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

Resposta da produtividade de grãos e outras características agronômicas do trigo EMBRAPA-22 irrigado ao nitrogênio em cobertura

As doses e a época de aplicação do nitrogênio (N) podem influenciar as características agronômicas do trigo (Triticum aestivum L.) irrigado e, conseqüentemente, a produtividade de grãos. Neste sentido, foram instalados dois experimentos na Estação Experimental da Universidade Federal de Viçosa, localizada em Coimbra (MG), em 1995 e 1996. Os tratamentos foram constituídos pela combinação de quatro doses de N (30, 60, 90 e 120 kg ha-1), quatro formas de parcelamento (dose total aos 20 dias da emergência (DAE); ½ aos 20 + ½ aos 40 DAE; 1/3 aos 20 + 2/3 aos 40 DAE e 2/3 aos 20 + 1/3 aos 40 DAE) e uma testemunha (sem N em cobertura), dispostos em esquema fatorial 4 x 4 + 1, no delineamento em blocos casualizados com quatro repetições. A altura e o acamamento das plantas, a biomassa seca, o índice de colheita, a massa de mil grãos, o peso hectolítrico e a produtividade de grãos foram influenciados pelas doses de N. Em 1996, o número de espigas por metro quadrado e o número de perfilhos férteis por planta diminuíram, em conseqüência do acamamento precoce das plantas, enquanto o número de grãos por espiga e o número de grãos por metro quadrado aumentaram com o incremento nas doses de N. As formas de parcelamento influenciaram somente o acamamento das plantas

Continuing Professional Development Is Associated With Increasing Physical Therapists' Roles in Arthritis Management in Canada and the Netherlands

Background and Objective. This study explored the relationships among the roles assumed by physical therapists in arthritis care and their previous participation in arthritis courses for continuing professional development (CPD). Design. A cross-sectional mail survey was conducted. Method. A total of 600 Canadian physical therapists and 461 Dutch physical therapists practicing in orthopedics were randomly selected to participate in a mail survey. The questionnaire covered areas related to their clinical practice, previous participation in arthritis-related CPD courses, and roles in the management of osteoarthritis (OA) and rheumatoid arthritis (RA). Poisson regression was used to explore the associations between physical therapists' participation in arthritis-related CPD courses and the number of roles they assumed in OA and RA care, after adjusting for personal characteristics, arthritis caseload, and country of practice. Results. The survey response rates were 47.7% in Canada and 50.5% in the Netherlands. A total of 424 participants (Canada=224, the Netherlands=200) had treated patients with OA in the previous month, and 259 participants (Canada=68, Netherlands 191) had treated patients with RA in the previous month. The most common roles reported by participants were providing traditional physical therapy interventions and providing postsurgical care. Arthritis-related CPD courses significantly increased (ie, multiplied) the expected number of roles assumed by physical therapists by a factor of 1.32 (95% confidence interval=1.11, 1.56) in OA management and 1.69 (95% confidence interval=1.34, 2.13) in RA management. Limitations. Physical therapists' roles in arthritis management were obtained through self-reporting, which might differ from their actual clinical practice. Conclusions. This exploratory analysis highlights the association between participation in arthritis-related CPD courses and the roles assumed by physical therapists in OA and RA management. Further research is needed to understand the effects of CPD activities on other areas of physical therapist practice and on patients' outcomes.Pathophysiology and treatment of rheumatic disease

Nonrandomized quality improvement intervention trials might overstate the strength of causal inference of their findings

Objective: To assess the strength of causal inferences reported in randomized and nonrandomized evaluations of quality improvement (QI) interventions in relation to the study design and the direction of results for the primary outcomes. Study Design and Setting: We searched 11 journals for QI intervention studies that aimed to change clinician behavior. Statements that addressed the causal inference between intervention and outcomes were extracted and were rated by 34 researchers for the strength of causality. Results: We found 38 randomized controlled trials (RCTs) and 35 non-RCTs, and extracted 68 quotes from the abstracts and 139 from the main text. A significant interaction was found between study design and direction of results for the abstract quotes (P = 0.022). The ratings for non-RCTs were higher when the results were mixed, but for RCTs, they were higher if the results were positive or no effect, although none of the differences were statistically significant at alpha = 0.05 after adjusting for multiple comparisons. For the main text quotes, the causality rating was higher by 0.43 for RCTs than for non-RCTs after adjusting for the direction of results (P < 0.001). Conclusion: Authors might have overstated the strength of causal inference in the abstracts of non-RCTs, but appeared to report causality appropriately in the main text