Time to surgery after hip fracture across Canada by timing of admission

The extent of Canadian provincial variation in hip fracture surgical timing is unclear. Provinces performed a similar proportion of surgeries within three inpatient days after adjustment. Time to surgery varied by timing of admission across provinces. This may reflect different approaches to providing access to hip fracture surgery.

INTRODUCTION

The aim of this study was to compare whether time to surgery after hip fracture varies across Canadian provinces for surgically fit patients and their subgroups defined by timing of admission.

METHODS

We retrieved hospitalization records for 140,235 patients 65 years and older, treated surgically for hip fracture between 2004 and 2012 in Canada (excluding Quebec). We studied the proportion of surgeries on admission day and within 3 inpatient days, and times required for 33%, 66%, and 90% of surgeries across provinces and by subgroups defined by timing of admission. Differences were adjusted for patient, injury, and care characteristics.

RESULTS

Overall, provinces performed similar proportions of surgeries within the recommended three inpatient days, with all provinces requiring one additional day to perform the recommended 90% of surgeries. Prince Edward Island performed 7.0% more surgeries on admission day than Ontario irrespective of timing of admission (difference = 7.0; 95% CI 4.0, 9.9). The proportion of surgeries on admission day was 6.3% lower in Manitoba (difference = - 6.3; 95% CI - 12.1, - 0.6), and 7.7% lower in Saskatchewan (difference = - 7.7; 95% CI - 12.7, - 2.8) compared to Ontario. These differences persisted for late weekday and weekend admissions. The time required for 33%, 66%, and 90% of surgeries ranged from 1 to 2, 2-3, and 3-4 days, respectively, across provinces by timing of admission.

CONCLUSIONS

Provinces performed similarly with respect to recommended time for hip fracture surgery. The proportion of surgeries on admission day, and time required to complete 33% and 66% of surgeries, varied across provinces and by timing of admission. This may reflect different provincial approaches to providing access to hip fracture surgery.

The structural flexibility of the human copper chaperone Atox1: Insights from combined pulsed EPR studies and computations

Metallochaperones are responsible for shuttling metal ions to target proteins. Thus, a metallochaperone's structure must be sufficiently flexible both to hold onto its ion while traversing the cytoplasm and to transfer the ion to or from a partner protein. Here, we sought to shed light on the structure of Atox1, a metallochaperone involved in the human copper regulation system. Atox1 shuttles copper ions from the main copper transporter, Ctr1, to the ATP7b transporter in the Golgi apparatus. Conventional biophysical tools such as X-ray or NMR cannot always target the various conformational states of metallochaperones, owing to a requirement for crystallography or low sensitivity and resolution. Electron paramagnetic resonance (EPR) spectroscopy has recently emerged as a powerful tool for resolving biological reactions and mechanisms in solution. When coupled with computational methods, EPR with site-directed spin labeling and nanoscale distance measurements can provide structural information on a protein or protein complex in solution. We use these methods to show that Atox1 can accommodate at least four different conformations in the apo state (unbound to copper), and two different conformations in the holo state (bound to copper). We also demonstrate that the structure of Atox1 in the holo form is more compact than in the apo form. Our data provide insight regarding the structural mechanisms through which Atox1 can fulfill its dual role of copper binding and transfer.

Ctr1 Intracellular Loop Is Involved in the Copper Transfer Mechanism to the Atox1 Metallochaperone

Understanding the human copper cycle is essential to understand the role of metals in promoting neurological diseases and disorders. One of the cycles controlling the cellular concentration and distribution of copper involves the copper transporter, Ctr1; the metallochaperone, Atox1; and the ATP7B transporter. It has been shown that the C-terminus of Ctr1, specifically the last three amino acids, HCH, is involved in both copper coordination and the transfer mechanism to Atox1. In contrast, the role of the intracellular loop of Ctr1, which is an additional intracellular segment of Ctr1, in facilitating the copper transfer mechanism has not been investigated yet. Here, we combine various biophysical methods to explore the interaction between this Ctr1 segment and metallochaperone Atox1 and clearly demonstrate that the Ctr1 intracellular loop (1) can coordinate Cu(I) via interactions with the side chains of one histidine and two methionine residues and (2) closely interacts with the Atox1 metallochaperone. Our findings are another important step in elucidating the mechanistic details of the eukaryotic copper cycle.

SOD mimetic activity and antiproliferative properties of a novel tetra nuclear copper (II) complex

The search for novel anticancer therapeutic agents is an urgent and important issue in medicinal chemistry. Here, we report on the biological activity of the copper-based bioinorganic complex Cu4 (2,4-di-tert-butyl-6-(1H-imidazo- [1, 10] phenanthrolin-2-yl)phenol)4]·10 CH3CN (2), which was tested in rat L6 myotubes, mouse NSC-34 motor neurone-like cells, and HepG-2 human liver carcinoma. Upon 96 h incubation, 2 exhibited a significant cytotoxic effect on all three types of cells via activation of two cell death mechanisms (apoptosis and necrosis). Complex 2 exhibited better potency and efficacy than the canonical cytotoxic drug cisplatin. Moreover, during shorter incubations, complex 2 demonstrated a significant SOD mimetic activity, and it was more effective and more potent than the well-known SOD mimetic TEMPOL. In addition, complex 2 was able to interact with DNA and, cleave DNA in the presence of sodium ascorbate. This study shows the potential of using polynuclear redox active compounds for developing novel anticancer drugs through SOD-mimetic redox pathways.

Sources of sport confidence, imagery type and performance among competitive athletes: the mediating role of sports confidence

AIM

This study explored the mediating role of sport confidence upon (1) sources of sport confidence-performance relationship and (2) imagery-performance relationship.

METHODS

Participants were 157 competitive athletes who completed state measures of confidence level/sources, imagery type and performance within one hour after competition.

