The association of objectively ascertained sibling fracture history with major osteoporotic fractures: a population-based cohort study.

We investigated the association of objectively ascertained sibling fracture history with major osteoporotic fracture (hip, forearm, humerus, or clinical spine) risk in a population-based cohort using administrative databases. Sibling fracture history is associated with increased major osteoporotic fracture risk, which has implications for fracture risk prediction. INTRODUCTION: We aimed to determine whether objectively ascertained sibling fracture history is associated with major osteoporotic fracture (MOF; hip, forearm, humerus, or clinical spine) risk. METHODS: This retrospective cohort study used administrative databases from the province of Manitoba, Canada, which has a universal healthcare system. The cohort included men and women 40+ years between 1997 and 2015 with linkage to at least one sibling. The exposure was sibling MOF diagnosis occurring after age 40 years and prior to the outcome. The outcome was incident MOF identified in hospital and physician records using established case definitions. A multivariable Cox proportional hazards regression model was used to estimate the risk of MOF after adjustment for known fracture risk factors. RESULTS: The cohort included 217,527 individuals; 91.9% were linked to full siblings (siblings having the same father and mother) and 49.0% were females. By the end of the study period, 6255 (2.9%) of the siblings had a MOF. During a median follow-up of 11 years (IQR 5-15), 5235 (2.4%) incident MOF were identified in the study cohort, including 234 hip fractures. Sibling MOF history was associated with an increased risk of MOF (hazard ratio [HR] 1.67, 95% confidence interval [CI] 1.44-1.92). The risk was elevated in both men (HR 1.57, 95% CI 1.24-1.98) and women (HR 1.74, 95% CI 1.45-2.08). The highest risk was associated with a sibling diagnosis of forearm fracture (HR 1.81, 95% CI 1.53-2.15). CONCLUSION: Sibling fracture history is associated with increased MOF risk and should be considered as a candidate risk factor for improving fracture risk prediction.

Risk of suicide and suicide attempts associated with physical disorders: a population-based, balancing score-matched analysis.

BACKGROUND: The association between physical disorders and suicide remains unclear. The aim of this study was to examine the relationship between physical disorders and suicide after accounting for the effects of mental disorders. METHOD: Individuals who died by suicide (n = 2100) between 1996 and 2009 were matched 3:1 by balancing score to general population controls (n = 6300). Multivariate conditional logistic regression compared the two groups across physician-diagnosed physical disorders [asthma, chronic obstructive pulmonary disease (COPD), ischemic heart disease, hypertension, diabetes, cancer, multiple sclerosis and inflammatory bowel disease], adjusting for mental disorders and co-morbidity. Secondary analyses examined the risk of suicide according to time since first diagnosis of each physical disorder (1-90, 91-364, ⩾ 365 days). Similar analyses also compared individuals with suicide attempts (n = 8641) to matched controls (n = 25 923). RESULTS: Cancer was associated with increased risk of suicide [adjusted odds ratio (AOR) 1.40, 95% confidence interval (CI) 1.03-1.91, p < 0.05] even after adjusting for all mental disorders. The risk of suicide with cancer was particularly high in the first 90 days after initial diagnosis (AOR 4.10, 95% CI 1.71-9.82, p < 0.01) and decreased to non-significance after 1 year. Women with respiratory diseases had elevated risk of suicide whereas men did not. COPD, hypertension and diabetes were each associated with increased odds of suicide attempts in adjusted models (AORs ranged from 1.20 to 1.73). CONCLUSIONS: People diagnosed with cancer are at increased risk of suicide, especially in the 3 months following initial diagnosis. Increased support and psychiatric involvement should be considered for the first year after cancer diagnosis.

Incidence and temporal trends of co-occurring personality disorder diagnoses in immune-mediated inflammatory diseases.

