Prevalence Of Inflammatory Back Pain Research Articles

Comparison of clinical characteristics between adult-onset and juvenile-onset non-radiographic axial spondyloarthritis in Chinese patients: results from the COCAS cohort

BackgroundAxial spondyloarthritis (axSpA) is a chronic inflammatory rheumatic disease predominantly affecting the axial skeleton. We aimed to describe the clinical characteristics of patients with non-radiographic axSpA (nr-axSpA) in China and compare the differences between adult- and juvenile-onset cases.MethodsA cross-sectional study was conducted using data from 776 patients with nr-axSpA in the Clinical Characteristic and Outcome in Chinese Axial Spondyloarthritis (COCAS) study cohort. Patients were divided into two groups including the adult-onset group (n = 662) and the juvenile-onset group (n = 114) according to age at disease onset. Baseline demographics and clinical characteristics were compared between patients with adult-onset and juvenile-onset nr-axSpA.ResultsOverall, the male-to-female ratio was 1.26:1, the prevalence of HLA-B27 positivity was 72.2%, and the median age at disease onset of nr-axSpA was 22 years. Nearly 75% of nr-axSpA patients had peripheral arthritis in the disease course, and the prevalence of extra-articular manifestations was 10.4%. The juvenile-onset group contained a higher proportion of men (66.7% vs. 53.9%, P = 0.011) and a longer baseline disease duration (4.0 [4.0] vs. 1.6 [3.5], P < 0.001) than the adult-onset group. A family history of spondyloarthritis was more frequent in the juvenile-onset group than in the adult-onset group (23.7% vs. 15.4%, P = 0.028), but no significant difference in the prevalence of HLA-B27 positivity was observed between the two groups (P = 0.537). Regarding initial symptoms, peripheral arthritis occurred more often in patients with juvenile-onset nr-axSpA, whereas patients with adult-onset nr-axSpA presented more frequently with axial involvement. The prevalence of inflammatory back pain (IBP) was higher in the adult-onset group than in the juvenile-onset group (85.0% vs. 75.4%, P = 0.010), whereas the juvenile-onset group showed a higher prevalence of peripheral arthritis and enthesitis than the adult-onset group (67.5% vs. 48.5%, P < 0.001; 35.1% vs. 23.3%, P = 0.007, respectively).ConclusionsCompared with adult-onset nr-axSpA, juvenile-onset nr-axSpA was more common in men and those with a family history of spondyloarthritis. Juvenile-onset nr-axSpA presents with a “peripheral predominant” mode at disease onset and a higher frequency of peripheral arthritis and enthesitis during the disease course.

A lower frequency of inflammatory back pain in male patients with ankylosing spondylitis compared with female patients.

In routine rheumatology practice, we noticed that a significant number of male ankylosing spondylitis (AS) patients did not experience inflammatory back pain (IBP). Based on this observation, we aimed to investigate the prevalence of IBP in male AS patients and compare it to that in female patients. Patients with AS who fulfilled the modified New York criteria were subjected to a face-to-face interview with a standardized questionnaire that addressed the IBP components based on the Berlin criteria. The study also included 63 patients with chronic mechanical back pain (MBP). Erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) levels were measured, and Bath Ankylosing Spondylitis Disease Activity, Function, and Metrology Indexes (BASDAI, BASFI, and BASMI) were evaluated in patients with AS. There were 181patients with AS (124 males, mean age 41.2years; 57 females, mean age 44.6years) and 63 patients with MBP (28 males, mean age 47.2years; 35 females, mean age 43.5years). The prevalence of IBP was found to be 87.7% in female and 66.1% in male patients with AS (p = 0.002). The specificity of the criteria was determined to be high both in females (85.7%) and males (89.2%). Female patients with AS had higher BASDAI levels than males (p = 0.048), but no difference was found in BASFI, BASMI, or serum CRP levels between genders. A considerable proportion of male patients with AS did not experience IBP, although they had similar CRP levels compared with females.

POS1102 THE PREVALENCE OF INFLAMMATORY BACK PAIN IN PATIENTS WITH SKIN PSORIASIS WITHOUT PSORIATIC ARTHRITIS. DATA FROM DERMATOLOGICAL REAL-WORLD SETTING.

