Doctor of Philosophy

dissertationThis dissertation focuses on two prominent issues encountered in analyzing questionnaire data. First, the summed score of all individual questions in a questionnaire is characteristically used as a measure of disease severity, even though it often does not have interval properties. Second, measurement errors exist whenever there is measurement. For example, questionnaires, composed of questions with predefined response categories, force patients to make choices. The data for the dissertation were binary response data from Simple Shoulder Test questionnaire (SST). A Rasch model was used to estimate Rasch scores. The minimum clinical important difference (MCID) in Rasch scores was then compared with the MCID in summed scores. MCID was defined as the statistically significant difference in change from baseline between patient groups (No Change and Minimal Improvement). Two anchored questions were used to delineate patient groups. In Rasch scores, conclusions about the MCID reached through both questions supported MCID in summed scores. To address issues of nonlinearity and measurement errors, I constructed a Rasch model accounting for measurement errors and mapped out Markov Chain Monte Carlo (MCMC) steps to estimate model parameters. The optimal setting of factors affecting MCMC implementation was identified. To evaluate the effect of measurement errors, I applied Rasch model accounting for measurement errors to SST data and obtained Rasch scores accounting for iv measurement errors (i.e., MCMC Rasch scores). MCID analysis was performed on MCMC Rasch scores. I found that MCID is unascertainable through MCMC Rasch scores. Inconsistent MCID findings in these two types of Rasch scores may be due to bias of estimates of Rasch SST when measurement errors are left unconsidered. In sum, Rasch scores accounting for measurement errors: 1) provide more accurate estimates for person abilities indicated by mean square errors; 2) provide unequal spaces between scores compared with summed scores, which may more accurately describe patients' experiences; 3) provide estimates corresponding to extreme summed scores with reasonable variances, which remain inestimable in the classical Rasch model; 4) may be used as a continuous variable, unlike summed and classical Rasch scores, because the measurement errors were treated as random effects

Analysis of patient flows for orthopedic procedures using small area analysis in Switzerland

BACKGROUND: In general cantons regulate and control the Swiss health service system; patient flows within and between cantons are thereby partially disregarded. This paper develops an alternative spatial model, based upon the construction of orthopedic hospital service areas (HSA(O)s), and introduces indices for the analysis of patient streams in order to identify areas, irrespective of canton, with diverse characteristics, importance, needs, or demands. METHODS: HSA(O)s were constructed using orthopedic discharge data. Patient streams between the HSA(O)s were analysed by calculating three indices: the localization index (% local residents discharged locally), the netindex (the ratio of discharges of nonlocal incoming residents to outgoing local residents), and the market share index (% of local resident discharges of all discharges in local hospitals). RESULTS: The 85 orthopedic HSA(O)s show a median localization index of 60.8%, a market share index of 75.1%, and 30% of HSA(O)s have a positive netindex. Insurance class of bed, admission type, and patient age are partially but significantly associated with those indicators. A trend to more centrally provided health services can be observed not only in large urban HSA(O)s such as Geneva, Bern, Basel, and Zurich, but also in HSA(O)s in mountain sport areas such as Sion, Davos, or St.Moritz. Furthermore, elderly and emergency patients are more frequently treated locally than younger people or those having elective procedures. CONCLUSION: The division of Switzerland into HSA(O)s provides an alternative spatial model for analysing and describing patient streams for health service utilization. Because this small area model allows more in-depth analysis of patient streams both within and between cantons, it may improve support and planning of resource allocation of in-patient care in the Swiss healthcare system

Management of low back pain in Ghana : a survey of self-reported practice

Background and Purpose: Practice variation exists in the physiotherapy management of low back pain (LBP) across several countries. Previous studies indicate that treatment strategies used may not always be in line with evidence-based practice. Most of these studies however were conducted in developed countries. This study sought to investigate the management of LBP in Ghana in order to add to the emergent literature regarding practice in developing nations. Methods: A web-based self-report questionnaire was made available to all eligible members of the Ghana Physiotherapy Association. Results: The survey achieved a response rate of 67%. Over 60% of physiotherapists in Ghana had less than 5years of practice experience, worked in large facility hospitals and had no post-graduate further training. Most LBP patients seen were chronic, and over 60% of treatment sessions used multiple therapies and included exercises, advice, massage, electrotherapy and manual therapy. Conclusion: This first mapping of physiotherapy management of LBP in Ghana shows an overt multimodal approach. There was potential good practice with the high use of exercise and advice, the equally high utilization of passive treatments however showed variance to recommendations of guidelines. The findings of this study have implications for clinical practice and physiotherapy education and research.</p