RESULTS

Among the current sample, confirmatory factor analysis revealed appropriate support for the nine-factor SSCQ and the five-factor SIQ. Mediational analysis revealed that sport confidence had a mediating influence upon the achievement source of confidence-performance relationship. In addition, both cognitive and motivational imagery types were found to be important sources of confidence, as sport confidence mediated imagery type- performance relationship.

CONCLUSION

Findings indicated that athletes who construed confidence from their own achievements and report multiple images on a more frequent basis are likely to benefit from enhanced levels of state sport confidence and subsequent performance.

The impact on utilities of differences in body weight among Canadian patients with type 2 diabetes

OBJECTIVE

The objective of this study was to estimate utility values for hypothetical health states that describe differences in weight and quality of life associated with type 2 diabetes mellitus (DM) from Canadians with type 2 DM. The impact on utility values was examined separately for participants with a body mass index (BMI) of 18 to less than 25 kg/m(2) ('healthy'), 25 to less than 30 ('overweight'), and 30 or more ('obese').

METHODS

The health state descriptions were modified from a published diabetes utility study. Health states included a base-case type 2 DM health state (at participants' current weight), and six health states where the weight and attendant quality of life impact varied (base case ±3%, ±5%, and ±7% weight). Utilities were elicited using the time trade-off technique. Linear regression modeling was used to estimate the utility increment or decrement associated with a one unit difference in BMI.

RESULTS

Among 96 participants, the mean age was 55 years and 51% were men. The mean BMI was 32 kg/m(2) and 84% wanted to lose weight. The mean (SD) utility for the base-case state was 0.911 (0.013). Mean utilities (utility decrements) were 0.907 (-0.004), 0.865 (-0.046) and 0.806 (-0.105) for the health states describing an increased weight of 3%, 5% and 7%, respectively; and 0.923 (+0.012), 0.940 (+0.029) and 0.949 (+0.038) for the health states describing a decreased weight of 3%, 5% and 7%, respectively. For every increase of 1 kg/m(2) BMI there was an associated decrease in utility of 0.0472 (95% CI: 0.0375, 0.0569) and for every decrease of 1 kg/m(2) BMI there was an associated increase in utility of 0.0171 (95% CI: 0.0103, 0.0238).

CONCLUSIONS

The preferences of Canadian patients with type 2 DM for diabetes-related health states varied according to the weight, and quality of life impact, associated with that health state. Increased weight had a greater effect on utilities than decreased weight.

Probing the structural flexibility of the human copper metallochaperone Atox1 dimer and its interaction with the CTR1 c-terminal domain

Both the essentiality and the toxicity of copper in human, yeast, and bacteria cells require precise mechanisms for acquisition, intimately linked to controlled distribution, which have yet to be fully understood. This work explores one aspect in the copper cycle, by probing the interaction between the human copper chaperone Atox1 and the c-terminal domain of the copper transporter, CTR1, using electron paramagnetic resonance (EPR) spectroscopy and circular dichroism (CD). The data collected here shows that the Atox1 keeps its dimer nature also in the presence of the CTR1 c-terminal domain; however, two geometrical states are assumed by the Atox1. One is similar to the geometrical state reported by the crystal structure, while the latter has not yet been constructed. In the presence of the CTR1 c-terminal domain, both states are assumed; however, the structure of Atox1 is more restricted in the presence of the CTR1 c-terminal domain. This study also shows that the last three amino acids of the CTR1 c-terminal domain, HCH, are important for maintaining the crystal structure of the Atox1, allowing less structural flexibility and improved thermal stability of Atox1.

Cost-effectiveness in Canada of azacitidine for the treatment of higher-risk myelodysplastic syndromes

OBJECTIVE

Our goal was to determine the economic value of azacitidine in Canada compared with conventional care regimens (ccrs), including best supportive care (bsc) and low- or standard-dose chemotherapy plus bsc in the treatment of higher-risk myelodysplastic syndromes (mdss) and acute myeloid leukemia (aml) with 20%-30% blasts.

METHODS

The cost-utility model is a lifetime probabilistic Markov model with a 35-day cycle length consisting of 3 health states: mds; transformation to aml with more than 30% blasts; and death. A third-party public payer perspective was adopted. Overall survival was extrapolated beyond the time horizon of the aza-001 trial comparing azacitidine with ccr. Resource use was determined through a questionnaire completed by Canadian hematologists. Utility values were obtained from two studies in which EQ-5D health questionnaire values were mapped from the European Organization for Research and Treatment of Cancer qlq-C30 survey, and SF-6D scores were mapped from the Short Form 12, elicited from 191 and 43 patients in two different trials.

RESULTS

In the base case, azacitidine had an incremental cost-effectiveness ratio (icer) of $86,182 (95% confidence limits: $69,920, $107,157) per quality-adjusted life year (qaly) gained relative to ccr. Comparing azacitidine with bsc, low-dose chemotherapy plus bsc, and standard-dose chemotherapy plus bsc, the icers were, respectively, $86,973, $84,829, and $2,152 per qaly gained. Results were most sensitive to the utility for azacitidine after 6 months of treatment and to overall survival.

CONCLUSIONS

The prolonged 9-month median overall survival with azacitidine relative to ccr fills a gap w hen treating patients with higher-risk mds and aml with 20%-30% blasts. The economic value of azacitidine is within the threshold of willingness-to-pay for third-party public payers for oncology treatments in Canada.

Changes in first hip fracture rates in British Columbia Canada, 1990-2004

We determined age-standardized first hip fracture rates in British Columbia between 1990 and 2004. We found sex and fracture type rates in keeping with previous reports and that fracture rates have decreased approximately 18% overall in both men and women.

INTRODUCTION

To determine whether there have been changes in the age-, sex-, and subtype-specific first hip fracture rates in Canadian province of British Columbia (BC) between 1990 and 2004.

