Baseline trabecular bone and its relation to incident radiographic knee osteoarthritis and increase in joint space narrowing score: directional fractal signature analysis in the MOST study

PURPOSE

To explore the association of baseline trabecular bone structure with incident tibiofemoral (TF) osteoarthritis (OA) and with increase in joint space narrowing (JSN) score.

METHODS

The Multicenter Osteoarthritis Study (MOST) includes subjects with or at risk for knee OA. Knee radiographs were scored for Kellgren-Lawrence (KL) grade and JSN at baseline, 30, 60 and 84 months. Knees (KL ≤ 1) at baseline were assessed for incident OA (KL ≥ 2) and increases in JSN score. For each knee image at baseline, a variance orientation transform method (VOT) was applied to subchondral tibial bone regions of medial and lateral compartments. Seventeen fractal parameters were calculated per region. Associations of each parameter with OA incidence and with medial and lateral JSN increases were explored using logistic regression. Analyses were stratified by digitized film (DF) vs computer radiography (CR) and adjusted for confounders.

RESULTS

Of 894 knees with CR and 1158 knees with DF, 195 (22%) and 303 (26%) developed incident OA. Higher medial bone roughness was associated with increased odds of OA incidence at 60 and 84 months and also, medial and lateral JSN increases (primarily vertical). Lower medial and lateral anisotropy was associated with increased odds of medial and lateral JSN increase. Compared to DF, CR had more associations and also, similar results at overlapping scales.

CONCLUSION

Baseline trabecular bone texture was associated with incident radiographic OA and increase of JSN scores independently of risk factors for knee OA. Higher roughness and lower anisotropy were associated with increased odds for radiographic OA change.

Mechanical symptoms as an indication for knee arthroscopy in patients with degenerative meniscus tear: a prospective cohort study

OBJECTIVE

According to prevailing consensus, patients with mechanical symptoms are those considered to most likely benefit from arthroscopic surgery. The aim of this study was to determine the value of using patients' pre-operative self-reports of mechanical symptoms as a justification surgery in patients with degenerative meniscus tear/knee disease.

DESIGN

Pragmatic prospective cohort of 900 consecutive patients with symptomatic degenerative knee disease and meniscus tear undergoing arthroscopic partial meniscectomy (APM) was collected from one public orthopedic referral center specialized in arthroscopic surgery during 2007-2011. The patients' subjective satisfaction, self-rated improvement, change in Western Ontario Meniscal Evaluation Tool (WOMET) score, and patients' ratings of the knee using a numerical rating scale (NRS) was assessed at 1 year postoperatively. Multivariable regression models, adjusted for possible confounders and intermediates, were used to compare the outcomes in those with and without preoperative mechanical symptoms.

RESULTS

The proportion of patients satisfied with their knee 12 months after arthroscopy was significantly lower among those with preoperative mechanical symptoms than among those without (61% vs 75%, multivariable adjusted risk ratio [RR] 0.84; 95% confidence interval [CI] 0.76, 0.92). Similarly, the proportion reporting improvement was lower (RR 0.91; 95% CI 0.85, 0.97). No statistically significant difference was found in change in WOMET or NRS between the two groups. Of those with preoperative mechanical symptoms, 47% reported persistent symptoms at 12 months postoperatively.

CONCLUSIONS

Our observational data contradicts the current tenet of using patients' self-report of mechanical symptoms as a justification for performing arthroscopic surgery on patients with degenerative meniscus tear.

Socioeconomic inequalities in knee pain, knee osteoarthritis, and health-related quality of life: a population-based cohort study in southern Sweden

OBJECTIVES

To determine socioeconomic inequalities in frequent knee pain (FKP), knee osteoarthritis (OA), and associated health-related quality of life (HRQoL) in Sweden.

