Social media: a review and tutorial of applications in medicine and health care.

BACKGROUND: Social media are dynamic and interactive computer-mediated communication tools that have high penetration rates in the general population in high-income and middle-income countries. However, in medicine and health care, a large number of stakeholders (eg, clinicians, administrators, professional colleges, academic institutions, ministries of health, among others) are unaware of social media's relevance, potential applications in their day-to-day activities, as well as the inherent risks and how these may be attenuated and mitigated. OBJECTIVE: We conducted a narrative review with the aim to present case studies that illustrate how, where, and why social media are being used in the medical and health care sectors. METHODS: Using a critical-interpretivist framework, we used qualitative methods to synthesize the impact and illustrate, explain, and provide contextual knowledge of the applications and potential implementations of social media in medicine and health care. Both traditional (eg, peer-reviewed) and nontraditional (eg, policies, case studies, and social media content) sources were used, in addition to an environmental scan (using Google and Bing Web searches) of resources. RESULTS: We reviewed, evaluated, and synthesized 76 articles, 44 websites, and 11 policies/reports. Results and case studies are presented according to 10 different categories of social media: (1) blogs (eg, WordPress), (2) microblogs (eg, Twitter), (3) social networking sites (eg, Facebook), (4) professional networking sites (eg, LinkedIn, Sermo), (5) thematic networking sites (eg, 23andMe), (6) wikis (eg, Wikipedia), (7) mashups (eg, HealthMap), (8) collaborative filtering sites (eg, Digg), (9) media sharing sites (eg, YouTube, Slideshare), and others (eg, SecondLife). Four recommendations are provided and explained for stakeholders wishing to engage with social media while attenuating risk: (1) maintain professionalism at all times, (2) be authentic, have fun, and do not be afraid, (3) ask for help, and (4) focus, grab attention, and engage. CONCLUSIONS: The role of social media in the medical and health care sectors is far reaching, and many questions in terms of governance, ethics, professionalism, privacy, confidentiality, and information quality remain unanswered. By following the guidelines presented, professionals have a starting point to engage with social media in a safe and ethical manner. Future research will be required to understand the synergies between social media and evidence-based practice, as well as develop institutional policies that benefit patients, clinicians, public health practitioners, and industry alike.

The role of diet in predicting iron deficiency anemia in HIV-positive women.

PURPOSE: The association between medical, social, and nutritional factors and iron deficiency anemia was examined in adult women who had tested positive for human immunodeficiency virus (HIV) and were living in the Greater Vancouver Area. METHODS: This was a cross-sectional observational study of 102 HIV-positive women, aged 19 or older, who were patients of one of three chosen community health clinics in Vancouver, British Columbia. Information on usual dietary intake and other nutrition-related factors was collected with a short diet survey, while medical information and laboratory data were obtained from each participant's medical chart. RESULTS: Of the predictors studied, a CD4 cell count below 200 cells/µL, a regular menstrual pattern, and African ethnicity were associated with an increased risk of iron deficiency anemia. Dietary intake was not independently associated with iron status. CONCLUSIONS: Iron deficiency anemia in HIV-positive women has multifactorial and complicated causation, but is strongly associated with poorer immune status and greater menstrual losses. Health disparities in Aboriginal and African women may lead to a higher risk for iron deficiency anemia. Routine screening and ongoing nutrition education are necessary for the prevention and management of iron deficiency anemia. Further research into factors associated with iron deficiency anemia is essential to improve prevention and management efforts.

Outcomes of emergency department patients presenting with adverse drug events.

