over shoulder was worse in males than females (mean 4.43 ± 3.37 vs 3.74 ± 3.06, p = 0.05) and most strongly correlated with mSASSS and BASMI among separate BASFI questions (r = 0.53, p < 0.001; r = 0.62, p < 0.001). The ability to climb stairs was worse in females than males (mean 2.49 ± 2.77 vs 1.54 ± 2.32, p < 0.001).

CONCLUSIONS

No difference between male and female r-axSpA patients was seen in BASFI despite significant sex differences in BASMI, mSASSS, and CRP levels. Our results underline the impact of fatigue and tenderness on BASFI. The ability to climb stairs without a handrail was scored worse among females compared to males. Furthermore, the ability to look over the shoulder was worse in males than females and closely related to spinal mobility and structural spinal changes.

Occurrence and relative risks for non-vertebral fractures in patients with ankylosing spondylitis compared with the general population: a register-based study from Sweden

OBJECTIVES

To estimate the incidence of non-vertebral fractures in ankylosing spondylitis (AS) compared with the general population.

METHODS

Nationwide register-based cohort study including patients with AS (n=11 611, 65% men, mean age 48 years), and matched general population controls (n=58 050). Five prespecified fracture outcomes: (1) non-vertebral; (2) fracture of the proximal humerus, distal forearm or hip; (3) proximal humerus; (4) distal forearm and (5) hip) were identified through register linkages with follow-up 2007-2016. We used Poisson regression to calculate incidence rates (IRs), number of fractures per 1000 person-years at risk and IR ratios (IRRs), overall and by sex and age. IRRs were adjusted for history of any prior fracture.

RESULTS

IRs (men/women) for non-vertebral fracture in AS were 11.9 (95% CI 11.0 to 12.9)/14.5 (95% CI 13.1 to 16.1) and in controls 10.0 (95% CI 9.7 to 10.4)/11.8 (95% CI 11.1 to 12.4), IRR (men/women) 1.2 (95% CI 1.1 to 1.3)/1.2 (95% CI 1.1 to 1.4). IRs (men/women) for fractures of the humerus, forearm or hip in AS were 4.0 (95% CI 3.5 to 4.6)/6.3 (95% CI 5.4 to 7.3) and in controls 2.7 (95% CI 2.5 to 2.9)/5.5 (95% CI 5.1 to 6.0), IRR (men/women) 1.5 (95% CI 1.3 to 1.7)/1.1 (95% CI 0.9 to 1.3). IRRs were statistically significantly elevated in men with AS versus controls for forearm fracture (1.4 (95% CI 1.1 to 1.7)) and hip fracture (1.8 (95% CI 1.4 to 2.3)), whereas not in women with AS where the IRRs were 1.1 (95% CI 0.9 to 1.4) and 1.0 (95% CI 0.6 to 1.4). For humerus fracture, IRRs were 1.4 (95% CI 0.99 to 1.9) in men with AS versus controls and 1.1 (95% CI 0.8 to 1.6) in women.

CONCLUSIONS

Both men and women with AS have a slightly higher risk of non-vertebral fractures than the general population. A statistically significantly higher risk of fractures of the proximal humerus, distal forearm or hip was found in men with AS in comparison to general population, where the relative risk was especially pronounced for hip fracture.

POS0150 ANKYLOSING SPONDYLITIS RELATED STRUCTURAL CHANGES IN THE SPINE INDEPENDENTLY INFLUENCE PATIENT REPORTED PHYSICAL FUNCTION IN MEN BUT NOT IN WOMEN. A COMPREHENSIVE CROSS-SECTIONAL ANALYSIS OF BATH ANKYLOSING SPONDYLITIS FUNCTIONAL INDEX AND ITS RELATION TO SEX

Background

Patient reported physical function assessed by Bath Ankylosing Spondylitis Functional Index (BASFI) is an important outcome in ankylosing spondylitis (AS) and is associated with health-related quality of life.

Objectives

To improve health care efforts, we aimed to investigate which demographic and disease related factors that influence BASFI in AS patients overall and stratified by sex. Further, we sought to elucidate if there are differences between sexes regarding specific BASFI items.

Methods

Patients fulfilling the modified New York criteria for AS were included in two geographically separate regions in Sweden for this observational cross-sectional study. Patients were assessed with 66/68 joint count and Bath Ankylosing Spondylitis Metrology Index (BASMI) measurements. Lateral X-rays of the spine were performed for modified stoke ankylosing spondylitis spine score (mSASSS) and BASFI, BASDAI, ASDAS CRP were registered. Multiple linear regression analyses were used to investigate influencing factors on BASFI. Independent variables were chosen based on what is previously known and on hypothetical reasoning. Models were performed overall and stratified by sex.

