Clinical validation of an Internet-based questionnaire for ascertaining hip and knee osteoarthritis

OBJECTIVE

To evaluate the measurement properties of an Internet-based self-administered questionnaire in ascertaining cases of hip and knee osteoarthritis (OA).

METHODS

Questionnaire data from 4269 Canadian subjects aged 45-85 were collected on hip and knee joint health including self-reported items on medically-diagnosed hip and knee OA and joint replacement. A sub-cohort of 100 subjects was recruited for clinical examination. The self-reported outcomes were evaluated using the American College of Rheumatology clinical classification criteria for hip and knee OA as the gold standard for clinical verification. Analysis was at the joint level (200 knees, 200 hips). Validity was examined using sensitivity, specificity, and predictive values; to account for correlated joints of the same subject, bootstrapping was performed to yield valid 95% confidence interval (CI's).

RESULTS

Self-reported measures for a medical diagnosis of knee OA had a positive predictive value of 86%, negative predictive value 91%, sensitivity 73% and specificity 96% for correctly identifying clinical knee OA. For hip OA, the values were 61%, 98%, 81% and 94% respectively.

CONCLUSION

Internet self-report of medically-diagnosed hip and knee OA in metro Vancouver residents correctly identified most cases and non-cases of clinical OA when compared with the ACR clinical classification criteria gold standard. In particular, specificity was very high, important in risk factor studies due to the profound effect of even small losses in specificity on the measure of association. The findings provide evidence that these questionnaire case definitions have utility for identifying hip and knee OA in community and population-based studies when the purpose is to link potential risk factors with knee and hip health.

Is lifelong knee joint force from work, home, and sport related to knee osteoarthritis?

Purpose. To investigate the association of cumulative lifetime knee joint force on the risk of self-reported medically-diagnosed knee osteoarthritis (OA). Methods. Exposure data on lifetime physical activity type (occupational, household, sport/recreation) and dose (frequency, intensity, duration) were collected from 4,269 Canadian men and women as part of the Physical Activity and Joint Heath cohort study. Subjects were ranked in terms of the "cumulative peak force index", a measure of lifetime mechanical knee force. Multivariable logistic regression was conducted to obtain adjusted effects for mean lifetime knee force on the risk of knee OA. Results. High levels of total lifetime, occupational and household-related force were associated with an increased in risk of OA, with odds ratio's ranging from approximately 1.3 to 2. Joint injury, high BMI and older age were related to risk of knee OA, consistent with previous studies. Conclusions. A newly developed measure of lifetime mechanical knee force from physical activity was employed to estimate the risk of self-reported, medically-diagnosed knee OA. While there are limitations, this paper suggests that high levels of total lifetime force (all domains combined), and occupational force in men and household force in women were risk factors for knee OA.

The association of magnetic resonance imaging (MRI)-detected structural pathology of the knee with crepitus in a population-based cohort with knee pain: the MoDEKO study

Osteoarthritis (OA) is the most common arthropathy of the knee joint(1). Symptoms reported by patients and signs noted during physical examination guide clinicians in identifying subjects with knee OA(2-4). Pain is one of the most important symptoms reported by subjects with knee OA(2,3). Although very common, pain is a non-specific symptom, related to pathology in several structures within the knee joint, and includes synovitis(5), subchondral bone marrow lesions(6), and joint effusion(7). Further, pain is a subjective symptom that cannot be directly measured or assessed during physical examination. Crepitus or crepitation in association with arthritis is defined as a crackling or grinding sound on joint movement with a sensation in the joint. Crepitus may occur with or without pain and is a common finding during physical examination in subjects with knee OA(2-4,8,9). It is not known whether crepitus is related to pathology in various structures within the knee. The aim of our study was to determine the cross-sectional associations of structural pathologies within the knee with crepitus in a population-based cohort with knee pain, using magnetic resonance imaging (MRI). Subjects with knee pain were recruited as a random population sample, with crepitus assessed in each compartment of the knee using a validated and standardized approach during physical examination(10). MRI of the knee was performed to assess cartilage morphology, meniscal morphology, osteophytes, cruciate ligaments, and collateral ligaments. For both compartment-specific and whole-knee analyses, a multiple logistic regression analysis was performed to assess the associations of MRI-detected structural pathology with crepitus, adjusting for potential confounders. Variables were selected by backwards elimination within each compartment and in the overall knee models, and only statistically significant variables remained in the "selected" models; remaining variables in these models are adjusted for each other. An increased risk for compartment-specific crepitus was associated with osteophytes at the patellofemoral (PF) and lateral tibiofemoral (LTF) joints. Crepitus was associated with osteophytes and medial collateral ligament (MCL) pathology at the medial tibiofemoral (MTF) compartment, but cartilage damage was negatively associated with crepitus at this compartment. In the selected whole-knee model, only meniscal tears were associated with an increased risk for general crepitus. Thus, it seems that crepitus may be associated with pathology in several internal structures.

Hip Osteoarthritis MRI Scoring System (HOAMS): reliability and associations with radiographic and clinical findings

OBJECTIVE

To develop a semiquantitative MRI-based scoring system (HOAMS) of hip osteoarthritis (OA) and test its reliability and validity.

DESIGN

Fifty-two patients with chronic hip pain were included. 1.5T magnetic resonance imaging (MRI) was performed on all patients. Pelvic radiographs were scored according to the Kellgren-Lawrence (KL) system. Clinical outcomes were assessed by the hip osteoarthritis outcome score (HOOS). MRIs were analyzed using a novel whole-joint MRI score that incorporated 13 articular features. Reliability was determined on a random subset of 15 cases. Weighted-kappa statistics and overall agreement were used as a measure of intra- and inter-observer reliability. Associations between MRI features and radiographic OA severity were calculated using Cochran-Armitage test for trend. Ordinal logistic regression was used to assess associations between MRI features and severity of pain and functional limitation.

RESULTS

Distribution of radiographic grading was: KL 0=12 (27%), KL 1=11 (25%), KL 2=14 (32%), KL 3=5 (11%) and KL 4=2 (5%). Intra-reader reliability for the different features ranged from 0.18 (cysts) to 0.85 (cartilage). Inter-reader reliability ranged between 0.15 (cysts) and 0.85 (BMLs). Low kappas were due to low frequencies of some features as overall percent agreement was good to excellent (83.8% and 83.1%). There was a strong association between MRI-detected lesions and radiographic severity (P=0.002). Non-significant trends were observed between MRI features and clinical outcomes.

