Life with Arthritis in Canada : A personal and public health challenge

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Data sources

Aboriginal Peoples Survey (APS), 2006

The Aboriginal Peoples Survey (APS) is a national survey of Aboriginal peoples living in Canada (First Nations peoples, Métis and Inuit) aged 6-14 years and 15 years and older, living in urban, rural and northern locations. It excludes people living in Indian settlements or on-reserves (although all Aboriginal people living in the territories were included) as well as those living in institutions. The survey provides data on Aboriginal identity and ancestry, education, language, labour activity, income, health, communication technology, mobility, housing and family background.

The APS is a post-censal sample survey with a cross sectional design. The sample was selected from people living in households whose response on their 2006 Census questionnaire indicated that they:

• Had Aboriginal ancestors, and/or
• Identified as First Nations and/or Métis and/or Inuit, and/or
• Had treaty or registered Indian status, and/or
• Had Indian Band membership.

The sample size was comprised of 61,041 individuals. Data for people aged 15 years and over are collected directly from survey respondents.

The APS asked respondents about long-term health conditions that have lasted or are expected to last six months or more. With respect to arthritis/rheumatism, the APS asked:

• Have you been told by a doctor, nurse or other health care professional that you have arthritis or rheumatism?

Canadian Community Health Survey (CCHS), 2007-2008

The Canadian Community Health Survey (CCHS) is a cross-sectional general population health survey that collects information related to health status, health care utilization and health determinants for the Canadian population. The CCHS 2007-2008 has a large sample and was designed to provide reliable estimates down to the health region level. A brief description of the survey is presented below, and a more detailed version is available from Statistics Canada.¹

The target population of the CCHS was people aged 12 years or older who were living in private dwellings in the 10 provinces and three territories. People living on Indian Reserves or Crown lands, living in institutions, full-time members of the Canadian Armed Forces and residents of certain remote regions were excluded. The overall response rate was 76%; 124,844 individuals participated. Data for people aged 15 years and over were included in the analysis for the report.

Starting in 2007, the wording of the question on arthritis was changed. In 2001, 2003 and 2005, the question included the term "rheumatism". The term was removed from the question in 2007-2008.

• Question in 2001–2005: Do you have arthritis/ rheumatism, excluding fibromyalgia?
• Question in 2007-2008: Do you have arthritis, excluding fibromyalgia?

All analyses performed on the CCHS data were weighted to ensure that derived estimates would be representative of the entire targeted Canadian population 15 years of age and older. If high sampling variability (coefficient of variation between 16.6% and 33.3%) was associated with any of the reported estimates, the symbol "E" was used to indicate that the estimate must be interpreted with caution. If cell sizes were less than 30, estimates were not released, in accordance with Statistics Canada release guidelines. To minimize sample size problems, the Northwest Territories, Yukon and Nunavut were combined under the category "Territories". In order to determine the statistical significance of differences between ratios (e.g. differences in proportions between men and women) the bootstrap method recommended by Statistics Canada was employed.³

Canadian Joint Replacement Registry (CJRR)

The Canadian Joint Replacement Registry (CJRR) is a national registry that collects information on primary and revision hip and knee replacement surgeries performed in Canada. Data are submitted to the CJRR on a voluntary basis by participating surgeons from across Canada. The overall participation of surgeons was 70% in 2006. The database contains demographic information, the type of replacement, surgical approach, fixation modes and implant types. It also contains information on weight and height. CJRR was used to supplement analyses on hip and knee replacements for Canada in 2005-2006 (see Table 4 for Canadian Classification of Health Interventions (CCI) and Canadian Classification of Diagnostic, Therapeutic, and Surgical Procedures codes (CPP) for joint replacement surgery used). For more information on the CJRR: www.cihi.ca

Canadian Mortality Database

Mortality rates were calculated using the Canadian mortality database for the years of 1999 –2005. The analysis included all deaths for which one of the types of arthritis was recorded as the underlying cause. The cause of death variable in the death database is classified according to the World Health Organization (WHO) "International Statistical Classification of Diseases and Related Health Problems" (ICD). ICD-9 was used from 1979 to 1999 and ICD-10 has been in use since 2000. ICD codes were used to identify death from specific arthritis types and then grouped into five categories (see Table 1 for arthritis ICD-9/10 codes).