AIMS: Although immune-mediated inflammatory diseases (IMID) are associated with multiple mental health conditions, there is a paucity of literature assessing personality disorders (PDs) in these populations. We aimed to estimate and compare the incidence of any PD in IMID and matched cohorts over time, and identify sociodemographic characteristics associated with the incidence of PD. METHODS: We used population-based administrative data from Manitoba, Canada to identify persons with incident inflammatory bowel disease (IBD), multiple sclerosis (MS) and rheumatoid arthritis (RA) using validated case definitions. Unaffected controls were matched 5:1 on sex, age and region of residence. PDs were identified using hospitalisation or physician claims. We used unadjusted and covariate-adjusted negative binomial regression to compare the incidence of PDs between the IMID and matched cohorts. RESULTS: We identified 19 572 incident cases of IMID (IBD n = 6,119, MS n = 3,514, RA n = 10 206) and 97 727 matches overall. After covariate adjustment, the IMID cohort had an increased incidence of PDs (incidence rate ratio [IRR] 1.72; 95%CI: 1.47-2.01) as compared to the matched cohort, which remained consistent over time. The incidence of PDs was similarly elevated in IBD (IRR 2.19; 95%CI: 1.69-2.84), MS (IRR 1.79; 95%CI: 1.29-2.50) and RA (IRR 1.61; 95%CI: 1.29-1.99). Lower socioeconomic status and urban residence were associated with an increased incidence of PDs, whereas mid to older adulthood (age 45-64) was associated with overall decreased incidence. In a restricted sample with 5 years of data before and after IMID diagnosis, the incidence of PDs was also elevated before IMID diagnosis among all IMID groups relative to matched controls. CONCLUSIONS: IMID are associated with an increased incidence of PDs both before and after an IMID diagnosis. These results support the relevance of shared risk factors in the co-occurrence of PDs and IMID conditions.

Rising incidence of psychiatric disorders before diagnosis of immune-mediated inflammatory disease.

AIMS: After the diagnosis of immune-mediated inflammatory diseases (IMID) such as inflammatory bowel disease (IBD), multiple sclerosis (MS) and rheumatoid arthritis (RA), the incidence of psychiatric comorbidity is increased relative to the general population. We aimed to determine whether the incidence of psychiatric disorders is increased in the 5 years before the diagnosis of IMID as compared with the general population. METHODS: Using population-based administrative health data from the Canadian province of Manitoba, we identified all persons with incident IBD, MS and RA between 1989 and 2012, and cohorts from the general population matched 5 : 1 on year of birth, sex and region to each disease cohort. We identified members of these groups with at least 5 years of residency before and after the IMID diagnosis date. We applied validated algorithms for depression, anxiety disorders, bipolar disorder, schizophrenia, and any psychiatric disorder to determine the annual incidence of these conditions in the 5-year periods before and after the diagnosis year. RESULTS: We identified 12 141 incident cases of IMID (3766 IBD, 2190 MS, 6350 RA) and 65 424 matched individuals. As early as 5 years before diagnosis, the incidence of depression [incidence rate ratio (IRR) 1.54; 95% CI 1.30-1.84) and anxiety disorders (IRR 1.30; 95% CI 1.12-1.51) were elevated in the IMID cohort as compared with the matched cohort. Similar results were obtained for each of the IBD, MS and RA cohorts. The incidence of bipolar disorder was elevated beginning 3 years before IMID diagnosis (IRR 1.63; 95% CI 1.10-2.40). CONCLUSION: The incidence of psychiatric comorbidity is elevated in the IMID population as compared with a matched population as early as 5 years before diagnosis. Future studies should elucidate whether this reflects shared risk factors for psychiatric disorders and IMID, a shared final common inflammatory pathway or other aetiology.

Development and validation of the Ontario acute myocardial infarction mortality prediction rules.