Results

A total of 353 patients, age (median, range) 53 (17-78) years, symptom duration 27 (2-56) years, men 62.3% and HLAB27 91.8 % were included. In multiple linear regression analysis age, BMI, ASDAS CRP, mSASSS, fatigue (BASDAI Q1) and tenderness (BASDAI Q4) were found to significantly associate with BASFI. In models separated by sex, mSASSS independently influenced BASFI in men (p<0.0001) but not in women (p=0.124)(Table 1). Further, separate BASFI items were compared between sexes. The ability to look over shoulder was scored the worst among men while getting up from the floor was hardest for women (Figure 1). Differences between sexes were found in the ability to look over shoulder (p=0.05) and the ability to climb stairs without handrail (p<0.001). Among the separate BASFI items, the ability to look over shoulder showed the highest correlation with mSASSS (r= 0.532, p<0.001).

Table 1.

Multiple linear regression analysis exploring factors associated with BASFI

AllMenWomenR20.580.620.54B (95% CI)p-valueB (95% CI)p-valueB (95% CI)p-valueAge0.06 (0.04;0.08)<0.00010.05 (0.03;0.07)<0.00010.08 (0.05;0.11)<0.0001BMI0.05 (0.01;0.09)0.0240.04 (-0.01;0.09)0.0930.05 (-0.03;0.13)0.209ASDAS CRP1.04 (0.74;1.34)<0.00010.84 (0.48;1.20)<0.00011.39 (0.86;1.93)<0.0001mSASSS0.03 (0.02;0.04)<0.00010.03 (0.02-0.05)<0.00010.02 (-0.01;0.06)0.124Fatigue0.34 (0.24;0.43)<0.00010.41 (0.29;0.53)<0.00010.27 (0.11;0.42)0.001Tenderness0.17 (0.07;0.26)0.0010.14 (0.02;0.27)0.0270.18 (0.02-0.34)0.027Women-0.29 (-0.74;0.17)0.214N/AN/AFigure 1.

Separate BASFI items women compared to men

Conclusion

AS related self-reported physical function measured by BASFI was influenced by disease activity, fatigue and tenderness in both men and women. Interestingly, structural changes in the spine, evaluated by mSASSS, independently influenced BASFI in men but not in women with AS.

The ability to look over the shoulder was worse in men vs women and excelled as more disease specific than other individual BASFI items in both sexes.

Disclosure of Interests

None declared

POS0959 RISK FACTORS FOR NON-VERTEBRAL FRACTURES IN ANKYLOSING SPONDYLITIS

Background

Osteoporosis is common in patients with ankylosing spondylitis (AS) and a risk factor for fragility fractures. Additional established risk factors for fractures in the general population include higher age, female sex, previous fracture, fall tendency, glucocorticoid treatment, insulin dependent diabetes, smoking and high alcohol consumption.

Objectives

To estimate the influence of established risk factors for fragility fractures on the development of non-vertebral fractures in AS and population controls.

Methods

Through linkage of national population and health care registers 2001-2016, patients with AS (n=11611, 65.5% men, mean age 48 years) and age-, sex- and geography-matched population controls (n=58050) were identified and from 1 January 2007 (or 3 months after the first registered AS diagnosis if this occurred later) followed prospectively until the time of a non-vertebral fracture, death, emigration or end of study (30 December 2016). Occurrence of established risk factors for a fracture and AS related characteristics at start of follow-up were identified in the National Patient and Prescribed Drug Registers using ICD-10 and ATC codes. Smoking status and anthropometric measurements are not available in these registers. Chi-square, Fischer’s exact test and T tests were used to compare between subjects with and without a non-vertebral fracture during follow-up, separately for AS and controls. Multivariable Poisson regression was used to estimate the influence of each established risk factor in AS and controls. Risk factors for which there were ≤20 observed events in the AS cohort were not included. Results are presented as incidence rate ratios (IRR) with 95% confidence intervals.

Results

In total 974 (8.4%) patients with AS and 4106 (7.1%) of their controls were registered with a non-vertebral fracture during the study period. The characteristics of the patients and controls at start of follow-up are presented in Table 1 stratified by fracture status during follow-up. Figure 1 displays the results from the Poisson regression.