CONCLUSION

MRI-based semiquantitative assessment of the hip shows adequate reliability. Presence of more severe MRI-detected intraarticular pathology shows a strong association with radiographic OA. The results suggest possible associations between MRI-detected pathology and clinical symptoms.

Natural history of cartilage damage and osteoarthritis progression on magnetic resonance imaging in a population-based cohort with knee pain

OBJECTIVES

To determine the natural history of cartilage damage and of osteoarthritis (OA) progression using magnetic resonance imaging (MRI); to evaluate whether OA progression varies by stage of disease.

METHODS

A population-based cohort with knee pain was assessed clinically, with X-ray (Kellgren-Lawrence [KL] grading) and MRI. Cartilage was graded 0-3 on six joint surfaces. Frequency of cartilage damage change was determined for each joint site. Progression of OA was defined as a worsening of MRI cartilage damage by ≥1 grade in at least two joint sites or ≥2 grades in at least one joint site. The association of KL grade with OA progression was evaluated using parametric lifetime regression analysis.

RESULTS

163 subjects were assessed at baseline and follow-up (mean 3.2 years). KL grade ≥2 was present in 39.4% at baseline. An increase in cartilage damage by ≥1 grade was seen in 8.0-14.1% of subjects at different joint sites. OA progression on MRI was present in 15.5%. Baseline KL grade was a significant predictor of OA progression with hazard ratio (HR) of 6.5 (95% confidence interval [CI] 1.4-30.7), 6.1 (95% CI 1.3-28.9), and 9.2 (95% CI 1.9-44.9) for KL grades 1, 2 and ≥3, respectively.

CONCLUSION

A low OA progression rate was seen over 3 years in this population-based symptomatic cohort. Radiographic severity, including KL grade 1, was a significant predictor of OA progression. Future interventions aimed at reducing progression will need to target not only radiographic OA, but also those with early abnormalities suggestive of pre-radiographic OA.

Influence of lifetime hip joint force on the risk of self-reported hip osteoarthritis: a community-based cohort study

OBJECTIVE

To investigate the influence of cumulative lifetime hip joint force on the risk of self-reported medically-diagnosed hip osteoarthritis (OA).

DESIGN

Prospective cohort.

SETTING

General population.

PARTICIPANTS

Members of Canadian Association of Retired Persons, community-dwelling.

MAIN OUTCOME

Health-professional diagnosed hip OA, self-reported.

METHODS

Exposure data on lifetime physical activity type (occupational, household, sport) and dose (frequency, intensity, duration) was collected in 2005. Subjects were ranked in terms of a 'cumulative peak force index' (CFPI), a measure of lifetime mechanical hip joint force. Multivariable survival analyses were performed to obtain adjusted effects for mean lifetime exposure and during 5-year age periods.

RESULTS

Of 2918 subjects aged 45-85, 176 (6.03%) developed hip OA during the 2-year follow up (43 men, 133 women). The highest quintile of mean lifetime hip CPFI (HR 2.32; 95% CI 1.31-4.12), and high hip force in three age periods (35-39, 40-44, 45-49) were independently associated with hip OA. Previous hip injury was an approximate five-fold risk for development of hip OA across all models. In analysis by activity domain (occupation, sport, household), there was a trend (non-significant) for the highest quintile of occupational force, but not sport or household, to be associated with hip OA.

CONCLUSIONS

A newly proposed measure of lifetime mechanical hip force was used to estimate the risk of self-reported, medically-diagnosed hip OA. While there are important limitations, this prospective study suggests that lifelong physical activity is generally safe. Very high levels of lifetime force from all domains combined, and in particular from occupational forces, may be important in the etiology of hip OA.

Lifetime trajectory of physical activity according to energy expenditure and joint force

OBJECTIVE

To develop and demonstrate the feasibility of a method for estimating lifetime hip and knee cumulative joint force using survey data on physical activity, and to construct and describe lifetime trajectories of energy expenditure and hip and knee joint force.

METHODS

Exposure data on lifetime physical activity, including type (occupational, household, and recreation) and dose (frequency, intensity, and duration), were collected from a Canada-wide population study of adults ages ≥45 years. Subjects were ranked in 2 ways: in terms of physical activity-related energy expenditure and in terms of a cumulative peak force index (CPFI) for the hip and knee, which is a measure of lifetime exposure and is a time/joint force product involving years of force and subject bodyweight. A relative joint loading index was calculated as the ratio of joint force (CPFI score) to energy expenditure.

RESULTS

A total of 4,269 subjects completed the baseline measurements. Lifetime energy expenditure and hip and knee CPFI scores were higher for occupational and household activity than sport. The mean lifetime energy expenditure from total physical activity in the study sample was 119.1 metabolic equivalent-hours/week. Women had slightly higher total lifetime energy expenditure and CPFI scores than men. The relative joint loading index was highest for male household and sport activity and lowest for female occupational activity.

CONCLUSION

Lifetime cumulative hip/knee joint force trajectories were successfully constructed from survey data and followed expected trends. Comparing energy expenditure with joint force revealed variation by age, sex, and activity type, indicating these measures may help distinguish the numerous benefits of physical activity from possible risks.

After patients are diagnosed with knee osteoarthritis, what do they do?

OBJECTIVE

To learn more about the health services and products that patients use after receiving a diagnosis of knee osteoarthritis (OA), as well as the trajectory of their health-related quality of life (HRQOL).

METHODS

Using a simple screening survey, community pharmacists identified 194 participants with previously undiagnosed knee OA. Of these participants, 190 were confirmed to have OA on further investigation. At baseline and 1, 3, and 6 months after diagnosis, a survey was administered to assess health services, product use, and HRQOL, including the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), the Medical Outcomes Study Short Form 36 (SF-36) health survey, the Paper Adaptive Test (PAT-5D-QOL), and the Health Utilities Index Mark 3.

