Gillian A Hawker

Women's College Hospital, Toronto, Ontario, Canada

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Publications (301)1433.87 Total impact

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    ABSTRACT: To evaluate the effectiveness of patient decision aids compared to usual education on appropriate and timely access to total joint arthroplasty in patients with osteoarthritis. A randomized controlled trial with patients undergoing orthopedic screening. Control and intervention arms received usual education; intervention arm also received a patient decision aid and a surgeon preference report. Wait times (primary outcome) were described using stratified Kaplan-Meier survival curves with patients censored at the time of death or loss to follow-up, and multivariable Cox proportional hazards regression. Secondary outcomes were compared using stratified Cochran-Mantel-Haenszel chi-squared tests. 343 patients were randomized to intervention (n=174) or control (n=169). The typical patient was 66 years old, retired, living with someone, and 51% had high school education or less. The intervention was associated with a trend towards reduction in wait time (hazard ratio 1.25, 95% confidence interval (CI) 0.99-1.60, p=0.0653). Median wait times were 3 weeks shorter in intervention than in control at the community site with no difference at the academic site. Good decision quality was reached by 56.1% intervention and 44.5% control (Relative risk (RR) 1.25; 95% CI 1.00-1.56, p=0.050). Surgery rates were 73.2% intervention and 80.5% controls (RR 0.91: 95% CI 0.81-1.03) with 12 intervention (7.3%) and 8 control participants (4.9%) returning to have surgery within 2 years (p=0.791). Compared to controls, decision aid recipients had shorter wait times at one site, fewer surgeries, and were more likely to reach good decision quality, but overall effect was not statistically significant. The full trial protocol is available at ClinicalTrials.Gov (NCT00911638). Copyright © 2015 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.
    Osteoarthritis and Cartilage 08/2015; DOI:10.1016/j.joca.2015.07.024 · 4.66 Impact Factor
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    ABSTRACT: Episode-of-care payments are defined as a single lump-sum payment for all services associated with a single medical event or surgery and are designed to incentivize efficiency and integration among providers and healthcare systems. A TKA is considered an exemplar for an episode-of-care payment model by many policymakers, but data describing variation payments between hospitals for TKA are extremely limited. We asked: (1) How much variation is there between hospitals in episode-of-care payments for primary TKA? (2) Is variation in payment explained by differences in hospital structural characteristics such as teaching status or geographic location, patient factors (age, sex, ethnicity, comorbidities), and discharge disposition during the postoperative period (home versus skilled nursing facility)? (3) After accounting for those factors, what proportion of the observed variation remains unexplained? We used Medicare administrative data to identify fee-for-service beneficiaries who underwent a primary elective TKA in 2009. After excluding low-volume hospitals, we created longitudinal records for all patients undergoing TKAs in eligible hospitals encompassing virtually all payments by Medicare for a 120-day window around the TKA (30 days before to 90 days after). We examined payments for the preoperative, perioperative, and postdischarge periods based on the hospital where the TKA was performed. Confounding variables were controlled for using multivariate analyses to determine whether differences in hospital payments could be explained by differences in patient demographics, comorbidity, or hospital structural factors. There was considerable variation in payments across hospitals. Median (interquartile range) hospital preoperative, perioperative, postdischarge, and 120-day payments for patients who did not experience a complication were USD 623 (USD 516-768), USD 13,119 (USD 12,165-14,668), USD 8020 (USD 6403-9933), and USD 21,870 (USD 19,736-25,041), respectively. Variation cannot be explained by differences in hospital structure. Median (interquartile range) episode payments were greater for hospitals in the Northeast (USD 26,291 [22,377-30,323]) compared with the Midwest, South, and West (USD 20,614, [USD 18,592-22.968]; USD 21,584, [USD 19,663-23,941]; USD 22,421, [USD 20,317-25,860]; p < 0.001) and for teaching compared with nonteaching hospitals (USD 23,152 [USD 20,426-27,127] versus USD 21,336 [USD 19,352-23,846]; p < 0.001). Patient characteristics explained approximately 15% of the variance in hospital payments, hospital characteristics (teaching status, geographic region) explained 30% of variance, and approximately 55% of variance was not explained by either factor. There is much unexplained variation in episode-of-care payments at the hospital-level, suggesting opportunities for enhanced efficiency. Further research is needed to ensure an appropriate balance between such efficiencies and access to care. Level II, economic analysis.