STUDY OBJECTIVE: Our objectives are to describe the outcomes of patients presenting to the emergency department (ED) because of an adverse drug event and to compare them with outcomes of patients presenting for other reasons. METHODS: This prospective observational study was conducted at Vancouver General Hospital, a 955-bed tertiary care hospital. We prospectively enrolled adults presenting to the ED between March and June 2006, using a systematic sampling algorithm. Pharmacists and physicians independently evaluated patients for adverse drug events. An independent committee reviewed and adjudicated cases in which assessments were discordant or uncertain. Data from the index visit were linked to vital statistics, administrative health services utilization, and cost of care data. RESULTS: Of 1,000 patients, 122 (12.2%; 95% confidence interval [CI] 10.3% to 14.4%) presented to the ED because of an adverse drug event. Of these, 48 presented because of an adverse drug reaction (one type of adverse drug event defined as an unintended response that occurred despite use of an appropriate drug dosage). We found no difference in mortality among patients presenting with and without adverse drug reactions (14.6% versus 5.9%; hazard ratio 1.57; 95% CI 0.70 to 3.52). After adjustment, patients with adverse drug events had a higher risk of spending additional days in the hospital per month (6.3% versus 3.4%; odds ratio 1.52; 95% CI 1.43 to 1.62) and higher rate of outpatient health care encounters (1.73 versus 1.22; rate ratio 1.20; 95% CI 1.03 to 1.40). The adjusted median monthly cost of care was 1.90 times higher (Can $325 versus $96; 95% CI 1.18 to 3.08). CONCLUSION: ED patients presenting with an adverse drug event incurred greater health services utilization and costs during a 6-month follow-up period compared with patients presenting for other reasons.

An epidemiological survey of chlamydial and gonococcal infections in a Canadian arctic community.

BACKGROUND: Sexually transmitted infections are leading causes of morbidity for Canadian Aboriginal women. To date, very few initiatives have been successful in screening, treating, and limiting these infections among these populations. OBJECTIVES: To evaluate the efficacy of universal screening, treatment and contact tracing as a means of capturing a more accurate count of chlamydia and gonorrhea prevalence and limiting transmission among Inuit communities. METHODS: 181 participants were screened for chlamydia and gonorrhea and interviewed in a cross-sectional survey (Aug-Sept/03). Information was collected on demographics, use of health services, sexual histories and STI knowledge among others. A random sample (n = 100) from the cross-sectional group was selected for the longitudinal cohort. Individuals were followed every two months post baseline for four visits (Oct/03-May/04). At each visit, participants were screened for chlamydia/gonorrhea. All positive cases and their partners were treated and contact tracing completed. Logistic Regression analysis and the McNemar Test of Correlated Proportions were used to analyze the data. RESULTS: Overall, 35 cases of chlamydia were detected, with 21 detected at baseline and 14 during follow-up. The baseline prevalence was 11.6% in comparison with 2.7% that was previously estimated. No gonorrhea was detected. The strongest factor associated with a positive chlamydia was having recent STI (OR 9.82, CI: 2.70, 35.77). CONCLUSIONS: Consistent with the literature, the results support the use of universal screening followed by prompt treatment and contact tracing in populations with greater than 10% chlamydia prevalence.

Treating hand fractures: population-based study of acute health care use in British Columbia.

OBJECTIVE: To examine trends in use of acute health care services for hand fractures in a large diverse population across a range of medical settings. DESIGN: Retrospective review of data from the British Columbia Linked Health Dataset on patients who had been treated for hand fractures between May 1, 1996, and April 30, 2001. SETTING: British Columbia. PARTICIPANTS: A total of 72 481 British Columbia residents identified from the British Columbia Linked Health Dataset as having received treatment for hand fractures. MAIN OUTCOME MEASURES: Initial treatment for fractures (who had provided treatment and where had the treatment taken place) and hospital use (type of hospital, physician responsible, wait time, length of stay,geographic variation). RESULTS: Almost all patients (97%) with hand fractures received initial treatment as outpatients. Just over half these patients (54%) received initial care in nonhospital settings, and more than two-thirds (70%) received initial care from primary care physicians. By far most patients (90%) were treated conservatively without surgical intervention. The few patients with more complicated hand fractures (10%) were most commonly treated in day surgery settings by specialist surgeons within 2 days of first presentation. Patients in the more rural, isolated,northern region of British Columbia had higher hospital admission rates (relative risk 2.1) for hand fractures than patients in other regions did. CONCLUSION: In contrast to other common fracture injuries that are routinely managed by specialist surgeons,most hand fractures in BC were managed initially as nonemergency medical problems by primary care physicians. Almost all patients were treated conservatively without surgical intervention. The few patients with more complicated hand fractures were referred to and treated quickly by specialist surgeons. Focused training and continuing education opportunities for primary care physicians on new approaches to management of acute hand fractures will ensure that patients with hand fractures in British Columbia and the whole of Canada continue to benefit from appropriate management by primary care physicians.

