Gillian A Hawker

Women's College Hospital, Toronto, Ontario, Canada

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Publications (255)1259.86 Total impact

  • Osteoarthritis and Cartilage 03/2015; DOI:10.1016/j.joca.2015.02.014 · 4.66 Impact Factor
  • 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; DOI:10.1016/j.joca.2014.06.018 · 4.66 Impact Factor
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    ABSTRACT: 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.
    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: 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.
    JAMA The Journal of the American Medical Association 10/2014; 312(13):1305-1312. DOI:10.1001/jama.2014.11492 · 30.39 Impact Factor
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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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    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.
    09/2014; DOI:10.1002/art.38886
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    ABSTRACT: A link between obstructive sleep apnea and cancer development or progression has been suggested, possibly through chronic hypoxemia, but supporting evidence is limited. We examined the association between the severity of obstructive sleep apnea and prevalent and incident cancer, controlling for known risk factors for cancer development.
    Canadian Medical Association Journal 08/2014; 186(13). DOI:10.1503/cmaj.140238 · 5.81 Impact Factor
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    ABSTRACT: We examined patients' experiences regarding bone mineral density (BMD) testing and bone health treatment after being screened through Ontario's Fracture Clinic Screening Program. Provider-level barriers to testing and treatment appeared to be as significant as patient-level barriers and potentially had more of an impact on treatment than on testing.
    Osteoporosis International 08/2014; 25(11). DOI:10.1007/s00198-014-2804-4 · 4.17 Impact Factor
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    ABSTRACT: Background: Numerous disease modifying drugs for osteoarthritis (DMOADs) are under investigation. However, patients' preferences for drugs to prevent progression of OA are not known. The objective of this study was to quantify patient preferences for potential DMOADs. Methods: We administered a conjoint analysis survey to 304 patients attending outpatient general medicine and specialty clinics. All patients seated in the waiting rooms were asked if they would participate in a survey to elicit opinions about arthritis treatments. We performed simulations to estimate preferences for four options to prevent worsening of knee OA: Best Case (pill, highest benefit, lowest risk, lowest cost), Worst Case (infusion, lowest benefit, highest risk, highest cost), Moderate Subcutaneous Injection (injection, lowest benefit, mid-level risk, mid-level cost), and Moderate Infusion (same as previous except administered by infusion). Results: Subjects' median age was 57 years; 55% were female and 69% were Caucasian. Segmentation analyses revealed 4 patterns of preferences. A small minority (5%) who do not want to perform subcutaneous injections and will only consider DMOADs under the Best-Case scenario. Approximately 20% are risk sensitive and are willing to take DMOADs under the Best-Case scenario, but start rejecting these medications as risk increases. A significant number reject DMOADs under all conditions (16.4%); however, the largest segment (59.2%) has a strong preference for DMOADs across all scenarios. Conclusion: Our results suggest that a significant percent of a non-selected outpatient population might be willing to accept at least a moderate degree of risk in order to prevent worsening knee OA. © 2014 American College of Rheumatology.
    08/2014; 66(8). DOI:10.1002/acr.22280
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    ABSTRACT: Objective: To estimate the current and future (to year 2032) impact of osteoarthritis (OA) health care seeking. Method: Population-based study with prospectively ascertained data from the Skane Healthcare Register (SHR), Sweden, encompassing more than 15 million person-years of primary and specialist outpatient care and hospitalizations. We studied all Skane region residents aged >= 45 by the end of 2012 (n = 531, 254) and determined the prevalence of doctor-diagnosed OA defined as the proportion of the prevalent population that had received a diagnosis of OA of the knee, hip, hand, or other locations except the spine between 1999 and 2012. We projected consultation prevalence of OA until year 2032 using Statistics Sweden's (SCB) projected age and sex structure and prevalence of overweight and obesity. Results: In 2012 the proportion of population aged >= 45 with any doctor-diagnosed OA was 26.6% (95% confidence interval (CI): 26.5-26.8) (men 22.4%, women 30.5%). The most common locations were knee (13.8%), hip (5.8%) and hand (3.1%). Of the prevalent cases 26.8% had OA in multiple joints. By the year 2032, the proportion of the population aged >= 45 with doctor-diagnosed OA is estimated to increase from 26.6% to 29.5% (any location), from 13.8% to 15.7% for the knee and 5.8-6.9% for the hip. Conclusion: In 2032, at least an additional 26,000 individuals per 1 million population aged >= 45 years are estimated to have consulted a physician for OA in a peripheral joint compared to 2012. These findings underscore the need to address modifiable risk factors and develop new effective OA treatments.