Table 1.ASControlsNo fracture (n=10637)Fracture (n=974)P-valueNo fracture (n=53944)Fracture (n=4106)P-valueMale sex7002 (65.8)603 (61.9)0.01435448 (65.7)2572 (62.6)<0.001Mean age (SD)47.6 (14.7)53.8 (14.8)<0.00147.8 (14.7)53.0 (15.0)<0.001Prior fracture667 (6.3)140 (14.4)<0.0012715 (5.0)486 (11.8)<0.001Osteoporosis*359 (3.4)83 (8.5)<0.001367 (0.7)85 (2.1)<0.001Fall injury without fracture714 (6.7)97 (10.0)<0.0013205 (5.9)350 (8.5)<0.001Harmful use of alcohol158 (1.5)26 (2.7)0.005889 (1.6)171 (4.2)<0.001Hyperthyroidism39 (0.4)7 (0.7)0.105180 (0.3)19 (0.5)0.173Diabetes type 1178 (1.7)30 (3.1)0.002651 (1.2)80 (1.9)<0.001Liver disease66 (0.6)10 (1.0)0.132197 (0.4)32 (0.8)<0.001Malnutrition8 (0.1)3 (0.3)0.05816 (0.0)2 (0.0)0.367Hypogonadism or premature menopause11 (0.1)1 (0.1)1.00033 (0.1)0 (0.0)0.169Use of oral glucocorticoids#1531 (14.4)152 (15.6)0.304839 (1.6)97 (2.4)<0.001Anterior uveitis2168 (20.4)204 (20.9)0.677317 (0.6)32 (0.8)0.126Psoriasis316 (3.0)34 (3.5)0.364605 (1.1)58 (1.4)0.091Inflammatory bowel disease675 (6.3)64 (6.6)0.783441 (0.8)35 (0.9)0.811Use of any DMARD¤3411 (32.1)266 (27.3)0.002465 (0.9)52 (1.3)0.008Use of TNF inhibitor¤1539 (14.5)109 (11.2)0.00543 (0.1)4 (0.1)0.573

The data is presented as number (%) if not stated otherwise. *Diagnosed osteoporosis and/or use of osteoporosis medication. #Prednisolone equivalent cumulative dose of ≥450 mg within the last year before start of follow-up. ¤Use within the last year before start of follow-up.

Figure 1.

Multivariable Poisson regression analyses for a non-vertebral fracture during follow-up, with results presented for each included baseline variable as IRR with 95% CI, separately for AS and controls.

Conclusion

The influence of established risk factors for fragility fractures in AS is similar to that in the general population; in both populations with advanced age, prior fracture and harmful use of alcohol being the strongest risk factors.

Disclosure of Interests

Karin Bengtsson: None declared, Johan Askling Grant/research support from: AbbVie, AstraZeneca, Bristol Myers Squibb, Eli Lilly, Janssen, Merck, Pfizer, Roche, Samsung Bioepis, Sanofi, and UCB, Mattias Lorentzon: None declared, Björn Rosengren: None declared, Anna Deminger: None declared, Eva Klingberg: None declared, Lennart T.H. Jacobsson Speakers bureau: Lecture and consulting fees from Novartis, Eli Lilly and Janssen, Helena Forsblad-d’Elia: None declared

AB0804 Associations between ultrasound chronic lesions in peripheral entheses and radiographic structural spinal changes in men and women with ankylosing spondylitis

Background

Ankylosing spondylitis (AS) is characterised by spinal bone formation and enthesitis. Whether patients with spinal bone formation have a generalised bone formation phenotype also involving the peripheral entheses is not fully known.

Objectives

To assess in cross-sectional analyses the association between chronic ultrasound (US) lesions in peripheral entheses with spinal bone formation and factors associated with spinal bone formation, overall and by sex.

Methods

The entheses at 14 sites at the extremities were examined in 173 patients (54 % men, mean age (SD) 55 (13) years and symptom duration 29 (13) years) with AS (modified NY criteria) using US. Entheses were assessed for structural components (enthesophytes, calcifications and erosions) according to the OMERACT definition [1]. Each lesion was evaluated 0 or 1 and summarised to a damage score (0-42). Spinal radiographs from the same time point were graded according to the modified Stoke Ankylosing Spondylitis Spine Score (mSASSS) and presence of syndesmophytes were determined. The associations between US damage score and mSASSS and factors associated with spinal bone formation were analysed with Spearman´s correlation analysis overall and by sex. Also, Mann Whitney´s test and multivariable logistic regression analysis with presence of ≥ 1 syndesmophyte as dependent variable and age, sex, BMI, smoking status, CRP, and US damage score as independent variables were used.

Results

Presence of any US structural component was found in 158 (91 %) of the patients with no significant difference between men and women (95 % vs 87 % respectively, p = 0.15). The US damage score was median (IQR) 4 (2 to 6) in the total group with a higher score in men compared to women, 4.5 (2 to 7) vs 3 (2 to 5), p = 0.002. In analogy, more men had presence of syndesmophytes in the spine compared to women, 63 % vs 35 %, p <0.001 and men had higher mSASSS compared to women; median (IQR) mSASSS in men 14 (3 to 43) compared to 2 (0 to 11.5), p<0.001. Men had higher body mass index (BMI), but there were no sex differences for age, symptom duration, CRP, and smoking status.

The results from correlation analyses for US damage score and mSASSS, age, symptom duration, CRP, smoking status, and BMI are presented in the Table 1. Spinal bone formation (mSASSS) was positively correlated with the US damage score in the total group and in men. In both men and women, higher age was associated with higher US damage score. A comparison between patients with and without syndesmophytes showed that patients with syndesmophytes had higher US damage score than patients without syndesmophytes, median (IQR) 5 (3 to 7) and 3 (1 to 5) respectively, p<0.001. In the multivariable logistic regression analyses the US damage score was not independently associated with presence of syndesmophyte in the total group or in men. If age was excluded from the analyses though, the US damage score was significantly associated with presence of syndesmophyte, odds ratio (95 % CI) for total group 1.20 (1.05 to 1.37) and for men 1.26 (1.05 to 1.51).