METHODS

Records of all persons aged 60 years and older hospitalized with hip fractures in BC between 1985 and 2004 were obtained from the Canadian Institute for Health Information Discharge Abstract Database. Only the first hip fracture records were included, and fractures likely due to causes other than trauma were excluded. Age- and sex-specific rates were calculated using population denominators from Statistics Canada and direct standardization was used. Age-standardized rates allowed for comparison across years with adjustment for age distribution.

RESULTS

There were 41,990 records of first hip fracture included, and 73% were in women. Trends in age-specific rates by fracture type were similar to previous reports. Between 1990 and 2004, there has been an age-adjusted 18% decrease in first hip fracture rates in women, and 19% decrease in first hip fracture rates in men. The decrease was statistically significant in femoral neck fractures in women, but not in men.

CONCLUSIONS

There has been a decrease in age-adjusted hip fracture rates in BC between 1990 and 2004, which is in contrast to previous projections for hip fracture rates in Canada.

Geographic trends in incidence of hip fractures: a comprehensive literature review

A comprehensive review of literature was conducted to investigate variation in hip fracture incident rates around the world. The original crude incidence rates were standardized for age and sex for comparability. After standardization, the highest rates of hip fracture were found in Scandinavia and the lowest rates in Africa.

INTRODUCTION

This study was conducted to investigate the geographic trends of the incidence of osteoporotic hip fractures through a comprehensive review of literature.

METHODS

Studies were identified for inclusion in the review by searching the MEDLINE database via PubMed and applying strict inclusion and exclusion criteria. Age-specific incidence rates were extracted from the articles, and in order to provide a common platform for analysis, we used directly age-standardized and age-sex-standardized rates (using the 2005 United Nations estimates of the world population as standard) to complete the analysis.

RESULTS

Forty-six full text articles spanning 33 countries/regions were included in the review. For ease of comparison, the results were analyzed by geographic regions: North America, Latin America, Scandinavia, Europe (excluding Scandinavia), Africa, Asia, and Australia. The highest hip fracture rates were found in Scandinavia and the lowest in Africa. We found comparable rates from countries in North America, Australia, and Europe outside of Scandinavia. The diverse makeup of the Asian continent also resulted in quite variable hip fracture rates: ranging from relatively high rates in Iran to low rates, comparable to those from Africa, in mainland China.

CONCLUSIONS

Given the aging of populations globally, and in the industrialized countries specifically, hip fractures will become a progressively larger public health burden. The geographic trends observed in hip fracture incidence rates can provide important clues to etiology and prevention.

Societal preference values for advanced melanoma health states in the United Kingdom and Australia

Background:

No studies measure preference-based utilities in advanced melanoma that capture both intended clinical response and unintended toxicities associated with treatment.

Methods:

Using standard gamble, utilities were elicited from 140 respondents in the United Kingdom and Australia for 13 health states.

Results:

Preferences decreased with reduced treatment responsiveness and with increasing toxicity.

Conclusions:

These general population utilities can be incorporated into treatment-specific cost-effectiveness evaluations.

Use of instrumental variables in the analysis of generalized linear models in the presence of unmeasured confounding with applications to epidemiological research

A major, often unstated, concern of researchers carrying out epidemiological studies of medical therapy is the potential impact on validity if estimates of treatment are biased due to unmeasured confounders. One technique for obtaining consistent estimates of treatment effects in the presence of unmeasured confounders is instrumental variables analysis (IVA). This technique has been well developed in the econometrics literature and is being increasingly used in epidemiological studies. However, the approach to IVA that is most commonly used in such studies is based on linear models, while many epidemiological applications make use of non-linear models, specifically generalized linear models (GLMs) such as logistic or Poisson regression. Here we present a simple method for applying IVA within the class of GLMs using the generalized method of moments approach. We explore some of the theoretical properties of the method and illustrate its use within both a simulation example and an epidemiological study where unmeasured confounding is suspected to be present. We estimate the effects of beta-blocker therapy on one-year all-cause mortality after an incident hospitalization for heart failure, in the absence of data describing disease severity, which is believed to be a confounder.

A Canadian cohort study of cognitive impairment and related dementias (ACCORD): study methods and baseline results

The overall objective of the Canadian Collaborative Cohort of Related Dementias (ACCORD) study is to describe the diagnostic distribution, natural history and treatment outcomes of individuals referred from the community to dementia clinics in Canada. Between 1997 and 1999, an inception cohort of 1,136 subjects entered into this longitudinal study. At the baseline assessment, 10.9% of the subjects were classified as "not cognitively impaired" (NCI), 30.1% as "cognitively impaired not demented" (CIND), and 59% as demented. A subclassification of CIND included amnestic 25.1%, vascular cognitive impairment 18.1%, psychiatric 17.2%, neurologic 7.3%, medical/toxic metabolic 3.5%, mixed 7.6% and not specified 19.0%. The percentage of the cohort referred with dementia increased progressively each decade, while the proportions of CIND and NCI decreased. Within the dementia group, Alzheimer's disease accounted for 47.2% of the subjects, mixed dementias 33.7%, vascular dementia 8.7%, frontotemporal degenerations 5.4%, dementia with Lewy bodies 2.5%, and unclassifiable 1.8%. The ACCORD cohort will allow a detailed study of the longitudinal course of CIND, and the longer-term outcomes of both treated and untreated dementia subjects.

Cost-effectiveness in Canada of intravenous proton pump inhibitors for all patients presenting with acute upper gastrointestinal bleeding

BACKGROUND

The administration of proton pump inhibitors intravenously after endoscopic treatment of peptic ulcers significantly reduces the recurrence of bleeding.

AIM

To evaluate the incremental cost-effectiveness in Canada of intravenous proton pump inhibitor before endoscopic therapy to patients presenting with acute upper gastrointestinal bleeding, compared with endoscopic treatment alone.