    Osteoarthritis and Cartilage 07/2014; 22(11). DOI:10.1016/j.joca.2014.07.015 · 4.66 Impact Factor
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    ABSTRACT: To examine messages perceived by members of an osteoporosis (OP) patient group from various healthcare providers regarding bone health. We conducted a phenomenological (qualitative) study in members of an OP patient group who resided in Canada, had sustained a fragility fracture at 50+ years old, and were not taking antiresorptive medication at the time of that fracture. Participants were interviewed for approximately 1 h by telephone and responded to questions about visits to healthcare providers for their bone health and what was discussed during those visits. We analyzed the data guided by Giorgi's methodology. We interviewed 28 members (2 males, 26 females; 78 % response rate), aged 51-89 years old. Most participants perceived that their specialist was more interested than their primary care physician in bone health and took the time to discuss issues with them. Participants perceived very few messages from the fracture clinic and other providers. We found many instances where perceived messages within and across various healthcare providers were inconsistent, suggesting there is a need to raise awareness of bone health management guidelines to providers who treat fracture patients.
    Rheumatology International 06/2014; 35(1). DOI:10.1007/s00296-014-3079-y · 1.63 Impact Factor
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    ABSTRACT: Rationale: Despite emerging evidence that obstructive sleep apnea (OSA) may cause metabolic disturbances independently of other known risk factors, it remains unclear whether OSA is associated with incident diabetes. Objective: To evaluate whether risk of incident diabetes was related to the severity and physiological consequences of OSA. Methods and Measurements: A historical cohort study was conducted using a clinical and provincial health administrative data. All adults without previous diabetes referred with suspected OSA who underwent a diagnostic sleep study at St Michael's Hospital (Toronto, Canada) between 1994 and 2010 were followed through health administrative data until May 2011 to examine the occurrence of diabetes. All OSA-related variables collected from the sleep study were examined as predictors in Cox-regression models, controlling for sex, age, body mass index, smoking status, comorbidities and income. Main Results: Over a median follow-up of 67 months, 1,017 (11.7%) of 8,678 patients developed diabetes, giving a cumulative incidence at five years of 9.1% (95%CI: 8.4% to 9.8%). In fully-adjusted models, patients with apnea-hypopnea index (AHI) > 30 had a 30% higher hazard of developing diabetes than those with AHI < 5. Among other OSA-related variables, AHI in rapid eye movement (REM) sleep, and time spent with oxygen saturation less than 90% were associated with incident diabetes, as were heart rate, neck circumference and sleep time. Conclusions: Among people with OSA, and controlling for multiple confounders, initial OSA severity and its physiologic consequences predicted subsequent risk for incident diabetes.
    American Journal of Respiratory and Critical Care Medicine 06/2014; DOI:10.1164/rccm.201312-2209OC · 11.04 Impact Factor
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    ABSTRACT: To identify a cut point in annual surgeon volume associated with increased risk of complications after primary elective total hip arthroplasty and to quantify any risk identified.DESIGN: Propensity score matched cohort study.SETTING: Ontario, CanadaPARTICIPANTS: 37 881 people who received their first primary total hip arthroplasty during 2002-09 and were followed for at least two years after their surgery.MAIN OUTCOME MEASURE: The rates of various surgical complications within 90 days (venous thromboembolism, death) and within two years (infection, dislocation, periprosthetic fracture, revision) of surgery.RESULTS: Multivariate splines were developed to visualize the relation between surgeon volume and the risk for various complications. A threshold of 35 cases a year was identified, under which there was an increased risk of dislocation and revision. 6716 patients whose total hip arthroplasty was carried out by surgeons who had done ≤35 such procedure in the previous year were successfully matched to patients whose surgeon had carried out more than 35 procedures. Patients in the former group had higher rates of dislocation (1.9% v 1.3%, P=0.006; NNH 172) and revision (1.5% v 1.0%, P=0.03; NNH 204).CONCLUSIONS: In a cohort of first time recipients of total hip arthroplasty, patients whose operation was carried by surgeons who had performed 35 or fewer such procedures in the year before the index procedure were at increased risk for dislocation and early revision. Surgeons should consider performing 35 cases or more a year to minimize the risk for complications. Furthermore, the methods used to visualize the relationship between surgeon volume and the occurrence of complications can be easily applied in any jurisdiction, to help inform and optimize local healthcare delivery.