Table 1.Ultrasound damage scoreTotal group (n=173)Men (n = 94)Women (n = 79)rsp-valuersp-valuersp-valueAge, years0.44<0.0010.43<0.0010.51<0.001Symptom duration, years0.28<0.0010.34<0.0010.270.015BMI, kg/m20.210.0060.110.280.190.10Current or past smoking0.0390.610.180.090-0.100.37CRP, mg/L0.120.130.0280.790.200.073mSASSS, score0.31<0.0010.270.0100.200.084

rs: Spearman´s correlations coefficient

Conclusion

Structural lesions were common in the entheses in patients with long-standing AS. Men had more severe bone formation in the spine and the peripheral entheses compared to women. Chronic lesions at the entheses accumulate with increasing age and US damage score could not independently identify patients with syndesmophytes in this cohort with long-standing AS. However, if age was not considered, there was an association between bone formation in the peripheral entheses and the spine in men with AS.

References

[1]Balint, P et al. Ann Rheum Dis 2018;77:1730-1735

Disclosure of Interests

Anna Deminger: None declared, Mats Geijer Speakers bureau: UCB Pharma, Novartis, Abbvie, Nicklas Nilsson: None declared, Martin Hedberg: None declared, Lennart T.H. Jacobsson: None declared, Helena Forsblad-d’Elia: None declared

Factors associated with changes in volumetric bone mineral density and cortical area in men with ankylosing spondylitis: a 5-year prospective study using HRpQCT

Patients with ankylosing spondylitis (AS) have impaired volumetric bone mineral density (vBMD) assessed with high-resolution peripheral computed tomography (HRpQCT). This first longitudinal HRpQCT study in AS shows that cortical and trabecular vBMD decreased at tibia and that signs of inflammation were associated with cortical bone loss at tibia and radius.

INTRODUCTION

Patients with ankylosing spondylitis (AS) have reduced volumetric bone mineral density (vBMD) in the peripheral skeleton assessed with high-resolution peripheral quantitative computed tomography (HRpQCT). The aims were to investigate longitudinal changes in vBMD, cortical area, and microarchitecture and to assess factors associated with changes in vBMD and cortical area in men with AS.

METHODS

HRpQCT of radius and tibia was performed in 54 men with AS at baseline and after 5 years. Univariate and multivariable linear regression analyses were used.

RESULTS

At tibia, there were significant decreases exceeding least significant changes (LSC) in cortical and trabecular vBMD, mean (SD) percent change -1.0 (1.9) and -2.7 (5.0) respectively (p<0.001). In multivariable regression analyses, increase in disease activity measured by ASDAS_CRP from baseline to follow-up was associated with decreases in cortical vBMD (β -0.86, 95% CI -1.31 to -0.41) and cortical area (β -1.66, 95% CI -3.21 to -0.10) at tibia. At radius, no changes exceeded LSC. Nonetheless, increase in ASDAS_CRP was associated with decreases in cortical vBMD, and high time-averaged ESR was associated with decreases in cortical area. Treatment with TNF inhibitor ≥ 4 years during follow-up was associated with increases in cortical vBMD and cortical area at tibia, whereas exposure to bisphosphonates was associated with increases in cortical measurements at radius. No disease-related variables or treatments were associated with changes in trabecular vBMD.

CONCLUSION

The findings in this first longitudinal HRpQCT study in patients with AS strengthen the importance of controlling disease activity to maintain bone density in the peripheral skeleton.

Incidence of extra-articular manifestations in ankylosing spondylitis, psoriatic arthritis and undifferentiated spondyloarthritis: results from a national register-based cohort study

OBJECTIVES

To estimate the incidence and strength of association of extra-articular manifestations [EAMs, here: anterior uveitis (AU), IBD and psoriasis] in patients with AS, undifferentiated SpA (uSpA) and PsA, compared with controls.

METHODS

Three mutually exclusive cohorts of patients aged 18-69 years with AS (n = 8517), uSpA (n = 10 245) and PsA (n = 22 667) were identified in the Swedish National Patient Register 2001-2015. Age-, sex- and geography-matched controls were identified from the Swedish Population Register. Follow-up began 1 January 2006, or six months after the first SpA diagnosis, whichever occurred later, and ended at the first date of the EAM under study, death, emigration, 70 years of age, and 31 December 2016. Incidence rates (IRs) and incidence rate ratios were calculated for each EAM, and stratified by sex and age.

RESULTS

Incidence rate ratios for incident AU, IBD and psoriasis were significantly increased in AS (20.2, 6.2, 2.5), uSpA (13.6, 5.7, 3.8) and PsA (2.5, 2.3, n.a) vs controls. Men with AS and uSpA had significantly higher IRs per 1000 person-years at risk for incident AU than women with AS (IR 15.8 vs 11.2) and uSpA (IR 10.1 vs 6.0), whereas no such sex difference was demonstrated in PsA or for the other EAMs.