METHODS

From a third-party payer perspective, we modelled the costs and effectiveness over 60 days of the two approaches using decision analysis. The probabilities of various outcomes, such as re-bleeding and the need for surgery, were taken from the published literature. We included the costs of intravenous proton pump inhibitor, therapeutic endoscopy, surgical procedures and hospitalizations, all expressed in 2001 Canadian dollars.

RESULTS

In a hypothetical cohort of 1000 patients, the intravenous proton pump inhibitor approach resulted in mean savings of 20,700 Canadian dollars with 37 re-bleeding episodes averted. The investigation of uncertainty resulted in a likelihood of intravenous proton pump inhibitor being cost-effective of at least 0.73.

CONCLUSION

It is common in Canada to administer intravenous proton pump inhibitors to patients with upper gastrointestinal bleeding even before endoscopic confirmation of bleeding peptic ulcers. Our results suggest that this approach has a high likelihood of being cost-effective.

Impact of reference-based pricing of nitrates on the use and costs of anti-anginal drugs

BACKGROUND

Reference-based pricing limits reimbursement for a group of drugs that are deemed therapeutically equivalent to the cost of the lowest-priced product within that group. We estimated the effect of reference-based pricing of nitrate drugs used for long-term prophylaxis on prescribing of and expenditures on nitrates and other anti-anginal drugs dispensed to senior citizens in British Columbia.

METHODS

We assessed trends in the monthly volume of prescriptions of anti-anginal drugs and the associated drug ingredient cost paid by the province's publicly funded drug subsidy program, Pharmacare, and by the patients themselves for the period April 1994 to May 1999. Trends in monthly rates of nitrate expenditures per 100,000 senior citizens before the introduction of reference-based pricing were extrapolated to infer what expenditures would have been without the policy.

RESULTS

During the 3 1/2 years after reference-based pricing was introduced, Pharmacare expenditures on nitrates prescribed to senior citizens declined by $14.9 million (95% confidence interval $10.7 to $19.1 million). Most of these savings were due to the lower prices that Pharmacare paid for sustained-release nitroglycerin tablets and the nitroglycerin patch, which were the 2 most frequently prescribed nitrates before the introduction of reference-based pricing; $1.2 million (8%) of the savings represented expenditures by senior citizens who purchased drugs that were only partially reimbursed. There were no compensatory increases in expenditures for other anti-anginal drugs. Use of sublingual nitroglycerin--a marker for deteriorating health in patients with angina--did not increase after the introduction of reference-based pricing. The nitroglycerin patch is now the most frequently prescribed nitrate, owing to the fact that Pharmacare resumed the provision of full subsidies for the drug after its manufacturers voluntarily reduced retail prices.

INTERPRETATION

Evidence to date suggests that reference-based pricing of nitrates has achieved its primary goal of reducing drug expenditures. The effects of this policy on patient health, associated health care costs and administrative costs remain to be investigated.

Cost-effectiveness of beta-blocker therapy with metoprolol or with carvedilol for treatment of heart failure in Canada

OBJECTIVE

The purpose of this study was to estimate the cost-effectiveness of beta-blocker therapy with either metoprolol or carvedilol in addition to conventional therapy for patients with heart failure (HF) in Canada.

DESIGN

A Markov simulation was used to estimate the costs and life expectancy for treating patients with conventional therapy alone and with the addition of metoprolol or carvedilol. Although carvedilol has been marketed in Canada since 1999, metoprolol succinate has yet to be marketed there, so the price is unknown. Therefore we input a Canadian price based on the price ratio of the 2 drugs in the United States.

RESULTS

For subjects aged 60 years at HF onset, the expected years of life are 4.53 years for those treated with conventional therapy alone, 5.70 years for those who receive conventional therapy plus metoprolol, and 6.21 years for those who receive conventional therapy plus carvedilol. The expected costs (in 1999 Canadian dollars) are $8,989, $13,833, and $18,114, respectively. This yields incremental cost-effectiveness ratios (ICERs) for metoprolol relative to conventional therapy alone of $4,140 per life-year gained, and for carvedilol relative to metoprolol, the ICER is $8,394 per life-year gained.

CONCLUSIONS

In addition to conventional therapy with furosemide and angiotensin converting enzyme inhibitors, treatment with either metoprolol or carvedilol confers a survival benefit that is attractive from a cost-effectiveness point of view. Until better information becomes available, it is not possible to distinguish between the two beta-blockers on the basis of cost-effectiveness. This means that the choice of beta-blockers for HF should be based largely on clinical considerations because both beta-blockers prolong life at relatively low cost.

Coding accuracy of hospital discharge data for elderly survivors of myocardial infarction

OBJECTIVE

To assess the coding accuracy of primary and secondary discharge diagnoses in the Quebec hospital discharge database for elderly persons with myocardial infarction (MI).

DESIGN

Retrospective chart review in a convenience sample of six Montreal hospitals. The diagnoses listed in the medical chart were compared with those listed in the hospital discharge database. For each subject, the Charlson comorbidity index was calculated twice, once based on the medical chart and again based on the hospital discharge database.

PATIENTS

Subjects aged 65 years and over who had an MI coded as the primary discharge diagnosis in the hospital discharge database and who were discharged alive.

MAIN RESULTS

For 234 MI survivors, the positive predictive value (ie, probability that a patient with MI reported in the hospital discharge database had an MI diagnosed by the discharging physician) for coding MI was 0.96 (95% CI 0.94, 0.98). Comorbid medical conditions and complications of the MI were under-reported in the hospital discharge database, which meant that the Charlson index based on the hospital discharge database was an average of 0.71 units lower than the Charlson index based on the medical chart.

CONCLUSIONS

When studying survivors of MI by using hospital discharge databases, the advantages must be weighed against potential drawbacks in the quality of the information. Hospital discharge databases are almost as reliable as medical charts for identifying MI patients, but there is substantial under-reporting of comorbid medical conditions.