METHOD

In 2007 a postal questionnaire about knee pain was sent to a random sample of 10 000 residents of Malmö, Sweden (7402 individuals responded). Subjects reporting pain with duration ≥ 4 weeks in one or both knees in the past 12 months were classified as having FKP. A random sample of 1527 subjects with and without FKP attended a clinical and radiographic knee examination and responded to generic and disease-specific HRQoL questionnaires. We used the individuals' level of education and occupation as socioeconomic status (SES) measures, and we calculated the relative index of inequality (RII) using Poisson regression with robust standard errors adjusted for age and gender. We applied weighting to account for a possible selection bias that might arise from non-responses in the study.

RESULTS

With education, the RIIs for FKP and knee OA were 0.71 [95% confidence interval (CI) 0.61-0.84] and 0.56 (95% CI 0.34-0.93), respectively. With occupation, the corresponding figures were 0.70 (95% CI 0.60-0.82) and 0.59 (95% CI 0.37-0.94), respectively. There were socioeconomic gradients in HRQoL in favour of people with better SES. RIIs for FKP and HRQoL but not knee OA were essentially similar after additional adjustment for mediators.

CONCLUSIONS

In Sweden there are socioeconomic gradients related to both FKP and knee OA as well as HRQoL in favour of people with better SES. SES should be taken into account in health resource allocation pertaining to knee-related disorders.

Changes in knee joint load indices from before to 12 months after arthroscopic partial meniscectomy: a prospective cohort study

OBJECTIVE

Patients undergoing arthroscopic partial meniscectomy (APM) are at increased risk of knee osteoarthritis (OA). Meniscal damage and/or surgery may alter knee joint loading to increase OA risk. We investigated changes in knee joint loading following medial APM surgery, compared with the contra-lateral leg.

METHODS

We estimated indices of knee joint loading (external peak knee adduction moment (KAM), KAM impulse and peak knee flexion moment (KFM)) normalized to body size (i.e., body mass (BM) and height (HT)) using 3D gait analysis in 23 patients (17 men, mean (SD) 46.2 (6.4) years, BMI 25.8 (3.4) kg/m(2)) without radiographic knee OA before and 12 months after medial APM. Static alignment was assessed by radiography and self-reported outcomes by Knee injury and Osteoarthritis Outcome Score (KOOS).

RESULTS

Peak KAM and KAM impulse increased in the APM leg compared to the contra-lateral leg from before to 12 months after surgery (change difference: 0.38 Nm/BM*HT% 95% CI 0.01 to 0.76 (P = 0.049) and 0.20 Nm*s/BM*HT% 95% CI 0.10 to 0.30 (P < 0.001)). Patients self-reported improvements on all KOOS subscales (KOOS pain improvement: 22.8 95% CI 14.5 to 31.0 (P < 0.01)).

CONCLUSIONS

A relative increase in indices of medial compartment loading was observed in the leg undergoing APM compared with the contra-lateral leg from before to 12 months after surgery. This increase may contribute to the elevated risk of knee OA in these patients. Randomized trials including a non-surgical control group are needed to determine if changes in joint loading following APM are caused by surgery or by changes in symptoms.

Influences on the decision to use an osteoarthritis diagnosis in primary care: a cohort study with linked survey and electronic health record data

OBJECTIVE

Clinicians may record patients presenting with osteoarthritis (OA) symptoms with joint pain rather than an OA diagnosis. This may have implications for OA research studies and patient care. The objective was to assess whether older adults recorded with joint pain are similar to those with a recorded OA diagnosis.

METHOD

A study of adults aged ≥50 years in eight United Kingdom general practices, with electronic health records linked to survey data. Patients with a recorded regional OA diagnosis were compared to those with a recorded joint pain symptom on socio-demographics, risk factors, body region, pain severity, prescribed analgesia, and potential differential diagnoses. A sub-group was compared on radiographic knee OA.

