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Biomedical subjects

G Hawker

Publications and source records attributed to G Hawker.

At least 19 recordsLinked to original sources
PubMed2001

Hip function in patients >55 years old: population reference values.

The purpose of this study was to establish population values for hip function for patients of different ages using the validated WOMAC scoring system and the traditional Harris hip scoring system. A random sample of 184 individuals who had no prior history of hip or knee pain or pathology was evaluated. The average WOMAC scores for pain, function, and stiffness were 0.01, 1.8, and 0.4. The average Harris hip score was 94 +/- 8.2. No significant correlation was noted between the summary WOMAC score, the WOMAC stiffness or pain subscales, or the overall Harris hip score for any of the 3 age groups studied. Patients with complaints in other joints, such as the back and neck, had lower WOMAC and Harris hip scores. Adults who are healthy and do not have a prior history of hip or knee pathology do not show a significant decline in hip function as they grow older. A deterioration in the function of a total hip arthroplasty over time cannot be attributed solely to the aging process.

Aged↗
PubMed2000

Patterns of use of the bone mineral density test in Ontario, 1992-1998.

BACKGROUND: There is ongoing controversy about who should be referred for bone mineral density (BMD) testing to estimate fracture risk and diagnose osteoporosis. The purpose of this study was to examine patterns of use of BMD testing in Ontario between 1992 and 1998. METHODS: All physician claims from the Ontario Health Insurance Plan (OHIP) claims database for BMD testing between Jan. 1, 1992, and Dec. 31, 1998, were categorized by age and sex of the patient and the specialty of the physician who ordered the test. Time trends and regional rate variation analyses were also performed. To examine the prevalence of repeat testing, an inception cohort of women who had a BMD test in 1996 was followed for 2 years from the date of first test. RESULTS: From 1992 to 1998 the number of BMD tests performed per year in women increased from 34,402 to 230,936 and in men from 2,162 to 13,579. In 1998 most tests were being ordered by family physicians (80.2% in 1998 v. 52.1% in 1992). Approximately 1 in 7 women aged 55-69 years had BMD tests done in 1998. Within a 2-year period 29.3% of these women had the test repeated; the mean time between tests was 16 months. Regional rate variation analyses of BMD tests performed in 1996-1998 indicated a 235-fold variation in BMD test rates across counties in Ontario, with a range from 0.2 to 47.1 per 1000 women in the population. INTERPRETATION: The number of BMD tests performed each year in Ontario is increasing rapidly. However, the significant variation between rates of testing in different regions indicates that the diffusion of this technology may not be taking place according to population need.

Absorptiometry, Photon↗
PubMed2000

Investigation and treatment of osteoporosis in patients with fragility fractures.

BACKGROUND: Many patients who have undiagnosed osteoporosis and a recent fragility fracture present to fracture clinics in Canadian hospitals, where the focus of management is on fracture care. The rate of diagnosis and treatment of osteoporosis in this patient group is unknown. METHODS: Patients who presented with fractures at sites consistent with fragility-type fractures were identified through a retrospective chart review of fracture clinic visits in 3 Ontario community hospitals in selected weeks in February and November 1996 and August and May 1997. These patients were contacted by mail and telephone follow-up to obtain consent to participate in a telephone interview. Patients were excluded if the index fracture had been traumatic, if they were younger than 18 years, or if they had medical conditions known to be associated with secondary bone loss. Eligible patients were questioned about their history of prior fractures, diagnosis of osteoporosis, and investigation and treatment of osteoporosis before or after the index fracture. RESULTS: Among 2694 fracture clinic visits, we identified 228 patients (8.4%) with fragility-type fractures. Of the 228, 128 (56.1%) were contacted and agreed to participate in an interview about 1 year from the date of the index fracture. Of the 128 patients, 108 (83 postmenopausal and 13 premenopausal women and 12 men) were confirmed as eligible. Of the 108, 43 had experienced 53 fractures in addition to the index fracture in the preceding 10 years, of which 71% were of the fragility type. At interview, only 20 (18.5%) (all postmenopausal women) of the 108 patients reported that they had received a diagnosis of osteoporosis. Of the 20, 90% and 45% respectively had been advised to take calcium and vitamin D supplements; 8 (40%) were receiving hormone replacement therapy (HRT), and 8 (40%) were taking bisphosphonates. Of the 88 patients who had not received a diagnosis of osteoporosis, 4 (4.5%) were receiving HRT, none was taking bisphosphonates, and less than 20% had been advised to take supplemental calcium or vitamin D. INTERPRETATION: In a representative sample of patients at urban fracture clinics, less than 20% who presented with a fragility-type fracture had undergone investigation and adequate treatment of osteoporosis at 1-year follow-up. Since previous fracture significantly increases the risk for future fracture, this clearly is a deficiency in management. Through improved identification and treatment of patients with osteoporosis-related fractures who present to fracture clinics, there is a significant opportunity to reduce the rates of illness and death associated with this condition.