Combined treatment of a large periodontal defect using GTR and DFDBA

The regeneration of periodontal structures lost to inflammatory disease is an elusive yet attainable goal of periodontal therapy. This article reports the successful treatment of a large periodontal defect using a combination of demineralized freeze-dried bone allograft (DFDBA) and guided tissue regeneration (GTR). The case presents endodontic and mucogingival complications in the combined GTR osseous graft technique. The combined techniques used in this 27-year-old patient achieved a reduction in probing depth, radiographic evidence of bone fill, and a reduction in clinical mobility.

Survival after percutaneous endoscopic gastrostomy among older residents of Quebec

CONTEXT

Percutaneous endoscopic gastrostomy has become a mainstay of nutritional support for individuals with swallowing dysfunction. There is little population-based data to guide the use of this intervention in older individuals.

OBJECTIVE

To describe the use of percutaneous endoscopic gastrostomy among older residents of Quebec and to evaluate patient characteristics associated with subsequent survival and hospital discharge.

DESIGN

A population-based cohort study.

SETTING

Quebec, Canada.

PATIENTS

175 individuals with a billing claim for percutaneous endoscopic gastrostomy performed in 1993.

MEASUREMENTS

Billing and hospitalization databases were used to collect patient characteristics, medical diagnoses, discharge destinations, and dates of death. The relationships between demographic and diagnostic variables before gastrostomy, and subsequent survival and discharge home, were evaluated using survival analysis.

RESULTS

Median survival after gastrostomy was 210 days. Mortality at 30 days was 18.3%. Decreased survival was associated with a previous diagnosis of malignancy (risk ratio (RR) = 1.71; 95% CI, 1.09-2.68); mortality did not increase with increasing age. Of 163 individuals hospitalized at the time of gastrostomy, 42 (26%) were discharged home. Individuals with a previous diagnosis of stroke (RR = 2.80; 95% CI 1.01-7.77) were more likely to be discharged home than other individuals.

CONCLUSIONS

Survival after percutaneous endoscopic gastrostomy is poor; the requirement for such a procedure appears to be a marker for severe underlying disease. The greater likelihood of return home after gastrostomy among individuals with stroke suggests that the use of this intervention as an adjunct to rehabilitation is appropriate in these individuals.

Adverse reproductive outcomes among women exposed to low levels of ionizing radiation from diagnostic radiography for adolescent idiopathic scoliosis

In a cohort of women followed up for adolescent idiopathic scoliosis, we assessed the association between exposure to ionizing radiation from diagnostic radiography received in adolescence and subsequent adverse reproductive outcomes in adulthood. We estimated risk for unsuccessful attempts at pregnancy, spontaneous abortions, low birthweight (<2,500 gm), congenital malformations, and stillbirths according to dose to the ovaries. We used regression models for binary and continuous outcomes, accounting for key covariates and for clustering in the data that arose from women having multiple pregnancies. Risks in the adolescent idiopathic scoliosis cohort were higher than in the reference group for unsuccessful attempts at pregnancy [adjusted odds ratio (OR) = 1.33; 95% confidence interval (CI) = 0.84-2.13], spontaneous abortions (OR = 1.35; 95% CI = 1.06-1.73), and congenital malformations (OR = 1.20; 95% CI = 0.78-1.84), but the odds ratios did not increase monotonically by dose to the ovaries. There were fewer stillbirths (OR = 0.38; 95% CI = 0.15-0.97) and low-birthweight infants in the adolescent idiopathic scoliosis cohort (OR = 0.84; 95% CI = 0.59-1.21). Nevertheless, when the analysis of low birthweight was restricted to the adolescent idiopathic scoliosis cohort, the adjusted odds ratios were found to increase by quartiles of dose (median dose of 0.69 cGy): 1; 1.43 (95% CI = 0.54-3.90); 2.24 (95% CI = 0.89-5.94); and 2.34 (95% CI = 1.02-5.62). We also found that the adjusted mean birthweight decreased with increasing dose by 37.6 gm per cGy (standard error = 23.5 gm per cGy). Associations between adverse reproductive outcomes and radiotherapy have been observed previously, but this is the first study in which an association with birthweight has been found with diagnostic radiography.

Inclement weather and the risk of hip fracture

An association between inclement weather and hip fractures has been documented, but specific subgroups of the population at particular risk have not been identified. We obtained information that included hospitalization data on all hip fractures in Montreal from 1982 to 1992, and meteorologic data on the amount of snow, rain, and freezing rain and the temperature on each day of study. We used a cross-level design to examine the association between the rate of hip fractures and the meteorologic conditions on the day of the accident in both sexes and five age strata. There were a total of 18,455 hip fractures over the 4,018-day study period. We found a cyclical pattern in occurrence of hip fractures, with the peak occurring in mid-December among women and the first week of January among men. The pattern was less pronounced among women than men, with peak-to-trough ratios of 1.2 and 1.4, respectively. Days with lower temperatures, snow, and freezing rain were associated with increased rates of hip fracture. The meteorologic condition carrying the greatest risk was freezing rain. The association between inclement weather and hip fractures was stronger among younger persons, both women and men. After adjusting for meteorologic variables, there remained increases in winter of 5% among women and 12% among men. The residual effect of winter may be related to cold temperatures or due to an accumulation of ice and snow even on fine days. Other possible mechanisms to explain the residual effect of winter include slower reaction times and winter bone loss, both of which could affect indoor as well as outdoor falls.

Hospitalization and case-fatality rates for subarachnoid hemorrhage in Canada from 1982 through 1991. The Canadian Collaborative Study Group of Stroke Hospitalizations

BACKGROUND AND PURPOSE

Subarachnoid hemorrhage (SAH) has a different epidemiological profile from other types of stroke and a different etiology. Although there has been a general decline in overall stroke incidence since the 1950s, secular trends for SAH have been modest. In contrast to other stroke types, changes in incidence over the last few decades have been less clear. The purpose of this study was to estimate hospitalization and case-fatality rates of SAH according to age, sex, calendar year, and season.

