Challenges to conquer from the gender perspective in medicine: The case of spondyloarthritis

[Sex-specific aspects in rheumatology]

Women and men differ in terms of the development and manifestation of inflammatory rheumatic diseases and outcomes as well as with respect to disease perception, health behavior and response to antirheumatic treatment. Sex-specific aspects are increasingly being researched in nearly all medical disciplines to optimize treatment strategies with the aim to improve individual treatment success. This article describes sex differences that can even now be taken into account in rheumatological care.

Sex Bias in Diagnostic Delay: Are Axial Spondyloarthritis and Ankylosing Spondylitis Still Phantom Diseases in Women? A Systematic Review and Meta-Analysis

Diagnostic delay (DD) is associated with poor radiological and quality of life outcomes in axial spondyloarthritis (ax-SpA) and ankylosing spondylitis (AS). The female (F) population is often misdiagnosed, as classification criteria were previously studied mostly in males (M). We conducted a systematic review to investigate (i) the difference in DD between the sexes, the impact of HLA*B27 and clinical and social factors (work and education) on this gap, and (ii) the possible influence of the year of publication (before and after the 2009 ASAS classification criteria), geographical region (Europe and Israel vs. extra-European countries), sample sources (mono-center vs. multi-center studies), and world bank (WB) economic class on DD in both sexes. We searched, in PubMed and Embase, studies that reported the mean or median DD or the statistical difference in DD between sexes, adding a manual search. Starting from 399 publications, we selected 26 studies (17 from PubMed and Embase, 9 from manual search) that were successively evaluated with the modified Newcastle-Ottawa Scale (m-NOS). The mean DD of 16 high-quality (m-NOS > 4/8) studies, pooled with random-effects meta-analysis, produces results higher in F (1.48, 95% CI 0.83-2.14, p < 0.0001) but with significant results at the second analysis only in articles published before the 2009 ASAS classification criteria (0.95, 95% CI 0.05-1.85, p < 0.0001) and in extra-European countries (3.16, 95% CI 2.11-4.22, p < 0.05). With limited evidence, some studies suggest that DD in F might be positively influenced by HLA*B27 positivity, peripheral involvement, and social factors.

[Morbidity due to chronic diseases and their health care in Asturias: a gender analysis]

OBJECTIVE

To determine gender differences in the magnitude and complexity of chronic diseases and gender inequalities in health care in the adult population of Asturias in 2022.

METHOD

A cross-sectional population study in people (>14 years) with at least one diagnosis of chronic disease (780,566 inhabitants).

SOURCES OF INFORMATION

computer program for morbidity groups (Ministry of Health), Electronic medical record of primary care and hospital. Comparative analysis by sex and age, the mean values of chronic diseases and complexity index (Student's t test and one-way ANOVA), and probability (odds ratio and 95% CI) of suffering from specific chronic diseases, making one or more visits to the hospital emergency department or one or more admissions to hospital.

RESULTS

89.9% of women and 82.1% of men were registered with at least one chronic disease. The mean was higher in women (4.36) than in men (3.22) (p<0.001). Complexity index: men 4.56 and women 5.85 (p<0.001). Results show that women are more likely to attend the hospital emergency department, with an attendance rate of 50% for the diseases cited, compared with men at 29%. The rate of hospital admission is higher in men in 13 of the 14 diseases studied (85%).

CONCLUSIONS

Gender analysis can also be applied to secondary sources of the National Health System. Despite the greater magnitude and complexity of chronic diseases in women, there is a higher frequency of hospital admissions in men compared to women with the same diseases. This implies an unequal care profile in the field of hospital admissions that the scientific literature associates with gender biases in health care.

A mixed methods study to uncover impediments to accurate diagnosis of nonradiographic axial spondyloarthritis in the USA

INTRODUCTION/OBJECTIVES

Delayed diagnosis of axial spondyloarthritis (axSpA) is well documented; little is known about the diagnostic journey and impediments for US patients with nonradiographic axSpA (nr-axSpA). It is hypothesized that impediments are varied and exist at both the healthcare provider (HCP) and patient levels. This study aims to understand patient experiences and contributors to delayed nr-axSpA diagnosis in the USA.