CONCLUSIONS

AU, followed by IBD and psoriasis, is the EAM most strongly associated with AS and uSpA. Among the SpA subtypes, AS and uSpA display a largely similar pattern of EAMs, whereas PsA has a considerably weaker association with AU and IBD.

Elevated serum level of hepatocyte growth factor predicts development of new syndesmophytes in men with ankylosing spondylitis

Objectives

To study baseline serum hepatocyte growth factor (s-HGF) as a predictor of spinal radiographic progression overall and by sex and to analyse factors correlated to changes in s-HGF in patients with AS.

Methods

At baseline and the 5-year follow-up, s-HGF was analysed with ELISA. Spinal radiographs were graded according to modified Stoke Ankylosing Spondylitis Spinal Score. Radiographic progression was defined as ≥2 modified Stoke Ankylosing Spondylitis Spinal Score units/5 years or development of ≥1 syndesmophyte. Logistic regression analyses were used.

Results

Of 204 baseline participants, 163 (80%) completed all examinations at the 5-year follow-up (54% men). Baseline s-HGF was significantly higher in men who developed ≥1 syndesmophyte compared with non-progressors, median (interquartile range) baseline s-HGF 1551 (1449–1898) vs 1436 (1200–1569) pg/ml, P = 0.003. The calculated optimal cut-off point for baseline s-HGF ≥1520 pg/ml showed a sensitivity of 70%, a specificity of 69% and univariate odds radio (95% CI) of 5.25 (1.69, 14.10) as predictor of development of ≥1 new syndesmophyte in men. Baseline s-HGF ≥1520 pg/ml remained significantly associated with development of ≥1 new syndesmophyte in men in an analysis adjusted for the baseline variables age, smoking, presence of syndesmophytes and CRP, odds radio 3.97 (1.36, 11.60). In women, no association with HGF and radiographic progression was found. Changes in s-HGF were positively correlated with changes in ESR and CRP.

Conclusion

In this prospective cohort study elevated s-HGF was shown to be associated with development of new syndesmophytes in men with AS.

FRI0310 HIGHER RISK OF INCIDENT FRACTURE IN PATIENTS WITH ANKYLOSING SPONDYLITIS COMPARED TO THE GENERAL POPULATION

Background:

Ankylosing spondylitis (AS) is characterized by pathologic new bone formation and bone loss. Vertebral fracture (VF) is a known complication of AS, whereas the risk of other major osteoporotic fractures (MOFs) is less studied.

Objectives:

To estimate incidence rates (IRs) of incident fractures (any, VF and other MOF (humerus, forearm and hip)) in patients with AS compared to controls from general population.

Methods:

This is a nationwide, register-based and observational cohort study including patients diagnosed with AS (n=11611, 65% men, mean age 48 years) identified in the National patient register (NPR) 2001 through 2015, and age- and sex-matched controls (n=58050) from the Swedish Population Register. The study period started 1 January 2007 or 3 months after the first AS diagnosis, whichever came later, and ended at the first occurrence of each fracture outcome (identified in the NPR), death, emigration or 31 December 2016. Patients and controls with any prior fracture in NPR within a 6-year period before start of the study period were not included. Any fracture (except skull and phalangeal fractures), VF and other MOF were identified in NPR according to pre-specified ICD codes. Each fracture outcome was analysed separately. Poisson regression was used to calculate IRs and incidence rate ratios (IRRs), overall and stratified by sex. Kaplan-Meier curves were plotted.

Results:

In total 807 (7.0%) of patients with AS and 3201 (5.5%) of matched controls had a history of prior fracture within a 6-year period, and were excluded from further analyses. We noted higher IRs for any fracture, VF and other MOF in AS vs controls, see Figure for Kaplan-Meier curves and Table for IRs and IRRs. In sex-stratified analyses, men with AS (vs. male controls) had a higher relative risk for all fracture outcomes, whereas among women with AS (vs. female controls), a higher relative risk was demonstrated for any fracture and VF. 5-year cumulative incidence for any fracture, VF and other MOF was 6.2%, 1.6% and 1.7%, respectively in AS and 4.3%, 0.3% and 1.2%, respectively in controls.

Figure.

Kaplan-Meier curves. A) Vertebral fractures B) Other MOF (humerus, hip, forearm)

Conclusion:

Patients with AS have a higher risk of any fracture, VF and other MOF compared to general population. This was especially pronounced for VF in both sexes and for hip fracture in men with AS.

Table.