The medical death certificate

When someone dies, the authority (usually a physician) who certifies the death is required to record all conditions considered to have caused or contributed to it on the death certificate. To comply with international administrative conventions, each death is classified by identifying a single, underlying cause. The underlying cause of death is defined as:

• the disease or injury that initiated the chain of events leading directly to death, or
• the circumstances of the accident or violence that produced the fatal injury.⁴

The certifier is also expected to list the causes so that the immediate, antecedent, underlying and any contributing causes are in an order that reflects the sequence of events that caused the death. In reality, people are often afflicted with several co-morbid conditions and death may result from a combination rather than a clear sequence of causes. Thus, it may be difficult to accurately certify the order of causes of a death.⁴

In recognition of this difficulty and to standardize the procedure of single-cause attribution when more than one condition contributes to a death, the WHO rules govern the selection of the underlying cause from information entered on the death certificate.⁴

In general, the cause entered alone on the lowest used line of Part I of the Medical Certificate of Death is selected as the underlying cause, if it reasonably could have brought about the conditions entered above it. Although the underlying cause should be entered alone on the lowest used line of Part I, frequently, several conditions are entered on this and the other lines. When the order in which causes of death have been entered on the certificate does not follow the standard, the underlying cause is derived using additional WHO coding rules.⁴

Discharge Abstract Database (DAD)

The Discharge Abstract Database (DAD) contains demographic, administrative and clinical data for hospital discharges (inpatient acute, chronic, rehabilitation) and day surgeries of hospitals in every province and territory except Quebec. It contains clinical, demographic and administrative data for hospital discharges. DAD was used to derive estimates of utilisation of day surgeries for all provinces except Quebec and Alberta from 2001-2002 to 2005-2006, and Ontario and some of Nova Scotia's facilities from 2003-2004 onward (see Table 3 for arthritis ICD-9/10 codes). For more information about the DAD: www.cihi.ca

First Nations Regional Health Survey (RHS), 2002-2003

The First Nations Regional Health Survey (RHS) is a national longitudinal survey that gathers information about health, wellness and health determinants of First Nations living on-reserve/on crown land in First Nations communities across Canada.⁵

RHS Phase 1 (2002-2003) collected the baseline data of this longitudinal survey. It included three questionnaires designed for adults (18 years and older), youth (12–17 years) and children (0–11 years). Data collection took place between 2002 and 2003. In total, 22,602 questionnaires were completed from 238 First Nations communities in ten regions.

The sampling frame included all communities except the James Bay Cree and Innu. The communities were defined by their sub-region and community size (small, medium, large). All large communities were invited to participate, and small/medium communities were randomly selected. Communities with populations under 75 people were deemed 'too small'. The samples were devised by age/sex groups. Individuals were randomly selected from the local Band Membership lists. Weights were created for the final dataset thereby permitting population estimates.⁶

The First Nations Information Governance Committee (a standing committee appointed by the Assembly of First Nations Chiefs Committee on Health) oversees and governs the survey.

The RHS asked First Nations adults about health-related conditions that had lasted at least six months, or were expected to last at least six months, and that had been diagnosed by a health care professional. With respect to arthritis/rheumatism, the RHS asked respondents three specific questions:

• Have you been told that you have arthritis or rheumatism?
• Are you currently undergoing treatment or taking medication for this condition?
• Has this limited the kinds or amount of activity that you do?

In order to enable comparisons to other populations and take into account the difference in age distribution between the First Nations people and the overall Canadian population, age-standardized prevalence estimates were calculated using the 1991 Canadian census population.

Hospital Morbidity Database (HMDB)

The Hospital Morbidity Database (HMDB) is a national data holding that captures administrative, clinical and demographic information on hospital inpatient events. It provides national discharge statistics from Canadian health care facilities by diagnoses and procedures. HMDB was used to estimate hospitalization rates in Canada and the provinces and territories from 2001- 2002 to 2005-2006 (see Table 3 for arthritis ICD-9/10 codes). For more information about HMDB: www.cihi.ca

IMS Health Canada (IMS) Canadian Disease and Therapeutic Index (CDTI)

The Canadian Disease and Therapeutic Index (CDTI) is an ongoing survey designed to provide information about disease and treatment patterns of office-based physicians in Canada. CDTI is used to understand prescription drug utilization at a national level in Canada. CDTI data help assist in describing current and longterm trends in drug therapy/utilization, as well as the medical conditions for which they are used.