METHODS

Data were obtained for each of Canada's 10 provinces for the 10 fiscal years 1982 through 1991. All hospitalizations of persons 15 years of age or older with a primary diagnosis at discharge coded 430 according to the International Classification of Diseases, 9th Revision, were included. Rates of SAH per 100,000 population were calculated for men and women for 5-year age groups, by calendar year, and by season. Annual age- and sex-specific (hospital) case-fatality rates up to 30 days were also calculated. Additionally, hospital deaths from this study were related to national SAH mortality statistics.

RESULTS

A total of 14145 women and 8995 men were discharged with a primary diagnosis of SAH during the 10-year period. In contrast to other types of stroke, the rates of SAH were higher for women than for men at all ages. The age-standardized rates of SAH in 1991-1992 were 11.2 per 100000 women and 8.0 per 100000 men. For women, there was a 6% (95% confidence interval [CI], -12% to 0%) decline in hospitalization rates over that period; for men, the decline was 15% (95% CI, -21% to -8%). The peak season for SAH among women was winter; for men the peaks were in the fall and spring. For both sexes, the lowest occurrence was in the summer. Over this period, 30-day case-fatality rates declined somewhat (statistically significant only in the age group of 35 to 44 years). The number of deaths enumerated from hospital discharges was 20% to 50% lower than the number recorded on national mortality statistics, indicating that a proportion of SAH deaths occurred before (or after) the hospital stay.

CONCLUSIONS

Although rates of hospitalization for SAH declined over this period, SAH remains an important neurological event affecting individuals at relatively young ages. The rates were higher for women than for men at all ages. Total (in-hospital) case-fatality rate remains high.

Reducing the lifetime risk of cancer from spinal radiographs among people with adolescent idiopathic scoliosis

STUDY DESIGN

Data from a retrospective cohort study of people with adolescent idiopathic scoliosis were combined with information on full-spinal radiographs to estimate contemporary x-ray doses and lifetime risks for development of cancer.

OBJECTIVES

To project the lifetime risk for development of cancer from diagnostic radiographs for people with adolescent idiopathic scoliosis.

SUMMARY OF BACKGROUND DATA

Although a twofold excess risk for breast cancer has been reported for women treated for scoliosis between 1925 and 1965, information on the cancer risks associated with scoliosis management today is sparse. Specifically, there is a lack of up-to-date information on the number of spinal radiographs taken, the organ-specific x-ray doses from current radiographic techniques, and the projected cancer risks.

METHODS

The cohort consisted of subjects with adolescent idiopathic scoliosis who were referred to the scoliosis clinic of a large pediatric hospital between 1965 and 1979 in Montreal, Quebec, Canada. Based on radiographic equipment and practices implemented in 1982, organ-specific x-ray doses to the thyroid gland, female breast, respiratory organs, digestive organs, and bone marrow were calculated using Monte Carlo methods. These doses were incorporated into a life table procedure to calculate theoretic lifetime cancer risks. For all organs except the thyroid gland, dose-response models from the United States National Academy of Sciences Fifth Committee on the Biological Effects of ionizing Radiation were used. For thyroid cancer, a risk model was derived from a study of thyroid cancer incidence after x-ray treatment for tinea capitis.

RESULTS

The average number of spinal radiographs was 12 for women (80% anteroposterior or posteroanterior) and 10 for men (78% anteroposterior or posteroanterior). Cumulative x-ray doses were in general higher in adolescents who were referred as younger teenagers than at later ages, and doses increased with the size of the spinal curve. Depending on the age at referral and curve size, the total excess lifetime cancer risks were calculated to range from 42 to 238 cases per 100,000 women and 14 to 79 cases per 100,000 men. For subjects who underwent surgery (those exposed to the highest doses), the lifetime number of cancer cases over and above background was almost as great as the number of thyroid cancers that would occur in the absence of radiation exposure. If the anteroposterior view was replaced by the posteroanterior view, a three- to sevenfold reduction in cumulative doses to the thyroid gland and the female breast would be achieved, yielding three- to fourfold reductions in the lifetime risk of breast cancer and a halving of the lifetime risk of thyroid cancer.

CONCLUSIONS

The cancer risks from full-spinal radiographs for scoliosis are not negligible and can be reduced from one half to three quarters if the anteroposterior view is replaced with the posteroanterior view.

Hospitalization and case-fatality rates for stroke in Canada from 1982 through 1991. The Canadian Collaborative Study Group of Stroke Hospitalizations

BACKGROUND AND PURPOSE

The purpose of this study was to estimate rates of hospitalization and in-hospital case-fatality for cerebral infarction and intracerebral hemorrhage in Canada and to describe variation in rates by age, sex, and calendar period.

METHODS

Data were obtained from hospitalization databases for each of Canada's 10 provinces for the 10 fiscal years of 1982 through 1991. All hospitalizations of persons 15 years of age or older with a primary diagnosis at discharge coded 431, 434, or 436 according to the International Classification of Disease, 9th Revision, were included. Rates per 100,000 population were calculated for intracerebral hemorrhage and cerebral infarction, for men and women, and for five age groups. Annual age- and sex-specific, 30-day, in-hospital case-fatality rates were also calculated.

RESULTS

A total of 335,283 discharges for stroke were enumerated over the 10-year period (309,631 cerebral infarctions and 25 652 intracerebral hemorrhages). A significant decline of approximately 1% per year was observed for the rate of cerebral infarctions. For hemorrhages, the reverse was seen. For men there was a 44% increase over the 10-year period, and for women there was a 34% increase. In-hospital case-fatality rates for cerebral infarctions increased with age but did not differ by sex when age was considered. For the five age groups of 15 to 54, 55 to 64, 65 to 74, 75 to 84 and > or = 85 years, rates were 6%, 8%, 12%, 18% and 27%, respectively. For intracerebral hemorrhage, the in-hospital case-fatality rates declined significantly over time from approximately 36% to 29%, 55% to 37%, 49% to 41%, 66% to 45%, and 72% to 59% for the five age groups, respectively.

