Change Point Estimation in Monitoring Survival Time

Precise identification of the time when a change in a hospital outcome has occurred enables clinical experts to search for a potential special cause more effectively. In this paper, we develop change point estimation methods for survival time of a clinical procedure in the presence of patient mix in a Bayesian framework. We apply Bayesian hierarchical models to formulate the change point where there exists a step change in the mean survival time of patients who underwent cardiac surgery. The data are right censored since the monitoring is conducted over a limited follow-up period. We capture the effect of risk factors prior to the surgery using a Weibull accelerated failure time regression model. Markov Chain Monte Carlo is used to obtain posterior distributions of the change point parameters including location and magnitude of changes and also corresponding probabilistic intervals and inferences. The performance of the Bayesian estimator is investigated through simulations and the result shows that precise estimates can be obtained when they are used in conjunction with the risk-adjusted survival time CUSUM control charts for different magnitude scenarios. The proposed estimator shows a better performance where a longer follow-up period, censoring time, is applied. In comparison with the alternative built-in CUSUM estimator, more accurate and precise estimates are obtained by the Bayesian estimator. These superiorities are enhanced when probability quantification, flexibility and generalizability of the Bayesian change point detection model are also considered.

Economic fluctuations and productivity in the Malaysian construction sector

Growth in productivity is the key determinant of the long-term health and prosperity of an economy. The construction industry being one of major strategic importance, its productivity performance has a significant effect on national economic growth. The relationship between construction output and economy has received intensive studies, but there is lack of empirical study on the relationship between construction productivity and economic fluctuations. Fluctuations in construction output are endemic in the industry. In part they are caused by the boom and slump of the economy as a whole and in part by the nature of the construction product. This research aims to uncover how the productivity of construction sector is influenced in the course of economic fluctuations in Malaysia. Malaysia has adopted three economic policies – New Economic Policy (1971-1990), National Development Policy (1991-2000) and the National Vision Policy (2001-2010) since gaining independence in 1959. The Privatisation Master Plan was introduced in 1991. Operating within this historical context, the Malaysian construction sector has experienced four business cycles since 1960. A mixed-method design approach is adopted in this study. Quantitative analysis was conducted on the published official statistics of the construction industry and the overall economy in Malaysia between 1970 and 2009. Qualitative study involved interviews with a purposive sample of 21 industrial participants. This study identified a 32-year long building cycle appears in 1975-2006. It is superimposed with three shorter construction business cycles in 1975-1987, 1987-1999 and 1999-2006. The correlations of Construction labour productivity (CLP) and GDP per capita are statistically significant for the 1975-2006 building cycle, 1987-1999 and 1999-2006 construction business cycles. It was not significant in 1975-1987 construction business cycles. The Construction Industry Surveys/Census over the period from 1996 to 2007 show that the average growth rate of total output per employee expanded but the added value per employee contracted which imply high cost of bought-in materials and services and inefficient usage of purchases. The construction labour productivity is peaked at 2004 although there is contraction of construction sector in 2004. The residential subsector performed relatively better than the other sub-sectors in most of the productivity indicators. Improvements are found in output per employee, value added per employee, labour competitiveness and capital investment but declines are recorded in value added content and capital productivity. The civil engineering construction is most productive in the labour productivity nevertheless relatively poorer in the capital productivity. The labour cost is more competitive in the larger size establishment. The added value per labour cost is higher in larger sized establishment attributed to efficient in utilization of capital. The interview with the industrial participant reveals that the productivity of the construction sector is influenced by the economic environment, the construction methods, contract arrangement, payment chain and regulatory policies. The fluctuations of construction demand have caused companies switched to defensive strategy during the economic downturn and to ensure short-term survival than to make a profit for the long-term survival and growth. It leads the company to take drastic measures to curb expenses, downsizing, employ contract employment, diversification and venture overseas market. There is no empirical evidence supports downsizing as a necessary step in a process of reviving productivity. The productivity does not correlate with size of firm. A relatively smaller and focused firm is more productive than the larger and diversified organisation. However diversified company experienced less fluctuation in both labour and capital productivity. In order to improve the productivity of the construction sector, it is necessary to remove the negatives and flaws from past practices. The recommended measures include long-term strategic planning and coordinated approaches of government agencies in planning of infrastructure development and to provide regulatory environments which encourage competition and facilitate productivity improvement.