BackgroundPsoriasis (PsO) is an inflammatory disease associated with psoriatic arthritis (PsA). PsA affects peripheral and axial joints1,2. Psoriasis can precede the onset of PsA by approximately 3 to 8 years, axial involvement often undiagnosed3. There are limited data about the prevalence of inflammatory back pain (IBP) in PsO patients (pts) without clinical symptoms of PsA4.ObjectivesTo study the prevalence of IBP in PsO pts without PsA symptomsMethods108 PsO pts without PsA over a 10-month period (March 2021 to December 2021) were incluided. Participants filled out a questionnaire on IBP. Additionaly the prevalence of stiffness in the back and neck was estimated. IBP was defined as an affirmative answer to the question ‘Did you suffer from low back pain for ≥3 months?’ and IBP criteria was based on criteria ASAS (the ASsessment in Ankylosing Spondylitis) and was confirmed if at least 3 out of the following 4 criteria were present: (a) onset before age 40, (b) insidious onset, (c) improvement with exercise, (d) associated with morning stiffnessResultsIt was found that more than 40% of patients complained of pain or stiffness in the back. Stiffness and pain in the neck were observed in every fourth patient on average. Of those patients who complained of pain in the back or neck, 37% noted that they had pain at rest (when they get up in the morning or lie down for a long time), and 21.3% had inflammatory pain at night (when patients are forced to woke up, they needed to do exercises) (Table 1). It was found that the risks of developing spondylitis with neck pain, neck stiffness, back pain, back stiffness were higher in 4,549 times (95% CI [1,720; 12,031]), in 19,444 times (95% CI [6,480; 58,343]) 15 times (95% CI [4.646; 48.427]) and 34.857 times (95% CI [7.583; 160.230]), respectively.ConclusionIBP was found in more than 40% PsO patients. Every fourth PsO patients complained of stiffness and pain in the neck. The presence of these symptoms significantly increased the risk of developing PsA with spondylitis. The presence of IBP should be taken into account for early diagnosis of PsA in the dermatological practice.

Prevalence of Inflammatory Back Pain in a Low-Income Population.

Inflammatory back pain (IBP) is a major criterion in identifying axial spondyloarthritis. Whether socioeconomic issues impact prevalence of IBP assessed using standardized questionnaires has not been assessed. We determined IBP prevalence and performance of IBP questionnaires in a low-income, low-literacy population. Individuals were interviewed in Fortaleza, Brazil, for the prevalence of IBP using Calin's, Berlin, and ASAS IBP questionnaires; monthly family income (US dollars), literacy (>/≤8 school years [SYs]), and smoking habit (present/absent) were registered. Two hundred nineteen individuals were included (mean age, 38.2 ± 12.9 years), 110 (50.2%) men, 58 (26.4%) White, and 38 (17.3%) smokers. Overall, 152 (69.4%) declared <US $720 (mean local income) earnings, and 64 (29.2%) had ≤8 SYs. Chronic back pain was declared by 134 (61%) with 32 (14.6%), 25 (11.9%), and 63 (28.3%) fulfilling ASAS, Berlin, and Calin's IBP criteria, respectively. Chronic back pain or IBP prevalence was similar regardless of ethnicity, smoking habit, income, or literacy with IBP prevalence higher among women (p = 0.006). This is the first report on IBP prevalence in a low-income, low-literacy population. Chronic back pain was highly prevalent with almost 15% having IBP using ASAS criteria. Inflammatory back pain prevalence looked similar using ASAS and Berlin criteria; values were higher using Calin's criteria. Literacy or income did not influence IBP prevalence in this population, which was higher among women. The higher prevalence of IBP using Calin's criteria in this population should be taken into account as it might impact studies aiming to determine prevalence of axial spondyloarthritis in clinical studies in this scenario.

Prevalence of inflammatory back pain and radiographic axial spondyloarthritis in a semi-urban community of Lahore, Pakistan.