Risk factors for neck pain in office workers: a prospective study

BACKGROUND: Persisting neck pain is common in society. It has been reported that the prevalence of neck pain in office workers is much higher than in the general population. The costs to the worker, employer and society associated with work-related neck pain are known to be considerable and are escalating. The factors that place office workers at greater risk of developing neck pain are not understood. The aim of this study is to investigate the incidence and risk factors of work-related neck pain in Australian office workers. METHODS/DESIGN: We will conduct a prospective cohort study. A cohort of office workers without neck pain will be followed over a 12 month period, after baseline measurement of potential risk factors. The categories of risk factors being evaluated are physical (cervical spine posture, range of movement, muscle endurance and exercise frequency), demographic (age, sex), work environment (sitting duration, frequency of breaks) and psychosocial (psychological distress and psychosocial work factors). Cox regression analysis will be used to identify risk factors associated with work-related neck pain, and will be expressed as hazard ratios with 95% confidence intervals. The data will also enable the incidence of neck pain in this population to be estimated. DISCUSSION: In addition to clarifying the magnitude of this occupational health problem these data could inform policy in workplaces and provide the basis for primary prevention of neck pain in office workers, targeting the identified risk factors

Work-related complaints of arm, neck and shoulder among computer office workers in an Asian country: prevalence and validation of a risk-factor questionnaire

<p>Abstract</p> <p>Background</p> <p>Complaints of arm, neck and/or shoulders (CANS) affects millions of computer office workers. However its prevalence and associated risk factors in developing countries are yet to be investigated, due to non availability of validated assessment tools for these countries. We evaluated the 1-year prevalence of CANS among computer office workers in Sri Lanka and tested the psychometric properties of a translated risk factor questionnaire.</p> <p>Methods</p> <p>Computer office workers at a telecommunication company in Sri Lankan received the Sinhalese version of the validated Maastricht Upper Extremity Questionnaire (MUEQ). The 94 items in the questionnaire covers demographic characteristics, CANS and evaluates potential risk factors for CANS in six domains. Forward and backward translation of the MUEQ was done by two independent bi-lingual translators. One-year prevalence of CANS and psychometric properties of the Sinhalese questionnaire were investigated.</p> <p>Results</p> <p>Response rate was 97.7% (n = 440). Males were 42.7%. Mean age was 38.2 ± 9.5 years. One-year prevalence of CANS was 63.6% (mild-53.7% and severe-10%). The highest incidences were for neck (36.1%) and shoulder (34.3%) complaints. Two factors for each domain in the scale were identified by exploratory factor analysis (i.e. work-area, computer-position, incorrect body posture, bad-habits, skills and abilities, decision-making, time-management, work-overload, work-breaks, variation in work, work-environment and social-support). Calculation of internal consistency (Cronbach's alpha 0.43-0.82) and cross-validation provided evidence of reliability and lack of redundancy of items.</p> <p>Conclusion</p> <p>One year prevalence of CANS in the study population corresponds strongly with prevalence in developed countries. Translated version of the MUEQ has satisfactory psychometric properties for it to be used to assess work-related risk factors for development of CANS among Sri Lankan computer office workers.</p

Frequency and Interrelations of Risk Factors for Chronic Low Back Pain in a Primary Care Setting