OBJECTIVES: To develop and validate simple statistical models that can be used with hospital discharge administrative databases to predict 30-day and one-year mortality after an acute myocardial infarction (AMI). BACKGROUND: There is increasing interest in developing AMI "report cards" using population-based hospital discharge databases. However, there is a lack of simple statistical models that can be used to adjust for regional and interinstitutional differences in patient case-mix. METHODS: We used linked administrative databases on 52,616 patients having an AMI in Ontario, Canada, between 1994 and 1997 to develop logistic regression statistical models to predict 30-day and one-year mortality after an AMI. These models were subsequently validated in two external cohorts of AMI patients derived from administrative datasets from Manitoba, Canada, and California, U.S. RESULTS: The 11-variable Ontario AMI mortality prediction rules accurately predicted mortality with an area under the receiver operating characteristic (ROC) curve of 0.78 for 30-day mortality and 0.79 for one-year mortality in the Ontario dataset from which they were derived. In an independent validation dataset of 4,836 AMI patients from Manitoba, the ROC areas were 0.77 and 0.78, respectively. In a second validation dataset of 112,234 AMI patients from California, the ROC areas were 0.77 and 0.78 respectively. CONCLUSIONS: The Ontario AMI mortality prediction rules predict quite accurately 30-day and one-year mortality after an AMI in linked hospital discharge databases of AMI patients from Ontario, Manitoba and California. These models may also be useful to outcomes and quality measurement researchers in other jurisdictions.

Impact of diabetes on employment and income in Manitoba, Canada.

OBJECTIVE: To compare employment and income of working-age (18-64 years) people with and without diabetes. RESEARCH DESIGN AND METHODS: We conducted a prospective population-based cohort study based in Manitoba, Canada, consisting of 25,554 individuals without diabetes and 608 with diabetes, of whom 242 had a complication of the disease. Adjusted odds ratios (ORs) of employment and income variables were determined. RESULTS: Diabetic individuals with complications were twice as likely not to be in the labor force (OR 2.07 [95% CI 1.49-2.87]) than nondiabetic individuals. This difference was not evident for diabetic individuals without complications (OR 1.20 [0.93-1.56]). Diabetic individuals without complications had incomes similar to those of nondiabetic individuals. The total income of diabetic individuals with complications was 72% of the income of nondiabetic individuals. When the analysis was limited to only those in the labor force, diabetic workers with complications still had only 85% the employment income of nondiabetic people. Diabetic individuals with complications received 58% more social support income. In a separate analysis of aboriginal individuals, complicated diabetes was not associated with an increased likelihood of not working or a decrease in employment income. CONCLUSIONS: In general, complications of diabetes and the absence of the disease affect the ability to earn income in Manitoba, Canada. This effect was not identified in the aboriginal population of the province.

Utilization of health care services in patients with severe obstructive sleep apnea.

We compared the health care utilization of 97 obese patients diagnosed with obstructive sleep apnea (OSA) and 97 matched control subjects. Over a 2-year period that ended 2 years prior to initial diagnosis, the OSA group had 251 nights in hospital, compared to 90 nights for the control group. During the same 2-year period, total expenditures from physician claims were $82,238 (Canadian dollars) in the OSA patients versus $41,018 in the control group (p < 0.01). Depending upon which assumptions one uses for the calculation of hospital costs, during the same 2-year period, the 97 OSA patients utilized between $100,000 and $200,000 more in services than their control counterparts. We conclude that sleep apnea patients are already heavy consumers of health care services prior to any specific evaluation and treatment for apnea.

The use of health-care resources in obesity-hypoventilation syndrome.