    Clinical Orthopaedics and Related Research 08/2015; DOI:10.1007/s11999-015-4445-0 · 2.88 Impact Factor
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    ABSTRACT: During OMERACT 12, a workshop was held with the aim to endorse a core set of domains for 3 settings: clinical trials of symptom and structure modification and observational studies. Additional goals were to endorse a core set of contextual factors for these settings, and to define preliminary instruments for each core domain. Finally, an agenda for future research in hand osteoarthritis (OA) was to be proposed. Literature reviews of preliminary instruments for each core domain of the proposed core set for hand OA in the settings described above. Literature review of radiographic scoring methods and modern imaging in hand OA were also performed. Proposed contextual factors for a core set were identified through 2 Delphi exercises with participation of hand OA experts, patient partners, and OMERACT participants. Results from Delphi exercises and systematic literature reviews were presented and discussed. It was agreed that a preliminary core domain set for the setting clinical trials of symptom modification should contain at least "pain, physical function, patient global assessment, joint activity and hand strength." The settings clinical trial of structure modification and observational studies would in addition include structural damage. Preliminary instruments for the proposed domains were agreed on. A list of prioritized contextual factors was defined and endorsed for further research. A research agenda was proposed for domain instrument validation according to the OMERACT Filter 2.0. Preliminary core sets for clinical trials of symptom and structure modification and observational studies in hand osteoarthritis, including preliminary instruments and contextual factors, were agreed upon during OMERACT 12.
    The Journal of Rheumatology 07/2015; DOI:10.3899/jrheum.141017 · 3.17 Impact Factor
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    ABSTRACT: We examined fracture patients' understanding of "high" fracture risk after they were screened through a post-fracture secondary prevention program and educated about their risk verbally, numerically, and graphically. Our findings suggest that messages about fracture risk are confusing to patients and need to be modified to better suit patients' needs. The aim of this study was to examine fracture patients' understanding of high risk for future fracture. We conducted an in-depth qualitative study in patients who were high risk for future fracture. Patients were screened through the Osteoporosis Exemplary Care Program where they were educated about fracture risk: verbally told they were "high risk" for future fracture, given a numerical prompt that they had a >20 % chance of future fracture over the next 10 years, and given a visual graph highlighting the "high risk" segment. This information about fracture risk was also relayed to patients' primary care physicians (PCPs) and specialists. Participants were interviewed at baseline (within six months of fracture) and follow-up (after visit with a PCP and/or specialist) and asked to recall their understanding of risk and whether it applied to them. We recruited 27 patients (20 females, 7 males) aged 51-87 years old. Fractures were sustained at the wrist (n = 7), hip (n = 7), vertebrae (n = 2), and multiple or other locations (n = 11). While most participants recalled they had been labeled as "high risk" (verbal cue), most were unable to correctly recall the other elements of risk (numerical, graphical). Further, approximately half of the patients who recalled they were high risk did not believe that high risk applied, or had meaning, to them. Participants also had difficulty explaining what they were at risk for. Our results suggest that health care providers' messages about fracture risk are confusing to patients and that these messages need to be modified to better suit patients' needs.
    Osteoporosis International 06/2015; DOI:10.1007/s00198-015-3214-y · 4.17 Impact Factor
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    ABSTRACT: RATIONALE: The cost of continuous positive airway pressure (CPAP) treatment and socioeconomic status (SES) have been reported as barriers to its acceptance. Ontario has a universal, single-payer health system that covers diagnostic services for obstructive sleep apnea (OSA) and 75% of the CPAP cost. This offers a unique environment to evaluate the effect of SES as the range of income does not affect the coverage. Using a large historical cohort of patients with OSA, we evaluated the association between patient income status and purchase of CPAP device as determined by provincial health administrative data, controlling for confounders. METHODS: All adults who underwent a first diagnostic sleep study at St Michael’s Hospital (Toronto, Ontario, Canada) between 2004 and 2010 and were diagnosed with OSA (apnea-hypopnea index [AHI] ≥5 events/hour), were included. Patient data were linked to Ontario health administrative data from 1991 to 2011 to determine who purchased CPAP equipment through the Assistive Devices Program, neighbourhood income status, comorbidities at baseline and a number of primary care visits over 3 years before baseline. OSA was classified as mild (AHI of 5 to 14.9), moderate (AHI of 15 to 30) or severe (AHI>30). Our main analysis was based on patients with severe OSA and extensive daytime sleepiness (DS) as measured by the Epworth Sleepiness Scale (ESS) (ESS≥10) following our assumption that most of them would have been prescribed CPAP. Patients with moderate multivariable logistic and Cox regressions. The characteristics that distinguished those who did versus did not purchase CPAP were determined using classification and regression trees. RESULTS: Of the 4,291 patients with AHI≥5 events/hour, 656 (15%) participants had AHI>30 and the ESS≥10 and 383 of 656 (58%) purchased a CPAP devise. Controlling for age, sex, body mass index, smoking status, comorbidities, severity of disease and primary care exposure, there was no significant relationship found between income level and CPAP purchase, irrespective of the modeling approach (Table 1). CONCLUSIONS: In a large cohort, we found that the probability of purchasing a CPAP machine among patients with moderate to severe OSA and extensive DS did not vary with the income status, suggesting that in the province of Ontario, financial concerns may be not an obstacle to CPAP treatment for this patient population. Despite this, even among this group of patients the CPAP acceptance rate was low.