CONCLUSIONS

The possibility that these changes are artifactual could not be ruled out, but because there is no obvious risk in assuming that they are not, it would be prudent to investigate their causes further.

How has extracorporeal shock-wave lithotripsy changed the treatment of urinary stones in Quebec?

OBJECTIVES

To determine the number of people who underwent treatment of urinary stones in Quebec before and after the introduction of extracorporeal shock-wave lithotripsy (ESWL) and to determine how the introduction of ESWL influenced resource utilization.

DESIGN

Before-after study; data were obtained from administrative databases and hospital-based cost estimates.

SETTING

The 68 acute care hospitals in Quebec in which treatment of urinary stones is undertaken.

PATIENTS

Quebec residents admitted to hospital for treatment of urinary stones between the fiscal years 1984 and 1992.

OUTCOME MEASURES

Number of people treated for urinary stones per year, total number of procedures per year (including open surgery, percutaneous procedures, retrograde procedures and ESWL), and annual resources (including number of hospital bed-days and direct costs) for treatment of urinary stones used overall and in hospitals with and without ESWL services.

RESULTS

Over the study period the number of people treated for urinary stones increased by 59%. As well, the combined frequency of ESWL and surgery (the two main treatment methods) increased by 107%. These increases were largely due to rates of treatment that grew by 52% among women and by 34% among men. The total number of hospital bed-days decreased by 28%, which reflected shorter hospital stays for ESWL. However, despite this decrease, the total direct annual costs were 7% higher in 1992 than in 1984 because of the increased numbers of people treated and procedures performed. In the three hospitals that offered ESWL the number of hospital bed-days and the direct costs of treating urinary stones increased by 49% and $2.5 million respectively. In the 65 other hospitals these figures decreased by 41% and about $2.9 million respectively.

CONCLUSIONS

Because of increased intervention rates the total cost of treating urinary stones has risen since the introduction of ESWL. The introduction of ESWL has also been associated with a shift in the use of resources for treating urinary stones to hospitals with a lithotriptor. The reasons for the increased intervention rates are unknown. However, given the possibility of negative health effects and the increased costs, studies to determine whether the increased rates improve health outcomes are warranted.

Rates of transcervical and pertrochanteric hip fractures in the province of Quebec, Canada, 1981-1992

Two distinct subtypes of hip fracture, transcervical and pertrochanteric, can be distinguished on the basis of the anatomical location of the injury. While the epidemiology of hip fractures has been well described, typically, little or no distinction is made between these subtypes. The objective of this study was to compare and contrast age- and sex-specific rates of transcervical and pertrochanteric fractures in Quebec, Canada. The data for this study were obtained from a database containing records of all persons discharged from all hospitals in Quebec from 1981 to 1992. Rates of hip fractures were calculated by using the population aged 50 years and older as the denominator, and changes in rates over time were assessed using Poisson regression. There were no statistically significant trends in the changes in rates over time (i.e., 95 percent confidence intervals overlapped the null value). Among women below age 70 years, transcervical fractures were more common, whereas among older women, pertrochanteric fractures predominated. Among men, pertrochanteric fractures predominated at all ages. There was a marked seasonal variation in the occurrence of all hip fractures combined: Compared with the summer months, the relative risk of all hip fractures during the winter was 1.32 (95 percent confidence interval 1.28-1.36). The results of this study indicate that the two subtypes of hip fracture, transcervical and pertrochanteric, have different patterns of occurrence, suggesting different risk factor profiles. Clearly, a multidisciplinary research approach is needed before it will be possible to untangle the complex relation between the metabolic processes occurring at the level of the individual and the distribution of the disease in the population.

A randomized trial of identification bracelets to prevent falls among patients in a rehabilitation hospital

This purpose of this study was to determine whether an identification bracelet is effective in preventing falls among high-risk patients who are undergoing in-patient physical rehabilitation. A stratified, randomized, balanced controlled clinical trial was conducted; participants were blinded as to the outcome and the study hypothesis. All patients having one or more risk factors that predisposed them to falls were randomized to receive either a blue identification bracelet or no bracelet. The identification bracelet was intended to increase patients' vigilance about falling. Two risk strata were specified. The high risk stratum consisted of patients with stroke or ataxia, urinary incontinence, or a history of falls. The low risk stratum comprised patients older than 80 years and those on one or more medications that had been identified as contributing to an individual's risk of falling. This report presents the effect of the identification bracelet only among persons in the high-risk stratum. Over 1 year, 65 high-risk subjects were randomized to receive the blue identification bracelet and 69 high-risk subjects were controls. In the intervention group, 27 persons (41%) fell at least once, whereas in the control group 21 persons (30%) fell at least once yielding a hazard ratio of 1.3 (95% confidence interval: 0.8 to 2.4). These results suggest that the identification system was of no benefit in preventing falls among high-risk persons.