To determine the prevalence of inflammatory back pain (IBP) and radiographic axial spondyloarthritis (SpA) in a semi-urban community of Lahore, Pakistan. This cross-sectional household survey was designed as per the Community Oriented Program for the Control of Rheumatic Diseases (COPCORD) model. In Phase 1, the subjects were interviewed for musculoskeletal (MSK) pain in the last 7days by clinical assistants. In Phase 2, physiotherapists identified subjects with spinal/back pain and interviewed for Assessment in Spondyloarthritis International Working Group (ASAS) criteria for IBP. In Phase 3 subjects having IBP or chronic back pain (CBP) with an age at onset ≤45years, were assessed and further investigated. A total of 4922 subjects with a mean age of 35.3±14.5years, including 2770 (56%) women were surveyed in Phase 1. MSK pain in last 7days was reported by 1407 (28.6%) of whom 1034 (21%) had spinal pain. The ASAS criteria for IBP were met in 329 (6.7%, 95% CI 6.0-7.0). In Phase 3, 222 with IBP and 83 having CBP with age at onset ≤45years were evaluated. Out of this total of 305, 144 (2.9%) were confirmed to have IBP by rheumatologists as per at least 1 of the 3 criteria. ASAS criteria were met in 107 (2.2%, 95% CI 1.8-2.6). ASAS criteria for radiographic axial SpA were met in 47 (1%, 95% CI 0.7-1.3) of the surveyed population. Inflammatory back pain was reported in 6.7% by physiotherapists, confirmed in 3% by rheumatologists. The prevalence of radiographic axial SpA was 1%.

Sacroiliitis in Systemic Lupus Erythematosus Revisited.

This study aims to investigate the prevalence of inflammatory back pain (IBP) and sacroiliitis in a systemic lupus erythematosus (SLE) population as well as the association between IBP and the frequency of human leukocyte antigen B27 (HLA-B27). The study included 281 SLE patients (16 males, 265 females; mean age 39.9±11.9 years; range, 20 to 69 years) and 100 healthy controls (HCs) (2 males, 98 females; mean age 41.2±10.1 years; range, 19 to 64 years). Participants were administered a five-item Assessment of SpondyloArthritis international Society-IBP questionnaire. Patients and controls with IBP underwent detailed clinical and laboratory examinations to detect sacroiliitis. Radiographic evaluations were performed by a blinded rheumatologist and radiologist. Interobserver reliability was assessed with Cohen's kappa test. According to the questionnaire, IBP was present in 46 SLE patients (46/281; 16.3%) whereas none of the HC had IBP (p<0.001). In radiological assessment, 22 SLE patients (7.8%) had sacroiliitis detected by conventional X-ray and/or magnetic resonance imaging. Only one SLE patient with sacroiliitis had HLA-B27. Our study showed that IBP is increased in SLE patients and IBP in SLE is not associated with HLA-B27.

Prevalence of inflammatory back pain among health professionals in Cyprus

Prevalence of inflammatory back pain among health professionals in Cyprus

Diagnostic accuracy of inflammatory back pain for axial spondyloarthritis in rheumatological care

ObjectiveInflammatory back pain (IBP), the key symptom of axial spondyloarthritis (axSpA), including ankylosing spondylitis, has been proposed as a screening test for patients presenting with chronic back pain in primary...

Clinical Evolution in Patients With New-Onset Inflammatory Back Pain: A Population-Based Cohort Study.

Inflammatory back pain (IBP) is often an early manifestation of spondyloarthritis (SpA), but the prognosis of patients with incident IBP is unknown. This study was undertaken to investigate long-term outcomes in patients with IBP, and predictors of progression to SpA, in a population-based cohort. We conducted a retrospective, longitudinal study using the Rochester Epidemiology Project, a longstanding population-based cohort of residents of Olmsted County, MN. Patients ages 16-35 years with clinical visits for back pain from 1999 to 2003 were identified, and we screened these patients for the presence of new-onset IBP and performed medical record reviews to collect data on clinical, laboratory, and imaging features of SpA. Outcomes in these patients were followed up until July 2016. We used survival analysis for competing risks to examine progression to either SpA, a non-SpA diagnosis, or resolution of back pain. Recursive partitioning was used to identify predictors of progression to SpA. Among 5,304 patients with back pain, we identified 124 patients with new-onset IBP. After a median follow-up of 13.2 years, IBP had progressed to SpA in 39 patients, 15 patients developed a non-SpA diagnosis, and 58 patients had resolution of IBP. At 10 years, the probability of having SpA was 30%, while the probability of resolution of IBP was 43%. The most important predictors for progression to SpA were uveitis, male sex, and family history of SpA. In a minority of patients, new-onset IBP progresses to SpA, while IBP resolves in many. That IBP often resolves may explain the difference between the prevalence of IBP (3-6%) and the prevalence of SpA (0.4-1.3%).

Inflammatory back pain and associated disease conditions among patients with chronic low back pain in Bangladesh.