RESULTS

Thirteen thousand eight hundred and thirty-one survey responders consented to record review. One thousand four hundred and twenty-seven (10%) received an OA (n = 616) or joint pain (n = 811) code with wide practice variation. Receiving an OA diagnosis was associated with age (75+ compared to 50-64 OR 3.25; 95% Credible intervals (CrI) 2.36, 4.53), obesity (1.72; 1.22, 2.33), and pain interference (1.45; 1.09, 1.92). Analgesia management was similar. Radiographic OA was common in both groups. A quarter of those with a joint pain record received an OA diagnosis in the following 6 years.

CONCLUSION

Recording OA diagnoses are less common than recording a joint pain symptom and associated with risk factors and severity. OA studies in primary care need to consider joint pain symptoms to understand the burden and quality of care across the spectrum of OA. Patients recorded with joint pain may represent early cases of OA with need for early intervention.

Osteoarthritis of the knee after meniscal resection: long term radiographic evaluation of disease progression

OBJECTIVE

To determine prevalence, incidence and progression of radiographic knee osteoarthritis (OA) in a cohort of subjects with previous meniscectomy.

METHODS

We assessed 221 subjects (177 men and 44 women) with weight bearing knee radiography twice (assessment A and B) with a follow-up time ranging from 4 to 10 years. All subjects had undergone meniscectomy 15-22 years before assessment A. At assessment B the mean (SD) age was 60 (11) years. We assessed prevalence and incidence of OA, as well as progression of radiographic features over time. Radiographic OA was defined as approximating Kellgren and Lawrence grade 2 or worse.

RESULTS

At assessment A, we found tibiofemoral radiographic OA in 107 subjects' index knee (48%) of which 41 subjects (38%) had bilateral tibiofemoral OA. At assessment B, the corresponding figures were 151 (68%) and 71 (32%). At assessment A, we found patellofemoral OA in 32 subjects' index knee (14%) of which 11 (34%) had bilateral patellofemoral OA. At assessment B, the corresponding figures were 51 (23%) and 19 (37%). There was an increase of the sum of joint space narrowing (JSN) and osteophyte grades in the tibiofemoral joint of 144 subjects' index knee (64%) and in the contralateral tibiofemoral joints of 79 subjects (36%). The corresponding progression in the patellofemoral joint was observed in 66 index knees (30%) and in 41 (19%) contralateral knees.

CONCLUSIONS

Overall, some 20-30 years after meniscectomy nearly three out of four persons had developed radiographic tibiofemoral OA and one out of four had developed patellofemoral OA.

Interleukin-6 and tumor necrosis factor alpha in synovial fluid are associated with progression of radiographic knee osteoarthritis in subjects with previous meniscectomy

OBJECTIVE

To explore potential associations between proinflammatory cytokines in synovial fluid and progression of osteoarthritis (OA) in meniscectomized subjects.

DESIGN

We studied 132 subjects on average 18 years after meniscectomy, with a second examination 4-10 years later. We measured concentrations of interleukin (IL)-6, -8 and tumor necrosis factor (TNF)-α by multiplex immunoassay, graded radiographic features of tibiofemoral and patellofemoral OA according to the Osteoarthritis Research Society International (OARSI) atlas, scored patient-reported outcomes using the Knee Injury and Osteoarthritis Outcome Score (KOOS), and used logistic regression (adjusted for age, gender, body mass index, and time between examinations) for assessment of associations.

RESULTS

Higher first examination concentrations of IL-6 and TNF-α were associated with increased risk for subsequent osteophyte progression (odds ratios (OR); 95% confidence intervals 1.05; 1.00-1.09 and 1.35; 1.03-1.75). Higher second examination concentrations of TNF-α were associated with having progressed in loss of joint space (OR 1.70; 1.15-2.52) or having worsened in the activity of daily living subscale of KOOS (OR 1.50; 1.07-2.09) in the preceding years. Subjects with increasing concentrations of IL-6 or TNF-α between examinations were five times more likely to have progressed in joint space narrowing between the same examinations, as compared to those with stable or decreasing concentrations (OR 5.17; 1.54-17.32 and 5.01; 1.32-18.92).

CONCLUSIONS

In subjects with previous meniscectomy, higher or over time increasing synovial fluid levels of IL-6 and TNF-α seems to be associated with increased risk for progression of radiographic OA.