    American Thoracic Society International Conference 2015; 05/2015
  • David H Wei · Gillian A Hawker · David S Jevsevar · Kevin J Bozic
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    ABSTRACT: Improving value in musculoskeletal health care has emerged as an important objective in both the United States and Canada. In order to achieve this objective, providers need to have a clear definition of value and an infrastructure for measuring outcomes of interest to patients and costs over the episode of care. Although national patient registries have been established in the United States and Canada, they nevertheless lag behind other registries worldwide in terms of collecting patient-reported outcomes and capturing data from a wide cross-section of hospitals and physicians. With the help of professional medical societies and the creation of national initiatives, patient-reported outcomes data collection on a large scale may be possible, but many challenges remain regarding implementation. Alternatives to the fee-for-service payment model, including pay-for-reporting and pay-for-performance, may help incentivize physicians and health-care providers to obtain and improve on patient-reported outcomes data collection. Other payment reforms, such as bundled payments, have been piloted in certain regions, but their sustainability and long-term success are unclear at this time. Novel health-care delivery strategies aimed at improving quality, coordinating multispecialty care, and enhancing patient participation in shared decision-making have shown promise in improving patient-centered outcomes, but delivery models continue to vary greatly throughout the United States and Canada. The current status of musculoskeletal health-care delivery requires substantial change before the goal of improving patient outcomes and lowering health-care costs can be achieved. Copyright © 2015 by The Journal of Bone and Joint Surgery, Incorporated.
    The Journal of Bone and Joint Surgery 05/2015; 97(9):769-774. DOI:10.2106/JBJS.N.00841 · 4.31 Impact Factor
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    ABSTRACT: Rigorous implementation research is important for testing strategies to improve the delivery of effective osteoarthritis (OA) interventions. The objective of this manuscript is to describe principles of implementation research, including conceptual frameworks, study designs and methodology, with specific recommendations for randomized clinical trials of OA treatment and management. This manuscript includes a comprehensive review of prior research and recommendations for implementation trials. The review of literature included identification of seminal articles on implementation research methods, as well as examples of previous exemplar studies using these methods. In addition to a comprehensive summary of this literature, this manuscript provides key recommendations for OA implementation trials. This review concluded that to date there have been relatively few implementation trials of OA interventions, but this is an emerging area of research. Future OA clinical trials should routinely consider incorporation of implementation aims to enhance translation of findings. Published by Elsevier Ltd.