Measure for measure? The challenge of new thinking about patient safety.

Penfold and colleagues, in this issue of Healthcare Papers, provide a comprehensive and substantive critique of the hospital standardized mortality ratio (HSMR) as a measure of patient safety, and suggest a useful alternative. However, although measurement is not trivial, new thinking about patient safety presents a much greater challenge than just issues related to measurement. The measurement issue highlights the need for a re-conceptualization of what it takes, from a systems perspective, to achieve safety. This commentary first reviews Penfold et al.'s arguments (agreeing with their conclusions regarding the HSMR). It then presents some key elements of the new thinking about patient safety, particularly the emerging concepts of resilience and resonance, and notes how and why these are beginning to be applied in healthcare. Finally, it considers a number of reasons why a more comprehensive adoption of these new perspectives may be prolonged and notes that, while difficult, the journey is worth taking.

The Delphi process in dental research.

OBJECTIVE: To explore how Delphi formal consensus procedures may augment decision making in oral health care in the absence of high-quality clinical and epidemiological data. METHODS: A review and appraisal of the literature regarding the Delphi method was conducted using Medline databases and Google. RESULTS: The Delphi method has a long history that highlights both its strengths and limitations. Delphi uses a series of anonymous questionnaires designed to develop a consensus of opinion and can provide guidance on topics that have not or cannot be studied in randomized controlled trials. The Delphi technique has been used to achieve consensus of opinion on a variety of issues including those related to oral health. Guidelines for the use of Delphi are presented. CONCLUSION: Like any other research methodology, the process guidelines need to be systematic and comprehensive. Delphi expert opinion consensus may improve decision making in a wide variety of oral health circumstances.

Carbohydrates and colorectal cancer risk among Chinese in North America.

Previous studies have analyzed total carbohydrate as a dietary risk factor for colorectal cancer (CRC) but obtained conflicting results, perhaps attributable in part to the embedded potential confounder, fiber. The aim of this study was to analyze the nonfiber ("effective") carbohydrate component (eCarb) separately and to test the hypothesis that effective carbohydrate consumption is directly related to CRC risk. The data (473 cases and 1192 controls) were from a large, multicenter, case-control study of Chinese residing in North America. Multivariate logistic regression was used to perform a secondary analysis controlling for age; sex; consumption of fat, fiber, calcium, and total kilocalories; body mass (Quetelet's) index; family history; education; and years in North America. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated to estimate risk among subgroups by sex and cancer site. A statistically significant positive association was observed between eCarb consumption and risk of CRC in both men (OR, 1.7 comparing highest with lowest tertile of eCarb consumption; 95% CI, 1.1-2.7) and women (OR, 2.7; 95% CI, 1.5-4.8). As expected, the ORs for total carbohydrate were somewhat lower than those for effective carbohydrate, but the differences were not large. A sex difference in risk by colorectal subsite was observed, with risk concentrated in the right colon for women (OR, 6.5; 95% CI, 2.4-18.4) and in the rectum for men (OR, 2.4; 95% CI, 1.2-4.8). These data indicate that increased eCarb and total carbohydrate consumption are both associated with increased risk of CRC in both sexes, and that among women, relative risk appears greatest for the right colon, whereas among men, relative risk appears greatest for the rectum.

