Exploring the intersectionality of characteristics among those who experienced opioid overdoses: A cluster analysis.

Background: As Canada continues to experience an opioid crisis, it is important to understand the intersection between the demographic, socioeconomic and service use characteristics of those experiencing opioid overdoses to better inform prevention and treatment programs. Data and methods: The Statistics Canada British Columbia Opioid Overdose Analytical File (BCOOAF) represents people's opioid overdoses between January 2014 and December 2016 (n = 13,318). The BCOOAF contains administrative health data from British Columbia linked to Statistics Canada data, including on health, employment, social assistance and police contacts. Cluster analysis was conducted using the k-prototypes algorithm. Results: The results revealed a six-cluster solution, composed of three groups (A, B and C), each with two distinct clusters (1 and 2). Individuals in Group A were predominantly male, used non-opioid prescription medications and had varying levels of employment. Individuals in Cluster A1 were employed, worked mostly in construction, had high incomes and had a high rate of fatal overdoses, while individuals in Cluster A2 were precariously employed and had varying levels of income. Individuals in Group B were predominantly female; were mostly taking prescription opioids, with about one quarter or less receiving opioid agonist treatment (OAT); mostly had precarious to no employment; and had low to no income. People in Cluster B1 were primarily middle-aged (45 to 65 years) and on social assistance, while people in Cluster B2 were older, more frequently used health services and had no social assistance income. Individuals in Group C were primarily younger males aged 24 to 44 years, with higher prevalence of having experienced multiple overdoses, were medium to high users of health care services, were mostly unemployed and were recipients of social assistance. Most had multiple contacts with police. Those in Cluster C1 predominantly had no documented use of prescription opioid medications, and all had no documented OAT, while all individuals in Cluster C2 were on OAT. Interpretation: The application of machine learning techniques to a multidimensional database enables an intersectional approach to study those experiencing opioid overdoses. The results revealed distinct patient profiles that can be used to better target interventions and treatment.

Changes to acute-care hospitalizations among Indigenous children and youth: Results from the 2006 and 2011 Canadian Census Health and Environment Cohorts.

Background: This study described the differences in the hospitalization rates of First Nations children and youth living on and off reserve, Inuit children and youth living in Inuit Nunangat (excluding Nunavik), and Métis children and youth, relative to non-Indigenous children and youth and examined rate changes across 2006 and 2011. Data and methods: The 2006 and the 2011 Canadian Census Health and Environment Cohorts provided five years of hospital records that Statistics Canada linked to peoples' self-reported Indigenous identity as recorded on the census. Causes of hospitalizations were based on the most responsible diagnosis coded according to the International Statistical Classification of Diseases and Related Health Problems, 10th Revision, Canada, aggregated by chapter code. Age-standardized hospitalization rates (ASHRs) were calculated per 100,000 population. Rate ratios (RRs) were reported for each Indigenous group relative to non-Indigenous children and youth. Results: For the 2006 and the 2011 cohorts, ASHRs were generally higher among Indigenous children and youth than among non-Indigenous children and youth. For some health conditions, hospitalization patterns also varied across the two time periods within the given Indigenous groups. Among children, leading elevated RRs occurred for diseases of the respiratory system, the digestive system and injuries. Elevated mental health-related RRs were observed among all Indigenous groups for both cohort years of youth. Significant increases in mental health-related ASHRs were observed in 2011 compared with 2006 among all youth groups, except for Inuit youth living in Inuit Nunangat, possibly due in part to data limitations. Among Indigenous youth, elevated RRs were observed for pregnancy, childbirth and the puerperium, and for injuries. For all youth (except Inuit), childbirth-related ASHRs decreased in 2011 compared with 2006. Interpretation: Findings align with previously observed hospitalization disparities between Indigenous and non-Indigenous children and youth. These data enabled the tracking of changes over time to partly address national information gaps about population health outcomes for children and youth, namely hospitalization.

Understanding the socioeconomic profile of people who experienced opioid overdoses in British Columbia, 2014 to 2016.