The role of physical activity in the lives of people with lymphoedema following cancer treatment : a social constructionist study

Lymphoedema is a chronic condition predominantly affecting the limbs, although it can involve the trunk and other areas of the body. It is characterised by swelling due to excess accumulation of fluid in body tissues. Secondary lymphoedema, which arises following cancer treatment, is the more common form of lymphoedema in developed countries. At least 20% of those diagnosed with the most common cancers will develop lymphoedema. This is a concern in Australia as incidence of these cancers is increasing. Cancer survival rates are also increasing. Currently, this equates to 9 300 new cases of secondary lymphoedema diagnosed each year. Considerable physical and psychosocial impacts of lymphoedema have been reported and its subsequent impact on health-related quality of life can exacerbate other side effects of cancer treatment. Exercise following cancer treatment has been shown to significantly reduce the impact of treatment side effects, improve quality of life and physical status. While participating in exercise does not increase risk nor exacerbate existing lymphoedema, reductions in incidence of lymphoedema exacerbations and associated symptoms have been observed in women participating in regular weight lifting following breast cancer treatment. Despite these benefits, lymphoedema prevention and management advice cautions people with lymphoedema against „repetitive use. or „overuse. of their affected arm. It is possible that this advice creates a barrier to participation in physical activity; however, little is known about the relationship between physical activity and lymphoedema. In addition, the majority of studies examining the experiences of people living with lymphoedema and the impact of the condition have been predominantly conducted internationally and have focused on women following breast cancer. This study sought to explore firstly, how men and women construct their experience of living with lymphoedema following treatment for a range of cancers in the context of everyday life in Australia; and secondly, to analyse the role of physical activity in the lives of those living with lymphoedema following cancer treatment. A social constructivist grounded theory approach was taken to explore these objectives as it is acknowledged that human actions and the meanings associated with these actions are influenced by the interaction between the self and the social world. It is also acknowledged that the research process itself is a social construction between the researcher and participant. Purposive sampling techniques were used to recruit a total of 29 participants from a variety of sources. Telephone interviews and focus groups were conducted to collect data. Data were concurrently collected and analysed and analysis was conducted using the constant comparative method. The core category that developed in objective one was „sense of self‟. The self was defined by perceptions participants held of themselves and their identity prior to a lymphoedema diagnosis and changes to their perceptions and identity since diagnosis. Three conceptual categories which related to each other and to „sense of self‟ were developed through the process of coding that represented the process of how participants constructed their experiences living with secondary lymphoedema in the context of everyday life. Firstly, altered normalcy reflected the physical and psychosocial changes experienced and the effect it had on their lives. Secondly, „accidental journey‟ reflected participants‟ journey with the heath care system prior to diagnosis through to longer term management. Thirdly, renegotiating control revealed participants perceived control over lymphoedema and their ability to participate in daily activities previously enjoyed. These findings revealed the failure of the broader health system to recognise the significant and chronic nature of a lymphoedema diagnosis following cancer treatment with greater understanding, knowledge and support from health professionals being needed. The findings also reveal access to health professionals trained in lymphoedema management, a comprehensive approach encompassing both physical and psychosocial needs and provision of practical and meaningful guidelines supported by scientific evidence would contribute to improved treatment and management of the condition. The key findings for objective two were that people with lymphoedema define physical activity in different ways. Physical activity post-diagnosis was perceived as important by most for a variety of reasons ranging from everyday functioning, to physical and psychosocial health benefits. Issues relating to the impact of lymphoedema on physical activity related to the impact on peoples‟ ability to be physically active, confusion about acceptable forms of physical activity and barriers that lymphoedema presented to being physically active. A relationship between how people construct their experiences with lymphoedema and the role of physical activity was also established. The contribution of physical activity to the lives of people living with lymphoedema following cancer treatment appeared to be influenced by their sense of self as socially constructed through their experiences prior to diagnosis and following diagnosis with lymphoedema. The influence of pre-lymphoedema habits, norms and beliefs suggests the importance of effective health promotion messages to encourage physical activity among the general population and specific messages and guidelines particular to the needs of those diagnosed with lymphoedema following cancer treatment. The influence of participant.s social constructions on the lymphoedema experience highlights the importance of improving interactions between the overall health care system and patients, providing a clear treatment plan, providing evidence-based and clear advice about participation in appropriate physical activity, which in doing so will limit the physical and psychosocial effect of lymphoedema and providing comprehensive physical and psychosocial support to those living with the condition and their families. This study has contributed to a deep understanding of people.s experiences with lymphoedema following cancer treatment and the role of physical activity in the context of daily life in Australia. Findings from this study lead to recommendations for advocacy, a comprehensive approach to diagnosis, treatment and management, and specific areas for future research.