OBJECTIVE: To document health-care utilization (ie, physician claims and hospitalizations) in patients with obesity-hypoventilation syndrome (OHS), for 5 years prior to the diagnosis and for 2 years after the diagnosis and initiation of treatment. DESIGN: Retrospective observational cohort study. SETTING: University-based sleep disorders center in Manitoba, Canada. PATIENTS AND CONTROL SUBJECTS: Twenty OHS patients (mean [+/- SD] age, 52.7 +/- 9.5 years; body mass index [BMI], 47.3 +/- 11.0 kg/m(2); PaCO(2), 59.7 +/- 13.8 mm Hg; PaO(2), 51.6 +/- 12.4 mm Hg) were matched to two sets of control subjects. First, each case was matched to 15 general population control subjects (GPCs) by age, gender, and geographic location, and, second, each case was matched to a single obese control subject (OBC) who was matched using the same criteria as for the GPCs, plus the measurement of BMI. MEASUREMENTS AND RESULTS: In the 5 years before diagnosis, the 20 OHS patients had (mean +/- SE) 11.2 +/- 1.8 physician visits per patient per year vs 5.7 +/- 0.8 (p < 0.01) visits for OBCs and 4.5 +/- 0.4 (p < 0.001) visits for GPCs. OHS patients generated higher fees, $623 +/- 96 per patient per year for the 5 years prior to diagnosis compared to $252 +/- 34 (p < 0.001) for OBCs and $236 +/- 25 (p < 0.001) for GPCs. OHS patients were much more likely to be hospitalized than were subjects in either control group in the 5 years prior to diagnosis (odds ratio [OR] vs GPCs, 8.6) (95% confidence interval [CI], 5.9 to 12.7); OR vs OBCs, 4.9 (95% CI, 2.3 to 10.1). In the 2 years after diagnosis and the initiation of treatment (usually continuous positive airway pressure or bilevel positive airway pressure), there was a significant linear reduction in physician fees. In the 2 years after the initiation of treatment, there was a 68.4% decrease in days hospitalized per year (5 years before treatment, 7.9 days per patient per year; after 2 years of treatment, 2.5 days per patient per year [p = 0.01]). CONCLUSIONS: OHS patients are heavy users of health care for several years prior to evaluation and treatment of their sleep breathing disorder; there is a substantial reduction in days hospitalized once the diagnosis is made and treatment is instituted.

Unemployment and health care utilization.

OBJECTIVES: This study attempted to determine whether prior use of health services predicts a subsequent risk of unemployment and also to describe the acute effects of exposure to unemployment on the use of health care services. MATERIAL AND METHODS: The 1986 census records were linked with comprehensive health care information for the period 1983-1989 for over 44629 randomly selected residents of Manitoba, Canada. All cause and cause-specific rates of hospital admission and ambulatory physician contacts were compared between 1498 unemployed and 18272 employed persons across 4 consecutive time periods related to the onset of unemployment. RESULTS: The adjusted rates of hospital admission and physician contacts were higher among the unemployed across all 4 periods. When persons with a history of mental health treatment were excluded, health care use in the period prior to the onset of unemployment was equivalent among the employed and unemployed. When a history of mental health treatment was controlled for, all-cause and cause-specific health care use was elevated among the unemployed during the unemployment spell. CONCLUSIONS: Unemployed persons had increased hospitalization rates before their current spell of unemployment. Much of this difference was due to the subgroup with prior mental health treatment. For persons without prior mental health care, hospitalization increased after a period of unemployment.

Prevalence of physician-diagnosed asthma by occupational groupings in Manitoba, Canada.

The objective of this research was to determine whether there are differences in the rate of physician-diagnosed asthma in various occupational groups. A prevalence survey using a population-based administrative database of a sample of the labor force in Manitoba, Canada was used. A sample of 22,561 individuals who were in the labor force at the time of the 1986 census were linked to the provincial administrative health database. The frequency of physician-diagnosed asthma and other obstructive respiratory conditions were measured. A case of asthma was defined as having at least three physician contacts for asthma between April 1, 1986, and March 31, 1990. Data on potential confounding factors such as age, gender, area of residence, income, and education were also available. The results showed that frequency of physician-diagnosed asthma by occupational grouping ranged from a low of 0.1/100 workers to a high of 4.8/100 workers. Three occupational groups, 1) other teaching and related occupations (SOC 279) (OR 2.54, 95% CI 1.18-5.44); 2) fabricating, installing, and repairing occupations of electrical electronic and related equipment (SOC 853) (OR 2.37, 95% CI 1.05-5.33); and 3) other occupations in laboring and other elemental work (SOC 992) (OR 2.51, 95% CI 1.21-5.24) were found to have elevated odds ratios for physician-diagnosed asthma. Datasets linking occupation and health care utilization may be useful tools for surveillance of work-related diseases in general, and for asthma in particular. However, further work should be done utilizing larger databases to determine the overall usefulness of this approach.