INTRODUCTION: Many risk factors have been identified for chronic low back pain (cLBP), but only one study evaluated their interrelations. We aimed to investigate the frequency of cLBP risk factors and their interrelations in patients consulting their general practitioners (GPs) for cLBP. METHODS: A cross-sectional, descriptive, national survey was performed. 3000 GPs randomly selected were asked to include at least one patient consulting for cLBP. Demographic, clinical characteristics and the presence of cLBP risk factors were recorded. The frequency of each cLBP risk factor was calculated and multiple correspondence analysis (MCA) was performed to study their interrelations. RESULTS: A total of 2068 GPs (68.9%) included at least 1 patient, for 4522 questionnaires analyzed. In the whole sample of patients, the 2 risk factors most commonly observed were history of recurrent LBP (72.1%) and initial limitation of activities of daily living (66.4%). For working patients, common professional risk factors were beliefs, that LBP was due to maintaining a specific posture at work (79.0%) and frequent heavy lifting at work (65.5%). On MCA, we identified 3 risk-factor dimensions (axes) for working and nonworking patients. The main dimension for working patients involved professional risk factors and among these factors, patients' job satisfaction and job recognition largely contribute to this dimension. DISCUSSION: Our results shed in light for the first time the interrelation and the respective contribution of several previously identified cLBP risk factors. They suggest that risk factors representing a "work-related" dimension are the most important cLBP risk factors in the working population

Cost-effectiveness analysis of physiotherapy interventions for low-back pain: a systematic review

Background: Due to the rapid increase in healthcare costs of low back pain (LBP), it is important to provide clinically and cost effective interventions to individuals with the condition. Objective: To evaluate all recent economic evaluations of physiotherapy interventions for patients with LBP. Data sources: Searches were undertaken on CINAHL, Medline, the National Health Service Economic Evaluation database (NHSEED), Health Technology Assessment (HTA), and Database of Abstracts of Review of Effects (DARE) from January 2008 to October 2018. Study selection: Randomised controlled trials, cohort studies that assessed the costeffectiveness of physiotherapy interventions on patients with LBP compared to a control group. A Consolidated Health Economic Evaluation Reporting Standards (CHEERS) checklist was used to assess the quality of the included studies. Data extraction/Data synthesis: Pairs of review authors independently extracted data. A descriptive synthesis was conducted to summarise the data. Results: A total of 1,531 articles were identified, and 11 studies fulfilled the inclusion criteria. The total number of participants included in the studies included in the review were 2,633 and their age ranged from 18 to 80 years. In the included studies, the duration of LBP ranged from 3 weeks to 1 year. Except in one study, all the included studies reported that physiotherapy intervention was cost effective compared to controls. Because of the heterogeneity of the included studies, meta-analysis was not possible. Conclusion: Although most of the included studies suggested that physiotherapy interventions were cost effective, it is difficult to pool their cost effectiveness for a conclusive evidence

Prediction of chronic disability in work-related musculoskeletal disorders: a prospective, population-based study

BACKGROUND: Disability associated with work-related musculoskeletal disorders is an increasingly serious societal problem. Although most injured workers return quickly to work, a substantial number do not. The costs of chronic disability to the injured worker, his or her family, employers, and society are enormous. A means of accurate early identification of injured workers at risk for chronic disability could enable these individuals to be targeted for early intervention to promote return to work and normal functioning. The purpose of this study is to develop statistical models that accurately predict chronic work disability from data obtained from administrative databases and worker interviews soon after a work injury. Based on these models, we will develop a brief instrument that could be administered in medical or workers' compensation settings to screen injured workers for chronic disability risk. METHODS: This is a population-based, prospective study. The study population consists of workers who file claims for work-related back injuries or carpal tunnel syndrome (CTS) in Washington State. The Washington State Department of Labor and Industries claims database is reviewed weekly to identify workers with new claims for work-related back injuries and CTS, and these workers are telephoned and invited to participate. Workers who enroll complete a computer-assisted telephone interview at baseline and one year later. The baseline interview assesses sociodemographic, employment-related, biomedical/health care, legal, and psychosocial risk factors. The follow-up interview assesses pain, disability, and work status. The primary outcome is duration of work disability over the year after claim submission, as assessed by administrative data. Secondary outcomes include work disability status at one year, as assessed by both self-report and work disability compensation status (administrative records). A sample size of 1,800 workers with back injuries and 1,200 with CTS will provide adequate statistical power (0.96 for low back and 0.85 for CTS) to predict disability with an alpha of .05 (two-sided) and a hazard ratio of 1.2. Proportional hazards regression models will be constructed to determine the best combination of predictors of work disability duration at one year. Regression models will also be developed for the secondary outcomes