METHOD

Interviews of adults with rheumatologist-diagnosed nr-axSpA, recruited through Spondylitis Association of America outreach and patient panels, and of rheumatologists, explored the diagnostic journey and diagnostic barriers. Emerging themes were further explored in an online patient survey. A multiple logistic regression analysis evaluated the main outcome variable, factors affecting time to nr-axSpA diagnosis.

RESULTS

Interviews were conducted with 25 patients and 16 rheumatologists. Survey responses from 186 eligible patients revealed median time from symptom onset to diagnosis of nr-axSpA was 3.25 years. Delayed diagnosis was significantly more likely for women and people in rural areas. Most patients consulted ≥4 different types of HCPs before a rheumatologist and ≥2 rheumatologists before diagnosis. Impediments to timely diagnosis included insidious chronic pain; episodic symptom patterns attributed to activity; symptoms other than chronic lumbosacral back pain requiring medical consultation; and unfamiliarity with and misperceptions about nr-axSpA among HCPs, radiologists, and rheumatologists.

CONCLUSIONS

Delayed nr-axSpA diagnosis is common and reflects HCP knowledge gaps and frequent patient presentation with dominant nonaxial symptoms. Targeted HCP education, research into early disease patterns, and interventions sensitive to the broader spectrum of nr-axSpA manifestations are needed to improve timely diagnosis. Key Points • Patients with nr-axSpA often see multiple types of HCPs, and multiple rheumatologists, before receiving a diagnosis. • Both patients and HCPs are unfamiliar with nr-axSpA and its symptoms, lacking understanding that nr-axSpA can occur in young people, females, and those presenting with normal x-rays. • Disease recognition by nonrheumatology HCPs is key for early referral. • Education on cardinal features, epidemiology, burden, and benefits of timely nr-axSpA diagnosis is warranted for HCPs who commonly manage back pain.

Impact of sex and gender on axSpA diagnosis and outcomes

Axial spondyloarthritis (axSpA) was historically considered a disease of men, largely due to the recognition of a more severe, progressive phenotype, ankylosing spondylitis (AS; or radiographic axSpA, r-axSpA) aiding the clinical diagnosis [1,2]. Data demonstrating the near equal prevalence of axSpA in women only started to emerge in the last decades, highlighting intrinsic differences in disease phenotype, and clinical and imaging characteristics between sexes, which partly explain the issue of underdiagnosis in women. Similar to the evolving understanding of spondyloarthritis and the diseases that term describes, the concepts of gender and sex also warrant further clarification to accurately assess their potential role in disease pathophysiology and phenotypic expression. This narrative review delves into the most recent evidence from the literature on the true prevalence of sex differences in axSpA, and the impact of sex and gender on diagnosis, disease characteristics and treatment response in this, still underserved, chronic disease.

Relationship between sex and clinical and imaging features of early axial spondyloarthritis: results from a 48 month follow-up (Italian arm of the SPondyloArthritis Caught Early (SPACE) study)

OBJECTIVES

To assess the association between sex and clinical and disease activity indices, and X-rays and magnetic resonance imaging (MRI) features, in early-stage axial spondyloarthritis (axSpA).

METHOD

Baseline data analysis was conducted on the Italian SPACE cohort, including patients with chronic back pain (duration ≥ 3 months and ≤ 2 years; onset < 45 years). Patients underwent MRI and X-rays of the sacroiliac joints (SIJs) to establish the diagnosis of axSpA, according to Assessment of SpondyloArthritis international Society criteria and physician's judgement. Clinical features, disease activity and functional indices, and images were collected at baseline and yearly during 48 months. Spinal and SIJ X-rays and MRI images were scored by two readers following Spondyloarthritis Research Consortium of Canada (SPARCC), modified Stoke Ankylosing Spondylitis Spinal Score, and modified New York criteria. Characteristics of axSpA patients according to sex (male/female) were compared over time using descriptive statistics.