Insulin, macronutrient intake, and physical activity: are potential indicators of insulin resistance associated with mortality from breast cancer?

High levels of insulin have been associated with increased risk of breast cancer, and poorer survival after diagnosis. Data and sera were collected from 603 breast cancer patients, including information on diet and physical activity, medical history, family history, demographic, and reproductive risk factors. These data were analyzed to test the hypothesis that excess insulin and related factors are directly related to mortality after a diagnosis of breast cancer. The cohort was recruited from breast cancer patients treated at the British Columbia Cancer Agency between July 1991 and December 1992. Questionnaire and medical record data were collected at enrollment and outcomes were ascertained by linkage to the BC Cancer Registry after 10 years of follow-up. The primary outcome of interest was breast cancer-specific mortality (n = 112). Lifestyle data were analyzed using Cox proportional hazards regression models to relate risk factors to outcomes, controlling for potential confounders, such as age and stage at diagnosis. Data for biological variables were analyzed as a nested case-control study due to limited serum volumes, with at least one survivor from the same cohort as a control for each breast cancer death, matched on stage and length of follow-up. High levels of insulin were associated with poorer survival for postmenopausal women [odds ratio, 1.9; 95% confidence interval (CI), 0.7-6.6, comparing highest to lowest tertile, P trend = 0.10], while high dietary fat intake was associated with poorer survival for premenopausal women (relative risk, 4.8; 95% CI, 1.3-18.1, comparing highest to lowest quartile). Higher dietary protein intake was associated with better survival for all women (relative risk, 0.4; 95% CI, 0.2-0.8, comparing highest to lowest quartile).

Modified Delphi survey for decision analysis for prophylaxis of post-radiation osteonecrosis.

OBJECTIVES: to augment epidemiological data from the literature, assist Bayesian perspectives and a decision analytic framework for the minimization of post-radiation osteonecrosis (PRON; osteoradionecrosis) and its impacts in irradiated head and neck cancer patients. MATERIALS AND METHODS: a modified Delphi process survey of 15 international clinical experts was used to identify and assess outcome data and factors related to PRON risk, extraction, and factor suitability for formal decision analysis. Clinimetric pain and function outcome scales were created and assessed for relevance to quality of life. RESULTS AND CONCLUSIONS: expert opinion qualitative assessments were generally adequate and consistent between open- and close-ended items, but many quantitative (e.g. PRON risk rate) estimates were not. A research agenda advocated to validate the epidemiological database for minimization of PRON and decision analysis includes: adoption of a uniform definition of PRON, and ICD code for non-experimental databases; more detailed, consistent data reporting in articles; and quality of life studies.

Conspicuous consumption: characterizing high users of physician services in one Canadian province.

OBJECTIVES: To examine medical care use and costs, patterns of morbidity and co-morbidity, and other patient characteristics of high users of physician services in British Columbia. METHODS: This population-based study uses physician claims, hospital discharge summaries and vital statistics data linked at the level of the individual to compare characteristics of high users, other users and non-users of physician services in the Province of British Columbia, Canada. The study included all enrolled adults in the universal health care plan during fiscal year 1996/97. High users were defined as the most costly 5% of users of fee-reimbursed services. Key variables included age, sex, an ecological socio-economic status indicator and a comprehensive set of morbidity indicators, derived from the diagnoses recorded on the utilization records. RESULTS: The top 5% of users consumed a disproportionate 30% of spending on physician services. High users were overwhelmingly characterized by a significant burden of morbidity. Over 80% had at least six different types of morbidity during the study year compared with fewer than 20% of other users. High users were also much more likely to have major diagnoses that were both acute and chronic in nature. Co-morbidity involving psychosocial and chronic medical conditions was also very common. CONCLUSIONS: High users of physician services are overwhelmingly characterized by multiple and complex health problems. Policy tools based on a philosophy of deterrence such as cost-sharing are unlikely to have much impact on their costs and will likely do considerable harm.