BACKGROUND: Following the 2016 opioid overdose emergency declaration in British Columbia (B.C.), provincial stakeholders collaborated to link data that resulted in the B.C. Provincial Overdose Cohort. This database provides information about people who have experienced opioid overdoses to inform policy and intervention developments. Subsequently, Statistics Canada likewise constructed a cohort and integrated federal data to broaden the scope of the B.C. initiative. This provided federally sourced information about people's circumstances that was not otherwise available. DATA AND METHODS: The Statistics Canada British Columbia Opioid Overdose Analytical File further characterizes the socioeconomic circumstances of 13,318 people who experienced illicit drug toxicity deaths and non-fatal opioid overdoses in B.C. between January 1, 2014, and December 31, 2016. Statistics Canada linked federal data on immigration, employment, the justice system and social assistance receipt in the year of, and prior to, people's first overdose. RESULTS: During the observation period, most people (78%) had one overdose episode, rather than several. Seven percent were immigrants or temporary residents, 41% of whom arrived in Canada more than 20 years before their index overdose. Half (49.6%) had not received social assistance, and one-third (33.8%) were employed-primarily within construction (21% of those employed)-in the year prior to their index overdose. Most employed people (65.5%) experienced periods of unemployment within five years prior to their index overdose. Employment was more prevalent among people who experienced illicit-drug toxicity death (36.1%). About 60% of people had not had any formal police contact within the two years prior to the index overdose. DISCUSSION: This project demonstrated further added value to existing data by using this linkage approach and aligned with strategies underway by BC public health partners to provide cross-sectoral evidence to inform efforts to prevent and manage opioid overdoses.

Significant factors associated with problematic use of opioid pain relief medications among the household population, Canada, 2018.

BACKGROUND: Reliance on the use of opioids to manage pain has increased over time, as have opioid-related morbidity and deaths. In 2018, 12.7% of Canadians reported having used opioid pain relief medications (OPRMs) in the previous year. Among these people, 9.6% had engaged in problematic use that could cause harm to their health. Though socioeconomic characteristics associated with opioid-related harms have previously been reported, population-level evidence based on administrative health data lacks important behavioural and psychosocial information. This analysis extends previous research by using modelling to report factors related to the problematic use of OPRMs for the household population aged 15 and older in Canada. DATA AND METHODS: This analysis uses responses to the 2018 Canadian Community Health Survey to identify factors that are significantly associated, after adjustment using multivariate logistic regression models, with elevated odds of problematic use of OPRMs. RESULTS: The fully adjusted model confirmed that being male, being younger (ages 20 to 24), having fair or poor mental health, having unmet needs for help with mental or emotional health or substance problems, being a smoker, or being unattached and living with others were significantly related to problematic OPRM use. INTERPRETATION: Subjective perceptions significantly related to problematic OPRM use, independent of socioeconomic circumstances, were examined in this study. While previous research based on administrative health data has contributed much to knowledge about factors associated with opioid harms, modelled results revealed that self-reported experiential factors also warrant consideration as they are significantly associated with problematic use. Having fair or poor mental health, having unmet perceived needs for help, and being unattached in terms of household arrangement relationship were related to problematic use of OPRMs, even after adjustment for socioeconomic and other health covariates. This study suggests risk profiles that could be used to inform health care providers, and strategies to support safe pain management.

Social and economic characteristics of those experiencing hospitalizations due to opioid poisonings.

Hospitalizations due to opioid poisonings are increasing. While considerable information is available on the demographic and geographic distribution of opioid-related events, national data on the social and economic circumstances of those experiencing these events are limited. This study uses data from the National Household Survey (2011) linked to the Discharge Abstract Database (2011 to 2016) to provide the first national-level estimates of the socio-economic characteristics of individuals experiencing opioid-related hospitalizations. Results reveal elevated hospitalization rates among people who have lower levels of income and education, are unemployed or out of the labour force, identify as Indigenous, live in lone-parent households, and spend more than 50% of their household income on housing. Understanding the circumstances of individuals who experienced adverse opioid events will help inform policies addressing potential determinants.