RESULTS

Ninety-one patients had axSpA (83.5% non-radiographic; 16.5% radiographic); 47.3% were male. Males were younger, with shorter duration of axial symptoms, and more frequently had HLA-B27 positivity, radiographic sacroiliitis with a bilateral/symmetric pattern, and more signs of spondylitis. Females more frequently showed peripheral/entheseal involvement and the non-radiographic phenotype. Males showed increased pelvic/spinal radiographic progression and more often had active sacroiliitis on MRI. Although the frequency of inflammatory corner lesions did not differ between males and females, localization varied, with more cervical/thoracic MRI-spine lesions in females and more lumbar lesions in males. We observed a significant downward trend of SPARCC SIJ/spine scores in all patients, irrespective of sex. More fat lesions were observed on MRI-spine in females and on MRI-SIJ in males.

CONCLUSION

Sex was associated with distinct axSpA features: females showed low-grade radiographic sacroiliitis and spinal progression, and a higher prevalence of cervical and thoracic spine MRI signs.

Gender biases in Spanish rheumatology: Perception and facts

OBJECTIVE

To identify perceptions of gender bias in Spanish rheumatology and to quantify the involvement of both sexes in all areas of the specialty.

METHODS

A survey was sent to all members of the SER on participation and perception of biases and of their own competencies, and actual data on participation in governing bodies, congresses, committees, and Spanish rheumatology departments in the last 5 years were reviewed.

RESULTS

The survey was answered by 95 rheumatologists, 4.8% of SER members (14 men and 81 women), both groups being similar in terms of age, academic level, and position and work centre. No differences were detected in the distribution of work and non-work tasks between sexes, nor in invitations to positions of power in the last five years, nor in the perception of capacity to occupy the different positions of power, which was high for both sexes. Male respondents more frequently consider that activities such as participating in a scientific committee or giving a conference are not empowering. A third of both sexes consider that the SER should review its processes with a gender perspective but less than a third believe that this should be done by quotas. The reality of the last 5 years is that 1) there is a male to female ratio of 3:2 on SER boards of directors and in this period there has been no female president or treasurer; 2) in the scientific committees of the congresses men predominate (2:1) although slightly less in the local organizing committee; 3) there are more male speakers and moderators than women (very striking in satellite symposia, 4: 1); 4) 9 out of 10 editors-in-chief are men; 5) in academic positions there are 3 men for every 2 women, 9 to 1 in professorships or emeritus positions; although more women supervise residents; and 6) there are more women (60%) than men (40%) in Spanish rheumatology departments, although 75% of department chiefs are men.

CONCLUSION

Although not perceived by either the men or the women, there are biases in the involvement of women in important and leadership positions in the specialty.

[Gender-specific differences in the diagnosis and treatment of inflammatory rheumatic diseases]

BACKGROUND

Gender differences in the diagnosis and treatment of various diseases are increasingly being researched with the aim of optimizing treatment strategies and improving individual treatment success.

METHODS

This paper summarizes the existing literature for gender differences in inflammatory rheumatic diseases.

RESULTS

Many, but not all, inflammatory rheumatic diseases occur more frequently in women than in men. Women more often have a longer duration of symptoms until diagnosis than men, which may be due to different clinical and radiological presentations. Across diseases, women more often have lower remission and treatment response rates to antirheumatic medication compared to men. Discontinuation rates are also higher in women than in men. Whether women are more likely to develop anti-drug antibodies to biologic disease-modifying antirheumatic drugs is still unclear. For Janus kinase inhibitors, there is no evidence of differential treatment response to date.

CONCLUSION

Whether individual dosing regimens and gender-adapted remission criteria are also required in rheumatology cannot be deduced from the evidence available to date.