Clinical decision rules to improve the detection of adverse drug events in emergency department patients.

OBJECTIVES: Adverse drug events (ADEs) are unintended and harmful consequences of medication use. They are associated with high health resource use and cost. Yet, high levels of inaccuracy exist in their identification in clinical practice, with over one-third remaining unidentified in the emergency department (ED). The study objective was to derive clinical decision rules (CDRs) that are sensitive for the detection of ADEs, allowing their systematic identification early in a patient's hospital course. METHODS: This was a prospective observational cohort study carried out in two Canadian tertiary care hospitals. Participants were adults presenting to the ED having ingested at least one prescription or over-the-counter medication within 2 weeks. Nurses and physicians evaluated patients for standardized clinical findings. A second evaluator performed interobserver assessments of predictor variables in a subset of patients. Pharmacists, who were blinded to the predictor variables, evaluated all patients for ADEs. An independent committee reviewed and adjudicated cases where the ADE assessment was uncertain or the pharmacist's diagnosis differed from the physician's working diagnosis. The primary outcome was an ADE that required a change in medical therapy, diagnostic testing, consultation, or hospital admission. CDRs were derived using kappa coefficients, chi-square statistics, and recursive partitioning. RESULTS: Among 1,591 patients, 131 (8.2%, 95% confidence interval [CI] = 7.0% to 9.7%) were diagnosed with the primary outcome. The following variables were associated with ADEs and were used to derive two CDRs: 1) presence of comorbid conditions, 2) antibiotic use within 7 days, 3) medication changes within 28 days, 4) age ≥ 80 years, 5) arrival by ambulance, 6) triage acuity, 7) recent hospital admission, 8) renal failure, and 9) use of three or more prescription medications. The more sensitive rule had a sensitivity of 96.7% (95% CI = 91.8% to 98.6%) and required 40.8% (95% CI = 37.7% to 42.9%) of patients to have medication review. The more specific rule had a sensitivity 90.8% (95% CI = 81.4% to 95.7%) and required 28.3% of patients to proceed to medication review. CONCLUSIONS: The authors derived CDRs that identified patients with ADEs with high sensitivity. These rules may improve the identification of ADEs early in a patient's hospital course while limiting the number of patients requiring a detailed medication review.

Birth outcomes among older mothers in rural versus urban areas: a residence-based approach.

PURPOSE: We examined the association between rural residence and birth outcomes in older mothers, the effect of parity on this association, and the trend in adverse birth outcomes in relation to the distance to the nearest hospital with cesarean-section capacity. METHODS: A population-based retrospective cohort study, including all singleton births to 35+ year-old women in British Columbia (Canada), 1999-2003. We compared birth outcomes in rural versus urban areas, and between 3 distance categories to a hospital (<50, 50-150, >150 km). Outcomes included labor induction, cesarean section, stillbirth, perinatal death, preterm birth (<37 weeks), small-for-gestational-age, large-for-gestational-age, and neonatal intensive care unit admission. We used multivariate regression to obtain adjusted odds ratios (ORs) and 95% confidence intervals (CIs). FINDINGS: Among the 29,698 subjects, 11.5% lived in rural areas; 5% lived within 50-150 km; and 1.1% lived >150 km from a hospital. Rural women were at lower risk of primary and repeat cesarean section (OR = 0.9, CI: 0.9-1.0; OR = 0.7, CI: 0.6-0.9) and small-for-gestational-age (OR = 0.8, CI: 0.7-0.9) births; they were at increased risk for perinatal death (OR = 1.5, CI: 1.1-2.1) and large-for-gestational-age (OR = 1.1, CI: 1.1-1.2) births. The association was stronger among multiparous versus primiparous women. No differences in emergency cesarean section, preterm birth, or neonatal intensive care admission were found, regardless of parity. Perinatal mortality increased with distance from hospital; OR = 1.5 (CI: 1.1-2.1) per distance category. CONCLUSIONS: Older women in rural versus urban areas had a lower rate of cesarean section and increased risk of perinatal death. The risk of perinatal death increased with the distance to hospital. Further studies need to evaluate the contribution of underlying perinatal risks, access to care, and decision making regarding referral and transport.