Using data linkage to report surgical treatment of breast cancer in Canada.

BACKGROUND: National population information about the surgical treatment rate for primary cancers, including breast cancer, has remained a significant data gap in Canada. This gap has implications for cancer care planning and evaluating health system performance. New linkages between the Canadian Cancer Registry and hospital discharge records were conducted by Statistics Canada in 2016. Using already existing, routinely collected health administrative data, these linkages allow viable reporting of surgical cancer treatment for the first time for all provinces and territories (except Quebec). DATA AND METHODS: Hospital record information about type and date of surgical treatment of tumours was provided by information from linked data. These linked data reported 50,740 incident primary malignant breast tumours diagnosed between January 1, 2010, and December 31, 2012, among females aged 19 years or older. The unadjusted treatment rate for primary surgical intervention within one year was calculated as the proportion of total tumours that were linkable to hospital records. RESULTS: For three combined years (2010, 2011 and 2012), 88.3% (N=44,780) of patients overall received at least one surgical treatment. Variations to the surgical rate occurred across jurisdictions, with the highest rate at 91-92% for Prince Edward Island, Newfoundland and Labrador, British Columbia and New Brunswick. Generally, there was an inverse gradient between surgical treatment rate and tumour stage. DISCUSSION: The surgical treatment rate of new primary breast cancers varied across provinces and territories from 2010 to 2012. New linked data could be used to further identify geographic and demographic inequities in terms of receiving surgical cancer treatment and contribute to the evaluation of cancer system performance and outcomes.

Acute care hospitalizations for mental and behavioural disorders among First Nations people.

BACKGROUND: National information about acute care hospitalizations for mental/behavioural disorders among Aboriginal people in Canada is limited. DATA AND METHODS: This study describes acute care hospitalizations for mental /behavioural disorders among First Nations people living on and off reserve. The 2006 Census was linked to the Discharge Abstract Database from 2006/2007 through 2008/2009 for all provinces (except Ontario and Quebec) and the three territories. Hospitalizations for seven types of disorders were identified. "Most responsible" diagnosis and secondary diagnoses were examined separately. Age-standardized hospitalization rates (ASHRs) per 100,000 population and rate ratios were calculated. RESULTS: ASHRs for most responsible and secondary diagnoses of mental/behavioural disorders were significantly higher for First Nations people living on and off reserve than for non-Aboriginal people. The leading diagnoses were the same for each group, but the rank order differed. Among First Nations people, the most common diagnoses were substance-related disorders, mood disorders, and schizophrenic/psychotic disorders. Among non-Aboriginal people, mood disorders were the leading most responsible diagnosis, followed by schizophrenic/psychotic disorders and substance-related disorders. The greatest rate differences between First Nations and non-Aboriginal people for both most responsible and secondary diagnoses were for substance-related disorders. DISCUSSION: The higher burden of hospitalizations due to mental/behavioural disorders among First Nations people provides benchmarks and points to the need of considering every hospital admission as an important opportunity for intervention and prevention. The Truth and Reconciliation Commission of Canada (2015) has recognized that the poorer health outcomes of Aboriginal people in Canada were rooted in the legacies of colonization. Further research is required to better understand the direct impacts on mental health.

Hospitalization for ambulatory care sensitive conditions among urban Métis adults.