A glance into the future of gout

Gout is characterized by monosodium urate (MSU) crystal deposits in and within joints. These deposits result from persistent hyperuricaemia and most typically lead to recurrent acute inflammatory episodes (gout flares). Even though some aspects of gout are well characterized, uncertainties remain; this upcoming decade should provide further insights into many of these uncertainties. Synovial fluid analysis allows for the identification of MSU crystals and unequivocal diagnosis. Non-invasive methods for diagnosis are being explored, such as Raman spectroscopy and imaging modalities. Both ultrasound and dual-energy computed tomography (DECT) allow the detection of MSU crystals; this not only provides a mean of diagnosis, but also has furthered gout knowledge defining the presence of a preclinical deposition in asymptomatic hyperuricaemia. Scientific consensus establishes the beginning of gout as the beginning of symptoms (usually the first flare), but the concept is currently under review. For effective long-term gout management, the main goal is to promote crystal dissolution treatment by reducing serum urate below 6 mg/dL (or 5 mg/dL if faster crystal dissolution is required). Current urate-lowering therapies' (ULTs) options are limited, with allopurinol and febuxostat being widely available, and probenecid, benzbromarone, and pegloticase available in some regions. New xanthine oxidase inhibitors and, especially, uricosurics inhibiting urate transporter URAT1 are under development; it is probable that the new decade will see a welcomed increase in the gout therapeutic armamentarium. Cardiovascular and renal comorbidities are common in gout patients. Studies determining whether optimal treatment of gout will positively impact these comorbidities are currently lacking, but will hopefully be forthcoming. Overall, the single change that will most impact gout management is greater uptake of international rheumatology society recommendations. Innovative strategies, such as nurse-led interventions based on these recommendations have recently demonstrated treatment success for people with gout.

Gender-Diverse Inclusion in Immunological Research: Benefits to Science and Health

The differences between male and female immune systems are an under-researched field, ripe for discovery. This is evidenced by the stark sex biases seen in autoimmunity and infectious disease. Both the sex hormones (oestrogen and testosterone), as well as the sex chromosomes have been demonstrated to impact immune responses, in multiple ways. Historical shortcomings in reporting basic and clinical scientific findings in a sex-disaggregated manner have led not only to limited discovery of disease aetiology, but to potential inaccuracies in the estimation of the effects of diseases or interventions on females and gender-diverse groups. Here we propose not only that research subjects should include both cis-gender men and cis-gender women, but also transgender and gender-diverse people alongside them. The known interaction between the hormonal milieu and the sex chromosomes is inseparable in cis-gender human research, without the confounders of puberty and age. By inclusion of those pursuing hormonal affirmation of their gender identity- the individual and interactive investigation of hormones and chromosomes is permitted. Not only does this allow for a fine-tuned dissection of these individual effects, but it allows for discovery that is both pertinent and relevant to a far wider portion of the population. There is an unmet need for detailed treatment follow-up of the transgender community- little is known of the potential benefits and risks of hormonal supplementation on the immune system, nor indeed on many other health and disease outcomes. Our research team has pioneered the inclusion of gender-diverse persons in our basic research in adolescent autoimmune rheumatic diseases. We review here the many avenues that remain unexplored, and suggest ways in which other groups and teams can broaden their horizons and invest in a future for medicine that is both fruitful and inclusive.

The impact of gender and sex on diagnosis, treatment outcomes and health-related quality of life in patients with axial spondyloarthritis

Axial spondyloarthritis (axSpA) is a chronic inflammatory rheumatic condition, historically considered a predominantly male disease. However, increasing evidence suggests a more equal prevalence between men and women. Of the limited research conducted to date, it is apparent that gender differences exist in terms of time to diagnosis, treatment outcomes and health-related quality of life (HRQoL). Despite this, women are underrepresented in clinical trials and most studies do not stratify by gender to identify potential differences in terms of disease manifestations and treatment response. In this perspectives article, we reflect on the potential biological and social factors contributing to these differences and propose three key areas of education and research that should be prioritised in order to address the unmet needs of female patients with axSpA, namely: (1) to identify ways to increase awareness of disease occurrence in female patients among healthcare professionals (HCPs), (2) to improve understanding of gender differences in disease manifestation and outcomes, and (3) to conduct gender-stratified clinical trials with a representative sample of female patients.