Inflammatory back pain (IBP) is the earliest symptom of axial and other forms of spondyloarthritis (SpA). However, there are no published data on prevalence of IBP among patients suffering from chronic low back pain (CLBP) in Bangladesh. In this study, we estimated the prevalence of IBP and the subtypes of SpA in a tertiary hospital in Bangladesh. This 1 year cross-sectional study was conducted among 240 CLBP patients in a rheumatology outpatient clinic. Assessment of Spondyloarthritis International Society classification criteria of IBP and predefined recognized classification criteria were followed to define different subtypes of SpA. Means and standard deviations were reported for continuous variables. Descriptive and bi-variate analyses were accordingly performed. Of 240 CLBP patients, 60 (25%) had IBP and 180 (75%) had mechanical back pain (MBP). Among the 60 IBP patients, 52 (86.6%) had predominantly axial SpA (axSpA) and eight (13.4%) had predominantly peripheral spondyloarthritis. In the axSpA group, 49 (94.2%) had radiographic axSpA (rd-axSpA) also known as AS and three (5.8%) had non-radiographic axSpA (nr-axspA). AxSpA patients could be divided into eight (15.35%) with psoriasis, two (3.8%) with reactive arthritis and one patient (1.9%) had arthritis associated with inflammatory bowel disease. Fifty (83.3%) IBP and 73 (40.6%) MBP patients had age at onset of back pain < 40 years. Forty-two (70%) of the IBP and 100 (55.6%) of the MBP patients had normal body mass index. All these differences were statistically significant (P ≤ 0.0001). Inflammatory back pain is common among patients presenting with CLBP. The commonest cause of IBP is AS, followed by PsA and nr-axSpA.

Prevalence of inflammatory back pain and radiologic sacroiliitis is increased in patients with primary Sjögren's syndrome.

IntroductionThe prevalence of Sjögren's syndrome (SS) in patients with the diagnosis of SpA has been reported to be higher than normal population. Yet, the vice-versa is unclear. In this study, we aimed to investigate the prevalence of IBP, radiologic sacroiliitis and SpA in patients with primary SS.Methods85 patients followed at the rheumatology clinics of the Marmara and Kocaeli Universities with the diagnosis of primary SS between November 2011 and August 2012 were included in this study. The control group consisted of 100 age-and gender-matched patients. Inflammatory back pain and axial SpA were diagnosed according to the assessment of spondylo arthritis International Society (ASAS) criteria.Results83 patients were (97%) female and 2 (3%) were male. Mean age of the patients was 49.1 (±11) years. Mean disease duration was 7.3 (±4) years. The patient and control groups were comparable in terms of age and gender (p > 0.05). Inflammatory back pain was observed in 21 (24.7%) of 85 primary SS patients and in 4 (4%) of 100 control subjects (p < 0.001), radiographic sacroiliitis was demonstrated in 9 (10.5%) of primary SS patients and 2 (2%) of the control subjects (p = 0.025). Remaining SpA findings were not encountered in either group.Conclusioninflammatory back pain and radiologic sacroiliitis is increased in patients with primary SS. Whether IBP, SI joint inflammation and radiologic sacroiliitis is due to the co-existence of SpA and primary SS or IBP is an underdiagnosed clinical feature of SS deserves further studies of large patient numbers.

The prevalence and clinical characteristics of nonradiographic axial spondyloarthritis among patients with inflammatory back pain in rheumatology practices: a multinational, multicenter study.