Incidence and demographics of hand fractures in British Columbia, Canada: a population-based study.

PURPOSE: To identify population-based hand fracture annual incidence rates, demographics, and seasonal and geographic variations from all patients seeking treatment for a hand fracture in British Columbia, Canada from May 1, 1996 to April 20, 2001. METHODS: All Medical Service Plan and Hospital Separation records that included International Classification of Diseases-9 codes for metacarpal (815), phalangeal (816), and multiple (817) fractures were extracted from the British Columbia Linked Health Dataset, along with the individual registry demographic records linked to each hand fracture. RESULTS: A total of 72,481 hand fractures were identified. Fifty percent were phalangeal fractures, 42% were metacarpal fractures, and 8% were multiple fractures. The total population annual incidence rate for a hand fracture was 36 per 10,000. Age-adjusted annual incidence rates ranged from 29 per 10,000 for people older than 20 years to 61 per 10,000 for people age 20 or younger. The most common age for a hand fracture was 14 years for males and 13 years for females. Males had a 2.08 greater relative risk for hand fracture and they maintained most of this increase in risk between the ages of 15 and 40. For females there was an increased relative risk for a hand fracture after the age of 65. Spring had the highest rates for hand fractures. People in the Northern half of the province had a 1.6 greater relative risk for sustaining a hand fracture, compared with people in the more urbanized, less-industrialized, and more-affluent Southwestern region. CONCLUSIONS: Our study provides a robust projection of annual incidence rates for hand fractures because we were able to review all occurrences of a hand fracture within a population base of approximately 4 million people over a 5-year period. Our study also allowed for the examination of how age, gender, season, and geographic location influenced hand fracture incidence rates within a large, diverse population.

Determinants of sexually transmitted infections among Canadian Inuit adolescent populations.

The health status of Canadian Inuit is considerably lower than that of their ancestors. The introduction of previously unknown diseases (e.g., tuberculosis), substance abuse (e.g., alcohol), and Western customs have permanently altered this population. As a result of Western assimilation, many Inuit have distanced themselves from their land and severed their ancestral ties. Consequently, many are now mired in a state of widespread poverty and malnutrition and have severe health problems (e.g., addictions) and communicable diseases, such as sexually transmitted infections (STIs). The purpose of this case report is to provide an overview of the STI crisis that exists among Canadian Inuit. More specifically, this case study is intended to assist public health nurses working in Inuit communities in understanding how certain determinants (e.g., Westernization, culture) may influence STI transmission among Inuit youth and, how to incorporate these determinants into nursing practice. Inuit adolescents have been subjected to intense acculturation pressures that do not exist for other adolescent populations. These pressures are creating problems for youth in their transition from childhood and adulthood; they also impact on the struggle to establish their own identity, caught between two opposing cultures: their native culture and the wider Canadian one.

Identification of modifiable work-related factors that influence the risk of work disability in rheumatoid arthritis.

OBJECTIVE: To define work-related factors associated with increased risk of work disability (WD) in people with rheumatoid arthritis (RA). METHODS: Questionnaires were mailed to all RA patients who used a province-wide arthritis treatment program between 1991 and 1998 (n = 1,824). The association between risk factors and WD (defined as no paid work due to RA for at least 6 months) was assessed using multiple logistic regression analysis, controlling for significant sociodemographic and disease-related variables. RESULTS: Of the original 1,824 patients, 581 were eligible and responded to the questionnaire. Work survival analysis revealed a steady rate of WD starting early, with 7.5%, 18%, and 27% work disabled at 1, 5, and 10 years, respectively. Significant determinants in multiple logistic regression were physical function (Health Assessment Questionnaire), pain (visual analog scale), and 6 work-related factors: self employment, workstation modification, work importance, family support toward employment, commuting difficulty, and comfort telling coworkers about RA. CONCLUSION: Work disability occurs early in RA. Novel work-related factors were identified, which are potentially modifiable, to help RA patients stay employed.