RESULTS

With a mean age of 63 years, participants were mostly women, white, and overweight. By 6 months, more than 90% of the participants had visited their family physician to discuss their OA, and more than 50% of participants took either prescription or nonprescription analgesics. In addition, three-quarters of the participants started exercising, one-third initiated activity aids, and one-third had started natural medicine products. At 6 months compared with baseline, significant improvements were seen in the SF-36 physical component summary (P = 0.001) and bodily pain domain scores (P = 0.02), the PAT-5D-QOL overall, pain, and usual daily activities scores (P < 0.001 for all), and the WOMAC total, pain, and function scores (P < 0.001 for all).

CONCLUSION

Within 6 months of receiving a diagnosis of knee OA, participants made several lifestyle interventions, often without the advice of a health professional, and saw improvements in their pain and function.

The effect of disease site (knee, hip, hand, foot, lower back or neck) on employment reduction due to osteoarthritis

BACKGROUND

Osteoarthritis (OA) has a significant impact on individuals' ability to work. Our goal was to investigate the effects of the site of OA (knee, hip, hand, foot, lower back or neck) on employment reduction due to OA (EROA).

METHODS AND FINDINGS

This study involved a random sample of 6,000 patients with OA selected from the Medical Service Plan database in British Columbia, Canada. A total of 5,491 were alive and had valid addresses, and of these, 2,259 responded (response rate = 41%), from which 2,134 provided usable data. Eligible participants were 19 or older with physician diagnosed OA based on administrative data between 1992 and 2006. Data of 688 residents were used (mean age 62.1 years (27 to 86); 60% women). EROA had three levels: no reduction; reduced hours; and total cessation due to OA. The (log) odds of EROA was regressed on OA sites, adjusting for age, sex, education and comorbidity. Odds ratios (ORs) represented the effect predicting total cessation and reduced hours/total cessation. The strongest effect was found in lower back OA, with OR = 2.08 (95% CI: 1.47, 2.94), followed by neck (OR = 1.59; 95% CI: 1.11, 2.27) and knee (OR = 1.43; 95% CI: 1.02, 2.01). We found an interaction between sex and foot OA (men: OR = 1.94; 95% CI: 1.05, 3.59; women: OR = 0.89; 95% CI = 0.57, 1.39). No significant effect was found for hip OA (OR = 1.33) or hand OA (OR = 1.11). Limitations of this study included a modest response rate, the lack of an OA negative group, the use of administrative databases to identify eligible participants, and the use of patient self-reported data.

CONCLUSIONS

After adjusting for socio-demographic variables, comorbidity, and other OA disease sites, we find that OA of the lower back, neck and knee are significant predictors for EROA. Foot OA is only significantly associated with EROA in males. For multi-site combinations, ORs are multiplicative. These findings may be used to guide resource allocation for future development/improvement of vocational rehabilitation programs for site-specific OA.

Quantifying the association of radiographic osteoarthritis in knee or hip joints with other knees or hips: the Johnston County Osteoarthritis Project

OBJECTIVE

To quantify the association of radiographic osteoarthritis (ROA) in one knee or hip joint with other knee or hip joints.

METHODS

We analyzed baseline data from the Johnston County Osteoarthritis Project (n = 3068). We fit 4 models for left/right knee/hip. The Kellgren-Lawrence (KL) radiographic grade severity scale was KL 0/1 (no/questionable ROA), 2 (mild ROA), or 3/4 (moderate/severe ROA). We estimated associations between KL grade in contralateral joints and other joint sites (e.g., worst hip in knee models), adjusting for sex, race/ethnicity (African American/white), age, and measured body mass index, using cumulative odds logistic regression models. Interactions were investigated: race/ethnicity by sex; race/ethnicity and sex by the 2 explanatory variables.

RESULTS

Contralateral joint KL grade was strongly associated with KL grade, with OR ranging from 9.2 (95% CI 7.1, 11.9) to 225.0 (95% CI 83.6, 605.7). In the left knee model, the contralateral joint association was stronger among African Americans than whites, but for the other models the associations by race/ethnicity were identical. Models examining other joint sites showed weaker but mostly statistically significant associations (OR 1.4 to 1.8).

CONCLUSION

We found a strong multivariable-adjusted association between KL grades in contralateral knees and hips, and a modest association with the other joint site (e.g., knees vs hips). These results suggest that diagnosis of ROA in 1 large joint may be a marker for risk of multijoint ROA, and warrant interventions to reduce the incidence or severity of ROA at these other joints.

Development of a population-based microsimulation model of osteoarthritis in Canada

OBJECTIVES

The purpose of the study was to develop a population-based simulation model of osteoarthritis (OA) in Canada that can be used to quantify the future health and economic burden of OA under a range of scenarios for changes in the OA risk factors and treatments. In this article we describe the overall structure of the model, sources of data, derivation of key input parameters for the epidemiological component of the model, and preliminary validation studies.

DESIGN

We used the Population Health Model (POHEM) platform to develop a stochastic continuous-time microsimulation model of physician-diagnosed OA. Incidence rates were calibrated to agree with administrative data for the province of British Columbia, Canada. The effect of obesity on OA incidence and the impact of OA on health-related quality of life (HRQL) were modeled using Canadian national surveys.

RESULTS

Incidence rates of OA in the model increase approximately linearly with age in both sexes between the ages of 50 and 80 and plateau in the very old. In those aged 50+, the rates are substantially higher in women. At baseline, the prevalence of OA is 11.5%, 13.6% in women and 9.3% in men. The OA hazard ratios for obesity are 2.0 in women and 1.7 in men. The effect of OA diagnosis on HRQL, as measured by the Health Utilities Index Mark 3 (HUI3), is to reduce it by 0.10 in women and 0.14 in men.

CONCLUSIONS

We describe the development of the first population-based microsimulation model of OA. Strengths of this model include the use of large population databases to derive the key parameters and the application of modern microsimulation technology. Limitations of the model reflect the limitations of administrative and survey data and gaps in the epidemiological and HRQL literature.