Disclosure of Interests:

Karin Bengtsson: None declared, Johan Askling Grant/research support from: JA acts or has acted as PI for agreements between Karolinska Institutet and the following entities, mainly in the context of the ARTIS national safety monitoring programme of immunomodulators in rheumatology: Abbvie, BMS, Eli Lilly, Merck, MSD, Pfizer, Roche, Samsung Bioepis, Sanofi, and UCB Pharma, Mattias Lorentzon Consultant of: Lecture or consulting fees from Amgen, Lilly, UCB Pharma, Radius Health, Renapharma, Meda, GE-Lunar, Consilient Health, and Tromp Medical., Björn Rosengren: None declared, Anna Deminger: None declared, Eva Klingberg Grant/research support from: Roche, Consultant of: Novartis, Speakers bureau: Eli Lilly, Lennart T.H. Jacobsson Consultant of: AbbVie, Eli Lilly, Janssen, Novartis and Pfizer, Helena Forsblad-d’Elia Grant/research support from: Unrestricted grant from Novartis., Consultant of: Advisory Board Fees from Sandoz, Novartis, and Abbvie

A distinct gut microbiota composition in patients with ankylosing spondylitis is associated with increased levels of fecal calprotectin

Background

Ankylosing spondylitis (AS) shares many characteristics with inflammatory bowel disease (IBD). Intestinal microbiota most likely plays an important role in the development of IBDs and may also be involved in the pathogenesis of AS. We aimed to define and compare the fecal microbiota composition in patients with AS, ulcerative colitis (UC), and healthy controls (HC) and to determine relationships between fecal microbiota, fecal calprotectin, and disease-related variables in AS.

Methods

Fecal microbiota composition was assessed with GA-map™ Dysbiosis Test (Genetic Analysis, Oslo, Norway), which also reports the degree of deviation of the microbiota composition compared with a healthy control population, a Dysbiosis Index (DI) score 1–5. The AS patients were assessed with questionnaires, back mobility tests, fecal calprotectin, erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP).

Results

Totally, 150 patients with AS (55% men, median age 55.5 years, median BASDAI 3.2), 18 patients with UC (56% men, median age 30.5 years), and 17 HC (65% men, median age 22 years) were included. Principal component analysis showed highly separate clustering of fecal microbiota from the patients with AS, UC, and HC. Compared with HC, fecal microbiota in AS was characterized by a higher abundance of Proteobacteria, Enterobacteriaceae, Bacilli, Streptococcus species, and Actinobacteria, but lower abundance of Bacteroides and Lachnospiraceae.

Further, fecal microbiota composition differed between patients with normal (≤ 50 mg/kg, n = 57) and increased (≥ 200 mg/kg, n = 36) fecal calprotectin. Patients with increased fecal calprotectin had lower abundance of bacteria with anti-inflammatory properties such as Faecalibacterium prausnitzii and Clostridium and higher abundance of the genus Streptococcus. No association was found between the fecal microbiota composition and HLAB27 status, disease activity, function, or medication. Dysbiosis (defined as DI ≥ 3) was found in 87% of AS patients.

Conclusions

Patients with AS have a distinct fecal microbiota signature, which is linked to fecal calprotectin levels, a marker of intestinal inflammation, but not to other clinical parameters. These findings suggest a local interplay between intestinal microbiota and gut inflammation in AS.

Trial registration

ClinicalTrials.gov, NCT00858819. Registered March 9, 2009.

Cardiac conduction disturbances in patients with ankylosing spondylitis: results from a 5-year follow-up cohort study

Objectives

To describe electrocardiographic (ECG) development in patients with ankylosing spondylitis (AS) and identify associations between baseline characteristics and cardiac conduction disturbances (CCD) at 5-year follow-up.

Methods

In a longitudinal cohort study, 172 patients (54% men, mean age (SD) of 50 (13) years at baseline) with AS underwent ECG, physical examination, questionnaires and laboratory testing at baseline and at 5-year follow-up. Descriptive statistics and univariate and age- and sex-adjusted logistic regression analyses were used. CCD included both atrioventricular and intraventricular blocks.

Results

Twenty-three of the 172 patients (13.4%) had a CCD at follow-up. Eight patients had developed a new CCD and eight had normalised their ECG. In the age- and sex-adjusted analyses, CCD at baseline (OR 24.8, 95% CI 7.3 to 84.5), male sex (OR 6.4, 95% CI 2.0 to 20.8), history of anterior uveitis (OR 4.4, 95% CI 1.3 to 14.5), higher ASDAS-CRP (OR 2.3, 95% CI 1.3 to 4.0), greater waist circumference (OR 1.3, 95% CI 1.1 to 1.6, per 5 cm), and medication with antiplatelets (OR 7.0, 95% CI 1.5 to 31.8) and beta-blockers (OR 3.4, 95% CI 1.0 to 11.5) were associated with a CCD at follow-up. Higher age and longer symptom duration were highly correlated and were both associated with a CCD at follow-up.

Conclusions

The presence of CCD in AS is in part dynamic and associated with both AS and non-AS characteristics. Our results suggest that patients especially prone to present with CCDs are older men with a previous CCD, longer symptom duration, higher AS disease activity, a history of anterior uveitis and medication reflecting cardiovascular disease.

