Soft tissue ossification and condylar cartilage degeneration following TMJ disc perforation in a rabbit pilot study.

OBJECTIVE: There are limited clinical treatments for temporomandibular joint (TMJ) pathologies, including degenerative disease, disc perforation and heterotopic ossification (HO). One barrier hindering the development of new therapies is that animal models recapitulating TMJ diseases are poorly established. The objective of this study was to develop an animal model for TMJ cartilage degeneration and disc pathology, including disc perforation and soft tissue HO. METHODS: New Zealand white rabbits (n = 9 rabbits) underwent unilateral TMJ disc perforation surgery and sham surgery on the contralateral side. A 2.5 mm defect was created using a punch biopsy in rabbit TMJ disc. The TMJ condyles and discs were evaluated macroscopically and histologically after 4, 8 and 12 weeks. Condyles were blindly scored by four independent observers using OARSI recommendations for macroscopic and histopathological scoring of osteoarthritis (OA) in rabbit tissues. RESULTS: Histological evidence of TMJ condylar cartilage degeneration was apparent in experimental condyles following disc perforation relative to sham controls after 4 and 8 weeks, including surface fissures and loss of Safranin O staining. At 12 weeks, OARSI scores indicated experimental condylar cartilage erosion into the subchondral bone. Most strikingly, HO occurred within the TMJ disc upon perforation injury in six rabbits after 8 and 12 weeks. CONCLUSION: We report for the first time a rabbit TMJ injury model that demonstrates condylar cartilage degeneration and disc ossification, which is indispensible for testing the efficacy of potential TMJ therapies.

Sustainability of a physical activity and nutrition program for seniors.

OBJECTIVE: This prospective cohort study aimed to determine the impact of a low cost, home-based physical activity and nutrition program for older adults at 6 months follow-up. DESIGN: A follow-up survey was conducted 6 months after program completion via computer-assisted telephone interviewing. The International Physical Activity Questionnaire and the Fat and Fibre Barometer were used to measure physical activity levels and dietary behaviours, respectively. Self-reported height, weight, waist and hip circumferences were obtained. Changes over three time points of data collection (baseline, post-program, follow-up) and differences between the intervention and control groups were assessed. The use of program materials was also evaluated. SETTING: Community and home-based. PARTICIPANTS: Insufficiently active 60 to 70 year olds (n = 176, intervention and n = 198, control) residing in suburbs within the Perth metropolitan area. RESULTS: A sustained improvement was observed for the intervention group in terms of fat avoidance behaviours (p interaction = .007). Significant improvements were found for strength exercises, fibre intake, body mass index and waist-to-hip ratio at either post-program or follow-up, however the overall effect was not significant. At post-program, the intervention group increased time spent participating in moderate activity by 50 minutes (p > .05), which was followed by a significant decline at follow-up (p < .05). Among intervention group participants, males and females differed with respect to strength exercises and moderate physical activity. CONCLUSION: This low-cost physical activity and nutrition intervention resulted in a sustained improvement in fat avoidance behaviours and overall short-term gains in physical activity. Future studies for older adults are recommended to investigate gender-specific behavioural barriers as well as booster interventions which focus on physical activity.

Public versus private hospital maternity length of stay: a gamma mixture modelling approach.

Application of a gamma mixture model to obstetrical diagnosis-related groups (DRGs) revealed heterogeneity of maternity length of stay (LOS). The proportion of long-stay subgroups identified, which can account for 30% of admissions, varied between DRGs. The burden of long-stay patients borne was estimated to be much higher in private hospitals than public hospitals for normal delivery, but vice versa for Caesarean section. Such differences highlights the impact of DRG-based casemix funding on inpatient LOS and have significant implications for health insurance companies to integrate casemix funding across the public and private sectors. The analysis also benefits hospital administrators and managers to budget expenditures accordingly.

Determinants of maternity length of stay: a Gamma mixture risk-adjusted model.

With obstetrical delivery being the most frequent cause for hospital admissions, it is important to determine health- and patient-related characteristics affecting maternity length of stay (LOS). Although the average inpatient LOS has decreased steadily over the years, the issue of the appropriate LOS after delivery is complex and hotly debated, especially since the introduction of the mandatory minimum-stay legislation in the USA. The purpose of this paper is to identity factors associated with maternity LOS and to model variations in LOS. A Gamma mixture risk-adjusted model is proposed in order to analyze heterogeneity of maternity LOS within obstetrical Diagnosis Related Groups (DRGs). The determination of pertinent factors would benefit hospital administrators and clinicians to manage LOS and expenditures efficiently.

Determining the effects of patient casemix on length of hospital stay: a proportional hazards frailty model approach.

OBJECTIVES: To identify factors associated with hospital length of stay (LOS) and to model variations in LOS within Diagnosis Related Groups (DRGs). METHODS: A proportional hazards frailty modelling approach is proposed that accounts for patient transfers and the inherent correlation of patients clustered within hospitals. The investigation is based on patient discharge data extracted for a group of obstetrical DRGs. RESULTS: Application of the frailty approach has highlighted several significant factors after adjustment for patient casemix and random hospital effects. In particular, patients admitted for childbirth with private medical insurance coverage have higher risk of prolonged hospitalization compared to public patients. CONCLUSIONS: The determination of pertinent factors provides important information to hospital management and clinicians in assessing the risk of prolonged hospitalization. The analysis also enables the comparison of inter-hospital variations across adjacent DRGs.

Zero-inflated Poisson regression with random effects to evaluate an occupational injury prevention programme.