BACKGROUND: Hospitalizations for ambulatory care sensitive conditions (ACSCs) are potentially preventable, but may be required if these conditions are not managed well. National-level information about ACSC hospitalizations is available for Canada, but not for Aboriginal groups. This study describes ACSC hospitalizations among urban Métis adults relative to their non-Aboriginal counterparts. DATA AND METHODS: The 2006/2007-to-2008/2009 Discharge Abstract Database, which contains hospitalization records from all acute care facilities (excluding Quebec), was linked to the 2006 Census to obtain Aboriginal identity information. Age-standardized ACSC hospitalization rates (ASHRs) per 100,000 population and rate ratios were calculated for Métis aged 18 to 74 relative to non-Aboriginal people of the same ages. Odds of ACSC hospitalizations were estimated using logistic regression models, adjusting for demographic, geographic, and socioeconomic characteristics. RESULTS: The ASHR for ACSCs among urban Métis adults was twice that among non-Aboriginal adults (393 versus 184 per 100,000 population). Even when demographic, geographic, and socioeconomic characteristics were taken into account, Métis had higher odds of ACSC hospitalizations overall (OR 1.5). Most commonly, these hospitalizations were for diabetes (OR 1.8) or chronic obstructive pulmonary disease (OR 1.5). Modelled factors partly reduced differences between Métis and non-Aboriginal adults, but variations between the groups remained after all adjustments. INTERPRETATION: Rates of ACSC hospitalizations were higher among Métis than among non-Aboriginal adults who lived in urban areas. Further research using other data sources is warranted to assess the roles of factors not available for this analysis, such as primary care, co-morbidity, and health behaviours.

Acute care hospitalization of Aboriginal children and youth.

BACKGROUND: Research that has examined Aboriginal children's hospitalization rates at the national level has been limited to analyses of areas with large percentages of Aboriginal residents, rather than of Aboriginal individuals. This study uses linked census and administrative data to describe hospitalization patterns among children and youth aged 0 to 19, by Aboriginal identity, for all provinces and territories except Quebec. DATA AND METHODS: The 2006 Census was linked to the 2006/2007-to-2008/2009 Discharge Abstract Database, which contains hospital records from all acute care facilities (except Quebec). Hospital records were examined by Aboriginal identity, as reported to the census, according to International Classification of Diseases chapters based on "the most responsible diagnosis." Age-standardized hospitalization rates (ASHRs) were calculated per 100,000 population, and age-standardized rate ratios (RRs) were calculated for Aboriginal groups relative to non-Aboriginal people. RESULTS: ASHRs were consistently higher among Aboriginal children and youth relative to their non-Aboriginal counterparts; rates for children aged 0 to 9 were 1.4 to 1.8 times higher; for youth aged 10 to 19, 2.0 to 3.8 times higher. For all children aged 0 to 9, the leading cause of hospitalization was "diseases of the respiratory system," but RRs for Aboriginal children ranged from 1.7 to 2.5, compared with non-Aboriginal children. Disparities between Aboriginal and non-Aboriginal 10- to 19-year-olds were pronounced for injuries due to assaults (RRs from 4.8 to 10.0), self-inflicted injuries (RRs from 2.7 to 14.2), and pregnancy, childbirth and the puerperium (RRs from 4.1 to 9.8). INTERPRETATION: Additional research is needed to examine reasons for the disparities in hospitalization rates between Aboriginal and non-Aboriginal children and youth.

Housing conditions and respiratory hospitalizations among First Nations people in Canada.

BACKGROUND: Respiratory diseases are among the leading causes of acute care hospitalization for First Nations people. Poor housing conditions are associated with respiratory disorders and may be related to the likelihood of hospitalization. This analysis examines whether First Nations identity is associated with higher odds of hospitalization for respiratory conditions relative to non-Aboriginal persons, and whether such differences in hospitalization rates remain after consideration of housing conditions. DATA AND METHODS: Data from the 2006 Census linked to the Discharge Abstract Database were used to analyze differences in hospitalization for respiratory tract infections and asthma between First Nations and non-Aboriginal people when housing conditions were taken into account. RESULTS: Rural on-reserve First Nations people were more likely than non-Aboriginal people to be hospitalized for a respiratory tract infection (1.5% versus 0.5%) or for asthma (0.2% versus 0.1%). For respiratory tract infection hospitalizations, adjustment for housing conditions, household income and residential location reduced differences, but the odds remained nearly three times higher for on-reserve First Nations people (OR = 2.83; CI: 2.69 to 2.99) and two times higher for off-reserve First Nations people (OR = 2.03; CI: 1.87 to 2.21), compared with the non-Aboriginal cohort. For asthma hospitalizations, adjustment for household income reduced the odds more than did adjustment for housing conditions. Even with full adjustment, the odds of asthma hospitalization relative to non-Aboriginal people remained significantly higher for First Nations people. INTERPRETATION: First Nations people are significantly more likely than non-Aboriginal people to be hospitalized for respiratory tract infections and asthma, even when housing conditions, household income and residential location are taken into account. While housing conditions are associated with such hospitalizations, household income may be more important.