Calcium↗
PubMed1999

Patient Outcomes Research Teams: contribution to outcomes and effectiveness research.

This paper describes the key methodological and substantive findings of Patient Outcomes Research Teams, the first outcomes and effectiveness research centers funded by the Agency for Health Care Policy and Research. Patient Outcomes Research Teams contributed to our increased understanding of how to perform meta analysis on nontrial data, use administrative data to characterize patterns of care, develop general and disease-specific outcome measures, and disseminate important outcome information to patients and physicians to reduce practice variation. Patient Outcomes Research Teams also influenced the development of outcomes measurement in the private sector.

Health Services Research↗
PubMed1999

Rates of revision knee replacement in Ontario, Canada.

BACKGROUND: The present study was designed to measure the longevity of knee replacements and to assess the determinants of revision knee replacements in order to enhance the potential for informed decision-making. METHODS: Data on all hospitalizations for knee replacement that occurred in Ontario, Canada, between April 1, 1984, and March 31, 1991, were acquired. To calculate the rates of revision knee replacement, two algorithms were developed: one distinguished primary knee replacements from revision knee replacements, and the second linked revision knee replacements to primary knee replacements. The Kaplan-Meier method was used to assess survivorship (absence of a revision) for primary knee replacement. A proportional-hazards regression model was estimated to assess the role of independent variables on the survival of primary knee replacements. RESULTS: During the period of the study, 7.0 percent (1301) of 18,530 knee replacements were classified as revisions. Significant differences were identified between hospitalizations for primary and revision knee replacements in terms of the patient and hospital characteristics. Patients who were more than fifty-five years old, lived in a rural area, or had a diagnosis of rheumatoid arthritis had a significantly (p < 0.05) longer duration before revision than did other patients. Primary knee replacements performed in a teaching or specialty hospital had a significantly (p < 0.05) shorter duration before revision than did those performed in a non-teaching hospital. The long-term rates of revision were uniformly low. Estimates of the proportion of knee replacements that would need to be revised within seven years ranged from a low of 4.3 percent, with use of the algorithm for the longest time to revision, to a high of 8.0 percent, with use of the algorithm for the shortest time to revision. CONCLUSIONS: Revision of a primary knee replacement was a rare event that depended on a patient's age, gender, and place of residence as well as on the hospital where the primary knee replacement was performed. Estimates of the rates of revision knee replacement after almost seven years ranged from a low of 4.3 percent to a high of 8.0 percent.

Aged↗
PubMed1998

Health-related quality of life after knee replacement.