A single measure of patellar kinematics is an inadequate surrogate marker for patterns of three-dimensional kinematics in healthy knees

Patellofemoral disorders, such as osteoarthritis and patellofemoral pain, are thought to be associated with abnormal patellar kinematics. However, assessments of three-dimensional patellar kinematics are time consuming and expensive. The aim of this study was to determine whether a single static measure of three-dimensional patellar kinematics provides a surrogate marker for three-dimensional patellar kinematics over a range of flexion angles. We assessed three-dimensional patellar kinematics (flexion, tilt and spin; lateral, anterior and proximal translation) at sequential static angles through approximately 45 degrees of loaded knee flexion in 40 normal subjects using a validated, MRI-based method. The surrogate marker was defined as the static measure at 30 degrees of knee flexion and the pattern of kinematics was defined as the slope of the linear best fit line of each subject's kinematic data. A regression model was used to examine the relationship between the surrogate marker and pattern of kinematics. The surrogate marker predicted 26% of the variance in pattern of patellar flexion (p<0.001), 27% of the variance in pattern of patellar spin (p=0.003), 11% of the variance in pattern of proximal translation (p=0.037) and 39% of the variance in pattern of anterior translation (p<0.001). No relationships were seen between the surrogate marker and tilt or lateral translation. The results suggest that a single measure of patellar parameters at 30 degrees knee flexion is an inadequate surrogate marker of three-dimensional patellar kinematics; therefore, a complete assessment of patellar kinematics, over a range of knee flexion angles, is preferable to adequately assess patterns of patellar kinematics.

Association of biomarkers with pre-radiographically defined and radiographically defined knee osteoarthritis in a population-based study

OBJECTIVE

To evaluate 10 biomarkers in magnetic resonance imaging (MRI)-determined, pre-radiographically defined osteoarthritis (pre-ROA) and radiographically defined OA (ROA) in a population-based cohort of subjects with symptomatic knee pain.

METHODS

Two hundred one white subjects with knee pain, ages 40-79 years, were classified into OA subgroups according to MRI-based cartilage (MRC) scores (range 0-4) and Kellgren/Lawrence (K/L) grades of radiographic severity (range 0-4): no OA (MRC score 0, K/L grade<2), pre-ROA (MRC score>or=1, K/L grade<2), or ROA (MRC score>or=1, K/L grade>or=2). Urine and serum samples were assessed for levels of the following biomarkers: urinary biomarkers C-telopeptide of type II collagen (uCTX-II), type II and types I and II collagen cleavage neoepitopes (uC2C and uC1,2C, respectively), and N-telopeptide of type I collagen, and serum biomarkers sC1,2C, sC2C, C-propeptide of type II procollagen (sCPII), chondroitin sulfate 846 epitope, cartilage oligomeric matrix protein, and hyaluronic acid. Multicategory logistic regression was performed to evaluate the association of OA subgroup with individual biomarker levels and biomarker ratios, adjusted for age, sex, and body mass index.

RESULTS

The risk of ROA versus no OA increased with increasing levels of uCTX-II (odds ratio [OR] 3.12, 95% confidence interval [95% CI] 1.35-7.21), uC2C (OR 2.13, 95% CI 1.04-4.37), and uC1,2C (OR 2.07, 95% CI 1.06-4.04), and was reduced in association with high levels of sCPII (OR 0.53, 95% CI 0.30-0.94). The risk of pre-ROA versus no OA increased with increasing levels of uC2C (OR 2.06, 95% CI 1.05-4.01) and uC1,2C (OR 2.06, 95% CI 1.12-3.77). The ratios of type II collagen degradation markers to collagen synthesis markers were better than individual biomarkers at differentiating the OA subgroups, e.g., the ratio of [uCTX-II][uC1,2C] to sCPII was associated with a risk of ROA versus no OA of 3.47 (95% CI 1.34-9.03) and a risk of pre-ROA versus no OA of 2.56 (95% CI 1.03-6.40).

CONCLUSION

Different cartilage degradation markers are associated with pre-ROA than are associated with ROA, indicating that their use as diagnostic markers depends on the stage of OA. Biomarker ratios contrasting cartilage degradation with cartilage synthesis are better able to differentiate OA stages compared with levels of the individual markers.

Trends in physician-diagnosed osteoarthritis incidence in an administrative database in British Columbia, Canada, 1996-1997 through 2003-2004

OBJECTIVE

Prevalence of osteoarthritis (OA) is expected to increase due to population aging. However, there is little information on the trends in the incidence of OA over time. The purpose of this study was to describe changes in physician-diagnosed OA incidence rates between 1996-1997 and 2003-2004 in British Columbia (BC), Canada.

METHODS

We used data on all visits to health professionals and hospital admissions covered by the Medical Services Plan of BC (population approximately 4 million) for the fiscal years 1991-1992 through 2003-2004. Rates were standardized to the BC population in 2000. We used 2 definitions of OA: 1) at least 1 visit or hospitalization with a diagnostic code for OA, and 2) at least 2 visits or 1 hospitalization with a code for OA. Incidence rates were calculated with a 5-year run-in period to exclude prevalent cases.

RESULTS

Between 1996-1997 and 2003-2004, crude incidence rates of OA based on definition 1 increased from 10.5 to 12.2 per 1,000 in men and from 13.9 to 17.4 per 1,000 in women. The age-standardized rates did not change in men and increased from 14.7 to 16.7 per 1,000 in women. Incidence rates based on definition 2 were almost 50% lower, but the trends were similar.

CONCLUSION

We observed an increase in the incidence of OA in both men and women due to population aging and an additional increase in women beyond the effect of aging. These trends have important implications for public health and provision of health services to this very large group of patients.

Reliability of the hip examination in osteoarthritis: effect of standardization

OBJECTIVE

To assess the reliability of the physical examination of the hip in osteoarthritis (OA) among rheumatologists and orthopedic surgeons, and to evaluate the benefits of standardization.

METHODS

Thirty-five physical signs and techniques were evaluated using a 6 x 6 Latin square design. Subjects with mild to severe hip OA, based on physical and radiographic signs, were examined in random order prior to and following standardization of physical examination techniques. For dichotomous signs, agreement was calculated as the prevalence-adjusted bias-adjusted kappa (PABAK), whereas for continuous and ordinal signs a reliability coefficient was calculated using analysis of variance. A PABAK >0.60 and a reliability coefficient >0.80 were considered to indicate adequate reliability.

RESULTS

Adequate post-standardization reliability was achieved for 25 (71%) of 35 signs. The most highly reliable signs included true and apparent leg length discrepancy > or =1.5 cm; hip flexion, abduction, adduction, and extension strength; log roll test for hip pain; internal rotation and flexion range of motion; and Thomas test for flexion contracture. The standardization process was associated with substantial improvements in reliability for a number of physical signs, although minimal or no change was noted for some. Only 1 sign, Trendelenburg's sign, was highly unreliable post-standardization.