A sample of 652 physicians is selected from 45,800 office-based physicians in Canada, stratified by region and specialty. These physicians fill out diaries (ver- batim) for two consecutive days out of every quarter detailing information on each patient contact. This information is projected to the universe of approximately 45,000 physicians in Canada. The sample of physicians used on the CDTI panel is kept as consistent as possible from quarter to quarter.

Patient demographics (such as age and sex) and information about patient diagnosis and concomitant diagnosis and drug therapy (such as product name, strength, and form) are captured in CDTI. Data from CDTI were extracted by medication type, age, sex and arthritis type. CDTI permits the examination of prescriptions written for people with arthritis.

Medication categories:

Health Canada's Therapeutic Products Directorate assigns a unique Drug Identification Number (DIN) to every drug product that it approves for sale in Canada. Using Health Canada's Drug Product Database (DPD), the DINs for all arthritis-related prescription medications were determined.

The DINs were organized into five drug categories:

• non-steroidal anti-inflammatory drugs (NSAIDs);
• corticosteroids;
• disease-modifying anti-rheumatic drugs (DMARDs);
• biologic response modifiers; and
• gastrointestinal (GI) protective agents.

Definition of arthritis:

Arthritis diagnoses are classified according to the International Statistical Classification of Diseases and Related Health Problems (ICD). ICD-9 codes were used to identify individuals with specific arthritis types and then grouped into five categories (see Table 1 for ICD-9/10 codes used).

Participation and Activity Limitation Survey (PALS), 2001

The Participation and Activity Limitation Survey (PALS) in 2001 is based on the 2001 Canadian census and is designed to collect information on adults and children with disabilities—that is, those whose everyday activities are limited because of a health condition. The PALS provides detailed information on the prevalence of various disabilities, support or aid for persons with disabilities, their labour force profile, and their income and participation in society.

The PALS included people who reported arthritis as the main reason for their limitations. To be considered part of the "disabled" population for the PALS, respondents had to have indicated a disability on both the census and at least one of the filter or screening questions in the PALS.

The population covered by the survey was persons living in private and some collective households in the 10 provinces. The population living in the Aboriginal communities, including all First Nations reserves, were excluded, as well as the population living in the three northern territories and the residents of institutional collectives. In addition, individuals living on military bases, Canadian Armed Forces vessels, merchant vessels and coast guard vessels, as well as campgrounds and parks were excluded for operational reasons.

The total size of the PALS 2001 sample is around 43,276 individuals, including 35,424 adults (over the age of 15 years) and 7,853 children (under the age of 15 years), living in private households and collective dwellings. An overall response rate of 82.5% was obtained. The analyses based on the PALS focused on the population aged 15 years and over with arthritis as the main cause of disability.

Provincial physician claims data

Canada's publicly funded healthcare system is province- and territory-based, consisting of 10 provincial and three territorial health insurance plans that cover medically necessary hospital and physician services. The large majority of Canadian physicians operate on a fee-for-service basis: in order to be paid, a physician must submit a claim form to their provincial/ territorial health insurance plan for each individual encounter.

Each physician claim includes a diagnostic code specifying the reason for the visit, and each province uses a classification scheme of diagnoses based on the International Statistical Classification of Diseases and Related Health Problems (ICD). ICD codes were used to identify individuals with specific arthritis types and then grouped into five categories (see Table 2 for ICD-9/10 codes used).

Physicians and individuals enrolled in alternative payment plans are not usually included. However, some physicians submit "shadow bills" to the provincial health insurance plan with diagnostic information. Shadow billing was included in the data where available.