A cross-sectional, community-based survey of a random sample of 1750 of 242,311 Medicare recipients was performed. The patients were at least sixty-five years old and had had a primary or revision knee replacement (either unilaterally or bilaterally) between 1985 and 1989. Three samples were surveyed separately: a national sample (to reflect the United States as a whole) and samples from Indiana and the western part of Pennsylvania (sites chosen for convenience to assess the validity of the findings for the national sample on a regional level). Each sample was stratified by race, age, residence (urban or rural), and the year of the procedure. Valid and reliable questionnaires were used to elicit the participants' assessments of pain, physical function, and satisfaction two to seven years after the knee replacement. Of the 1486 patients who were eligible for inclusion in the survey, 1193 (80.3 per cent) responded. The mean age of the respondents was 72.6 years. Eight hundred and forty-nine respondents (71.2 per cent) were white, and 849 (71.2 per cent) were women. The participants reported that they had little or no pain in the knee at the time of the survey, regardless of the age at the time of the knee replacement, the body-mass index, or the length of time since the knee replacement. After adjustment for potential confounding variables, predictors of better physical function after the replacement were an absence of problems with the contralateral knee, primary knee replacement (rather than revision) (Indiana sample only), and a lower body-mass index (Indiana and western Pennsylvania samples). Four hundred and fifteen (85.2 per cent) of the 487 patients in the national sample were satisfied with the result of the knee replacement. In what we believe to be the first community-based study of the outcome of knee replacement, patients reported having significant (p = 0.0001) and persistent relief of pain, improved physical function, and satisfaction with the result two to seven years postoperatively. The findings of the present study suggest that age and obesity do not have a negative impact on patient-relevant outcomes (pain and physical function). Dissemination of these findings has the potential to increase appropriate referrals for knee replacement and thereby reduce the pain and functional disability due to osteoarthrosis of the knee.

Aged↗
PubMed1997

Comparison of general internists, family physicians, and rheumatologists managing patients with symptoms of osteoarthritis of the knee.

OBJECTIVE: To evaluate the nature, risks, and benefits of osteoarthritis (OA) management by primary care physicians and rheumatologists. METHODS: Subjects were 419 patients followed for symptoms of knee OA by either a specialist in family medicine (FM) or general internal medicine (GIM) or by a rheumatologist (RH). Management practices were characterized by in-home documentation by a visiting nurse of drugs taken to relieve OA pain or to prevent gastrointestinal side effects of nonsteroidal anti-inflammatory drugs (NSAIDs) and by patient report (self-administered survey) of nonpharmacologic treatments. Changes in outcomes (knee pain and physical function) over 6 months were measured with the Western Ontario and McMaster Universities Osteoarthritis Index. RESULTS: Patients of RHs were 2-3 years older (P = 0.035) and tended to exhibit greater radiographic severity of OA (P = 0.064) and poorer physical function (P = 0.076) at baseline than the other 2 groups. In all 3 groups, knee pain and physical function improved slightly over 6 months; however, between-group differences were not significant. Compared to drug management of knee pain by FMs or RHs, that by the GIMs was distinguished by greater utilization of acetaminophen and nonacetylated salicylates (P = 0.008), lower prescribed doses of NSAIDs (P = 0.007), and, therefore, lower risk of iatrogenic gastroenteropathy (P < 0.001). In contrast, patients of RHs were more likely than those of FMs and GIMs to report that they had been instructed in use of isometric quadriceps and range-of-motion exercises (P < or = 0.001), application of heat (P = 0.051) and cold (P < 0.001) packs, and in the principles of joint protection (P = 0.016). Neither physician specialty nor specific management practices accounted for variations in patient outcomes. CONCLUSION: This observational study identified specialty-related variability in key aspects of the management of knee OA in the community (i.e., frequency and dosing of NSAIDs, use of nonpharmacologic modalities) that bear strong implications for long-term safety and cost. However, changes in knee pain and function over 6 months were unrelated to variations in management practices.

Activities of Daily Living↗
PubMed1997

Osteoarthritis of the hip and knee and mechanical occupational exposure--a systematic overview of the evidence.