Acute care hospitalization by Aboriginal identity, Canada, 2006 through 2008.

BACKGROUND: National data about acute care hospitalization of Aboriginal people are scarce. This study addresses that information gap by describing patterns of hospitalization by Aboriginal identity for leading diagnoses for all provinces and territories except Quebec. DATA AND METHODS: The 2006 Census was linked to the 2006/2007-to-2008/2009 Discharge Abstract Database, which contains hospital records from all acute care facilities in Canada (excluding Quebec). With these linked data, hospital records could be examined by Aboriginal identity, as reported to the census. Hospitalizations were grouped by International Classification of Diseases (ICD-10) chapters based on "the most responsible diagnosis." Age-standardized hospitalization rates were calculated per 100,000 population, and rate ratios (RR) were calculated for Aboriginal groups relative to non-Aboriginal people. RESULTS: Hospitalization rates were almost invariably higher for First Nations living on and off reserve, Métis, and Inuit living in Inuit Nunangat than for the non-Aboriginal population, regardless of ICD diagnostic chapter. The ranking of age-standardized hospitalization rates by frequency of diagnoses varied slightly by Aboriginal identity. RRs were highest among First Nations living on reserve, especially for endocrine, nutritional and metabolic diseases (RR = 4.9), mental and behavioural disorders (RR = 3.6), diseases of the respiratory system (RR = 3.3), and injuries (RR = 3.2). As well, the rate for endocrine, nutritional and metabolic diseases was high among First Nations living off reserve (RR = 2.7). RRs were also high among Inuit for mental and behavioural disorders (RR = 3.3) and for diseases of the respiratory system (RR = 2.7). INTERPRETATION: Hospitalization rates varied by Aboriginal identity, and were consistent with recognized health disparities between Aboriginal and non-Aboriginal people. Because many factors besides health affect hospital use, further research is required to understand differences in hospital use by Aboriginal identity. These national data are relevant to health policy formulation and service delivery planning.

Using personal health insurance numbers to link the Canadian Cancer Registry and the Discharge Abstract Database.

BACKGROUND: Linking cancer registry and administrative data can reveal health care use patterns among cancer patients. The Canadian Cancer Registry (CCR) contains personal health insurance numbers (HINs) that facilitate linkage to hospitalization information in the Discharge Abstract Database (DAD). DATA AND METHODS: Valid HINs, captured in the CCR or obtained through probabilistic linkages to provincial health insurance registries, were used to deterministically link prostate, female breast, colorectal and lung cancers diagnosed from 2005 through 2008 with the DAD for fiscal years 2004/2005 to 2010/2011. RESULTS: At least 98% of tumours diagnosed from 2005 through 2008 had valid HINs in the CCR or obtained through probabilistic linkages. For provinces submitting day surgeries to the DAD, linkage rates to at least one DAD record were higher for female breast (95.6% to 98.1%), colorectal (96.9% to 98.7%) and lung cancers (92.8% to 96.3%) than for prostate cancers (77.2% to 91.6%). Among linked records, agreement was high for sex (99% or more) and complete date of birth (97% or more); the likelihood of a consistent diagnosis in the CCR and on at least one linked DAD record was higher for female breast (86.8% to 97.2%), colorectal (94.6% to 97.7%) and lung cancers (90.3% to 95.5%) than for prostate cancers (77.4% to 87.8%). INTERPRETATION: Deterministically linking the CCR and DAD using personal HINs is a feasible and valid approach to obtaining hospitalization information about cancer patients.