Factors Associated With Diagnostic Delay of Axial Spondyloarthritis in Colombian Patients

BACKGROUND/OBJECTIVE

The diagnostic delay of axial spondyloarthritis (axSpA) is globally reported to be between 3 and 11 years. Early diagnosis and treatment have long-term benefits for patients and the health care system. Several international studies have evaluated some factors associated with diagnostic delay, but there are no known studies in the Colombian population. This study assesses the factors associated with diagnostic delay of axSpA in a rheumatology center in Bogota, Colombia.

METHODS

This monocentric analytical cross-sectional study was done in a specialized rheumatology center. Patients who fulfilled the 2009 Assessment of Spondyloarthritis International Society (ASAS) classification criteria for axSpA were included. Information was obtained from medical records and a phone call. Bivariate and multivariate analyses were done to assess the associated factors with diagnostic delay.

RESULTS

One hundred one patients were included, 54 were women (53.5%). The median diagnostic delay was 2 years (interquartile range, 1-7). The bivariate analysis showed that a younger age at diagnosis (p = 0.042) and previous diagnosis of lumbar degenerative disease (p = 0.029) were associated with a longer diagnostic delay. The logistical regression showed that previous lumbar degenerative disc disease (odds ratio, 2.8; 95% confidence interval, 1.09-7.53) and fibromyalgia (odds ratio, 4.0; 95% confidence interval, 1.2-13.1) diagnosis were both associated with a longer diagnostic delay.

CONCLUSIONS

Factors associated with a longer diagnostic delay were previous diagnosis of lumbar degenerative disc disease and fibromyalgia. Additional studies are needed so that the reasons for diagnostic delay are understood and early diagnosis and management of axSpA are enabled.

A Benchmarking Study Evaluating Axial Spondyloarthritis Burden in Spain and Other European Countries. Results from the Spanish Atlas and the European Map of Axial Spondyloarthritis (EMAS) Studies

AIM

To compare the burden of disease in Spanish patients with axial spondyloarthritis (axSpA) vs other European countries (OEC).

METHODS

Data from 2846 unselected patients from the European Map of Axial Spondyloarthritis (EMAS) and the Atlas of Axial Spondyloarthritis in Spain (Atlas) were collected through online surveys. Comparative analysis was carried out between Spanish patients (2016) and patients from 12 OEC ( 2017-2018). Socio-demographic characteristics, life habits, and patient-reported outcomes (Bath Ankylosing Spondylitis Disease Activity Index 0-10, spinal stiffness 3-12, functional limitation 0-54, the 12-Item General Health Questionnaire [GHQ-12] for psychological distress 0-12) were compared. Chi-square and Mann-Whitney tests were used for qualitative and quantitative variables respectively.

RESULTS

680 (23.9%) Spanish axSpA patients were compared to 2166 axSpA patients (76.1%) from OEC. Compared to Spain, the OEC group had a higher percentage of females (64.1% vs 52.5%; P < .001) and university-educated participants (51.7% vs 36.9%; P < .001). Spanish patients showed a greater diagnostic delay (8.5 ± 7.7 vs 7.2 ± 8.6 years; P < .001), visits to orthopedic specialists before diagnosis (56.9% vs 25.3%; P < .001), human leukocyte antigen-B27 carriership (77.1% vs 70.1%; P = .003), disease activity (5.7 ± 2.0 vs 5.4 ± 2.0; P = .024), and higher unemployment rates (21.7% vs 9.2%; P < .001). Despite lower rates of diagnosed anxiety and depression, Spanish patients were at higher risk of psychological distress according to the GHQ-12 (5.7 ± 4.5 vs 4.8 ± 4.0; P < .001).