On secrets, lies, and fiction : girls learning the art of survival

This chapter’s interest in fiction’s relationship to truth, lies, and secrecy is not so much a matter of how closely fiction resembles or mirrors the world (its mimetic quality), or what we can learn from fiction (its epistemological value). Rather, the concern is both literary and philosophical: a literary concern that takes into account how texts that thematise secrecy work to withhold and to disclose their secrets as part of the process of narrating and sequencing; and a philosophical concern that considers how survival is contingent on secrets and other forms of concealment such as lies, deception, and half-truths. The texts selected for examination are: Secrets (2002), Skim (2008), and Persepolis: The Story of a Childhood (2003). These texts draw attention to the ways in which the lies and secrets of the female protagonists are part of the intricate mechanism of survival, and demonstrate the ways in which fiction relies upon concealment and revelation as forms of truth-telling.

Malnutrition and its impact on cost of hospitalization, length of stay, readmission and 3-year mortality

Background & aims: The confounding effect of disease on the outcomes of malnutrition using diagnosis-related groups (DRG) has never been studied in a multidisciplinary setting. This study aims to determine the prevalence of malnutrition in a tertiary hospital in Singapore and its impact on hospitalization outcomes and costs, controlling for DRG. Methods: This prospective cohort study included a matched case control study. Subjective Global Assessment was used to assess the nutritional status on admission of 818 adults. Hospitalization outcomes over 3 years were adjusted for gender, age, ethnicity, and matched for DRG. Results: Malnourished patients (29%) had longer hospital stays (6.9 ± 7.3 days vs. 4.6 ± 5.6 days, p < 0.001) and were more likely to be readmitted within 15 days (adjusted relative risk = 1.9, 95%CI 1.1–3.2, p = 0.025). Within a DRG, the mean difference between actual cost of hospitalization and the average cost for malnourished patients was greater than well-nourished patients (p = 0.014). Mortality was higher in malnourished patients at 1 year (34% vs. 4.1 %), 2 years (42.6% vs. 6.7%) and 3 years (48.5% vs. 9.9%); p < 0.001 for all. Overall, malnutrition was a significant predictor of mortality (adjusted hazard ratio = 4.4, 95% CI 3.3-6.0, p < 0.001). Conclusions: Malnutrition was evident in up to one third of the inpatients and led to poor hospitalization outcomes and survival as well as increased costs of care, even after matching for DRG. Strategies to prevent and treat malnutrition in the hospital and post-discharge are needed.

Is flapless implant surgery a viable option in posterior maxilla? : a review

This article reviews the literature on the outcome of flapless surgery for dental implants in the posterior maxilla. The literature search was carried out in using the keywords: flapless, dental implants and maxilla. A hand search and Medline search were carried out on studies published between 1971 and 2011. The authors included research involving a minimum of 15 dental implants with a followup period of 1 year, an outcome measurement of implant survival, but excluded studies involving multiple simultaneous interventions, and studies with missing data. The Cochrane approach for cohort studies and Oxford Centre for Evidence- Based Medicine were applied. Of the 56 published papers selected, 14 papers on the flapless technique showed high overall implant survival rates. The prospective studies yielded 97.01% (95% CI: 90.72–99.0) while retrospective studies or case series illustrated 95.08% (95% CI: 91.0–97.93) survival. The average of intraoperative complications was 6.55% using the flapless procedure. The limited data obtained showed that flapless surgery in posterior maxilla areas could be a viable and predictable treatment method for implant placement. Flapless surgery tends to be more applicable in this area of the mouth. Further long-term clinical controlled studies are needed.

The influence of smoking status on malnutrition risk and 1-year mortality in outpatients with chronic obstructive pulmonary disease.