BackgroundPatients with ankylosing spondylitis (AS), who by definition have radiographic sacroiliitis, typically experience symptoms for a decade or more before being diagnosed. Yet, even patients without radiographic sacroiliitis (i.e., nonradiographic axial spondyloarthritis [nr-axSpA]) report a significant disease burden. The primary objective of this study was to estimate the prevalence and clinical characteristics of nr-axSpA among patients with inflammatory back pain (IBP) in rheumatology clinics in a number of countries across the world. A secondary objective was to estimate the prevalence of IBP among patients with chronic low back pain (CLBP).MethodsData were collected from 51 rheumatology outpatient clinics in 19 countries in Latin America, Africa, Europe, and Asia. As consecutive patients with CLBP (N = 2517) were seen by physicians at the sites, their clinical histories were evaluated to determine whether they met the new Assessment of SpondyloArthritis international Society criteria for IBP. For those who did, their available clinical history (e.g., family history, C-reactive protein [CRP] levels) was documented in a case report form to establish whether they met criteria for nr-axSpA, AS, or other IBP. Patients diagnosed with nr-axSpA or AS completed patient-reported outcome measures to assess disease activity and functional limitations.ResultsA total of 2517 patients with CLBP were identified across all sites. Of these, 974 (38.70 %) fulfilled the criteria for IBP. Among IBP patients, 29.10 % met criteria for nr-axSpA, and 53.72 % met criteria for AS. The prevalence of nr-axSpA varied significantly by region (p < 0.05), with the highest prevalence reported in Asia (36.46 %) and the lowest reported in Africa (16.02 %). Patients with nr-axSpA reported mean ± SD Ankylosing Spondylitis Disease Activity Scores based on erythrocyte sedimentation rate and CRP of 2.62 ± 1.17 and 2.52 ± 1.21, respectively, indicating high levels of disease activity (patients with AS reported corresponding scores of 2.97 ± 1.13 and 2.93 ± 1.18). Similarly, the overall Bath Ankylosing Spondylitis Disease Activity Index score of 4.03 ± 2.23 for patients with nr-axSpA (4.56 ± 2.17 for patients with AS) suggested suboptimal disease control.ConclusionsThese results suggest that, in the centers that participated in the study, 29 % of patients with IBP met the criteria for nr-axSpA and 39 % of patients with CLBP had IBP. The disease burden in nr-axSpA is substantial and similar to that of AS, with both groups of patients experiencing inadequate disease control. These findings suggest the need for early detection of nr-axSpA and initiation of available treatment options to slow disease progression and improve patient well-being.

The discriminative value of inflammatory back pain in patients with persistent low back pain

Objectives: To estimate the prevalence of inflammatory back pain (IBP) characteristics and analyse the discriminative value of IBP relative to axial spondyloarthritis (SpA) according to the Assessment of SpondyloArthritis international Society (ASAS) criteria.Method: Patients who had low back pain for > 3 months were selected from a cohort of secondary care patients aged 18–40 years. Data included information on SpA features, human leucocyte antigen (HLA)-B27 typing, C-reactive protein (CRP) level, magnetic resonance imaging (MRI) of the sacroiliac joints, and self-reported IBP questions covering the pain characteristics included in the Calin, Berlin, and ASAS IBP definitions.Results: Of the 759 included patients, 99% [95% confidence interval (CI) 98–100] had at least one IBP characteristic. The prevalence of the single IBP characteristics ranged from 10% (95% CI 7–12) for ‘pain worst in the morning’ to 79% (95% CI 76–82) for ‘morning stiffness’. Two-thirds of the patients (67%, 95% CI 63–70), met at least one of the three IBP definitions. In all, 86 (11%) were classified as ‘SpA according to ASAS’. All three IBP definitions were significantly associated with ‘SpA according to ASAS’; however, the discriminative value was low, with sensitivity, specificity, and balanced accuracy values of 64, 50, and 57% for Calin, 59, 60, and 60% for Berlin, and 35, 79, and 57% for ASAS IBP definitions, respectively.Conclusions: In this study population, IBP characteristics were in general common and the discriminative value was low, as IBP could not differentiate patients with SpA according to ASAS criteria from patients with other causes of back pain.

Prevalence of Inflammatory Back Pain and Axial Spondyloarthritis Among University Employees in Izmir, Turkey.

To estimate the prevalence of inflammatory back pain (IBP) and axial spondyloarthritis (axSpA) using the Assessment of SpondyloArthritis International Society (ASAS) classification criteria among employees in a university. In the first stage of the study, a face-to-face interview was done using a standard questionnaire to investigate IBP in 381 subjects randomly selected from 2894 employees at Dokuz Eylul University in Izmir, Turkey. In the second stage, subjects with back pain for ≥ 3 months and age at onset < 45 years were evaluated for axSpA using the ASAS criteria. Both the European Spondyloarthropathy Study Group (ESSG) criteria and Amor criteria were used for the classification of the whole group of spondyloarthritis (SpA). There were 131 male and 250 female subjects (mean age: 38.0 yrs). Twenty-five subjects (6.6%) were classified as having IBP according to the ASAS criteria. The prevalence of IBP according to the Berlin and Calin criteria was 7.1% and 21.5%, respectively. The prevalence of axSpA was estimated at 1.3% according to the ASAS classification criteria (0.5% for radiographic axSpA and 0.8% for nonradiographic axSpA). A total of 7 patients (1.8%) fulfilled both the Amor and ESSG criteria for the whole group of SpA. This is the first prevalence study of IBP and axSpA using ASAS classification criteria in the Turkish population. The prevalence estimates of IBP and axSpA reported here are within the upper range of other studies in European countries and the United States.