Call for standardized definitions of osteoarthritis and risk stratification for clinical trials and clinical use

Osteoarthritis (OA) is a heterogeneous disorder. The goals of this review are (1) To stimulate use of standardized nomenclature for OA that could serve as building blocks for describing OA and defining OA phenotypes, in short to provide unifying disease concepts for a heterogeneous disorder; and (2) To stimulate establishment of ROAD (Risk of OA Development) and ROAP (Risk of OA Progression) tools analogous to the FRAX™ instrument for predicting risk of fracture in osteoporosis; and (3) To stimulate formulation of tools for identifying disease in its early preradiographic and/or molecular stages - REDI (Reliable Early Disease Identification). Consensus around more sensitive and specific diagnostic criteria for OA could spur development of disease modifying therapies for this entity that has proved so recalcitrant to date. We fully acknowledge that as we move forward, we expect to develop more sophisticated definitions, terminology and tools.

Fracture predictive ability of physical performance tests and history of falls in elderly women: a 10-year prospective study

In a large cohort of elderly women followed for 10 years, we found that balance, gait speed, and self-reported history of fall independently predicted fracture. These clinical risk factors are easily evaluated and therefore advantageous in a clinical setting. They would improve fracture risk assessment and thereby also fracture prevention.

INTRODUCTION

The aim of this study was to identify additional risk factors for osteoporosis-related fracture by investigating the fracture predictive ability of physical performance tests and self-reported history of falls.

METHODS

In the population-based Osteoporosis Prospective Risk Assessment study (OPRA), 1044 women were recruited at the age of 75 and followed for 10 years. At inclusion, knee extension force, standing balance, gait speed, and bone mineral density (BMD) were examined. Falls the year before investigation was assessed by questionnaire. Cox proportional hazards regression analysis was used to determine fracture hazard ratios (HR) with BMD, history of fracture, BMI, smoking habits, bisphosphonate, vitamin D, glucocorticoid, and alcohol use as covariates. Continuous variables were standardized and HR shown for each standard deviation change.

RESULTS

Of all women, 427 (41%) sustained at least one fracture during the 10-year follow-up. Failing the balance test had an HR of 1.98 (1.18-3.32) for hip fracture. Each standard deviation decrease in gait speed was associated with an HR of 1.37 (1.14-1.64) for hip fracture. Previous fall had an HR of 1.30 (1.03-1.65) for any fracture; 1.39 (1.08-1.79) for any osteoporosis-related fracture; and 1.60 (1.03-2.48) for distal forearm fracture. Knee extension force did not show fracture predictability.

CONCLUSION

The balance test, gait speed test, and self-reported history of fall all hold independent fracture predictability. Consideration of these clinical risk factors for fracture would improve the fracture risk assessment and subsequently also fracture prevention.

The risk of pneumococcal infections after immunization with pneumococcal conjugate vaccine compared to non-vaccinated inflammatory arthritis patients

OBJECTIVES

To examine the risk of putative pneumococcal infections in adult arthritis patients on different anti-rheumatic drugs immunized with heptavalent pneumococcal conjugate vaccine (Prevenar 7; PCV7) and non-vaccinated individually matched arthritis patients.

METHOD

All individuals in a cohort of 505 patients with rheumatoid arthritis (RA) or spondylarthropathy (SpA) receiving different anti-rheumatic treatments were immunized with a single dose of PCV7 (exposed group). Of these, 497 patients (RA = 248; SpA = 249) were included. For each vaccinated patient, we identified four reference subjects (n = 1988) from the same geographic area, individually matched for age, gender, and diagnosis. These were considered unexposed to conjugated pneumococcal vaccination. The Skåne Healthcare Register (SHR) was searched for all individuals seeking health care for putative pneumococcal infections occurring 4 years before vaccination and up to 4.5 years after vaccination using ICD-10 diagnostic codes. The following infections were considered as serious cases: pneumonia, other lower respiratory infections, meningitis, sepsis, and septic arthritis. The relative risk (RR) of infection was calculated as the number of events after/number of events before vaccination. Ratios of relative risk (RRRs) were calculated between vaccinated and non-vaccinated groups of patients. A generalized estimating equation (GEE) was used to handle correlated data for several events in the same individual.