CONCLUSION

With the exception of gait, a comprehensive hip examination can be performed with adequate reliability. Post-standardization reliability is improved compared with pre-standardization reliability for some physical signs. The application of these findings to future OA studies will contribute to improved outcome assessments in OA.

Development and preliminary psychometric testing of a new OA pain measure--an OARSI/OMERACT initiative

OBJECTIVE

To evaluate the measurement properties of a new osteoarthritis (OA) pain measure.

METHODS

The new tool, comprised of 12 questions on constant vs intermittent pain was administered by phone to 100 subjects aged 40+ years with hip or knee OA, followed by three global hip/knee questions, the Western Ontario and McMaster Universities (WOMAC) pain subscale, the symptom subscales of the Hip Disability and OA Outcome Score (HOOS) or Knee Injury and OA Outcome Score (KOOS), and the limitation dimension of the Late Life Function and Disability Instrument (LLFDI). Test-retest reliability was assessed by re-administration after 48-96h. Item response distributions, inter-item correlations, item-total correlations and Cronbach's alpha were assessed. Principle component analysis was performed and test-retest reliability was assessed by intra-class correlation coefficient (ICC).

RESULTS

There was good distribution of response options across all items. The mean intensity was higher for intermittent vs constant pain, indicating subjects could distinguish the two concepts. Inter-item correlations ranged from 0.37 to 0.76 indicating no item redundancy. One item, predictability of pain, was removed from subsequent analyses as correlations with other items and item-total correlations were low. The 11-item scale had a corrected inter-item correlation range of 0.54-0.81 with Cronbach's alpha of 0.93 for the combined sample. Principle components analysis demonstrated factorial complexity. As such, scoring was based on the summing of individual items. Test-retest reliability was excellent (ICC 0.85). The measure was significantly correlated with each of the other measures [Spearman correlations -0.60 (KOOS symptoms) to 0.81 (WOMAC pain scale)], except the LLFDI, where correlations were low.

CONCLUSIONS

Preliminary psychometric testing suggests this OA pain measure is reliable and valid.

Understanding the pain experience in hip and knee osteoarthritis--an OARSI/OMERACT initiative

OBJECTIVE

To examine the pain experience of people with hip or knee osteoarthritis (OA), particularly changes over time and most distressing features.

METHOD

Focus groups in individuals aged 40+ years with painful hip or knee OA obtained detailed descriptions of OA pain from early to late disease. A modified Patient Generated Index (PGI) was used to assess the features of OA pain that participants found most distressing. Content analysis was performed to examine response patterns; descriptive statistics were used to summarize PGI responses.

RESULTS

Mean age of the 143 participants (52 hip OA; 91 knee OA) was 69.5 years (47-92 years); 60.8% were female and 93.7% Caucasian. Participants described two distinct types of pain - a dull, aching pain, which became more constant over time, punctuated increasingly with short episodes of a more intense, often unpredictable, emotionally draining pain. The latter, but not the former, resulted in significant avoidance of social and recreational activities. From PGI responses, distressing pain features were: the pain itself (particularly intense and unpredictable pain) and the pain's impact on mobility, mood and sleep.

CONCLUSIONS

Two distinct pain types were identified. Intermittent intense pain, particularly when unpredictable, had the greatest impact on quality of life.

Improving osteoarthritis detection in the community: pharmacist identification of new, diagnostically confirmed osteoarthritis

OBJECTIVE

Osteoarthritis (OA) is the most common arthritis and a leading cause of disability. Many persons with knee OA are not diagnosed and not referred for treatment. Therefore, identification of patients with knee pain who have undiagnosed OA needs to be improved. Our objective was to determine if pharmacists, using a simple screening questionnaire, can identify individuals with previously undiagnosed knee OA.

METHODS

Patients with knee pain and no previous diagnosis of knee OA were recruited by community pharmacists who used a simple questionnaire (<10 minutes to complete) to determine likelihood of knee OA. Patients who were likely to have knee OA were referred for a standardized knee examination and radiograph.

RESULTS

Of the 411 patients screened by pharmacists, 274 were eligible. Of these, 44 declined, 35 were ineligible (18 had a previous OA diagnosis,16 had other inflammatory conditions, and 1 was excluded for other reasons), and 1 died. The remaining 194 were mostly female (62%) with a mean age of 62 years and were mostly white (86%). Body mass index (BMI) was classified as normal (18.5-24.9 kg/m(2)) in 29%, overweight (25.0-29.9 kg/m(2)) in 45%, and obese (>30.0 kg/m(2)) in 26%. Of those examined, 190 (98%) of 194 met the American College of Rheumatology clinical criteria for knee OA. The radiographic results revealed that most participants likely had mild OA.

CONCLUSION

Pharmacists administering a simple screening questionnaire can identify >80% of patients with knee pain who have undiagnosed knee OA. Based on radiographs and BMI, much of this OA is early and may be amenable to intervention.

Relationship between varus-valgus alignment and patellar kinematics in individuals with knee osteoarthritis

BACKGROUND

Abnormal varus-valgus alignment is a risk factor for patellofemoral osteoarthritis, but tibiofemoral alignment alone does not explain compartmental patellofemoral osteoarthritis progression. Other mechanical factors, such as patellar kinematics, probably play a role in the initiation and progression of the disease. The objective of this study was to determine which three-dimensional patellar kinematic parameters (patellar flexion, spin, and tilt and patellar proximal, lateral, and anterior translation) are associated with varus and valgus alignment in subjects with osteoarthritis.

METHODS

Ten individuals with knee osteoarthritis and varus (five subjects) or valgus (five subjects) knee alignment underwent assessment of three-dimensional patellar kinematics. We used a validated magnetic resonance imaging-based method to measure three-dimensional patellar kinematics in knee flexion while the subjects pushed against a pedal with constant load (80 N). A linear random-effects model was used to test the null hypothesis that there was no difference in the relationship between tibiofemoral flexion and patellar kinematics between the varus and valgus groups.