    BMJ Clinical Research 05/2014; 348:g3284. DOI:10.1136/bmj.g3284 · 14.09 Impact Factor
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    ABSTRACT: Introduction & Objective: Obstructive sleep apnea (OSA) has been postulated to cause cancer, possibly through chronic hypoxemia, but the evidence on this relationship is limited. Our objective was to explore the association between OSA severity, expressed by apnea-hypopnea index (AHI) and oxygen desaturation, and either prevalent or incident cancer after controlling for known risk factors for cancer such as older age, smoking, and being overweight. Methods: All adults who were referred with suspected OSA and underwent a first diagnostic sleep study at St Michael’s Hospital (Toronto, Canada) between 1994 and 2010, were included. Patient data was linked to Ontario health administrative data from 1991 to 2013. Two outcomes were explored: prevalent and incident cancer derived from the Ontario Cancer Registry. Logistic regression analysis was performed to predict prevalent cancer at baseline among patients with OSA. In a cohort free of cancer at baseline, Cox regression models were used to investigate the relationships between OSA and incident cancer. Models controlled for known risk factors. Results: In total, 10,149 subjects were included in our analyses. Participants with prevalent cancer at baseline (n=520) were older, with a higher percentage of ex-smokers, a greater number of comorbid conditions, more severe OSA, and higher mortality compared to those without cancer. Over a median follow-up of 93 months, 627 of 9,629 participants (6.5%) developed incident cancer. Cumulative incidence of cancer at 5 years for the entire cohort was 3.7% (95%CI: 3.3-4.0) and decreased significantly with greater baseline OSA severity (2.6% for AHI<5 vs. 4.9% for AHI>30). In multivariable regression models OSA severity was not a significantly associated with either prevalent or incident cancer controlling for age, sex, body mass index and smoking status at baseline. Conclusions: In a large cohort, OSA was not found to be independently associated with either prevalent or incident cancer. Additional studies are needed to elucidate whether there is an independent effect of OSA on specific types of cancer.
    2014 American Thoracic Society (ATS) International Conference in San Diego, California, May 17 - May 20; 05/2014
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    ABSTRACT: Background Physicians often classify patients’ osteoarthritis (OA) severity subjectively. As treatment decisions are influenced by severity classifications, it is important to understand the factors that influence physicians’ OA severity ratings. This research sought to empirically identify physician and patient characteristics that lead to a patient being perceived as having more severe OA. Methods Data were analyzed from the Osteoarthritis IX Disease Specific Program, a large cross-sectional survey of OA physicians and patients in Germany, the UK, and USA between September 2011 and January 2012. Eligible, consenting physicians completed a Patient Record Form (PRF) for ten consecutive OA patients. The PRF asked physicians to report the patient’s demographics (age, gender, BMI, ethnicity), their assessment of the patients’ symptom severity, treatment, probability for surgery, to rate their overall OA severity (mild, moderate or severe) and the factors that had influenced the rating. Ordered logistic regression modeling was used to identify patient characteristics that significantly impacted physicians' OA severity ratings. Controlling for the significant patient characteristics, we then examined the impact of physician specialty on physician's OA severity ratings. Finally, we investigated the differences in physician-reported factors that influenced the physicians' rating of patients' severity between physician specialties. Results 363 physicians [220 primary care physicians (PCP), 48 rheumatologists, 95 orthopedic surgeons] recruited 3,561 patients. Patients with greater age and BMI, worse symptoms and greater health care use were given higher OA severity ratings. Controlling for these factors, orthopedic surgeons rated their OA patients as more severe than PCPs and rheumatologists [adjusted odds ratio (OR) 1.8, 95% confidence interval (CI) 1.4 to 2.4]. Specialists (rheumatologists and orthopedic surgeons) were more likely than PCPs to use joint spaced narrowing based on X-ray and severity of joint deterioration radiographic severity to assess patients’ OA severity (joint space narrowing: 79% and 78% vs. 55% p <0.0001). Conclusions Patient age, BMI, presence and severity of symptoms and health care use significantly impacted physicians' OA severity ratings, but radiographic changes appeared to be given greater weight among orthopedic surgeons and rheumatologists than PCPs when assessing patient severity. Whether these differences translate into different treatment recommendations for similar patients is unknown, and warrants study.