CONCLUSION

Compared to European axSpA patients, Spanish patients experience a longer diagnostic delay and greater psychological distress. Being wrongly referred to orthopedic specialists and facing a more precarious labor scenario appear as possible causal factors, highlighting the need to increase the number of rheumatologists, the training of healthcare professionals, and improving axSpA patients' working conditions.

Identifying Parameters Associated with Delayed Diagnosis in Axial Spondyloarthritis: Data from the European Map of Axial Spondyloarthritis

Objective

To identify the parameters associated with self-reported diagnostic delay (DD) in axial spondyloarthritis (axSpA) patients across Europe.

Methods

Data from 2652 patients from 13 countries who participated in the European Map of Axial Spondyloarthritis (EMAS) were collected through an online survey (2017–2018). DD was calculated as the difference between age at diagnosis and age at symptom onset reported by participants. Associations between DD and sociodemographic characteristics, as well as disease-related factors were explored through univariable and multivariable linear regression analysis.

Results

Average DD was 7.4  (8.4) years with a variation between countries. The variables associated with longer DD in the final multivariable regression model were: younger age at symptom onset (b = −0.26; 95% CI: −0.28, −0.23), female gender (b = 1.34; 95% CI: 0.73, 1.96) and higher number of health-care professionals (HCPs) seen before diagnosis (b = 1.19; 95% CI: 0.95, 1.43). There was a significant interaction between the female gender and the number of HCPs seen before diagnosis. A substantial variation of the DD across European countries was observed.

Conclusion

In this sample of axSpA patients, average DD was greater than 7 years. Younger age at symptom onset, female gender, higher number of HCPs seen before diagnosis, and being diagnosed by rheumatologist were the parameters associated with a longer DD in axSpA. These findings indicate a need for continuing efforts dedicated to recognition of patients with a high probability of axSpA on the level of non-rheumatology specialists and facilitating referral to a rheumatologist for timely diagnosis.

Reviewing Disease Activity Indices in Spondyloarthritis From the Sex Perspective: A Systematic Review and Metaanalysis

OBJECTIVE

To determine whether the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) and the Ankylosing Spondylitis Disease Activity Score (ASDAS) exhibited differences between women and men.

METHODS

We systematically searched MEDLINE, Embase, Web of Science, and other sources in English or Spanish from January 1, 1995, to July 31, 2020, to assess the differences according to sex in BASDAI and ASDAS. We performed a comparative analysis by sex using t test and mean difference by sex metaanalyses for BASDAI and ASDAS, as well as a random-effects model using the inverse-variance method.

RESULTS

Forty-one studies included BASDAI (6785 women, 12,929 men) and 16 of them included ASDAS (2046 women, 4403 men). Disease activity detected using BASDAI was significantly higher in women than in men (mean 4.9 vs 4.2, P = 0.02), whereas ASDAS did not detect differences between sexes (mean 2.8 women vs 2.8 men). In the metaanalyses, BASDAI detected significant differences between women and men (mean difference = 0.55 [95% CI 0.46-0.65], P < 0.00001), but ASDAS did not identify significant mean difference between sexes (0.04, 95% CI -0.05 to 0.12], P = 0.38).

CONCLUSION

The 2 most widely used indices of disease activity in spondyloarthritis (SpA) discriminate differently according to sex by their different evaluations of peripheral disease. The different components and weights in BASDAI and ASDAS influence their values. BASDAI may be affected by fatigue, and in predominantly peripheral manifestations such as enthesitis, ASDAS may not be sensitive enough to detect activity. This may represent a sex bias unfavorable to women, because peripheral SpA is more common in women than in men.

Gender differences in patient journey to diagnosis and disease outcomes: results from the European Map of Axial Spondyloarthritis (EMAS)

Introduction/objectives

To evaluate the journey to diagnosis, disease characteristics and burden of disease in male and female patients with axial spondyloarthritis (axSpA) across Europe.