Regional variation in angiography, coronary artery bypass surgery, and percutaneous transluminal coronary angioplasty in Manitoba, 1987 to 1992: the funnel effect.

OBJECTIVES: Administrative data from Manitoba, Canada document variation in procedure utilization rates over a period of 15 years. With coronary angiography and cardiovascular surgery centralized in the capital, Winnipeg, previous analyses from 1977 to 1983 found angiography and coronary artery bypass surgery (CABS) rates to be higher for residents of Winnipeg. Residents of the Western region had consistently lower rates; this variation in regional access appeared due to physician practice patterns. In this study all angiography patients were followed from 1987 to 1992 and rates of CABS and percutaneous transluminal coronary angioplasty (PTCA) calculated. METHODS: Cox proportional hazard multivariate regression models with five sociodemographic variables and two clinical variables (time from angiography to revascularization, and comorbidities) also were examined. RESULTS: Consistent regional variation was documented; rates in the Western region remain consistently low. A "funnel effect" is found; the fewer patients from a region referred for angiography, the fewer patients from that region who have CABS or PTCA. CONCLUSIONS: Implications of the persistence of these findings are discussed. Individuals in Western Manitoba probably have some of the lowest rates of coronary artery bypass surgery and percutaneous transluminal coronary angioplasty in North America.

Cardiovascular medication use in patients with undiagnosed obstructive sleep apnoea.

BACKGROUND: A study was undertaken in patients with undiagnosed sleep apnoea/hypopnoea syndrome (OSAS) to document the use of prescribed medications, especially those used in cardiovascular diseases, in the year before the OSAS diagnosis was confirmed. METHODS: A total of 549 patients with OSAS (401 men of mean age 47.2 years, mean body mass index (BMI) 35.5 kg/m(2), mean apnoea/hypopnoea index (AHI) 47.2 and148 women of mean age 50.2 years, BMI 39.6 kg/m(2), AHI 32.6) were each matched to one general population control by age, sex, geographical location, and family physician. Medication use was evaluated for patients and controls using a database containing information about all prescriptions completed in the province of Manitoba, Canada. RESULTS: In the year before OSAS was diagnosed, prescribed medication costs were $155.91 (Canadian dollars) (95% CI $91.34 to $220.49) greater for cases than for controls. Cases were dispensed 3.3 (95% CI 1.5 to 5.2) more prescriptions, were on 1.2 (95% CI 0.8 to 1.6) more medications, and were supplied with 157.4 (95% CI 95.9 to 218.8) more daily doses of medication. The odds ratio of OSAS cases being on a prescribed medication was 1.88 relative to controls (95% CI 1.38 to 2.54, p<0.0001). In the same year 36.6% of cases and 19.7% of controls were using medications for cardiovascular disease (OR 2.82, 95% CI 2.05 to 3.89, p<0.0001), consuming 79.4 (95% CI 48.9 to 109.8) more daily doses of medication, having been dispensed 1.7 (95% CI 1.0 to 2.4) more prescriptions, and at a $75.26 (95% CI $44.03 to $106.50) greater cost. The odds ratio of patients with OSAS being on medications indicated for the treatment of systemic hypertension was 2.71 (95% CI 1.96 to 3.77) relative to controls; however, such medications might also be prescribed for other indications such as angina pectoris and congestive heart failure, and for the secondary prevention of myocardial infarction. The use of medications indicated for the treatment of systemic hypertension was predicted significantly by age (odds ratio (OR) 1.10 per year), BMI (OR 1.05 per unit), and AHI (OR 1.01 per unit). CONCLUSIONS: In the year before OSAS was diagnosed, patients with OSAS were heavy users of medications, particularly those used to treat cardiovascular diseases.