RESULTS

Patellar spin was significantly different between groups (p = 0.0096), with the varus group having 2 degrees of constant internal spin and the valgus group having 4.5 degrees of constant external spin. In the varus group, the patellae tracked with a constant medial tilt of 9.6 degrees with flexion, which was significantly different (p = 0.0056) from the increasing medial tilt (at a rate of 1.8 degrees per 10 degrees of increasing knee flexion) in the valgus group. The patellae of the valgus group were 7.5 degrees more extended (p = 0.0093) and positioned 8.8 mm more proximally (p = 0.0155) than the varus group through the range of flexion that was studied. The pattern of anterior translation differed between the groups (p = 0.0011).

CONCLUSIONS

Our results suggest that authors of future large-scale studies of the relationships between knee mechanics and patellofemoral osteoarthritis should not rely solely on measurements of tibiofemoral alignment and should assess three-dimensional patellar kinematics directly.

OMERACT/OARSI initiative to define states of severity and indication for joint replacement in hip and knee osteoarthritis

OBJECTIVE

Time to theoretical indication of joint replacement surgery has been proposed as a primary outcome for potential structure-modifying interventions for osteoarthritis (OA). The objectives of this OMERACT/OARSI Working Group were to identify pain, physical function, and structure states that represent the progression from early to late disease for individuals with OA of the hip and knee, and to create a composite measure of these 3 domains to define states of OA severity and a surrogate measure of "need for joint replacement surgery."

METHODS

For pain, focus groups and one-on-one interviews were used. For function, Rasch analysis was performed on existing indices the Hip Dysfunction and Osteoarthritis Outcome Score (HOOS) and the Knee injury and Osteoarthritis Outcome Score (KOOS), each of which subsumes the Western Ontario and McMaster University Osteoarthritis Index (WOMAC) questions. For structure, a comparison of existing indices (Kellgren-Lawrence, OARSI stages, and joint space width) was performed for the hip and the knee.

RESULTS

For pain, key features of pain that are most distressing to people with OA from early to late disease were identified. For function, the reduction of the number of items based on the existing indices continues. For structure, the analysis is also ongoing.

CONCLUSION

Preliminary results were presented at OMERACT 8; the final objective will be to combine the 3 domains (pain, function, and structure) and to create a composite index that could define states of severity and "need for total joint replacement," which could be used to evaluate treatment response to disease-modifying drugs in OA clinical trials.

Descriptive epidemiology of osteoarthritis in British Columbia, Canada

OBJECTIVE

Osteoarthritis (OA) is a highly prevalent and often disabling disease. Data on the incidence of OA in the general population are limited. Our objectives were (1) to estimate OA prevalence and incidence rates by age and sex in a geographically defined population of 4 million people [British Columbia (BC), Canada] using an administrative database; and (2) to determine the effects of different administrative definitions of OA and observation (run-in) time on such estimates.

METHODS

We used data on all visits to health professionals and hospital admissions covered by the Medical Services Plan (MSP) of BC for the fiscal years 1991-92 through 2000-01. OA was defined based on International Classification of Diseases, 9th Revision, diagnostic codes required for administrative purposes.

RESULTS

The overall prevalence of OA in 2001 was 10.8%: 8.9% in men and 12.6% in women. Prevalence was higher in women in all age groups. By age 70-74 years, about one-third of men and 40% of women had OA. Incidence rates in 2000-01 were 11.7 per 1000 person-years in the total population, 10.0 in men and 13.4 in women. Rates increased linearly with age between 50 and 80 years. Both prevalence and incidence depended strongly on the definition of OA and the run-in period.

CONCLUSION

Prevalence of physician-diagnosed OA in BC was slightly lower than self-reported prevalence of arthritis in population surveys. Routinely collected administrative data could be a valuable source of information for OA surveillance, but more research is needed on the validity of OA diagnosis in administrative databases.

Do we need radiographs to diagnose osteoarthritis?

The usefulness of plain radiography in the diagnosis of osteoarthritis is reviewed. While plain radiography is frequently used to define osteoarthritis in research and is traditionally discussed as a diagnostic modality in clinical practice, recent magnetic resonance imaging studies suggest that plain radiography has limited ability to detect osteoarthritic features at an early stage of disease such as might be encountered in general practice. Nevertheless, X-rays do play a role in the diagnostic process in general practice, but their usefulness relates more importantly to the exclusion of other diagnostic possibilities rather than confirmation of disease. More research is needed to develop diagnostic tools for osteoarthritis, particularly in clinical practice, as well as algorithms and guidelines for use of plain radiography in patients with chronic joint pain.

Glucosamine sulfate and cartilage type II collagen degradation in patients with knee osteoarthritis: randomized discontinuation trial results employing biomarkers

OBJECTIVE

To determine whether glucosamine sulfate has an effect on cartilage type II collagen degradation in patients with knee osteoarthritis (OA).

METHODS

A randomized, double blind, placebo controlled glucosamine discontinuation trial was conducted in 137 subjects with knee OA, who had had at least moderate relief of knee pain after starting glucosamine. Subjects were randomized to glucosamine at prestudy dose or placebo at an equivalent dose. Treatment was continued to Week 24 or disease flare, whichever occurred first. Serum and urine samples were collected at Weeks 0, 4, 12, and 24 or flare visit. Samples were analyzed in triplicate for 2 type II collagen degradation biomarkers: C2C epitope (COL2-3/4C(long)) and C1,2C epitope (COL2-3/4C(short)). The primary outcome was the mean change in serum and urine C1,2C/C2C ratio in the glucosamine and placebo groups from baseline to final (flare or Week 24) visit. Linear regression analyses were conducted to adjust for potential confounders. Due to non-normal distributions, the data were log-transformed (lnC1,2C/C2C). Secondary outcomes included comparison of mean change scores at final visit compared to baseline for serum and urine C1,2C and C2C in the 2 treatment groups and in Flare versus No-Flare groups.

