Primary care physicians' perceptions about and confidence in deciding which patients to refer for total joint arthroplasty of the hip and knee.

OBJECTIVE: The purpose of this study is to examine the perceptions of primary care physicians (PCPs) regarding indications, contraindications, risks and benefits of total joint arthroplasty (TJA) and their confidence in selecting patients for referral for TJA. DESIGN: PCPs recruited from among those providing care to participants in an established community cohort with hip or knee osteoarthritis (OA). Self-completed questionnaires were used to collect demographic and practice characteristics and perceptions about TJA. Confidence in referring appropriate patients for TJA was measured on a scale from 1 to 10; respondents scoring in the lowest tertile were considered to have 'low confidence'. Descriptive analyses were conducted and multiple logistic regression was used to determine key predictors of low confidence. RESULTS: 212 PCPs participated (58% response rate) (65% aged 50+ years, 45% female, 77% >15 years of practice). Perceptions about TJA were highly variable but on average, PCPs perceived that a typical surgical candidate would have moderate pain and disability, identified few absolute contraindications to TJA, and overestimated both the effectiveness and risks of TJA. On average, PCPs indicated moderate confidence in deciding who to refer. Independent predictors of low confidence were female physicians (OR = 2.18, 95% confidence interval (CI): 1.06-4.46) and reporting a 'lack of clarity about surgical indications' (OR = 3.54, 95% CI: 1.87-6.66). CONCLUSIONS: Variability in perceptions and lack of clarity about surgical indications underscore the need for decision support tools to inform PCP - patient decision making regarding referral for TJA.

Return to work and workplace activity limitations following total hip or knee replacement.

OBJECTIVE: Total hip (THR) and knee (TKR) replacements increasingly are performed on younger people making return to work a salient outcome. This research evaluates characteristics of individuals with early and later return to work following THR and TKR. Additionally, at work limitations pre-surgery and upon returning to work, and factors associated with work limitations were evaluated. METHODS: 190 THR and 170 TKR of a total 931 cohort participants were eligible (i.e., working or on short-term disability pre-surgery). They completed questionnaires pre-surgery and 1, 3, 6 and 12 months post-surgery that included demographics, type of occupation, and the Workplace Activity Limitations Scale (WALS). RESULTS: 166 (87%) and 144 (85%) returned to work by 12 months following THR and TKR, respectively. Early (1 month) return to work was associated with, male gender, university education, working in business, finance or administration, and low physical demand work. People with THR returned to work earlier than those with TKR. For both groups, less pain and every day functional limitations were associated with less workplace activity limitations at the time return to work. CONCLUSIONS: The majority of individuals working prior to surgery return to work following hip or knee replacement for osteoarthritis (OA) and experience fewer limitations at work than pre-surgery. The changing workforce dynamics and trends toward surgery at younger ages mean that these are important outcomes for clinicians to assess. Additionally, this is important information for employers in understanding continued participation in employment for people with OA.

The trajectory of recovery and the inter-relationships of symptoms, activity and participation in the first year following total hip and knee replacement.

OBJECTIVE: Primary total hip (THR) and knee (TKR) replacement outcomes typically include pain and function with a single time of follow-up post-surgery. This research evaluated the trajectory of recovery and inter-relationships within and across time of physical impairments (PI) (e.g., symptoms), activity limitations (AL), and social participation restrictions (PR) in the year following THR and TKR for osteoarthritis. DESIGN: Participants (hip: n=437; knee: 494) completed measures pre-surgery and at 2 weeks, 1, 3, 6 and 12 months post-surgery. These included PI (Hip Disability and Osteoarthritis Outcome Score (HOOS)/Knee Injury and Osteoarthritis Outcome Score (KOOS) symptoms and Chronic Pain Grade); AL (HOOS/KOOS activities of daily living and sports/leisure activities); and, PR (Late Life Disability and the Calderdale community mobility). Repeated measures analysis of variance (RANOVA) was used to evaluate the trajectory of recovery of outcomes and the inter-relationships of PI, AL and PR were evaluated using path analysis. All analyses were adjusted for age, sex, obesity, THR/TKR, low back pain and mood. RESULTS: THR: age 31-86 years with 55% female; TKR: age 35-88 years with 65% female. Significant improvements in outcomes were observed over time. However, improvements were lagged over time with earlier improvements in PI and AL and later improvements in PR. Within and across time, PI was associated with AL and AL was associated with PR. The magnitude of these inter-relationships varied over time. CONCLUSION: Given the lagged inter-relationship of PI, AL and PR, the provision and timing of interventions targeting all constructs are critical to maximizing outcome. Current care pathways focusing on short-term follow-up with limited attention to social and community participation should be re-evaluated.