    Osteoarthritis and Cartilage 05/2015; 23(5):826-838. DOI:10.1016/j.joca.2015.02.772 · 4.66 Impact Factor
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    ABSTRACT: As total joint arthroplasty (TJA) rates for osteoarthritis (OA) rise, there is a need to ensure appropriate use. In prior work, we used qualitative methods to separately assess OA patients' and arthroplasty surgeons' perceptions regarding patient appropriateness for TJA. The current study reviewed the appropriateness themes that emerged from each group, and a series of statements were developed to reflect each unique theme or criterion. A group of arthroplasty surgeons then indicated their level of agreement with each statement using electronic voting. Where ≤70% agreed or disagreed, the criterion was discussed, revised and re-voting occurred. In standardized telephone interviews, OA focus group participants indicated their level of agreement with each revised criterion. Qualitative research in 58 patients with OA and 14 arthroplasty surgeons identified eleven appropriateness criteria. Member-checking in 15 surgeons (including 5 qualitative study participants) resulted in agreement on six revised criteria: arthritis on joint examination; patient-reported symptoms negatively impacting quality-of-life; appropriate non-surgical treatment tried; patient's surgical expectations realistic; patient mentally and physically ready for surgery; patient and surgeon agree that potential benefit exceeds risk. Thirty-six of 58 OA focus group participants (62.1%) participated in the member-check interviews and endorsed all six criteria. Patients and surgeons jointly endorsed six criteria for assessment of appropriateness of TJA in patients with OA. Prospective validation of these criteria, assessed pre-operatively, as predictive of post-operative patient-reported outcomes is underway and will inform development of a surgeon-patient decision-support tool for assessment of appropriateness of TJA. This article is protected by copyright. All rights reserved. © 2015 American College of Rheumatology.
    04/2015; 67(7). DOI:10.1002/art.39124
  • L. Carlesso · G. Hawker · E. Waugh · A. Davis
    Osteoarthritis and Cartilage 04/2015; 23:A346-A347. DOI:10.1016/j.joca.2015.02.636 · 4.66 Impact Factor
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    ABSTRACT: To develop a plan for harmonizing outcomes for people undergoing total joint replacement (TJR), to achieve consensus regarding TJR outcome research. The TJR working group met during the 2014 Outcome Measures in Rheumatology (OMERACT) 12 meeting in Budapest, Hungary. Multiple conference calls preceded the face-to-face meeting. Brief presentations were made during a 1.5-h meeting, which included an overview of published systematic reviews of TJR trials and the results of a recent systematic review of TJR clinical trial outcome domains and measures. This was followed by discussion of potential core set areas/domains for TJR clinical trials (as per OMERACT Filter 2.0) as well as the challenges associated with the measurement of these domains. Working group participants discussed which TJR clinical trial outcome domains/areas map to the inner versus outer core for core domain set. Several challenges were identified with TJR outcomes including how to best measure function after TJR, elucidating the source of the pre- and post-TJR joint pain being measured, joint-specific versus generic quality of life instruments and the importance of patient satisfaction and revision surgery as outcomes. A preliminary core domain set for TJR clinical trials was proposed and included pain, function, patient satisfaction, revision, adverse events, and death. This core domain set will be further vetted with a broader audience. An international effort with active collaboration with the orthopedic community to standardize key outcome domains and measures is under way with the TJR working group. This effort will be further developed with new collaborations.
    The Journal of Rheumatology 04/2015; DOI:10.3899/jrheum.141201 · 3.17 Impact Factor
  • Osteoarthritis and Cartilage 04/2015; 23:A342. DOI:10.1016/j.joca.2015.02.625 · 4.66 Impact Factor
  • Osteoarthritis and Cartilage 03/2015; 23(6). DOI:10.1016/j.joca.2015.02.014 · 4.66 Impact Factor
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    ABSTRACT: Objective Therapeutic intra-articular injections are used in the management of hip osteoarthritis (OA). Some studies suggest their use increases risk for infection, and thus revision, after THA, while others do not. We sought to clarify the relationship between prior intra-articular injection and the risk of complication in a subsequent total hip arthroplasty (THA).Methods In a cohort with hip OA who received a primary elective THA between 2002 and 2009, we identified those who received ≥1 intra-articular injection by a radiologist in the five years preceding their THA. Multivariable Cox proportional hazards models were used to determine the relationship between receipt of a pre-surgical injection (none, 1-5 years prior, or < 1year prior) and the occurrence of post-surgical joint infection and revision THA in the following 2 years, while controlling for confounders.ResultsOf 37,881 eligible THA recipients, 2,468 (6.5%) received an intra-articular injection from a radiologist within five years of their THA (<1y: 1,691; 1-5years: 777). Controlling for age, sex, co-morbidity, frailty, income, and provider volume, those who had an injection in the year preceding surgery were at increased risk for infection (adjusted HR 1.37, p=0.03) and revision (adjusted HR 1.53, p=0.03) within 2 years of the THA, relative to patients that did not. The association between prior injection and revision arthroplasty was attenuated and became non-significant (adjusted HR 1.41, p=0.13) after occurrence of post-operative infection was included in the regression model. No effect was found for injection 1-5 years prior to surgery.Conclusions Intra-articular injection in the year preceding THA independently predicted increased risk for infection leading to early revision. Further studies are warranted to elucidate explanations for these findings. © 2014 American College of Rheumatology.