    Osteoarthritis and Cartilage 05/2014; DOI:10.1016/j.joca.2014.03.001 · 4.66 Impact Factor
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    ABSTRACT: Internationally, chronic disease self-management programs (CDSMPs) have been widely promoted with the assumption that confident, knowledgeable patients practicing self-management behavior will experience improved health and utilize fewer healthcare resources. However, there is a paucity of published data supporting this claim and the majority of the evidence is based on self-report.
    BMC Health Services Research 05/2014; 14(1):198. DOI:10.1186/1472-6963-14-198 · 1.66 Impact Factor
    This article is viewable in ResearchGate's enriched format
  • Osteoarthritis and Cartilage 04/2014; 22:S16. DOI:10.1016/j.joca.2014.02.052 · 4.26 Impact Factor
  • Osteoarthritis and Cartilage 04/2014; 22:S378-S379. DOI:10.1016/j.joca.2014.02.706 · 4.66 Impact Factor
  • Osteoarthritis and Cartilage 04/2014; 22:S391. DOI:10.1016/j.joca.2014.02.729 · 4.66 Impact Factor

Publication Stats

9k Citations
1,259.86 Total Impact Points


  • 1995–2014
    • Women's College Hospital
      Toronto, Ontario, Canada
  • 1993–2014
    • University of Toronto
      • • Institute for Clinical Evaluative Sciences
      • • Department of Physical Therapy
      • • Institute of Health Policy, Management and Evaluation
      • • Department of Medicine
      • • Department of Electrical and Computer Engineering
      • • Faculty of Medicine
      • • Division of Rheumatology
      Toronto, Ontario, Canada
    • Newton-Wellesley Hospital
      Boston, Massachusetts, United States
  • 2013
    • Yale University
      New Haven, Connecticut, United States
  • 2012
    • Dalhousie University
      • College of Pharmacy
      Halifax, Nova Scotia, Canada
  • 2011
    • St. Michael's Hospital
      Toronto, Ontario, Canada
  • 2008–2011
    • Toronto Western Hospital
      Toronto, Ontario, Canada
  • 2007–2011
    • Université René Descartes - Paris 5
      • Faculté de Médecine
      Paris, Ile-de-France, France
  • 2003–2011
    • Institute for Clinical Evaluative Sciences
      Toronto, Ontario, Canada
  • 2010
    • Women's College Research Institute
      Toronto, Ontario, Canada
    • University of Bristol
      Bristol, England, United Kingdom
    • University of Massachusetts Boston
      Boston, Massachusetts, United States
    • Arthritis Research UK
      Chesterfield, England, United Kingdom
  • 2005–2010
    • University Health Network
      • • Division of Healthcare and Outcomes Research
      • • Department of Medicine
      Toronto, Ontario, Canada
  • 2009
    • Centre Hospitalier Universitaire de Dijon
      Dijon, Bourgogne, France
    • University of British Columbia - Vancouver
      • School of Population and Public Health
      Vancouver, British Columbia, Canada
  • 2006–2009
    • University of Ottawa
      • • Institute of Population Health
      • • Department of Medicine
      Ottawa, Ontario, Canada
    • University of Burgundy
      Dijon, Bourgogne, France
    • Haukeland University Hospital
      Bergen, Hordaland, Norway
  • 2002–2008
    • SickKids
      Toronto, Ontario, Canada
  • 2003–2006
    • Sunnybrook Health Sciences Centre
      Toronto, Ontario, Canada
  • 2001
    • Harbor-UCLA Medical Center
      Torrance, California, United States
  • 1999
    • Mount Sinai Hospital, Toronto
      Toronto, Ontario, Canada
  • 1996
    • Indiana University-Purdue University Indianapolis
      • Department of Biostatistics
      Indianapolis, IN, United States