RESULTS

Although statistically non-significant, the point estimate of the RRR [0.55, 95% confidence interval (CI) 0.25-1.22] suggested a reduced risk of serious pneumococcal infections in vaccinated patients compared to the unexposed group.

CONCLUSIONS

Vaccination with PCV7 tended to reduce the risk of putative serious pneumococcal infections by about 45% compared to non-vaccinated patients in this observational cohort study.

Current and future impact of osteoarthritis on health care: a population-based study with projections to year 2032

OBJECTIVE

To estimate the current and future (to year 2032) impact of osteoarthritis (OA) health care seeking.

METHOD

Population-based study with prospectively ascertained data from the Skåne Healthcare Register (SHR), Sweden, encompassing more than 15 million person-years of primary and specialist outpatient care and hospitalizations. We studied all Skåne region residents aged ≥45 by the end of 2012 (n = 531, 254) and determined the prevalence of doctor-diagnosed OA defined as the proportion of the prevalent population that had received a diagnosis of OA of the knee, hip, hand, or other locations except the spine between 1999 and 2012. We projected consultation prevalence of OA until year 2032 using Statistics Sweden's (SCB) projected age and sex structure and prevalence of overweight and obesity.

RESULTS

In 2012 the proportion of population aged ≥45 with any doctor-diagnosed OA was 26.6% (95% confidence interval (CI): 26.5-26.8) (men 22.4%, women 30.5%). The most common locations were knee (13.8%), hip (5.8%) and hand (3.1%). Of the prevalent cases 26.8% had OA in multiple joints. By the year 2032, the proportion of the population aged ≥45 with doctor-diagnosed OA is estimated to increase from 26.6% to 29.5% (any location), from 13.8% to 15.7% for the knee and 5.8-6.9% for the hip.

CONCLUSION

In 2032, at least an additional 26,000 individuals per 1 million population aged ≥45 years are estimated to have consulted a physician for OA in a peripheral joint compared to 2012. These findings underscore the need to address modifiable risk factors and develop new effective OA treatments.

Imaging of non-osteochondral tissues in osteoarthritis

OBJECTIVE

The aim of this review is to describe imaging techniques for evaluation of non-osteochondral structures such as the synovium, menisci in the knee, labrum in the hip, ligaments and muscles and to review the literature from recent clinical and epidemiological studies of OA.

METHODS

This is a non-systematic narrative review of published literature on imaging of non-osteochondral tissues in OA. PubMed and MEDLINE search for articles published up to 2014, using the keywords osteoarthritis, synovitis, meniscus, labrum, ligaments, plica, muscles, magnetic resonance imaging (MRI), ultrasound, computed tomography (CT), scintigraphy, and positron emission tomography (PET).

RESULTS

Published literature showed imaging of non-osteochondral tissues in OA relies primarily on MRI and ultrasound. The use of semiquantitative and quantitative imaging biomarkers of non-osteochondral tissues in clinical and epidemiological OA studies is reported. We highlight studies that have compared both imaging methodologies directly, and those that have established a relationship between imaging biomarkers and clinical outcomes. We provide recommendations as to which imaging protocols should be used to assess disease-specific changes regarding synovium, meniscus in the knee, labrum in the hip, and ligaments, and highlight potential pitfalls in their usage.

CONCLUSION

MRI and ultrasound are currently the most useful imaging modalities for evaluation of non-osteochondral tissues in OA. MRI evaluation of any tissue needs to be performed using appropriate MR pulse sequences. Ultrasound may be particularly useful for evaluation of small joints of the hand. Nuclear medicine and CT play a limited role in imaging of non-osteochondral tissues in OA.