Method

Data from 2846 unselected patients participating in the European Map of Axial Spondyloarthritis (EMAS) study through an online survey (2017–2018) across 13 countries were analysed. Sociodemographic characteristics, lifestyle, diagnosis, disease characteristics and patient-reported outcomes (PROs) [disease activity –BASDAI (0–10), spinal stiffness (3–12), functional limitations (0–54) and psychological distress (GHQ-12)] were compared between males and females using chi-square (for categorical variables) and student t (for continuous variables) tests.

Results

In total, 1100 (38.7%) males and 1746 (61.3%) females participated in the EMAS. Compared with males, females reported considerable longer diagnostic delay (6.1 ± 7.4 vs 8.2 ± 8.9 years; p < 0.001), higher number of visits to physiotherapists (34.5% vs 49.5%; p < 0.001) and to osteopaths (13.3% vs 24.4%; p < 0.001) before being diagnosed and lower frequency of HLA-B27 carriership (80.2% vs 66.7%; p < 0.001). In addition, females reported higher degree of disease activity in all BASDAI aspects and greater psychological distress through GHQ-12 (4.4 ± 4.2 vs 5.3 ± 4.1; p < 0.001), as well as a greater use of alternative therapies.

Conclusion

The patient journey to diagnosis of axSpA is much longer and arduous in females, which may be related to physician bias and lower frequency of HLA-B27 carriership. Regarding PROs, females experience higher disease activity and poorer psychological health compared with males. These results reflect specific unmet needs in females with axSpA needing particular attention.

Key Points • Healthcare professionals’ perception of axSpA as a predominantly male disease may introduce some bias during the diagnosis and management of the disease. However, evidence about male-female differences in axSpA is scarce. • EMAS results highlight how female axSpA patients report longer diagnostic delay and higher burden of the disease in a large sample of 2846 participants of 13 European countries. • Results reflect unmet needs of European female patients. Healthcare professionals should pay close attention in order to accurately diagnose and efficiently manage axSpA cases while further research should be developed on the cause of reported gender differences.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10067-020-05558-7.

Predictive values of inflammatory back pain, positive HLA B27 antigen and acute and chronic magnetic resonance changes in early diagnosis of Spondyloarthritis. A study of 133 patients

OBJECTIVES

To analyse the predictive values of inflammatory back pain (IBP), positive HLA B27 antigen, increased C-reactive protein (CRP), Spondyloarthritis (SpA) features, familial history (FH), magnetic resonance sacroiliac joints (MRI-SIJ) imaging and its weight in early SpA diagnosis.

METHODS

133 patients with back pain, aged <50, duration of the pain <2 years were included. Data such as IBP, HLA B27, increased CRP, SpA features, FH, SIJ´s radiography and MRI were collected for each patient. STIR sequences were classified as strongly positive bone morrow oedema (SPBME ≥2), clearly present and easily recognisable as positive according to the ASAS criterion, weakly positive (WPBME ≥2), suggestive, but not easily recognisable and, clearly negative none of those features. T1-weighted sequences were assessed as positive/negative for erosion, fat metaplasia, backfill and sclerosis, if ≥1, for each lesion was present. MRI images were read by three blinded readers.

RESULTS

The average age was 38.9 years. 47 (35.3%) patients received SpA diagnosis according to the clinical opinion. IBP was highly specific, 0.81 and sensitive, 0.83. HLA B27 was positive in a half of the SpA patients. SPBME ≥2 provided a great specificity, 0.94 and an acceptable sensitivity, 0.79. Erosion was significantly more frequent in SpA patients (72% vs 7%), specificity 0.93. The addition of erosion ≥1 to the WPBME ≥2 noticeably improved specificity, 0.98, although slightly decreased sensitivity, 0.64. Fat metaplasia and backfill were highly specific, but poorly sensitive. Factors forecasting positive diagnosis were IBP, followed by SpA features and increased CRP.

CONCLUSIONS

At the onset, IBP might be a good marker for selecting patients with suspicion of SpA. The addition of erosion to the ASAS criterion might be helpful for early diagnosis, especially in patients with doubtful STIR imaging where BME is present but it is hard to determinate whether the ASAS "highly suggestive" criterion is met.