The prevalence of inflammatory back pain in a UK primary care population

Inflammatory back pain (IBP) is the earliest and most common symptom of axial SpA. However, there is very little information about the prevalence of IBP in the UK. In this cross-sectional cohort study we examined the prevalence of IBP in a UK primary care population using three published IBP criteria. Potential participants aged 18-80 years were identified from the records of a large general practice in Norfolk, UK, with 17 177 patients. Read codes were used to identify those who had consulted their general practitioner on at least one occasion with back pain. A self-completed screening questionnaire was sent to a sample of 978 patients, enquiring about symptoms of IBP and extra-spinal manifestations of SpA. Questionnaire responses were used to determine whether patients met the Assessment of SpondyloArthritis international Society (ASAS), Calin and Berlin IBP criteria. Five hundred and five completed questionnaires were returned (response rate 51.6%). The median age of respondents was 60 years [interquartile range (IQR) 48-67] and 44.8% were male. The minimum prevalence of IBP among patients with at least one previous consultation for back pain was 7.7% (95% CI 6.2, 9.5) using the ASAS criteria, 13.5% (11.5, 15.8) using the Calin criteria and 15.4% (13.3, 17.8) using the Berlin criteria. There was no significant difference in prevalence between men and women, and between different age groups. Extrapolated to the practice population as a whole, the minimum prevalence of IBP in a UK primary care population is 1.7-3.4%. The prevalence of IBP varies significantly depending on the criteria used for classification.

AB0670 Prevalence of chronic back pain and inflammatory back pain in cohort young lithuanian people

BackgroundInflammatory back pain (IBP) is one of the main presenting symptoms in spondyloarthropathies (SpA). The prevalence of inflammatory back pain in young people population is unknown. The identification of chronic...

OP0191-PC Prevalence of inflammatory back pain in a UK primary care population

BackgroundIt is accepted that seronegative spondyloarthritides such as Ankylosing Spondylitis (AS) are frequently misdiagnosed or diagnosed late in the disease course; early diagnosis and subsequent treatment improves patient symptoms and...

AB0536 Prevalence of inflammatory back pain among workers of a university health sciences campus

BackgroundThe early identification of IBP may provide early diagnosis of axial spondyloarthritis. However the exact prevalence of inflammatory back pain (IBP) in the general population is not well documented.ObjectivesThe aim...

AB0546 The prevalence of inflammatory back pain in a uk primary care population

BackgroundInflammatory back pain (IBP) is the earliest and commonest symptom of axial spondyloarthropathy (SpA). SpA can be difficult to diagnose in its early stages, but the identification of patients with...

A Community-Based Study on the Prevalence of Spondyloarthritis and Inflammatory Back Pain in Mexicans

The prevalence of spondyloarthritis (SpA) varies across populations. In Mexicans, the prevalence of SpA is still unknown. The objective of this study was to determine the prevalence of SpA in the community as well as that of inflammatory back pain (IBP) and ankylosing spondylitis (AS). We identified individuals older than 18 years with nontraumatic back pain (BP) in a door-to-door nurse survey using the Community Oriented Program for the Control of Rheumatic Diseases. Then, general physicians and rheumatology fellows selected those likely to have IBP (Berlin criteria). Finally, 2 expert rheumatologists assessed IBP individuals according to clinical data and classification criteria and requested HLA-B27 and radiographic studies to determine the clinical condition of the individual and SpA (European SpA Study Group) classification. The prevalence of BP among 4059 individuals was 14.6% (95% confidence interval [CI], 13.6-15.8). The prevalence of IBP and SpA was 1.3% (95% CI, 1.0-1.7) and 0.6% (95% CI, 0.4-0.9), respectively. Ankylosing spondylitis prevalence was 0.1% (95% CI, 0.02-0.2). Inflammatory back pain and SpA percentage of males and females was similar. The percentage of individuals with IBP according to the 2 experts was lower than that determined by general physicians and rheumatology fellows, but all cases with HLA-B27, radiographic sacroiliitis, SpA, and AS had previous IBP confirmation by the expert. The prevalence and sex distribution of patients classified with SpA in this community study--as well as that of patients diagnosed with AS--are consistent with those found in recent studies. Expert assessment of individuals with positive responses to questionnaires is relevant for the classification of IBP and SpA.