RESULTS

Baseline and final visit samples were available in 130 subjects for serum analysis and 126 subjects for urinalysis. No significant difference was seen between placebo and glucosamine groups in the serum C1,2C/C2C ratio, with a mean (SD) change from baseline to final visit of 0.8 (27.8) and -0.1 (1.8), respectively (mean difference 0.9; 95% CI -6.0, 7.7, p = 0.80). Similarly, no differences between treatment groups were seen for mean change in urine C1,2C/C2C (p = 0.82), or for mean change in C2C or C1,2C. In linear regression analysis, after adjustment for sex, radiographic severity, baseline lnC1,2C/C2C ratio, WOMAC function, and flare status, treatment was not a significant predictor of final serum or urine lnC1,2C/C2C ratio. When those who experienced flare were contrasted with those without flare, there was a nonsignificant trend toward a difference in mean baseline to final visit change score for serum C1,2C/C2C ratio (p = 0.12). In addition, in the multivariable linear regression analysis, flare status showed a borderline association with final visit serum lnC1,2C/C2C ratio (p = 0.16).

CONCLUSION

No statistically significant effect of glucosamine sulfate on type II collagen fragment levels in serum or urine was observed for knee OA over 6 months. Further research is necessary to elucidate which biopathologic systems, if any, are affected by glucosamine treatment. While collagen degradation products may be of value in predicting progression, at least as defined by clinical flare, a larger dataset would be needed to prove this.

Randomized, double-blind, placebo-controlled glucosamine discontinuation trial in knee osteoarthritis

OBJECTIVE

To assess the efficacy of glucosamine sulfate in knee osteoarthritis (OA).

METHODS

A 4-center, 6-month, randomized, double-blind, placebo-controlled glucosamine discontinuation trial was conducted in 137 current users of glucosamine with knee OA who had experienced at least moderate improvement in knee pain after starting glucosamine. Study medication dosage was equivalent to the dosage of glucosamine taken prior to the study (maximum 1,500 mg/day). Followup continued for 6 months or until disease flare, whichever occurred first. The primary outcome was the proportion of disease flares in the glucosamine and placebo groups using an intent-to-treat analysis. Secondary outcomes included time to disease flare; analgesic medication use; severity of disease flare; and change in pain, stiffness, function and quality of life in the glucosamine and placebo groups.

RESULTS

Disease flare was seen in 28 (42%) of 66 placebo patients and 32 (45%) of 71 glucosamine patients (difference -3%; 95% confidence interval [95% CI] -19, 14; P = 0.76). In the Cox regression analysis, after adjustment for sex, study site, and OA radiographic severity, time to disease flare was not significantly different in the glucosamine compared with placebo group (hazard ratio of flare = 0.8; 95% CI 0.5, 1.4; P = 0.45). At final study visit, acetaminophen was used in 27% and 21% of placebo and glucosamine patients, respectively (P = 0.40), nonsteroidal antiinflammatory drugs were used in 29% and 30% (P = 0.92), and both were used in 20% and 21% (P = 0.84). No differences were found in severity of disease flare or other secondary outcomes between placebo and glucosamine patients.

CONCLUSION

In patients with knee OA with at least moderate subjective improvement with prior glucosamine use, this study provides no evidence of symptomatic benefit from continued use of glucosamine sulfate.

Reliability of the knee examination in osteoarthritis: Effect of standardization

OBJECTIVE

To assess the reliability of physical examination of the osteoarthritic (OA) knee by rheumatologists, and to evaluate the benefits of standardization.

METHODS

Forty-two physical signs and techniques were evaluated using a 6 x 6 Latin square design. Patients with mild to severe knee OA, based on physical and radiographic signs, were examined in random order prior to and following standardization of techniques. For those signs with dichotomous scales, agreement among the rheumatologists was calculated as the prevalence-adjusted bias-adjusted kappa (PABAK), while for the signs with continuous and ordinal scales, a reliability coefficient (R(c)) was calculated using analysis of variance. A PABAK of >0.60 and an R(c) of >0.80 were considered to indicate adequate reliability.

RESULTS

Adequate poststandardization reliability was achieved for 30 of 42 physical signs/techniques (71%). The most highly reliable signs identified by physical examination of the OA knee included alignment by goniometer (R(c) = 0.99), bony swelling (R(c) = 0.97), general passive crepitus (R(c) = 0.96), gait by inspection (PABAK = 0.78), effusion bulge sign (R(c) = 0.97), quadriceps atrophy (R(c) = 0.97), medial tibiofemoral tenderness (R(c) = 0.94), lateral tibiofemoral tenderness (R(c) = 0.85), patellofemoral tenderness by grind test (R(c) = 0.94), and flexion contracture (R(c) = 0.95). The standardization process resulted in substantial improvements in reliability for evaluation of a number of physical signs, although for some signs, minimal or no effect of standardization was noted. After standardization, warmth (PABAK = 0.14), medial instability at 30 degrees flexion (PABAK = 0.02), and lateral instability at 30 degrees flexion (PABAK = 0.34) were the only 3 signs that were highly unreliable.

CONCLUSION

With the exception of physical examinations for instability, a comprehensive knee examination can be performed with adequate reliability. Standardization further improves the reliability for some physical signs and techniques. The application of these findings to future OA studies will contribute to improved outcome assessments in OA.

Agreement among Ayurvedic practitioners in the identification and treatment of three cases of inflammatory arthritis

OBJECTIVE

To conduct a preliminary investigation into the consistency of approach between three Ayurvedic medicine experts on treatments for inflammatory polyarthritis.

METHODS

A convenience sample of three experienced Ayurvedic practitioners was recruited. These practitioners independently assessed three subjects with inflammatory polyarthritis for health status, treatment history, and lifestyle, conducted a physical examination, and then independently determined the treatment plan. The treatment plan was recorded on standardized collection forms. The subject examination order was randomized for each practitioner. Following completion of the assessments, a facilitated discussion among the practitioners permitted each to discuss all aspects of the recommended therapies. Proceedings were audio-taped and the content analyzed.

RESULTS

All three practitioners agreed upon a unified concept of Ayurvedic disease origin, disease diagnosis, and treatment approach for each patient. Seven specific treatment groupings (i.e. modalities) emerged: diet, exercise, relaxation, analgesic, anti-inflammatory, immune-enhancing, and detoxification/cleansing. Based on the single visit, the practitioners agreed upon 17 of 21 treatment groups for the three patients.

CONCLUSION

Despite Ayurvedic medicine's individualized approach, considerable agreement existed among the practitioners studied. The identified Ayurvedic treatment approaches require investigation in a controlled clinical setting.