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

OBJECTIVES: The purpose of the study was to develop a population-based simulation model of osteoarthritis (OA) in Canada that can be used to quantify the future health and economic burden of OA under a range of scenarios for changes in the OA risk factors and treatments. In this article we describe the overall structure of the model, sources of data, derivation of key input parameters for the epidemiological component of the model, and preliminary validation studies. DESIGN: We used the Population Health Model (POHEM) platform to develop a stochastic continuous-time microsimulation model of physician-diagnosed OA. Incidence rates were calibrated to agree with administrative data for the province of British Columbia, Canada. The effect of obesity on OA incidence and the impact of OA on health-related quality of life (HRQL) were modeled using Canadian national surveys. RESULTS: Incidence rates of OA in the model increase approximately linearly with age in both sexes between the ages of 50 and 80 and plateau in the very old. In those aged 50+, the rates are substantially higher in women. At baseline, the prevalence of OA is 11.5%, 13.6% in women and 9.3% in men. The OA hazard ratios for obesity are 2.0 in women and 1.7 in men. The effect of OA diagnosis on HRQL, as measured by the Health Utilities Index Mark 3 (HUI3), is to reduce it by 0.10 in women and 0.14 in men. CONCLUSIONS: We describe the development of the first population-based microsimulation model of OA. Strengths of this model include the use of large population databases to derive the key parameters and the application of modern microsimulation technology. Limitations of the model reflect the limitations of administrative and survey data and gaps in the epidemiological and HRQL literature.

Insomnia and health problems in Canadians.

STUDY OBJECTIVES: The objective of this study was to determine the prevalence of, and to identify the relative contribution of selected factors associated with insomnia in the Canadian population age 15 and older. DESIGN: Weighted analysis of cross-sectional data from the Canadian General Social Survey, Cycle 6, 1991. Prevalence estimates were calculated for the total and age-specific Canadian population age 15 and older. Multiple logistic regression techniques were employed to study the contribution of an array of sociodemographic, lifestyle, stress, and physical health factors to the experience of insomnia. SETTING: N/A. PARTICIPANTS: A representative sample of the Canadian household population age 15+ (n=11,924). INTERVENTIONS: N/A. MEASUREMENTS AND RESULTS: Twenty-four percent of the Canadian population age 15+ report insomnia. The following factors were associated with insomnia in multivariate logistic regression: female gender, being widowed or single, low education, low income, not being in the labor force, ever having smoked, life stress, specific chronic physical health problems (circulatory, digestive and respiratory disease, migraine, allergy and rheumatic disorders), pain, activity limitation and health dissatisfaction. Age was not significantly associated with insomnia. CONCLUSIONS: Insomnia was highly prevalent among the non-institutionalized Canadian population age 15 and older. A very stressful life, severe pain and dissatisfaction with one's health demonstrated the highest odds ratios associated with insomnia. Increasing age per se and lifestyle factors were not significantly associated with insomnia.

Rasch analysis of the Western Ontario McMaster (WOMAC) Osteoarthritis Index: results from community and arthroplasty samples.