    01/2015; 67(1). DOI:10.1002/art.38886
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    ABSTRACT: The incidence of chronic diseases, including diabetes mellitus (DM), heart failure (HF) and chronic obstructive pulmonary disease (COPD) is on the rise. The existing health care system must evolve to meet the growing needs of patients with these chronic diseases and reduce the strain on both acute care and hospital-based health care resources. Paramedics are an allied health care resource consisting of highly-trained practitioners who are comfortable working independently and in collaboration with other resources in the out-of-hospital setting. Expanding the paramedic’s scope of practice to include community-based care may decrease the utilization of acute care and hospital-based health care resources by patients with chronic disease. This will be a pragmatic, randomized controlled trial comparing a community paramedic intervention to standard of care for patients with one of three chronic diseases. The objective of the trial is to determine whether community paramedics conducting regular home visits, including health assessments and evidence-based treatments, in partnership with primary care physicians and other community based resources, will decrease the rate of hospitalization and emergency department use for patients with DM, HF and COPD. The primary outcome measure will be the rate of hospitalization at one year. Secondary outcomes will include measures of health system utilization, overall health status, and cost-effectiveness of the intervention over the same time period. Outcome measures will be assessed using both Poisson regression and negative binomial regression analyses to assess the primary outcome. The results of this study will be used to inform decisions around the implementation of community paramedic programs. If successful in preventing hospitalizations, it has the ability to be scaled up to other regions, both nationally and internationally. The methods described in this paper will serve as a basis for future work related to this study. Trial registration NCT02034045. Date: 9 January 2014.
    Trials 12/2014; 15(1-1):473. DOI:10.1186/1745-6215-15-473 · 2.12 Impact Factor
  • Susan M Goodman · Bheeshma Ravi · Gillian Hawker
    12/2014; 9(6):585-593. DOI:10.2217/ijr.14.47
  • G.A. Hawker · I. Stanaitis
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    ABSTRACT: A systematic search was conducted for the time period April 1 2013 to March 30 2014 using PubMed to identify major osteoarthritis (OA) clinical research themes of the past year. Articles within each theme were selected for inclusion in this review based on study quality and relevance. Two major themes emerged, which relate to the current understanding of OA as a heterogeneous condition with multiple pathogenic mechanisms and clinical manifestations. Theme 1 stems from the role of systemic inflammation in OA pathogenesis, and the concept of 'metabolic OA'. Over the past year, research has examined the effect of OA on incidence and progression of other 'metabolic syndrome'-related conditions, especially cardiovascular disease (CVD) and diabetes and the impact of multi-morbidity on the clinical management of OA. Theme 2 focuses on the concept of personalized medicine as it relates to the treatment of OA. It is hypothesized that the modest efficacy of available OA treatments is a result of inclusion of heterogeneous groups of OA patients in clinical trials. Prognostic studies in the past year have been helpful in identifying 'OA phenotypes' that are more or less likely to respond to treatments - e.g., the presence of synovitis on imaging, central pain sensitization on quantitative sensory testing (QST), or coping efficacy by self-reported patient questionnaire. Their findings are being increasingly used to target interventions to these identified 'OA responder' subgroups with the hopes that treatment effect will be amplified. Copyright © 2014 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.
    Osteoarthritis and Cartilage 11/2014; 22(12). DOI:10.1016/j.joca.2014.06.018 · 4.66 Impact Factor
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    ABSTRACT: Background While some studies have identified patient readiness as a key component in their decision whether to have total joint replacement surgery (TJR), none have examined how patients determine their readiness for surgery. The study purpose was to explore the concept of patient readiness and describe the factors patients consider when assessing their readiness for TJR. Methods Nine focus groups (4 pre-surgery, 5 post-surgery) were held in four Canadian cities. Participants had been either referred to or seen by an orthopaedic surgeon for TJR or had undergone TJR. The method of analysis was qualitative thematic analysis. Results There were 65 participants, 66% female and 34% male, 80% urban, with an average age of 65 years (SD 10). Readiness reflected both the surgeon’s advice that the patient was clinically ready for surgery and the patient’s feeling that they were both mentally and physically ready for surgery. Mental readiness was described as an internal state or feeling of being ready or prepared while physical readiness was described as being physically fit and in good shape for surgery. Factors associated with readiness included: 1) pain: its severity, the ability to cope with it, and how it affected their quality of life; 2) mental preparation; 3) physical preparation; 4) the optimal timing of surgery, including age, anticipated rate of deterioration, prosthesis lifespan and the length of the waiting list. Conclusions Patient readiness should be assessed prior to TJR. By assessing patient readiness, health professionals can elucidate and deal with concerns and fears, understand and calibrate expectations, assess coping strategies, and use this information to help determine optimal timing, both before and after the surgical consultation.