Two approaches to linking census and hospital data.

BACKGROUND: This study compares registry and non-registry approaches to linking 2006 Census of Population data for Manitoba and Ontario to hospital data from the Discharge Abstract Database (DAD). DATA AND METHODS: Using a probabilistic linkage, the registry approach linked the census data to provincial health insurance registries, followed by a deterministic linkage to the DAD based on health insurance number (HIN). The non-registry approach used hierarchical deterministic exact matching based on three variables common to both files to link census data to the DAD. The approaches were compared in terms of linkage and coverage rates, sensitivity and specificity, and consistency of HINs on the linked records. RESULTS: Results of the registry and non-registry linkage approaches were similar. In Manitoba, 7% and 6% of census long-form respondents linked to the DAD with the registry and non-registry linkage approaches, respectively; in Ontario, the linkage rate was 5% for both approaches. With the registry approach, the linked census-DAD data represented 84% (weighted) of hospital admissions in the 2006/2007 DAD in both provinces, compared with 82% in Manitoba and Ontario with the non-registry approach. INTERPRETATION: In the absence of access to provincial health insurance registries with which census data can be linked, a non-registry approach can be used to create a research-quality dataset.

Rates of cancer incidence across terciles of the foreign-born population in Canada from 2001-2006.

OBJECTIVES: To address the issue of comparative risk of cancer in Canada's immigrant population, an area-based methodology was applied to examine whether or not estimated cancer incidence rates among individuals living in given areas vary systematically according to the concentration of foreign-born individuals living in the same area. This method provides an alternative, accessible surveillance method in the absence of linked individual-level information to extend the work of others by providing both national and subnational standardized, hence comparable, results to address this issue. METHODS: Canadian Cancer Registry data (2001 to 2006) and 2006 Census data provided dissemination area information regarding the concentration of the foreign-born population and population estimates for rate denominators. Cancer (all cause and cause-specific) incidence rate ratios (age-standardized and by age/sex) were calculated by foreign-born concentration areas at both national and regional levels. RESULTS: An inverse gradient was identified between cancer incidence rates and area concentration of foreign-born, with the all-sites cancer rate ranging from a low of 388 per 100,000 among individuals living in areas with a high concentration of foreign-born to a high of 493 per 100,000 among individuals living in areas with a low concentration of foreign-born. This pattern occurred nationally for lung, colorectal, prostate and female breast cancers. However, for liver, nasopharynx, and thyroid cancers, higher cancer rates were observed in areas with a higher versus lower concentration of foreign-born populations. CONCLUSION: The study findings provide suggestive evidence of decreased cancer risk among foreign-born populations for most cancers except nasopharynx, liver and thyroid for which risks were higher. The results of this study demonstrate the value of ecological-based methods for disease surveillance in the absence of individual-level information on immigrant status in the national cancer registry.

Area-based methods to calculate hospitalization rates for the foreign-born population in Canada, 2005/2006.

BACKGROUND: Hospital records lack information about country of birth. This study describes a method for calculating hospitalization rates by the percentage of foreign-born in Census Dissemination Areas (DAs). DATA AND METHODS: Data from the 2006 Census were used to classify DAs by the percentage of the foreign-born population who lived in them. Quintile and tercile thresholds were created to classify DAs as having low to high percentages of foreign-born residents. This information was appended to the 2005/2006 Hospital Morbidity Database via postal codes. Age-sex standardized hospitalization rates were calculated for low to high foreign-born concentration DAs, nationally and subnationally. RESULTS: Nationally, quintile thresholds had better discriminatory power to detect variations in hospitalization rates by foreign-born concentration, but tercile thresholds produced reliable results at subnational levels. All-cause hospitalization rates were lowest among residents of the high foreign-born concentration terciles. Similar gradients emerged in hospitalization rates for heart disease, diseases of the circulatory system, and mental health conditions. The pattern varied more at the subnational level. INTERPRETATION: With this approach, administrative data can be used to calculate hospitalization rates by foreign-born concentration.