OBJECTIVE: To clarify examine the epidemiologic evidence linking work related exposure to osteoarthritis (OA) of the hip and knee. METHODS: We investigated MEDLINE and EMBASE 1966-1994 with search terms of osteoarthritis, osteoarthrosis, arthrosis; risk factors, exposure; occupational diseases, agricultural workers' diseases, work. From 123 original studies on risk factors for OA, 17 studies were identified as providing a comparison group and relating the presence or absence of radiologically diagnosed OA to occupational factors. The quality of the methodology of each study was evaluated independently by 4 reviewers using a standardized protocol. RESULTS: Common methodological problems were encountered in areas such as representatives, recall of exposure, and evaluation of exposure and outcome. These problems often made a cause-effect relationship difficult to interpret. However, 7 of the 17 studies met our criteria for good methodological quality. A critical analysis of their results led to the following conclusions: (1) A consistently positive relationship exists between work involving knee bending and knee OA in men (range of odds ratio: 1.4-6). (2) The evidence suggesting a relationship between knee OA and occupational exposure in women is inconclusive. (3) A consistently positive but weak relationship exists between work related exposure (i.e., farming in particular) and hip OA in men. We felt we could not conclude with confidence that this relationship is strong due to the potential biases that exist in each of these studies. (4) No study attempted to investigate occupational exposure and hip OA in women. CONCLUSION: Studies suggest a strong positive relationship between work related knee bending exposure and knee OA. The evidence between work related exposure, farming in particular, and hip OA is consistently positive but weak.

Female↗
PubMed1997

The relationship between variations in knee replacement utilization rates and the reported prevalence of arthritis in Ontario, Canada.

OBJECTIVE: To determine the relationship between regional variations in knee replacement (KR) utilization rates in Ontario, Canada, and the reported prevalence of arthritis and rheumatism as a chronic health problem. METHODS: Utilization data were acquired from the Canadian Institute for Health Information for KR procedures performed in Ontario between fiscal years 1984 and 1990. Census information was obtained from Statistics Canada. Disease prevalence data were derived from the 1990 Ontario Health Survey (OHS). Public Health Units (PHU) were used as the unit of analysis, with utilization rates defined as the number of KR performed on all PHU residents (irrespective of where these procedures were performed) divided by the population. Direct methods were used to standardize utilization for age, sex, and disease prevalence. The extremal quotient, the weighted coefficient of variation, and the systematic component of variation were used as measures of variation. The relationship between the number of KR performed in each age-sex-year strata and various demographic (age and sex), disease prevalence, and regional dummy variables was estimated using a Poisson regression model. RESULTS: Regional variation in the standardized utilization of KR surgery was wide, but declined over the study period; the extremal quotient fell from 8.0 to 3.3, the weighted coefficient of variation fell from 0.49 to 0.30, and the systematic component of variation fell from 0.20 to 0.17. Variation in the provision of KR surgery remained even after controlling for the demographic composition of the population and disease prevalence. Moreover, while demographic, regional, and temporal covariates were significant (p < 0.0001) in accounting for over 90% of the variation in utilization, disease prevalence was not significant (p > 0.05). CONCLUSION: This study merged population based reports of disease prevalence with administrative data to account for regional variations in utilization. While regional variations in KR surgery have fallen over time, variations remain even after adjusting for patient reported disease prevalence. The finding that demographic variables and the reported prevalence of disease were poorly correlated suggests that current area variation studies may not be adjusting fully for disease prevalence or severity.

Aged↗
PubMed1996

Appropriateness of primary total hip and knee replacements in regions of Ontario with high and low utilization rates.