Waiting times for surgical procedures.

OBJECTIVES: Polls show that nearly two thirds of Canadians believe that waiting times prior to surgery have increased in recent years. A study was undertaken in Manitoba to determine whether public perceptions about long and increasing waits were valid. RESEARCH DESIGN: Using administrative data, waiting times for 10 types of surgery-ranging from coronary artery bypass surgery and mastectomy to cataract surgery and hernia repairs-were studied over a 5-year period. RESULTS: Using each patient's preoperative visit to the surgeon as the beginning of the waiting time, median waiting times for most of the procedures studied were found to have, in fact, remained stable or fallen slightly over the period studied. CONCLUSIONS: Further, an examination of waiting times for cataract surgery demonstrated that allowing surgeons to practice in both public and private arenas seems to be counterproductive to providing good public service.

Record linkage strategies, outpatient procedures, and administrative data.

By understanding the range of approaches implicit in modern record linkage, epidemiologists and health services researchers can better decide its suitability for their needs. The authors discuss a small record linkage project, providing a sense of where mistakes were made. The research first uses existing identification numbers as a gold standard for linking hospital abstracts and physician claims to investigate whether or not coronary angiography was performed on a given individual. Even if identification numbers are not available, a successful linkage (with more than 95% of the cases matched) may be possible under some circumstances. The linkage process highlights problems with the consistent recording of coronary angiography in inpatient and outpatient hospital abstracts. Our approach should prove useful when the same procedure is recorded in more than one place on a single file and when validating a procedure (or other event) across files is important. Given the growing number of health care databases and ongoing changes in the delivery of care, record linkage often can provide quality control and expand research opportunities in a timely fashion.

Short-term mortality after repair of hip fracture. Do Manitoba elderly do worse?

This article uses administrative data from Manitoba and New England to address the reasons underlying Manitoba's relatively high mortality in the 30 days after hip fracture repair. Both the Manitoba and New England data sets are population based, containing information on individuals 65 years of age or older in Manitoba (1979-1992; n = 10,007) and New England (1984-1985); n = 16,206). Various logistic regression models were estimated on pooled and separate data from Manitoba and New England; the models all showed similar predictive accuracy, having C statistics in the .71 to .74 range. Manitoba postsurgical 30-day mortality rates were greater than the 1984 to 1985 New England rate for each of the 14 years considered. In particular, New England residents with very short waits before hip fracture repair (0 or 1 day) had mortality rates both markedly lower than expected and significantly less than those of Manitobians with such short waits. Attention to the Manitoba hospitals with very poor 30-day survival and to the process surrounding selection of patients for early versus late surgery in Manitoba are clearly in order. The extent to which longer-term survival reflects 30-day survival also is discussed. Our findings highlight the utility of comparative data for understanding quality of care problems within a single region.

The relationship between inflammatory bowel disease and socioeconomic variables.