Factors related to health-related quality of life in ankylosing spondylitis, overall and stratified by sex

Background

Ankylosing spondylitis (AS) begins early in life and often leads to reduced physical function, but less is known about the impacts it has on health-related quality of life (HRQoL). The aims of this study were to assess HRQoL using the Short Form-36 (SF-36) in a cohort of patients with AS compared with controls and to examine associations between SF-36 scores and spinal radiographic changes, physical function, disease activity and demographic data overall and stratified by sex.

Methods

A cohort of patients with AS from Western Sweden were assessed using the Modified Stoke Ankylosing Spondylitis Spine Score (mSASSS) with spinal radiographs, clinical examination and questionnaires, including the Bath Ankylosing Spondylitis Metrology Index, Bath Ankylosing Spondylitis Functional Index (BASFI), Ankylosing Spondylitis Disease Activity Score-C-reactive protein (ASDAS-CRP), Bath Ankylosing Spondylitis Disease Activity Index, Bath Ankylosing Spondylitis Patient Global (BASG) and SF-36. Each patient’s SF-36 results were compared with those of five age-matched and sex-matched persons (n = 1055) from the SF-36 Swedish normative population database. Associations between SF-36 physical component summary (PCS) and mental component summary (MCS) scores and disease-related and demographic factors were investigated using univariate and multivariable ogistic regression analyses with PCS and MCS below/above their respective median values as dependent variables.

Results

A total of 210 patients, age (median, IQR) 49.0 (21.2) years, symptom duration 24.0 (21.0) years, men 57.6% and HLAB27 87.1% were included. Patients with AS scored significantly lower (p < 0.001) compared to controls in all SF-36 domains and component summaries; PCS 42.4 (14.5) in AS versus 52.4 (11.8) in controls and MCS 47.9 (20.0) in AS versus 54.1 (10.1) in controls. Both men and women scored significantly lower in PCS compared with MCS. Multivariable logistic regression analyses revealed that living without a partner (OR 2.38, 95% CI 1.00–5.67), long symptom duration (year in decade OR 1.66, 95% CI 1.16–2.37), higher BASFI (OR 1.98, 95% CI 1.46–2.70) and ASDAS ≥ 2.1 (OR 3.32, 95% CI 1.45–7.62) were associated with worse PCS, while living without a partner (OR 3.04, 95% CI 1.34–6.91), fatigue (visual analogue scale for global fatigue greater than the median (OR 6.36, 95% CI 3.06–13.19) and ASDAS ≥ 2.1 (OR 2.97, 95% CI 1.41–6.25) with worse MCS. Some differences between sexes were observed in the results.

Conclusions

The patients with AS had significantly lower HRQoL compared with controls. PCS was more affected compared to MCS in both sexes. Both disease-related and demographic factors were associated with HRQoL, partly overlapping for PCS and MCS. Factors associated with HRQoL showed some differences between sexes. By modifying factors, such as ASDAS-CRP and fatigue, HRQoL may potentially be improved.

Trial registration

ClinicalTrials.gov, NCT00858819. Registered on 9 March 2009. Last updated on 28 May 2015.

Electronic supplementary material

The online version of this article (10.1186/s13075-018-1784-8) contains supplementary material, which is available to authorized users.

A five-year prospective study of spinal radiographic progression and its predictors in men and women with ankylosing spondylitis

Background

Knowledge about predictors of new spinal bone formation in patients with ankylosing spondylitis (AS) is limited. AS-related spinal alterations are more common in men; however, knowledge of whether predictors differ between sexes is lacking. Our objectives were to study spinal radiographic progression in patients with AS and investigate predictors of progression overall and by sex.

Methods

Swedish patients with AS, age (mean ± SD) 50 ± 13 years, were included in a longitudinal study. At baseline and at 5-year follow up, spinal radiographs were graded according to the modified Stoke Ankylosing Spondylitis Spine Score (mSASSS). Predictors were assessed by questionnaires, spinal mobility tests and blood samples.

Results

Of 204 patients included, 166 (81%) were re-examined and 54% were men. Men had significantly higher mean mSASSS at baseline and higher mean increase in mSASSS than women (1.9 ± 2.8 vs. 1.2 ± 3.3; p = 0.005) More men than women developed new syndesmophytes (30% vs. 12%; p = 0.007). Multivariate logistic regression analyses with progression ≥ 2 mSASSS units over 5 years or development of new syndesmophytes as the dependent variable showed that presence of baseline AS-related spinal radiographic alterations and obesity (OR 3.78, 95% CI 1.3 to 11.2) were independent predictors of spinal radiographic progression in both sexes. High C-reactive protein (CRP) was a significant predictor in men, with only a trend seen in women. Smoking predicted progression in men whereas high Bath Ankylosing Spondylitis Metrology Index (BASMI) and exposure to bisphosphonates during follow up (OR 4.78, 95% CI 1.1 to 20.1) predicted progression in women.