    BMC Health Services Research 10/2014; 14(1):454. DOI:10.1186/1472-6963-14-454 · 1.66 Impact Factor
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    ABSTRACT: Importance Hospital readmissions are common and costly, and no single intervention or bundle of interventions has reliably reduced readmissions. Virtual wards, which use elements of hospital care in the community, have the potential to reduce readmissions, but have not yet been rigorously evaluated.Objective To determine whether a virtual ward—a model of care that uses some of the systems of a hospital ward to provide interprofessional care for community-dwelling patients—can reduce the risk of readmission in patients at high risk of readmission or death when being discharged from hospital.Design, Setting, and Patients High-risk adult hospital discharge patients in Toronto were randomly assigned to either the virtual ward or usual care. A total of 1923 patients were randomized during the course of the study: 960 to the usual care group and 963 to the virtual ward group. The first patient was enrolled on June 29, 2010, and follow-up was completed on June 2, 2014.Interventions Patients assigned to the virtual ward received care coordination plus direct care provision (via a combination of telephone, home visits, or clinic visits) from an interprofessional team for several weeks after hospital discharge. The interprofessional team met daily at a central site to design and implement individualized management plans. Patients assigned to usual care typically received a typed, structured discharge summary, prescription for new medications if indicated, counseling from the resident physician, arrangements for home care as needed, and recommendations, appointments, or both for follow-up care with physicians as indicated.Main Outcomes and Measures The primary outcome was a composite of hospital readmission or death within 30 days of discharge. Secondary outcomes included nursing home admission and emergency department visits, each of the components of the primary outcome at 30 days, as well as each of the outcomes (including the composite primary outcome) at 90 days, 6 months, and 1 year.Results There were no statistically significant between-group differences in the primary or secondary outcomes at 30 or 90 days, 6 months, or 1 year. The primary outcome occurred in 203 of 959 (21.2%) of the virtual ward patients and 235 of 956 (24.6%) of the usual care patients (absolute difference, 3.4%; 95% CI, −0.3% to 7.2%; P = .09). There were no statistically significant interactions to indicate that the virtual ward model of care was more or less effective in any of the prespecified subgroups.Conclusions and Relevance In a diverse group of high-risk patients being discharged from the hospital, we found no statistically significant effect of a virtual ward model of care on readmissions or death at either 30 days or 90 days, 6 months, or 1 year after hospital discharge.Trial Registration Identifier: NCT01108172
    JAMA The Journal of the American Medical Association 10/2014; 312(13):1305-1312. DOI:10.1001/jama.2014.11492 · 30.39 Impact Factor
  • Lisa C. Carlesso · Gillian A. Hawker · Esther J. Waugh · Aileen M. Davis
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    ABSTRACT: Aim of Investigation: The association of comorbid low back pain (LBP) with hip and knee osteoarthritis (OA) is reported in the literature as having an additive effect on OA pain related disability. It is also established in both LBP and OA populations that psychosocial variables are associated with poor outcomes. It is unknown if the additive effect of LBP to hip/knee OA on future pain related disability differs depending on baseline psychosocial factors. It was therefore our intent to examine if the effect of psychosocial variables on pain impact (PI) in people with hip and knee OA differs in those with and without LBP. We hypothesized that PI would be associated with pain catastrophizing, depression, anxiety, fatigue, and social support and that the magnitude of the effect would be amplified in those with LPB. Methods: We analyzed data from an established population-based cohort of residents from Ontario, Canada who were 55 years or older and reported symptomatic hip/knee OA. Initial recruitment occurred between 1995 and 1997 through screening of 100% of the population in two communities. An initial cohort of n=2411 was followed annually using telephone interviews. The current study utilized data collected in 2006 (baseline) and 2008 (follow-up). Participants