OBJECTIVES: Inflammatory bowel diseases (IBD) are chronic diseases associated with considerable morbidity. This morbidity may have an impact on the ability of patients to remain employed, on their marital status, and on their ability to complete a course of higher education. It has long been held that IBD patients are of a higher socioeconomic status and more educated than the general population. Our aim was to determine the relationship between IBD and employment, income, disability, education, and marital status in two population-based data sets based in the province of Manitoba, Canada. METHODS: Two studies are reported here. In study A, we surveyed persons with IBD, using the population-based University of Manitoba IBD Database, created in 1995-1996. We compared these IBD patients to the general population with respect to employment, education, and marital status using data from the 1996 National Population Health Survey. IBD patients were queried as to their socioeconomic status as of the time of diagnosis and also at the time of the survey (1995-1996). In study B, we used a database that linked health care and census variables to determine differences in employment, income, occupation, and marital status among individuals who met the administrative definition of IBD (created in forming the University of Manitoba IBD Database, based on ICD-9-CM codes 555 for Crohn's disease and 556 for ulcerative colitis) compared with the rest of working-age population. RESULTS: In study A we found that, compared with the general population, patients with IBD were more likely to be unemployed. Crohn's disease appeared to affect employment more than ulcerative colitis. IBD patients, however, had a low rate of reporting themselves as disabled (1.3%). Among those married when diagnosed with IBD, approximately 10% of men and up to 20% of women were no longer married 5 yr later. More patients with IBD were married in 1995 compared with the general population; however, more were also divorced. Fewer patients with IBD achieved postsecondary education. In study B, we found that individuals with IBD were twice as likely to be out of the labor force as were controls. Sedentary occupations were twice as likely to be associated with IBD. The income, education level, and marital status of IBD patients were not significantly different from those of controls. CONCLUSIONS: Individuals with IBD at some time in the course of their illness are more likely not to be working than are those in the general population. Based on employment status and job classification, as well as income and education, IBD patients are not of a higher socioeconomic status as previously reported. IBD patients are at least as likely as the general population to be married.

Restless legs syndrome in 218 patients: associated disorders.

Background: Restless legs syndrome (RLS) is a disorder characterized by disagreeable sensations in the legs that occur at rest and are relieved by movement. These symptoms, which are worse at night, may result in sleep onset or sleep maintenance insomnia. Most patients are found on polysomnography (PSG) to have periodic limb movements in sleep (PLMS). The disorder, idiopathic in most cases, may be sometimes associated with specific disorders.Methods: Using the Province of Manitoba Health database, we compared the diagnoses made in the 5 years prior to sleep laboratory evaluation of 218 patients (103 men and 115 women) with RLS and 872 matched control subjects from the general population.Results: We found that 43.7% of male RLS patients vs. 10.4% of male controls and 46.1% of female RLS patients vs. 22.8% of female controls had been diagnosed as having psychological/psychiatric (most often depression) disorders (P<0.05). Extrapyramidal disease or movement disorders were previously diagnosed in 17.5% of male RLS patients vs. 0.2% of male controls and in 23.5% of female patients vs. 0.2% of female controls (P<0.05). Many patients had been previously diagnosed with disorders of the musculoskeletal system: 35.9% of male patients vs. 22.8% of male controls and 49.6% of female RLS patients vs. 23.3% of female controls had been diagnosed as having diseases of joints (male; P=ns, female; P<0.05). Disorders of the back were also more frequently diagnosed in RLS patients: 21.4% of male patients vs. 13.1% of male controls and 38.3% of female patients vs. 15.0% of female controls (male; P=ns, female; P<0.05).Conclusions: We conclude that RLS patients are much more likely to have previously been diagnosed with extrapyramidal disorders, musculoskeletal disorders, depression, and painful conditions such as joint and back disorders.

Epidemiology of varicella zoster virus infection in Canada and the United Kingdom.

Many countries are currently studying the possibility of mass vaccination against varicella. The objective of this study was to provide a comprehensive picture of the pre-vaccine epidemiology of the varicella zoster virus (VZV) to aid in the design of immunization programs and to adequately measure the impact of vaccination. Population-based data including physician visit claims, sentinel surveillance and hospitalization data from Canada and the United Kingdom were analysed. The key epidemiological characteristics of varicella and zoster (age specific consultation rates, seasonality, force of infection, hospitalization rates and inpatient days) were compared. Results show that the overall epidemiology of varicella and zoster is remarkably similar between the two countries. The major difference being that, contrary to Canada, the epidemiology of varicella seems to be changing in the United Kingdom with an important decrease in the average age at infection that coincides with a significant increase in children attending preschool. Furthermore, differences exist in the seasonality between the United Kingdom and Canada, which seem to be primarily due to the school calendar. These results illustrate that school and preschool contact patterns play an important role in the dynamics of varicella. Finally, our results provide baseline estimates of varicella and zoster incidence and morbidity for VZV vaccine effectiveness and cost-effectiveness studies.