Projecting the lifetime risk of cancer from exposure to diagnostic ionizing radiation for adolescent idiopathic scoliosis

Adolescent idiopathic scoliosis (AIS) is a disorder characterized by lateral curvature of the spine and is the most prevalent orthopedic disorder in this age group. The diagnosis and management of AIS requires multiple full-spinal radiographs, leading to potentially high doses of ionizing radiation. The purpose of this study was to estimate in a cohort of subjects with AIS the organ-specific doses of x-ray radiation from spinal radiographs and to calculate the lifetime number of cancers attributable to these exposures. The cohort consisted of AIS patients referred from 1960 to 1979 to a large pediatric hospital in Montreal, Quebec. Organ-specific x-ray doses were estimated using a Monte Carlo procedure that accounted for the radiant energy of the x-ray beam. Cumulative doses for each subject were obtained by summing the estimated doses over all radiographs. These estimates of dose and published estimates of risk from the U.S. National Academy of Sciences Fifth Committee on the Biological Effects of Ionizing Radiation were then incorporated into a life table procedure to project the excess lifetime risk of cancer. About 85% of the 2,181 subjects in the cohort were first referred for scoliosis between the ages of 11 and 17 y. The mean number of radiographs over an average 3-y follow-up period was 12. Organs receiving the highest mean cumulative doses (about 0.03 Gy) were the thyroid gland and the female breast. About 10 excess incident cancer cases (out of a total of 399 projected) and about four excess deaths (out of a total of 247 projected) were estimated to occur over the lifetime of the 1,847 women in the cohort. This is equivalent to an excess lifetime risk of about 1 to 2% (12-25/1,000) among women. Although doses today from spinal radiographs are considerably lower than two decades ago, doses and risks can be further reduced through the use of the posteroanterior view in place of the more traditional anteroposterior view.

Value of routine preoperative chest x-rays: a meta-analysis

The purpose of this study was to estimate the frequency with which routine postoperative chest x-rays lead to clinically relevant new information. All articles in English, French and Spanish relating to routine chest radiography in North American or European populations were reviewed, using the Medline database and references listed in reviews and periodicals published from 1966 to 1992, inclusive. Twenty-one reports which supplied sufficient information were included for meta-analysis. On average, abnormalities were found in 10% of routine preoperative chest films. In only 1.3% of films were the abnormalities unexpected, i.e., were not already known or would not otherwise have been detected (95% CI: 0 to 2.8%). These findings were of sufficient importance to cause modification of management in only 0.1% (95% CI: 0 to 0.6%). The frequency with which the new information influenced health could not be estimated. Assuming only the direct cost to the health care system of each radiograph ($23), each finding which influenced management in any way would cost $23,000. It is concluded that in North American or European populations when a reliable history and a clinical examination are carried out, the cost of this test is so high relation to the clinical information provided that it is no longer justifiable.

Risk factors for fractures due to falls

A matched case-control study was carried out to identify risk factors for fractures due to falls. All falls that occurred at a rehabilitation hospital from 1981 to 1988 were identified and classified as index falls (falls resulting in fractures) or referent falls (falls not resulting in fractures). For each of the 94 index falls, four referent falls were chosen at random (n = 376) from all other falls occurring in the same four week period. The average age of the individuals sustaining the index fall was 76.8 +/- 10.4 years, and 68% were female; in contrast, the average age of the individuals sustaining the referent fall was 72.0 years (+/- 13.2), and 32% were female. Fractures of the hip predominated (n = 40; 42.6%) and fractures of the ribs were the second most prevalent (n = 20; 21.4%). Fractures most often ensured from a fall from the upright position. Of the 24 variables considered in the conditional logistic regression model, advanced age, being female, being ambulatory, experiencing disorientation, use of vitamin supplements, and use of antiulcer medications were significantly associated with the risk of a fracture. Thus, because fractures are potentially life-threatening, strategies to prevent falls should be targeted especially towards those who are at risk to sustain a fracture from a fall. However, to be compatible with rehabilitation goals, the preventive strategies must strike a balance between the achievement of functional autonomy and patient safety.

Changing rates of stroke in the province of Quebec, Canada: 1981-1988

Using more than 37,000 hospital discharges attributed to hemorrhagic or occlusive stroke in the province of Quebec, Canada, we analyzed trends in stroke incidence during the period 1981-1988. There were large and statistically significant (p less than 0.05) increases in the rates of hemorrhagic stroke over this period. Dramatic increases occurred among men in the rates of both intracerebral (International Classification of Diseases--Ninth Revision [ICD9] code 431) and intracranial (ICD9 code 432) hemorrhagic strokes (40-204% depending on age). In contrast, the rates of occlusion of the precerebral arteries (ICD9 code 433) declined in younger men and women but increased substantially (107%) in older men. Rates of occlusion of the cerebral arteries (ICD9 code 434) declined in men over the age of 50 years and in women aged 50-79 years. Despite the decline in the rate of occlusion of the cerebral arteries, the rate of hemorrhagic stroke appears to have increased. Changes in the hospitalization rates for hemorrhagic stroke were not accompanied by consistent decreases in the case-fatality rate. This finding tends to support the hypothesis of an actual increase in the hospitalization rate fo hemorrhagic stroke rather than an artifactually elevated rate due to enhanced diagnosis by computed tomography.

A fused central incisor. Periodontal considerations in comprehensive treatment

This report details the treatment of a permanent central incisor fused to a supernumerary tooth. The level of fusion was first determined by radiographs, but surgical visibility indicated a more extensive fusion. The two roots were separated, and the supernumerary tooth was removed. At 10 weeks postoperatively, orthodontic treatment was instituted, bringing the retained tooth through the healing socket left by the supernumerary, and into contact with the interdental septum. After endodontic treatment and splinting, a periodontal re-entry procedure was necessitated by the persistence of inflammation caused by incomplete removal of the furcation-like area between the fused teeth. The improved periodontal prognosis of this case at 1-year follow-up can be attributed to careful postsurgical evaluation and subsequent removal of this plaque-retentive area.

The relationship between attachment height and attachment area of teeth using a digitizer and a digital computer

Nine lower first bicuspid teeth were mounted in blocks of plastic and their roots were serially sectioned and photographed. Data from the photographs were compiled by a digitizer and a digital computer, which calculated the cumulative root surface area for each millimeter of root height. From these data, three variables, which relate root surface area to root height, were calculated. It was found that if one-half of the height of attachment to the root were lost due to periodontal disease, a mean of 61.5% of the actual attachment area to the root is lost. If a mean of 5.72 mm of root attachment height is lost, or if a mean of 60.6% of the same root height remains, only one-half of the total root attachment area remains to provide tooth support.