Conclusion

This first report on sex-specific predictors of spinal radiographic progression shows that predictors may partly differ between the sexes. New predictors identified were obesity in both sexes and exposure to bisphosphonates in women. Among previously known predictors, baseline AS-related spinal radiographic alterations predicted radiographic progression in both sexes, high CRP was a predictor in men (with a trend in women) and smoking was a predictor only in men.

Trial registration

ClinicalTrials.gov, NCT00858819. Registered on 9 March 2009. Last updated 28 May 2015.

Which measuring site in ankylosing spondylitis is best to detect bone loss and what predicts the decline: results from a 5-year prospective study

BACKGROUND

Studies have shown increased prevalence of osteoporosis and increased risk for vertebral fractures in patients with ankylosing spondylitis (AS). Measurements of bone mineral density (BMD) in the lumbar spine anterior-posterior (AP) projection may be difficult to interpret due to the ligamentous calcifications, and the lateral projection might be a better measuring site. Our objectives were to investigate BMD changes after 5 years at different measuring sites in patients with AS and to evaluate disease-related variables and medications as predictors for BMD changes.

METHODS

In a longitudinal study, BMD in Swedish AS patients, 50 ± 13 years old, was measured with dual-energy x-ray absorptiometry (DXA) at the hip, the lumbar spine AP and lateral projections, and the total radius at baseline and after 5 years. Patients were assessed with questionnaires, blood samples, and spinal radiographs for grading of AS-related alterations in the spine with the modified Stoke Ankylosing Spondylitis Spinal Score (mSASSS) and assessment of vertebral fractures by the Genant score. Multiple linear regression analyses were used to investigate predictors for BMD changes.

RESULTS

Of 204 patients included at baseline, 168 (82%) were re-examined after 5 years (92 men and 76 women). BMD decreased significantly at the femoral neck and radius and increased significantly at the lumbar spine, both for AP and lateral projections. Mean C-reactive protein during follow-up predicted a decrease in the femoral neck BMD (change in %, β = -0.15, p = 0.046). Use of bisphosphonates predicted an increase in BMD at all measuring sites (p < 0.001 to 0.013), except for the total radius. Use of tumor necrosis factor inhibitors (TNFi) predicted an increase in AP spinal BMD (β = 3.15, p = 0.012).

CONCLUSION

The current study (which has a long follow-up, many measuring sites, and is the first to longitudinally assess the lateral projection of the spine in AS patients) surprisingly showed that lateral projection spinal BMD increased. This study suggests that the best site to assess bone loss in AS patients is the femoral neck and that inflammation has an adverse effect, and the use of bisphosphonates and TNFi has a positive effect, on BMD in AS patients.

A longitudinal study of fecal calprotectin and the development of inflammatory bowel disease in ankylosing spondylitis

Background

Patients with ankylosing spondylitis (AS) are at increased risk of developing inflammatory bowel disease (IBD). We aimed to determine the variation in fecal calprotectin in AS over 5 years in relation to disease activity and medication and also to study the incidence of and predictors for development of IBD.

Methods

Fecal calprotectin was assessed at baseline (n = 204) and at 5-year follow-up (n = 164). The patients answered questionnaires and underwent clinical evaluations. At baseline and at 5-year follow-up, ileocolonoscopy was performed in patients with fecal calprotectin ≥500 mg/kg and ≥200 mg/kg, respectively. The medical records were checked for diagnoses of IBD during the follow-up period.

Results

Fecal calprotectin >50 mg/kg was found in two-thirds of the patients at both study visits. In 80% of the patients, fecal calprotectin changed by <200 mg/kg between the two measuring points. Baseline fecal calprotectin was positively correlated with Ankylosing Spondylitis Disease Activity Score based on C-reactive protein, Bath Ankylosing Spondylitis Disease Activity Index, Bath Ankylosing Spondylitis Functional Index, C-reactive protein, erythrocyte sedimentation rate, and fecal calprotectin at 5-year follow-up. The use of nonsteroidal anti-inflammatory drugs (NSAIDs) was associated with higher fecal calprotectin, and 3-week cessation of NSAIDs resulted in a drop of a median 116 mg/kg in fecal calprotectin. The use of tumor necrosis factor (TNF) blockers was associated with lower fecal calprotectin at both visits, but the users of TNF receptor fusion proteins had significantly higher fecal calprotectin than users of anti-TNF antibodies at 5-year follow-up. The 5-year incidence of Crohn’s disease (CD) was 1.5% and was predicted by high fecal calprotectin.

Conclusions

Fecal calprotectin was elevated in a majority of the patients and was associated with disease activity and medication at both visits. CD developed in 1.5% of the patients with AS, and a high fecal calprotectin was the main predictor thereof. The results support a link between inflammation in the gut and the musculoskeletal system in AS. We propose that fecal calprotectin may be a potential biomarker to identify patients with AS at risk of developing IBD.

Trial registration

ClinicalTrials.gov identifier: NCT00858819. Registered 9 March 2009. Last updated 28 May 2015.