Beneath the calm surface: the changing face of physician-service use in British Columbia, 1985/86 versus 1996/97.

BACKGROUND: Although expenditures on health care are continually increasing and often said to be unsustainable, few studies have examined these trends at the level of services delivered to individual patients. We analyzed trends in the various components that contributed to changes in overall expenditures for physician services in British Columbia from 1985/86 to 1996/97. METHODS: We obtained data on all fee-for-service payments to physicians in each study year using the British Columbia Linked Health Data set and analyzed these at the level of individual patients. We disaggregated overall billing levels by year into the following components: number of physicians seen by each patient, number of visits per physician, number of services rendered on each visit and average price of those services. We removed the effect of inflation on fees by adjusting to those in 1988. We used direct age-standardization to isolate and measure the effect of demographic changes. We used the Consumer Price Index to determine the effects of inflation. RESULTS: Total payments to fee-for-service physicians in British Columbia rose 86.3% over the study period. The increase was entirely accounted for by the combined effects of population growth (28.9%), aging (2.1%) and general inflation (41.4%). Service use per capita rose 10.5%; this increase was offset by a decline of 9.4% in inflation-adjusted fees. The average cost of age-adjusted per-capita services rendered by general or family practitioners (GP/FPs) increased very little (3.3%) over the 11-year period, compared with a nearly one-third (31.8%) increase for medical specialists. Although there was a dramatic increase in the number of GP/FPs seen on average by each patient (32.9%), this increase was offset by the combination of decreases in the number of visits per physician (-14.9%), the number of services provided per visit (-8.0%) and the "real cost" of each service provided (-3.5%). Visits to medical specialists increased by about 20% over the study period in all age groups. However, for each person 65 years of age or over receiving any services, the average fee-adjusted expenditures increased 24.8%, almost 4 times the rate of increase for people younger than 65. The use of surgical services grew 26.5% for seniors while declining -2.0% for people under age 65. INTERPRETATION: These findings suggest a form of "homeostasis" in aggregate-level service use and cost. The supposed inflationary effects of population aging and increasing "abuse of the system" by patients were not found.

Waist-to-hip ratio and breast cancer mortality.

High insulin levels have been associated with increased risk of breast cancer and poorer survival after a breast cancer diagnosis. Waist-to-hip ratio (WHR) is a marker for insulin resistance and hyperinsulinemia. In this study, the authors tested the hypothesis that elevated WHR is directly related to breast cancer mortality. For identification of modifiable factors affecting survival, data were collected on 603 patients with incident breast cancer who visited the Vancouver Cancer Centre of the British Columbia Cancer Agency (Vancouver, British Columbia, Canada) in 1991-1992, including body measurements and information on demographic, medical, reproductive, and dietary factors. These patients were followed for up to 10 years. Cox proportional hazards regression models were used to relate the variables to breast cancer mortality (n = 112). After adjustment for age, body mass index, family history, estrogen receptor (ER) status, tumor stage at diagnosis, and systemic treatment (chemotherapy or tamoxifen), WHR was directly related to breast cancer mortality in postmenopausal women (for highest quartile vs. lowest, relative risk = 3.3, 95% confidence interval: 1.1, 10.4) but not in premenopausal women (relative risk = 1.2, 95% confidence interval: 0.4, 3.4). Stratification according to ER status showed that the increased mortality was restricted to ER-positive postmenopausal women. Elevated WHR was confirmed as a predictor of breast cancer mortality, with menopausal status and ER status at diagnosis found to be important modifiers of that relation.