A randomized double blind, placebo controlled trial of topical Tripterygium wilfordii in rheumatoid arthritis: reanalysis using logistic regression analysis

OBJECTIVE

To assess the efficacy of topical Tripterygium wilfordii (TW), a Chinese herbal therapy, in rheumatoid arthritis (RA).

METHODS

A 6 week randomized double blind placebo controlled study of 61 patients with RA meeting American College of Rheumatology (ACR) criteria was conducted in China. The primary outcome was a modified ACR-20 response rate, analyzed by logistic regression analysis.

RESULTS

The modified ACR-20 response rate differed significantly (topical TW 58% vs placebo 20%; p = 0.002). There was an 8.1-fold (95% CI 1.9-35.4) increase in the modified ACR-20 response for the TW compared to the placebo group, adjusted for age and erythrocyte sedimentation rate.

CONCLUSION

Topical TW appears efficacious for the treatment of RA, but larger studies are needed.

Rheumatologists' adherence to guidelines for misoprostol use in patients at high risk for nonsteroidal antiinflammatory drug gastropathy

OBJECTIVE

To determine the extent of evidence based practice among rheumatologists in the prevention of nonsteroidal antiinflammatory drug (NSAID) associated peptic ulcer disease and to seek ways to improve the management of high risk NSAID users.

METHODS

In March 1996 all 7 rheumatologists from Saskatoon participated in a consensus conference to develop local guidelines for the prophylaxis of NSAID associated peptic ulcer disease. We performed a retrospective chart review for September/October 1995 (baseline) and for June/July 1996 (post-consensus guideline) of all patients from Saskatoon rheumatologists who were being treated with NSAID for either rheumatoid arthritis (RA) or undifferentiated inflammatory polyarthritis (IP). A prospective crossover intervention study was performed from January to April 1997 in which 2 subgroups of rheumatologists (university or private practice) had a reminder sheet of gastrointestinal (GI) bleeding risk assessment placed into the front of each patient's chart prior to each office visit. The GI bleeding risk for each patient at time of visit was later determined by chart review. The primary outcome was the proportion of adherence to guidelines for high risk NSAID users in the combined intervention group (reminder sheet) compared to the combined control group (no reminder sheet) in the prospective controlled crossover study.

RESULTS

A total of 484 patients with RA or IP received NSAID during the 4 study periods. Of these, 82 patients (16.9%) were at high risk of GI bleed. In 1995, the proportion of high risk patients taking misoprostol was 29% for university and 33% for private practice rheumatologists. The establishment of local consensus guidelines in 1996 temporarily increased adherence to guidelines to 43%, but only for private practice rheumatologists. During the prospective study, adherence to guidelines was significantly greater in the intervention (reminder sheets) group compared to the control (no reminder sheets) group (53% vs 15%; p = 0.014).

CONCLUSION

The simple intervention of reminder sheets for GI bleeding risk assessment resulted in a significant increase in rheumatologists' adherence to guidelines, although a substantial number of patients remained untreated with misoprostol. This study illustrates the difficulty of incorporating new knowledge and recommendations into clinical practice. Additional strategies should be investigated to more effectively incorporate new knowledge in the practice of rheumatology.

Systemic lupus erythematosus and the risk of malignancy

The objective of this study was to determine the relative risks of malignancy and of site-specific malignancies in patients with systemic lupus erythematosus (SLE). A cohort of 297 patients (91% Caucasian) with SLE were seen between 1975 and 1994 and followed for a mean of 12 years at the University of Saskatchewan Rheumatic Disease Unit. Expected cancer incidence rates were determined based on Province of Saskatchewan population statistics matched to each study patient for age, sex and calendar year of follow-up. Standardized incidence ratios (SIRs) of observed to expected cancers and 95% confidence intervals (95% CI) were calculated. A total of 27 cases of cancer were observed, whereas only 16.9 were expected (SIR 1.59 (95% CI 1.05-2.32)). For site-specific malignancies, an excess of cancer of the cervix (SIR 8.15 (95% CI 1.63-23.81)) as well as hemopoietic malignancy (SIR 4.9 (95% CI 1.57-11.43)) was found. The hemopoietic cancers were predominantly non-Hodgkin's lymphoma (SIR 7.01 (95% CI 1.88-17.96)). We did not find an association of malignancy with known risk factors, including use of cytotoxic agents. Increased risk of malignancy, notably non-Hodgkin's lymphoma and perhaps cervical cancer, should be regarded as a complication of SLE.

Rheumatoid arthritis and the risk of malignancy

OBJECTIVE

To determine the relative risks of malignancy and of site-specific malignancies in patients with rheumatoid arthritis (RA).

METHODS

In a prospective cohort study, 862 patients with RA (96% white) were enrolled from 1966 to 1974 and were followed up for up to 35 years (mean 17.4 years) at the University of Saskatchewan Rheumatic Disease Unit. All diagnoses of cancer were cross-referenced with the Provincial Cancer Registry. Expected cancer incidence rates were determined based on province of Saskatchewan population statistics matched to each study patient for age, sex, and calendar year. Standardized incidence ratios (SIRs) of the observed-to-expected cancer incidence and 95% confidence intervals (95% CI) were then calculated.

RESULTS

A total of 136 cases of cancer were observed compared with 168 expected (SIR 0.80, P = 0.011 [95% CI 0.67-0.95]). The relative risk of colorectal malignancy was significantly reduced in the RA study population (SIR 0.52, P = 0.037 [95% CI 0.25-0.96]). A significant excess of leukemia was found (SIR 2.47, P = 0.026 [95% CI 1.12-4.69]), whereas the incidence rates for Hodgkin's disease and non-Hodgkin's lymphoma and all other site-specific malignancies were not found to be significantly different from general population rates.

CONCLUSION

In our cohort of RA patients, colorectal cancer was detected in only half the expected number of patients. This risk reduction may be related to long-term nonsteroidal antiinflammatory drug (NSAID) use in RA, as has been suggested in several other studies of long-term NSAID use. An increased risk of leukemia was confirmed. This may be due to the persistent immune stimulation associated with RA itself, since other potential explanatory factors for increased leukemia were not apparent. Despite the excess of hemopoietic malignancy and despite treatment of RA with potentially oncogenic agents, the overall risk of malignancy was reduced in this RA cohort.