OBJECTIVE: To compare the appropriateness of case selection for primary hip and knee replacements between two regions in Ontario: one with a high population-based utilization rate and one with a low rate. DESIGN: Random audit of medical records sampled from hospital discharge abstracts, with subsequent implicit and explicit criteria-based assessments of the appropriateness of surgery. STUDY POPULATION: People aged 60 years or over who underwent elective, single-joint, non-fracture-related, primary hip or knee replacement between Apr. 1, 1992, and Mar. 31, 1993, at one of seven hospitals in a high-rate region (comprising Brant, Huron and Oxford countries) or one of eight hospitals in a low-rate region (comprising the cities of Scarborough and Toronto). INTERVENTIONS: Structured review of hospital medical records, with additional review of information from surgeons and family physicians' office charts if necessary. Three physicians reviewed patient data and rated the preoperative pain level and functional status of patients, with agreement among at least two reviewers. The proportion of inappropriate cases was then assessed according to explicit criteria defined by a multidisciplinary panel using the delphi process. Profiles of each case were also subjected to independent implicit review by two rheumatologists and two orthopedic surgeons. OUTCOME MEASURES: Proportion of joint replacements deemed inappropriate in the high- and low-rate regions according to either the explicit criteria or the implicit review, as well as preoperative pain levels and functional status of patients in the high- and low-rate regions. RESULTS: Hip replacements were more common among patients sampled in the low-rate region than among those in the high-rate region (57.3% v. 39.3%; p < 0.002), although the patients' baseline characteristics, including severity of preoperative pain and dysfunction, were otherwise similar between the regions. Inappropriate surgery, determined by explicit criteria, was equally uncommon in the two regions (6.4% and 6.1%). On implicit review, the two rheumatologists rated fewer cases as appropriate than did the two orthopedic surgeons (63.0% v. 80.0%; p < 0.001); however, the proportion of cases rated as inappropriate by the subspecialists was similar in the high- and low-rate regions (11.4% and 11.0%, respectively, by the rheumatologists, and 6.3% and 10.4%, respectively, by the orthopedic surgeons). CONCLUSIONS: Patients selected for primary hip or knee replacement are similar in the high- and low-rate regions of Ontario. Inappropriate use of this procedure does not account for the high rate of surgery in some areas. Further studies will be required to determine which other factors account for the regional variations in the utilization rates and whether there is underservicing in low-rate areas.

Chi-Square Distribution↗
PubMed1996

Demographic variation in the rate of knee replacement: a multi-year analysis.

OBJECTIVE: The aim of this study is to describe the practice variation of knee replacements (KRs) in the elderly ( > or = 65) over time from 1985-1990 in terms of the number of primary, bilateral, and revision KRs; the extent of large area variation in performance rates; and the degree to which demographic variables are the determinants of area rates. DATA SOURCES/STUDY SETTING: Data analyzed are from every hospital in the United States that performed a KR on a Medicare patient during the study period. Data were obtained from the MEDPAR, HISKEW, and denominator files of the Medicare Statistical System. STUDY DESIGN: This is a cohort study of all Medicare beneficiaries who received a KR between 1985 and 1990. The dependent variable in the analyses was the count of the KRs performed in each area. DATA COLLECTION/EXTRACTION METHODS: This is a population-based sample of Medicare enrollees in the United States. All hospitalizations for Medicare-reimbursed KRs were included in the initial data set. Exclusion criteria were used to identify the Medicare covered population with a definite KR. These criteria resulted in 7.3 percent exclusions and a final set of 414,079 KR hospitalizations. PRINCIPAL FINDINGS: The number of Medicare-funded KRs increased in each of the study years corresponding to an annual rate of increase of 18.45 percent. The likelihood of receiving a KR was a function of age, gender, and race. For each year, KRs were almost-twice as likely to be performed on women than on men. The odds of whites getting the surgery were over 1.5 times greater than for blacks. Even after adjusting for demographic factors, significant regional variation remained. CONCLUSIONS: Much about area variation and the rate of growth in KR rates remains unexplained. For answers to emerge, better data and different types of studies are required.

Age Factors↗
PubMed1996

Variation in rheumatologists' and family physicians' perceptions of the indications for and outcomes of knee replacement surgery.

OBJECTIVE: To assess agreement among rheumatologists and family physicians (FP) about the indications for knee replacement (KR) referral, use of nonsurgical management options, and perceived outcomes of KR, and to determine the relationship between these opinions and the number of patients seen with severe osteoarthritis (OA) of the knee. METHODS: 98 adult rheumatologists and a random sample of 250 FP in Ontario, Canada were surveyed. Of the practising and traceable rheumatologists and FP, 70.0 and 5.16% responded, respectively. RESULTS: FP disagreed on how 28 of 32 patient factors affected their KR referral decision, while rheumatologists disagreed on 26 of these 32 factors (p = 0.03). Rheumatologists and FP consistently disagreed on the use of 8 of 10 treatments for knee OA (p = 0.37). While rheumatologists and FP reported similar KR outcomes, FP were less in agreement (p = 0.03). Clinical disagreement for the indications for KR (p < 0.0001) and KR outcomes (p < 0.0001) were greater among FP than among orthopedic surgeons who were surveyed in a prior study. Clinical disagreement about the indications for KR was greater among rheumatologists than among surgeons (p = 0.04), but there was no difference in perceived KR incomes (p = 0.18). CONCLUSION: Referring physicians disagreed on the indications for KR referral an on the treatments for knee arthritis, but were in general agreement regarding KR outcomes. Clinical disagreement was greater among FP than among rheumatologists, who in turn reported more disagreement than orthopedic surgeons. Explanations for these difference in perceptions should be the focus of research, but guidelines specifically tailored for each physician specialty may be required to reduce clinical uncertainty.