Association between delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) and joint space narrowing and osteophytes: a cohort study in patients with partial meniscectomy with 11 years of follow-up

OBJECTIVE

To examine the association between the relaxation time (T1Gd) of delayed gadolinium-enhanced magnetic resonance imaging of cartilage (dGEMRIC) and grade of tibiofemoral joint space narrowing (JSN) and osteophytosis 11 years later, in a cohort of meniscectomized patients.

DESIGN

Patients (n = 45) aged 35-50 who had undergone an arthroscopic partial medial meniscectomy 1-6 years earlier, due to degenerative meniscal tear, were examined using dGEMRIC. These patients had no cartilage changes defined as deep clefts or visible bone at the time of arthroscopy. Eleven years later (12-16 years after surgery) 34 of these subjects (76%) were evaluated by weight-bearing knee radiography, and tibiofemoral joint changes were graded according to the Osteoarthritis Research Society International Atlas.

RESULTS

Lower T1Gd in the medial compartment was associated with higher grade of medial JSN (grade 0, 351 ms; grade 1, 386 ms; grade 2, 342 ms; grade 3, 259 ms [P for trend < 0.001]) and more osteophytosis (score 0, 371 ms; score 1, 389 ms; score 2, 354 ms; score 3, 289 ms; score 4, 265 ms; score 5, 275 ms [P for trend = 0.001]). Lower T1Gd in the lateral compartment was associated with higher grade of lateral JSN (grade 0, 436 ms; grade 1, 346 ms [P for trend = 0.026]).

CONCLUSION

The current study suggests that lower T1Gd measured with dGEMRIC of medial and lateral femoral cartilage is associated with higher grade of JSN 11 years later, and medially, also with more osteophytosis.

Imaging following acute knee trauma

Joint injury has been recognized as a potent risk factor for the onset of osteoarthritis. The vast majority of studies using imaging technology for longitudinal assessment of patients following joint injury have focused on the injured knee joint, specifically in patients with anterior cruciate ligament injury and meniscus tears where a high risk for rapid onset of post-traumatic osteoarthritis is well known. Although there are many imaging modalities under constant development, magnetic resonance (MR) imaging is the most important instrument for longitudinal monitoring after joint injury. MR imaging is sensitive for detecting early cartilage degeneration and can evaluate other joint structures including the menisci, bone marrow, tendons, and ligaments which can be sources of pain following acute injury. In this review, focusing on imaging following acute knee trauma, several studies were identified with promising short-term results of osseous and soft tissue changes after joint injury. However, studies connecting these promising short-term results to the development of osteoarthritis were limited which is likely due to the long follow-up periods needed to document the radiographic and clinical onset of the disease. Thus, it is recommended that additional high quality longitudinal studies with extended follow-up periods be performed to further investigate the long-term consequences of the early osseous and soft tissue changes identified on MR imaging after acute knee trauma.

Knee cartilage assessment with MRI (dGEMRIC) and subjective knee function in ACL injured copers: a cohort study with a 20 year follow-up

OBJECTIVE

To assess knee cartilage quality and subjective knee function, 20 years after injury in anterior cruciate ligament (ACL) injured copers.

METHOD

We examined 32 knees using delayed gadolinium-enhanced magnetic resonance imaging (MRI) of cartilage (dGEMRIC), 20 years after a complete ACL tear. Only subjects who had coped with the ACL injury without ACL reconstruction (ACLR), and who presented without radiographic signs of osteoarthritis (OA) at an earlier 16-year follow-up, were included in this study. The quality of the central weight-bearing parts of the medial and lateral femoral cartilage was estimated with dGEMRIC (T1Gd). These results were compared with corresponding results in 24 healthy individuals, and with the subjects' self-reported subjective knee function using the Knee Injury and Osteoarthritis Outcome Score (KOOS) questionnaire.