Cancer patterns in Inuit Nunangat: 1998-2007.

OBJECTIVES: To compare cancer incidence patterns between residents of Inuit Nunangat and the rest of Canada. STUDY DESIGN: Cancer cases were geographically linked to either Inuit Nunangat or the rest of Canada using postal codes or other geographic information. Population estimates were derived from the 2001 and 2006 censuses. METHODS: Cancer cases were combined from 1998 to 2007 for Inuit Nunangat and the rest of Canada. Age-standardised incidence rates were calculated for all site cancers and sub-sites by sex. Standardised rate ratios between these 2 areas were calculated for all site cancers and sub-sites. RESULTS: The age-standardised incidence rate for all cancer sites (1998-2007) was 14% lower for the Inuit Nunangat male population and 29% higher for the female population by comparison to the rest of Canada. Cancers of the nasopharynx, lung and bronchus, colorectal, stomach (males), and kidney and renal pelvis (females), were elevated in the Inuit Nunangat population compared to the rest of Canada, whereas prostate and female breast cancers were lower in the Inuit Nunangat population. CONCLUSIONS: Cancers with potentially modifiable risk factors, such as buccal cavity and pharynx, nasopharynx, lung and bronchus, and colorectal cancer were elevated in the Inuit Nunangat population compared to the rest of Canada. Besides greater smoking prevalence within Inuit Nunangat by comparison to the rest of Canada, distinct socioeconomic characteristics between respective area populations including housing, and income may have contributed to incidence differentials. This study demonstrated that a geographic approach can be used in cancer surveillance when populations of interest are spatially distinguishable, and reside across distinct jurisdictions whose combined cancer registries will not completely provide information to identify the population of interest.

Geozones: an area-based method for analysis of health outcomes.

BACKGROUND: Administrative datasets often lack information about individual characteristics such as Aboriginal identity and income. However, these datasets frequently contain individual-level geographic information (such as postal codes). This paper explains the methodology for creating Geozones, which are area-based thresholds of population characteristics derived from census data, which can be used in the analysis of social or economic differences in health and health service utilization. DATA AND METHODS: With aggregate 2006 Census information at the Dissemination Area level, population concentration and exposure for characteristics of interest are analysed using threshold tables and concentration curves. Examples are presented for the Aboriginal population and for income gradients. RESULTS: The patterns of concentration of First Nations people, Métis, and Inuit differ from those of non-Aboriginal people and between urban and rural areas. The spatial patterns of concentration and exposure by income gradients also differ. INTERPRETATION: The Geozones method is a relatively easy way of identifying areas with lower and higher concentrations of subgroups. Because it is ecological-based, Geozones has the inherent strengths and weaknesses of this approach.

Waiting time for medical specialist consultations in Canada, 2007.

BACKGROUND: Waiting for specialist consultations can represent a substantial component of overall waiting time in the continuum of care. However, relatively little is known about the factors associated with how long patients wait for an initial specialist consultation. DATA AND METHODS: The analysis is based on a subsample of 5,515 respondents aged 15 or older to the 2007 Canadian Community Health Survey who had consulted a specialist about a new condition in the previous 12 months and reported a waiting time. Multivariate logistic regression models were used to identify patient- and provider-related factors associated with waiting time. RESULTS: Female patients were less likely than male patients to see a specialist within a month. The nature of the new condition and the source of referral were significantly associated with waiting time. Compared with those referred by a family physician, patients referred by another specialist or a health care provider other than a physician, or who did not require a referral, were more likely to have a shorter waiting time. For men, but not women, household income and immigrant status were associated with waiting time. INTERPRETATION: This analysis suggests that factors beyond medical need are associated with how long patients wait to see a specialist. More research could usefully explore decision-making and communication processes between primary care physicians and specialists to better understand how urgency is assessed, how patients are triaged for specialist consultations, and how these patterns differ among various groups of patients.