BACKGROUND AND OBJECTIVE: This study is based on secondary analysis of Western Ontario McMaster Osteoarthritis Index (WOMAC) data from a community sample over 55 years and total hip or knee arthroplasty samples presurgery and 1-year postoperative. METHODS: The WOMAC data were evaluated by Rasch analysis. Data were considered to fit the Rasch mathematical model for the pain and physical dimensions of the WOMAC if unidimensionality was confirmed by principle component analysis of the subscale and the residuals from the Rasch analysis, infit and outfit statistics were in the range of 0.80 to 1.20; if there was no differential item functioning based on gender or hip vs. knee subjects; and, if there was stability of the item logits across the three data samples. RESULTS: A three-item pain dimension (excluding night pain and pain on standing) and a 14-item physical dimension (excluding heavy domestic duties, getting in and out of the bath and getting on and off the toilet) fit the Rasch model based on these criteria. CONCLUSION: In evaluating existing health status questionnaires using Rasch methodology, it is important to evaluate relevant patient samples and longitudinal data when the measure is intended to evaluate change in status. By these criteria, a modified WOMAC questionnaire fits the Rasch model and has interval-level scaling properties.

The prevalence and severity of major disabling conditions--a reappraisal of the government social survey on the handicapped and impaired in Great Britain.

This paper re-examines the data gathered for the Government Social Survey on the Handicapped and Impaired in Great Britain. The underlying cause of disablement is considered in conjunction with severity and prevalence. When these are taken together a picture emerges in which stroke, arthritis, and circulatory disorders are the most frequent cause of severe disability in the community. An attempt is also made to examine the way in which the survey might be biased by the non-inclusion of those in institutions.

The impact of disabling arthritis.

OBJECTIVE: To use the WHO International Classification of Impairments, Disabilities, and Handicaps (ICIDH) as a framework to conceptualize how arthritis affects people and how the effects might be minimized. METHODS: The ICIDH framework emphasizes that the impact of arthritis in terms of handicap is a product of an interaction between a person's social and environmental setting and his or her level of impairment and disability. Data from the Canadian Health and Activity Limitation Survey are used to illustrate the impact for the handicap dimensions. RESULTS: Among persons who have arthritis, 25% cannot leave their residence or can leave only with help (mobility dimension), 45% have at least some level of physical dependence (physical independence dimension), 18% never participate in social activities (social integration dimension), 51% of those under age 65 are not in the labor force and 76% never go out to events such as sports or movies (occupation dimension), and 42% have out-of-pocket expenses because of disability (economic self-sufficiency dimension). CONCLUSION: Policies for the control of handicap require not only medical and rehabilitation interventions to reduce disability, but also consideration of environmental and other social factors.

Determining suitability for home versus community-based ambulatory therapy services for adults with arthritis.

OBJECTIVE: A survey of clients seen by a community-based arthritis therapy service was conducted to investigate how characteristics of clients might provide information to assist in the development of guidelines for services delivered in the home versus in a community-based ambulatory setting. METHODS: Clients completed a self-administered questionnaire, which included the Health Assessment Questionnaire, and a mobility handicap measure. Two indicator variables selected as criteria for suitability for ambulatory therapy were the therapists' rating of client suitability and the clients' report of going out more than once weekly. RESULTS: Based on these indicator variables, 60-76% of clients currently receiving home therapy by this service could potentially receive services in a community-based ambulatory setting. CONCLUSION: The results demonstrate the usefulness of considering client characteristics when deciding whether clients need to be seen at home. This study emphasizes the need to determine the most efficient and effective methods of providing services to people in the community with chronic conditions.

Modeling physical dependence in arthritis: the relative contribution of specific disabilities and environmental factors.

OBJECTIVES: To explore the relationship between disability and physical dependence handicap, and the mediating effect of personal (demographic) and environmental factors as modeled by the International Classification of Impairments, Disability, and Handicaps. METHODS: Data on people with arthritis-associated disabilities were abstracted from a national population survey (n = 16,017). A hierarchical physical dependence variable was formulated. Nominal logistical regression was used to determine predictors of physical dependence related to specific disability, personal characteristics, and environmental adaptation variables. RESULTS: The risk of physical dependence only increased substantially at age > or = 75 years. Specific types of physical disability differentially predicted different levels of physical dependence. The major predictor of physical dependence was disability alone and in conjunction with environmental factors. CONCLUSIONS: There appears to be a specific and ordered relationship between the level of physical dependence and various types of physical disabilities. The findings could have implications for therapeutic intervention and health status measures.