Introduction:  Smoking status in outpatients with chronic obstructive pulmonary disease (COPD) has been associated with a low body mass index (BMI) and reduced mid-arm muscle circumference (Cochrane & Afolabi, 2004). Individuals with COPD identified as malnourished have also been found to be twice as likely to die within 1 year compared to non-malnourished patients (Collins et al., 2010). Although malnutrition is both preventable and treatable, it is not clear what influence current smoking status, another modifiable risk factor, has on malnutrition risk. The current study aimed to establish the influence of smoking status on malnutrition risk and 1-year mortality in outpatients with COPD. Methods:  A prospective nutritional screening survey was carried out between July 2008 and May 2009 at a large teaching hospital (Southampton General Hospital) and a smaller community hospital within Hampshire (Lymington New Forest Hospital). In total, 424 outpatients with a diagnosis of COPD were routinely screened using the ‘Malnutrition Universal Screening Tool’, ‘MUST’ (Elia, 2003); 222 males, 202 females; mean (SD) age 73 (9.9) years; mean (SD) BMI 25.9 (6.4) kg m−2. Smoking status on the date of screening was obtained for 401 of the outpatients. Severity of COPD was assessed using the GOLD criteria, and social deprivation determined using the Index of Multiple Deprivation (Nobel et al., 2008). Results:  The overall prevalence of malnutrition (medium + high risk) was 22%, with 32% of current smokers at risk (who accounted for 19% of the total COPD population). In comparison, 19% of nonsmokers and ex-smokers were likely to be malnourished [odds ratio, 1.965; 95% confidence interval (CI), 1.133–3.394; P = 0.015]. Smoking status remained an independent risk factor for malnutrition even after adjustment for age, social deprivation and disease-severity (odds ratio, 2.048; 95% CI, 1.085–3.866; P = 0.027) using binary logistic regression. After adjusting for age, disease severity, social deprivation, smoking status, malnutrition remained a significant predictor of 1-year mortality [odds ratio (medium + high risk versus low risk), 2.161; 95% CI, 1.021–4.573; P = 0.044], whereas smoking status did not (odds ratio for smokers versus ex-smokers + nonsmokers was 1.968; 95% CI, 0.788–4.913; P = 0.147). Discussion:  This study highlights the potential importance of combined nutritional support and smoking cessation in order to treat malnutrition. The close association between smoking status and malnutrition risk in COPD suggests that smoking is an important consideration in the nutritional management of malnourished COPD outpatients. Conclusions:  Smoking status in COPD outpatients is a significant independent risk factor for malnutrition and a weaker (nonsignificant) predictor of 1-year mortality. Malnutrition significantly predicted 1 year mortality. References:  Cochrane, W.J. & Afolabi, O.A. (2004) Investigation into the nutritional status, dietary intake and smoking habits of patients with chronic obstructive pulmonary disease. J. Hum. Nutr. Diet.17, 3–11. Collins, P.F., Stratton, R.J., Kurukulaaratchym R., Warwick, H. Cawood, A.L. & Elia, M. (2010) ‘MUST’ predicts 1-year survival in outpatients with chronic obstructive pulmonary disease. Clin. Nutr.5, 17. Elia, M. (Ed) (2003) The ‘MUST’ Report. BAPEN. http://www.bapen.org.uk (accessed on March 30 2011). Nobel, M., McLennan, D., Wilkinson, K., Whitworth, A. & Barnes, H. (2008) The English Indices of Deprivation 2007. http://www.communities.gov.uk (accessed on March 30 2011).

Prevalence and prognostic significance of secondary lymphedema following breast cancer

Background The adverse consequences of lymphedema following breast cancer in relation to physical function and quality of life are clear; however, its potential relationship with survival has not been investigated. Our purpose was to determine the prevalence of lymphedema and associated upper-body symptoms at 6 years following breast cancer and to examine the prognostic significance of lymphedema with respect to overall 6-year survival (OS). Methods and Results A population-based sample of Australian women (n=287) diagnosed with invasive, unilateral breast cancer was followed for a median of 6.6 years and prospectively assessed for lymphedema (using bioimpedance spectroscopy [BIS], sum of arm circumferences [SOAC], and self-reported arm swelling), a range of upper-body symptoms, and vital status. OS was measured from date of diagnosis to date of death or last follow-up. Kaplan-Meier methods were used to calculate OS and Cox proportional hazards models quantified the risk associated with lymphedema. Approximately 45% of women had reported at least one moderate to extreme symptom at 6.6 years postdiagnosis, while 34% had shown clinical evidence of lymphedema, and 48% reported arm swelling at least once since baseline assessment. A total of 27 (9.4%) women died during the follow-up period, and lymphedema, diagnosed by BIS or SOAC between 6–18 months postdiagnosis, predicted mortality (BIS: HR=2.5; 95% CI: 0.9, 6.8, p=0.08; SOAC: 3.0; 95% CI: 1.1, 8.7, p=0.04). There was no association (HR=1.2; 95% CI: 0.5, 2.6, p=0.68) between self-reported arm swelling and OS. Conclusions These findings suggest that lymphedema may influence survival following breast cancer treatment and warrant further investigation in other cancer cohorts and explication of a potential underlying biology.