with inflammatory arthritis or a prior total joint replacement were excluded resulting in an analyzable sample of 462. The primary outcome was PI at follow-up using the Pain Impact Questionnaire 6 item version. The following standardized baseline measures were used for our independent variables: Pain Catastrophizing Scale, the Centre for Epidemiologic Studies Depression Scale, The Hospital Anxiety and Depression Scale –anxiety subscale, Profile of Moods States – fatigue inertia subscale; the abbreviated Lubben Social Network Scale and the Western Ontario and McMaster Universities’ Osteoarthritis Index (WOMAC). Persistent LBP in the past year (yes/no) was identified from a comorbidities questionnaire. Bivariate analyses compared participants with and without LBP. Next a sequential series of four linear regression analyses with the listed independent variables were conducted in the following order: 1. Psychosocial variables; 2. Psychosocial variables and LBP; 3. Psychosocial variables, LBP and demographics (age, sex, marital status, education); and 4. Psychosocial variables, LBP, demographics and disease-related variables (WOMAC, knee pain (yes/no), hip pain, hip and knee pain, BMI, number of comorbidities). Given the results, we then proceeded to test if WOMAC mediated the effect of fatigue, pain catastrophizing (PC) and LBP on pain impact. Analyses were conducted with multiple imputation for missing values on the independent variables. Results: In 462 participants, the mean age was 76 years (range 58 to 96), most were female (77%) and 35% reported LBP at baseline. Bivariate analyses revealed significant differences between those with and without LBP (p<0.05) in all psychosocial variables, with those with LBP having greater PC, depression, anxiety, fatigue and smaller social networks. Initial regression analyses demonstrated that PC, fatigue, LBP and female gender predicted pain impact at follow-up. When WOMAC summary score was added to the model, only it and female gender were significant. Subsequent testing of the mediation model showed that WOMAC fully mediated the effect of PC and LBP on pain impact [ß 0.367 (0.173, 0.561) p=0.002]. The effect of full mediation by the WOMAC was present in people with and without LBP. Conclusions: In our population-based cohort, WOMAC fully mediated the effects of PC and LBP on PI indicating that interventions directly addressing disease severity are the most effective way to mitigate PI related to hip and knee OA. However, given that baseline psychological variables and future PI were worse in those with LBP, these interventions may need to be tailored. Identification of the role of LBP and its contribution to pain mechanisms may attenuate future PI. Interventions addressing PC that improve perceptions of disease severity may limit the future negative impact of pain.
    World Congress on Pain; 10/2014
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Publication Stats

11k Citations
1,433.87 Total Impact Points


  • 1995–2015
    • Women's College Hospital
      Toronto, Ontario, Canada
  • 1993–2015
    • University of Toronto
      • • Institute for Clinical Evaluative Sciences
      • • Institute of Health Policy, Management and Evaluation
      • • Department of Physical Therapy
      • • Sunnybrook Health Sciences Centre
      • • Faculty of Medicine
      • • Department of Medicine
      • • Division of Rheumatology
      Toronto, Ontario, Canada
  • 2011
    • Toronto Western Hospital
      Toronto, Ontario, Canada
    • University of Ottawa
      • Institute of Population Health
      Ottawa, Ontario, Canada
  • 2010
    • University of Bristol
      Bristol, England, United Kingdom
  • 2003–2008
    • Sunnybrook Health Sciences Centre
      • Department of Medicine
      Toronto, Ontario, Canada
    • Institute for Clinical Evaluative Sciences
      Toronto, Ontario, Canada
  • 2007
    • University Health Network
      Toronto, Ontario, Canada
  • 2006
    • Haukeland University Hospital
      Bergen, Hordaland, Norway
    • University of Burgundy
      Dijon, Bourgogne, France
    • Brigham and Women's Hospital
      Boston, Massachusetts, United States
  • 2002
    • SickKids
      Toronto, Ontario, Canada
  • 2001
    • Harbor-UCLA Medical Center
      Torrance, California, United States
  • 2000
    • St. Michael's Hospital
      • Department of Surgery
      Toronto, Ontario, Canada
  • 1999
    • Mount Sinai Hospital, Toronto
      Toronto, Ontario, Canada
  • 1996
    • Indiana University East
      Ричмонд, Indiana, United States