Investigating non-response bias in a survey of disablement in the community: implications for survey methodology.

STUDY OBJECTIVE: The aim was to investigate the pattern of age specific non-response bias in a two phase survey of disablement in the community. It seeks to examine patterns of response in different age groups to a household based postal questionnaire, and the implication of such trends for the estimation of prevalence of reported dependence. It also looks at the effect that the readiness to respond during the first phase postal questionnaire had on participation in the interview based second phase of the study. DESIGN AND SETTING: A two stage survey of disablement in the population was undertaken. A first phase postal questionnaire was sent to 25,168 households in Calderdale, West Yorkshire, England, to ascertain the prevalence of physical disability. The second phase comprised in depth interviews with a sample of individuals identified in the first phase as being disabled. RESPONDENTS: A total of 21,889 postal questionnaires were returned (87%) representing households containing 42,826 people aged 16 years and over. A disproportionately stratified random sample of 950 respondents reporting disability was taken for the second phase. Of these 891 were still available, and 838 (94%) were interviewed. MEASUREMENTS AND MAIN RESULTS: A study of the timing of response to a postal questionnaire showed that patterns differed for different age groups. The estimated prevalence of those aged 65 years and over who were dependent was steady over time whereas for those in the 16-64 age range the estimated prevalence fell as the survey progressed, indicating a tendency for those who were dependent to respond sooner. Examination of the relationship of responses at phase 1 and phase 2 showed that response to invitation to interview was much less in those who had responded later, and presumably more reluctantly, in the first phase. CONCLUSIONS: These findings raise questions about how different patterns of response might be indicative of bias which could differentially affect final age specific prevalence estimates. They also have methodological implications for the follow up of reluctant responders both to increase the response rate and to secure cooperation in the second phase of a two phase survey.

A confidence interval approach to investigating non-response bias and monitoring response to postal questionnaires.

STUDY OBJECTIVE: The aim was to develop an alternative method of investigating non-response bias in postal surveys, including a method of calculating a final full (100%) coverage confidence interval which avoids the wide intervals of existing approaches. DESIGN AND SETTING: As part of a two stage survey of disablement in the community, a first phase postal questionnaire was sent to 25,168 households in Calderdale, West Yorkshire, England. Confidence intervals were calculated to investigate the precision of estimates using a "no bias" model, where the prevalence in non-responders is assumed to be the same as in responders. RESPONDENTS: A total of 21,889 postal questionnaires were returned (87%), representing households containing 42,826 people aged 16 years and over. This was achieved by the original post (1st wave, 57% response); two further postal follow ups (2nd and 3rd waves, taking the response to 73% and 81% respectively), the latter including a small personal call back; and a final postal follow up (the 4th wave). RESULTS: The cumulative estimated prevalence of those with dependence was plotted as the survey progressed. The final wave full coverage estimated prevalence for those aged 16-64 years was 12.8 per 1000 with 95% confidence intervals of 11.3-14.4 per 1000. The integrity of this estimate holds as long as the true prevalence in non-responders is within the calculated non-response confidence interval under the no bias assumption, 9.7-16.0 per 1000 people. This latter interval represents the tolerance of prevalence in non-responders implied by the no bias assumption. CONCLUSIONS: The findings have general implications for monitoring non-response bias in postal screening questionnaires. The confidence interval approach developed in this paper offers an alternative to existing regression based estimates, giving an indication of the range of prevalence amongst non-responders that could be tolerated before the no bias assumption used by the model is breached. It is suggested that this approach can be used to determine both the extent of bias, and to aid decision making about the appropriate juncture to terminate follow up. It highlights the potential, particularly in the context of a computerised survey operation, of methodological investigation occurring simultaneously with survey operation.

Investigating the proxy effect and the saliency principle in household based postal questionnaires.

