Health data, although widely and diligently collected, continue to be under-utilised for research and evaluation in most countries. This protocol aims to make these data more easily available to researchers by providing a controlled and secure mechanism that guarantees privacy protection.

Objective To investigate the time relations between long haul air travel and venous thromboembolism. Design Record linkage study using the case crossover approach. Setting Western Australia. Participants 5408 patients admitted to hospital with venous thromboembolism and matched with data for arrivals of international flights during 1981-99. Results The risk of venous thromboembolism is increased for only two weeks after a long haul flight; 46 Australian citizens and 200 non-Australian citizens had an episode of venous thromboembolism during this so called hazard period. The relative risk during this period for Australian citizens was 4.17 (95% confidence interval, 2.94 to 5.40), with 76% of cases (n = 35) attributable to the preceding flight. A "healthy traveller" effect was observed, particularly for Australian citizens. Conclusions The annual risk of venous thromboembolism is increased by 12% if one long haul flight is taken yearly. The average risk of death from flight related venous thromboembolism is small compared with that from motor vehicle crashes and injuries at work. The individual risk of death from flight related venous thromboembolism for people with certain pre-existing medical conditions is, however, likely to be greater than the average risk of 1 per 2 million for passengers arriving from a flight. Airlines and health authorities should continue to advise passengers on how to minimise risk.

Objective: This article outlines a protocol for facilitating access to administrative data for the purpose of health services research, when these data are sourced from multiple organisations. This approach is designed to

Estimates of the health-care costs associated with diabetes-related complications can be used in modeling the long-term costs of diabetes and in evaluating the cost-effectiveness of improving care.

BACKGROUND: Exacerbations in chronic respiratory diseases (CRDs) are sensitive to seasonal variations in exposure to respiratory infectious agents and allergens and patient factors such as non-adherence. Hence, regular general practitioner (GP) contact is likely to be important in order to recognise symptom escalation early and adjust treatment. OBJECTIVE:To examine the association of regularity of GP visits with all-cause mortality and first CRD hospitalisation overall and within groups of pharmacotherapy level in older CRD patients. DESIGN:A retrospective cohort design using linked hospital, mortality, Medicare and pharmaceutical data for participant, exposure and outcome ascertainment. GP visit pattern was measured during the first 3 years of the observation period. Patients were then followed for a maximum of 11.5 years for ascertainment of hospitalisations and deaths.PARTICIPANTS: We studied 108,455 patients aged ≥65 years with CRD in Western Australia (WA) during 1992-2006. MAIN MEASURES:A GP visit regularity score (range 0-1) was calculated and divided into quintiles. A clinician consensus panel classified levels of pharmacotherapy. Cox proportional hazards models, controlling for multiple factors including GP visit frequency, were used to calculate hazard ratios and confidence intervals. KEY RESULTS: Differences in survival curves and hospital avoidance pattern between the GP visit regularity quintiles were statistically significant (p= 0.0279 and p<0.0001, respectively). The protective association between GP visit regularity and death appeared to be confined to the highest pharmacotherapy level group (P for interaction=0.0001). Higher GP visit regularity protected against first CRD hospitalisation compared with the least regular quintile regardless of pharmacotherapy level (medium regular: HR=0.84, 95% CI=0.77-0.92; 2nd most regular: HR= 0.74, 95% CI=0.67-0.82; most regular HR=0.77, 95% CI=0.68-0.86). CONCLUSIONS: The findings indicate that regular and proactive 'maintenance' primary care, as distinct from 'reactive' care, is beneficial to older CRD patients by reducing their risks of hospitalisation and death.