Adult↗
PubMed1996

Variations in knee replacement utilization rates and the supply of health professionals in Ontario, Canada.

OBJECTIVE: To measure regional variations in knee replacement (KR) utilization rates across the 49 counties of Ontario, Canada, since April 1, 1984, and to evaluate its relationship with the supply of health professionals. METHODS: Utilization data were acquired from the Canadian Institute for Health Information, and physician data were acquired from the Ontario Ministry of Health. There were 18,530 hospitalizations for KR in Ontario between April 1, 1984 and March 31, 1991. Utilization rates were defined as the number of KR procedures for all residents of each county (irrespective of where these procedures were performed) divided by the resident population. Direct methods were used to standardize utilization for age and sex. The extremal quotient, the weighted coefficient of variation, and the systematic coefficient of variation were used as measures of variation. RESULTS: Between fiscal years 1984 and 1990, the extremal quotient fell from 8.1 to 3.4, the weighted coefficient of variation fell from 0.430 to 0.315, and the systematic coefficient of variation fell from 0.215 to 0.142. Utilization was greater in southwestern Ontario (p < 0.001) and lower in Toronto and Durham (p < 0.001) than elsewhere. Utilization in remote areas was not different from that for the province as a whole (p < 0.001). The correlation coefficient between standardized KR utilization and the density of orthopedic surgeons was not significant (p = 0.26) at -0.16, but those for rheumatologists (r = -0.25, p = 0.08) and physical medicine specialists (r = -0.42, p = 0.002) were significant. CONCLUSION: Regional variation in KR surgery has fallen since fiscal year 1984 from "very high" variability to "moderate" variability. KR utilization was shown to be negatively, but not significantly, related to orthopedic surgeon density. Therefore, proposals to modify surgeons' fees or to influence their practice locations may equalize the supply of surgeons, but are unlikely to affect the pattern of KR utilization.

Adult↗
PubMed1995

Variation in orthopedic surgeons' perceptions of the indications for and outcomes of knee replacement.

OBJECTIVE: To determine the agreement among orthopedic surgeons' indications for knee replacement, their perceptions of the usefulness of various treatments for osteoarthritis of the knee and their expected outcomes of knee replacement, and to determine the relation between these opinions and the number of knee replacement procedures performed by individual surgeons. DESIGN: Survey. SETTING: Ontario. PARTICIPANTS: All 392 orthopedic surgeons in the province. Of the 325 practising traceable surgeons 234 (72.0%) responded. OUTCOME MEASURES: Indications for knee replacement, perceived usefulness of treatments for osteoarthritis, perceived outcomes of knee replacement and number of knee replacement procedures performed by individual surgeons. RESULTS: The respondents disagreed on how 20 of 34 patient characteristics affected their decision to perform knee replacement surgery. They also disagreed on the usefulness of seven of eight treatments for arthritis of the knee. The respondents demonstrated variation in their expected outcomes of knee replacement. The surgeons who performed more procedures judged, on average, the outcomes to be better and to have fewer complications than the surgeons who performed fewer procedures. CONCLUSIONS: Orthopedic surgeons demonstrated disagreement about some of the indications for knee replacement, the usefulness of treatments for arthritis of the knee and the perceived outcomes of knee replacement. The areas of greatest disagreement should be the focus of future research and the development of practice guidelines.

Adult↗