STUDY OBJECTIVE: The aim was to investigate two possible sources of bias inherent in using a household based postal questionnaire, the "proxy effect", inaccurate reporting about characteristics of others, and the "saliency principle", reporting of only the most salient features. This is of importance in surveys concerned with screening the population to identify individuals with certain characteristics, and so possibly relying on one member of the household to reply on behalf of all others. DESIGN AND SETTING: A two stage survey of disablement in the population was undertaken. A first phase postal questionnaire was sent to 25,168 households in Calderdale, West Yorkshire, England, to ascertain the prevalence of physical disability and of troubles with the joints. The second phase comprised in depth interviews with a sample of individuals identified in the first phase as being disabled. RESPONDENTS: A total of 21,889 postal questionnaires were returned (87%) representing households containing 42,826 people aged 16 years and over. A disproportionately stratified random sample of 950 respondents reporting disability was taken in the second phase. Of these 891 were still available, and 838 (94%) were interviewed. MEASUREMENTS AND MAIN RESULTS: The postal questionnaire found that almost 29% of those who lived "alone" (without another adult) reported some level of disability, compared to only 10% of those who lived with others. The difference remained significant after standardisation. This apparent underreporting or "proxy effect" was present for reporting about disability overall, but not for severe disability (dependence on help of others), which suggests the operation of the "saliency principle". Reporting on joint troubles appeared to be affected by the proxy effect both for any joint problems, and when more than five joints were affected. Analysis of a small set of postal questionnaires from respondents who reported joint problems only at interview and where we could identify who had completed the postal questionnaire supports the hypothesis of a proxy effect; two thirds of the original postal questionnaires had been completed by a proxy. The results were further complicated by an interaction between reporting of disability and joint troubles: the greater the level of disability, the less likely the reporting of joint troubles. CONCLUSIONS: The findings have general implications for studies involving postal household screening questionnaires, and raises additional concerns about those that are multitopic in content. In surveys of symptoms and minor disability, a proxy effect is likely to be operative. This effect is not apparent for obvious and long standing problems such as dependence on others for help. However the interaction between the reporting of disability and joint symptoms carries important implications for the development of multitopic postal screening questionnaires.

Determinants of self rated health for Canadians with chronic disease and disability.

OBJECTIVE: To identify the factors associated with self rated health of people with and without chronic health conditions or long term disability. SETTING: Canadian household population. DESIGN: Analysis of 1994/95 National Population Health Survey interview data with 13,995 respondents aged 20 years and older. Determinants of poor and good compared with excellent health were examined using multivariate nominal logistic regression. Factors included in the analyses were illness related (chronic disease, long and short-term disability, and pain) demographic, lifestyle (smoking, physical activity, drinking), and social psychological resources (mastery, chronic stress, distress, self esteem, and social support). RESULTS: Illness related variables were associated with poor health, with smaller but significant contributions from demographic and lifestyle factors. Psychological resources, especially high mastery and self esteem, are associated with better health in those with chronic conditions or disability. CONCLUSION: The determinants of self rated health for people with chronic illness and disability make the greatest contribution to the findings for the overall population.

Models of disablement, universalism and the international classification of impairments, disabilities and handicaps.

A review and critique of models of disability is presented, tracing the development of frameworks and classificatory instruments (International Classification of Impairments, Disabilities and Handicaps) over the past 20 years. While the 'social' model is now universally accepted, it is argued that universalism as a model for theory development, research and advocacy serves disabled persons more effectively than a civil rights or 'minority group' approach. The development of the revised International Classification (ICIDH-2) is discussed in this light.

Adaptation to chronic illness and disability and its relationship to perceptions of independence and dependence.

This study extends research on living with chronic physical illness and disability by examining how adaptation processes are associated with different activity domains and how the combination of adaptations and activity domains relate to older adults' perceptions of their independence and dependence, helplessness, emotional reactivity, and coping efficacy. The study investigated the behavioral efforts that 286 older adults with osteoarthritis and/or osteoporosis used to adapt to disability arising from their condition. The findings revealed that adults used a wide range of adaptations, including compensations for loss, optimizing performance, limiting or restricting activities, and gaining help from others. The relative use of each of these adaptations varied across 5 domains of activity: personal care, in-home mobility, community mobility, household activities, and valued activities. Moreover, older adults' perceptions of their independence, dependence, helplessness, emotional reactivity, and coping efficacy varied depending on the domain of activity examined and the type of adaptation used.