RESULTS

The values of T1Gd in the medial and lateral femoral cartilage of the study group (mean (95% CI)), were 404 (385-423) and 427 (399-455) ms, not statistically different from those of the healthy reference group (P = 0.065 and 0.31). The subjective knee function 20 years after the injury, according to the five domains of the KOOS score, was good, with a mean score of 90 ± 11. Values of T1Gd for the medial femoral cartilage were correlated with the KOOS subgroup QOL (P = 0.021, Pearson correlation).

CONCLUSIONS

Subjects who have managed to cope with their ACL injury for 20 years with sustained good subjective knee function also seem to have knee cartilage of good quality, with T1Gd values not very different from a healthy reference group.

The association between metacarpal ratio, radiographic hand and knee osteoarthritis and its progression after meniscectomy

OBJECTIVE

To examine whether the ratio of the second and fourth metacarpal bone length (MC2:MC4) in subjects with prior meniscectomy of the knee is associated with radiographic hand and knee osteoarthritis (OA) and its progression.

DESIGN

We assessed 219 subjects (175 men and 44 women) twice with a follow-up time ranging from 4 to 10 years. Participants had all undergone prior meniscectomy. The subjects were of mean (SD) 53 (11) years of age at the first radiographic examination. One observer measured the metacarpal lengths of both hands. We used the average MC2:MC4 from left and right hand divided into tertiles as the exposure variable, using the highest tertile, i.e., "female" pattern as reference category. Radiographic OA of both hands and knees and its progression were evaluated on subject level as our outcomes. We used logistic regression to evaluate the possible association of MC2:MC4 with hand and knee OA and its progression with adjustment for age, sex, body mass index, and follow-up time.

RESULTS

We found no statistically significant association between the lower MC2:MC4 tertile "male" pattern and prevalent hand OA (odds ratio [OR] 0.70; 95% confidence interval [CI] 0.24-1.99) and prevalent knee OA (OR 1.08; 95% CI 0.56-2.07). Neither did we find any corresponding significant association for the progression of hand OA (OR 0.89; 95% CI 0.34-2.32), nor knee OA (OR 0.69; 95% CI 0.33-1.46).

CONCLUSIONS

We did not detect any association between MC2:MC4 and radiographic hand and knee OA and its progression in subjects with prior meniscectomy.

Prevalence and incidence of systemic sclerosis in southern Sweden: population-based data with case ascertainment using the 1980 ARA criteria and the proposed ACR-EULAR classification criteria

OBJECTIVES

To estimate the prevalence and incidence of systemic sclerosis (SSc) in southern Sweden.

METHODS

In Skåne, the southernmost region of Sweden (total population 1.2 million), healthcare provided is registered in the Skåne Healthcare Register. We identified all Skåne residents who had received an International Classification of Diseases 10 diagnosis of SSc (M34) or Raynaud's phenomenon (I73.0) between 1998 and 2010. Every single case was ascertained by review of medical records in reference to the 1980 American Rheumatism Association preliminary classification criteria for SSc and the proposed American College of Rheumatology (ACR)-European League Against Rheumatism (EULAR) classification criteria presented at the ACR/Association of Rheumatology Health Professionals Annual Meeting 2012. We calculated the point prevalence by the end of 2010 by linkage with the population register to exclude deceased persons and we also estimated the mean annual cumulative incidence for 2006-2010.

RESULTS

Using the 1980 ARA criteria, the adult prevalence and annual incidence of SSc in the Skåne region were 235 and 14 per 1 million inhabitants respectively. Applying the proposed ACR-EULAR criteria, the corresponding figures were 305 and 19 per 1 million inhabitants. A majority (82%) of the prevalent cases had the limited cutaneous SSc subtype.

CONCLUSIONS

The prevalence and incidence of SSc in southern Sweden, based on the 1980 ARA criteria, are higher than previously reported in northern Europe and do not support the concept of a north-south gradient of SSc occurrence in Europe. Application of the proposed ACR-EULAR classification criteria in this population results in about 30-40% higher estimates of SSc prevalence and incidence compared to the 1980 ARA criteria.