This study presents a zero-inflated Poisson regression model with random effects to evaluate a manual handling injury prevention strategy trialled within the cleaning services department of a 600 bed public hospital between 1992 and 1995. The hospital had been experiencing high annual rates of compensable injuries of which over 60 per cent were attributed to manual handling. The strategy employed Workplace Risk Assessment Teams (WRATS) that utilized a workplace risk identification, assessment and control approach to manual handling injury hazard reduction. The WRATS programme was an intervention trial, covering the 1988-1995 financial years. In the course of compiling injury counts, it was found that the data exhibited an excess of zeros, in the context that the majority of cleaners did not suffer any injuries. This phenomenon is typical of data encountered in the occupational health discipline. We propose a zero-inflated random effects Poisson regression model to analyse such longitudinal count data with extra zeros. The WRATS intervention and other concomitant information on individual cleaners are considered as fixed effects in the model. The results provide statistical evidence showing the value of the WRATS programme. In addition, the methods can be applied to assess the effectiveness of intervention trials on populations at high risk of manual handling injury or indeed of injury from other hazards.

Consultative team to assess manual handling and reduce the risk of occupational injury.

OBJECTIVES: To describe the formation of a consultative team to assess the risk of manual handling in the workplace that started in October 1992 within the cleaning services department of a 600 bed hospital, and to evaluate the effectiveness of its recommendations in reducing the rate and severity (time lost and cost) of workers' compensation injury. METHODS: The consultative team identified, assessed, and recommended controls for manual handling and other injury risks. Data on injuries counted before and after implementation of the team's recommendations were obtained for the cleaning services study group, an orderly services comparison group, as well as cleaners from a peer hospital and for the State of Western Australia. Evaluation of the four groups was undertaken 3 years after the end of the study period, to allow maturation of the costs of the claims (adjusted to July 1998 consumer price index) and hours lost from work. RESULTS: Statistical analysis showed that implementation of the recommendations significantly reduced numbers and rates of injury, but not the severity of injury, in the cleaning services study group. There was no difference in numbers or severity of injuries for the comparison groups before and after implementation of the recommendations. CONCLUSIONS: The recommendation of the consultative team can produce a meaningful and sustained reduction in rates of injury within an at risk population. The results support a consultative approach to reducing workplace injuries from manual handling. The team process has potential for application to occupational groups at risk of exposure to other types of hazards.

Preoperative assessment of prognostic factors in breast cancer.

The adoption of preoperative diagnostic strategies involving fine needle aspiration cytology (FNAC) or core biopsy is well established, allowing the planning of operating lists and bed occupancy and patient involvement in therapeutic management. In addition to diagnosis, however, pathologists are increasingly being asked to provide pathological prognostic information from preoperative samples. This leader describes techniques for predicting prognosis and response to treatment on these specimens and some of the problems inherent in the determination of prognosis on small samples. For example, although histological grade can be assessed relatively reliably on either core or FNAC samples, the evaluation of tumour type (which includes an overall assessment of the architecture of a given tumour) may be less reliable on small preoperative samples. Other well recognised histological prognostic factors, such as vascular channel invasion or tumour size, cannot be determined accurately on small preoperative samples. For those patients who might benefit from neoadjuvant treatment, predicting the response to such treatments--for example, by the assessment of oestrogen receptor status--can readily be performed on either core biopsy or FNAC. In the future, other molecular markers such as C-erbB-2 might also prove beneficial in predicting response to newly developed treatments.

Assessing quality of life for adolescents in western Australia.

This study investigates the quality of life (QOL) for adolescents residing in Perth, Western Australia. The Quality of Life Profile-Adolescent Version (QOLPAV), a generic self-reported questionnaire, was administered to 363 adolescents aged between ten and 18 years who were enrolled in 20 high schools within metropolitan Perth. Stepwise regression analysis of the data showed that age, control, opportunity and perceptions of health have significant associations with QOL. It was also found that adolescents with a chronic condition and those without have similar QOL scores. This suggests that, in terms of QOL, the chronically ill adolescents do not view themselves as different from their healthy counterparts.

Determinants of length of stay: implications on differential funding for rural and metropolitan hospitals.

This study analysed and compared the determinants of length of inpatient stay between the rural and metropolitan public hospitals. The investigation was based on the 1998/99 Western Australia patient discharge data. A Cox regression model was used due to the high proportion of patient transfers in the rural hospitals. It was found that several variables were associated with length of stay (LOS) variations within Diagnosis Related Groups (DRG). The method provides additional insights to hospital management and clinicians in assessing the risk of prolonged hospitalisation. From a state government perspective, a DRG payment adjustment strategy may be developed for different categories of admitted patient episodes. The analysis has implications on the formulation of differential funding rates between rural and metropolitan hospitals.

A discordancy test approach to identify outliers of length of hospital stay.

A discordancy test approach is proposed to identify outliers of inpatient length of stay. This has implications not only for benchmarking service delivery but also for linking budget allocation procedures to efficiency of health service provisions. The effects of shifting trim point thresholds on hospital payments are assessed in a case study of a group of obstetrical patients.

A Delphi evaluation of the factors influencing length of stay in Australian hospitals.

Using a modified Delphi method, the factors influencing length of inpatient stay (LOS) were explored. Row/column effects loglinear modelling was used to compare ratings between the first and second rounds, and between the clinical and non-clinical groups. Rating scale modelling was used to classify and determine the relative importance of each factor. Six important and 48 significant determinants of LOS were found, and four unimportant factors were identified. The relationship among these factors and the implications of this study are explored.