Assessing damage in individual joints in rheumatoid arthritis: a new method based on the Larsen system.

OBJECTIVES: To evaluate observer agreement using the Larsen system (LS) and a Modified Larsen system (ML) when assessing individual joints of the hands and wrists in rheumatoid arthritis, and to compare the two systems. To determine the minimally important difference (MID) for the ML. METHODS: Thirty radiographs of hands and wrists from 10 patients who presented with RA were graded by two blinded observers, using the LS and then the ML. Patients were followed for a mean of 7.2 years (range: 4-10 years). Inter- and intra-observer agreement were calculated using the kappa statistic with linear incremental weights. Inter-observer agreement was also computed for the summed score, using an intraclass correlation coefficient. Inter-observer error was estimated by calculating the mean and standard deviation of the grading differences between the two observers. Prevalence of damage was calculated as a ratio of damage: no damage and expressed as a percentage. Pairs of radiographs were comparatively graded using a seven-point Likert scale. RESULTS: The kappa statistic for inter-observer agreement was 0.38 (marginal reproducibility) for the LS and 0.52 (good reproducibility) for the ML (P = 0.004). Using a difference of one grade as perfect agreement, it was 0.56 (good reproducibility) for the LS and 0.87 (excellent reproducibility) for the ML (P = 0.001). Intra-observer agreement was high in both systems. The distribution of ML-grade differences varied according to the level of the Likert scale: for "a little bit worse", representing the smallest amount of detectable damage progression, the distribution differences peaked around two grades. This value represented a MID 87% of the time. CONCLUSIONS: The LS lacks precision for individual joints. The ML, it is proposed, has more detailed definitions of grades, and is more reliable. When pairs of radiographs were compared, a two-grade difference on the ML was the MID.

The nature of increased hospital use in poor neighbourhoods: findings from a Canadian inner city.

The relationship between socioeconomic factors and hospital use is not well understood in the Canadian context. We used the 1991 Canada census and 1990-92 Ontario hospital discharge abstracts for residents of southeast Toronto to calculate crude and age-sex adjusted rates of hospital admission, bed days, and costs by quintile of low-income households. Population-based rates of admission to hospital, bed days and costs were all significantly related to census tract income (p < 0.01 for males and females). The number of admissions per person admitted was significantly associated with census tract income (p < 0.01 for males and females), but length of stay and resource intensity weight were not. Hospital costs were 50.0% higher for the poorest quintile of neighbourhoods than for the wealthiest and 35.8% higher than for the middle-income quintile. Poor urban neighbourhoods may require more resources than previously anticipated, related to higher hospital admission and readmission rates.

The genesis of handicap: definition, models of disablement, and role of external factors.

Handicap has proved to be the most contentious and arguably most misunderstood concept of the International Classification of Impairments, Disabilities, and Handicaps (ICIDH). This paper reviews the definition and characteristics of handicap as presented in the original introduction to the ICIDH, and presents some of the alternative suggested definitions. Limitations in the way the original conceptual model for the consequences of disease was depicted have led to the development of alternative models which draw attention to the importance of external factors, particularly for the genesis of handicap. The nature of these external factors and the implications of alternative models for the testing of the conceptual framework are discussed. The expression of handicap as a product of an interaction of a person with impairment and disability and the environment draws attention to the options available for the decrease of handicap through the modification of the environment, and not only by attempting to ameliorate the impairment or disability.

An introduction to the concepts and classifications of the international classification of impairments, disabilities, and handicaps.

This paper aims to introduce the International Classification of Impairments, Disabilities, and Handicaps (ICIDH) and to set the scene for the forthcoming revision process. The consequences of diseases and disorders at the level of the body (impairment), the person (disability), and the person as a social being (handicap) are defined and described. Bearing in mind some of the controversies and confusions which have become apparent in attempts to apply the ICIDH since its publication in 1980, the distinctions between the different concepts are explored: namely, impairment--disability; impairment--functional limitation--disability; and between disability--handicap. The nature of the classification schemes for these concepts is described, together with some implications for methods of assessment. Finally, the contribution the ICIDH has made, and its potential uses are briefly reviewed.