 

Table 1: Arthritis ICD-9/10 codes used in Chapters 5 and 7

Category	Conditions	ICD-9 codes	ICD-10 codes
Lupus and other connective tissue diseases	Systemic lupus erythematosus	710.0	M32.1, M32.8, M32.9
	Vasculitis	446.x	M30.x, M31.x
	Inflammatory myopathies; dermatomyositis	710.3, 710.4	M33.x
	Systemic sclerosis/Scleroderma	710.1	M34.x
	Sicca syndrome/Sjögren	710.2	M35.0
	Overlap syndrome	n/a	M35.1
	Undifferentiated connective tissue disease	710.9	M35.8, M35.9
Rheumatoid arthritis	Rheumatoid Arthritis	714.x	M05.x-M06.x
Osteoarthritis	Osteoarthritis	715.x	M15.x-M19.x
Other inflammatory arthritis	Reiter's Disease	99.3	M02.3
	Gout	274.x	M10.x
	Psoriatic Arthritis	696.0	M07.0-M07.3
	Infectious arthropathies	711.x	M00-M03.x excluding M02.3
	Crystal arthropathies	712.x	M11.x
	Arthopathy associated with other disorders classified elsewhere	713.x	M14.x
	Ankylosing spondylitis	720.x	M45.x
Other arthritis conditions	Other unspecified arthropathies	716.x	M12.x-M13.x
	Internal derangement of knee	717.x	M23.x
	Other derangement of joint	718.x	M24.x
	Other and unspecified disorders of joint	719.x	M25.x
	Polymyalgia rheumatica	725.x	M35.3
	Peripheral enthesopathies and allied syndromes	726.x	M75.x, M76.x, M77.x
	Other disorders of synovium, tendon and bursa	727.x	M65.X-M68.X
	Disorders of muscle, ligament and fascia	728.x	M60.x-M63.x
	Other disorders of soft tissues	729.x	M79.x

 

Table 2: Arthritis ICD-9/10 codes used in Chapter 8

Category	ICD-9 codes	ICD-10 codes
# = codes not used in Ontario The codes for psoriatic arthritis and Reiter's disease (i.e. ICD-9: 696.0 and 99.3, respectively) were excluded in provinces where 4 digit ICD-9 codes were not available.
All arthritis conditions	All the codes listed below combined together	M00-M25 M45 M46 M30-M36 M65-M79
Osteoarthritis	715.x	M15-M19
Rheumatoid arthritis	714.x	M05-M06
Other inflammatory and connective tissue diseases	99.3 274.x 446.x 696.0 710.x 711.x 712.x 713.x# 720.x	M07 M10 M11-M14 M30-M36
Other arthritis conditions	716.x 718.x 728.x 717.x# 719.x# 725.x# 726.x# 727.x 728.x 729.x	M00-M03 M20-M25 M65-M79

 

Table 3: Arthritis ICD-9/10 codes used in Chapter 9

Category	Conditions	ICD-9 codes	ICD-10 codes
Inflammatory Arthritis	Crystal arthropathies	274.x 712.x	M10.x (excluding M10.1) M11.x
	Arthropathy associated with other disorders	713.x (excluding 713.2)	M07.x M14.x
	Rheumatoid arthritis	714.x	M05.x-M06.x
	Ankylosing spondylitis	720.x 722.9	M45.x M46.x
	Other unspecified arthropathies	716.x (excluding 716.7 & 716.8) 719.2 719.3	M12.x M13.x M08.x M09.x
Osteoarthritis	Osteoarthritis	715.x	M15.x-M19.x
Systemic connective tissue	Polyarteritis nodosa and allied conditions	446.x 447.5	M30.x M31.x
	Diffuse diseases of connective tissue	710.x 725.x 279.4 728.5	M32.x-M36.x
Soft tissue disorder	Peripheral enthesopathies and allied syndromes	726.x	M70.0-M70.1 M70.3-M70.5 M70.9 M75.x-M77.x M73.8
	Other disorders of synovium, tendon and bursa	727.x (excluding 727.1)	M65.x M67.3 M68.0 M70.2 M70.6-M70.8
	Disorders of muscle, ligament and fascia	728.x (excluding 728.4 & 728.5)	M60.x-M63.x M72.x M79.x
	Other disorders of soft tissue	729.x	M66.x, M67.x (excluding M67.3), M68.8 M71.x, M73.0 M73.1
Other arthritis	Infectious arthropathies	711.x 716.8	M00.x-M03.x
	Internal derangement of knee	717.X-719.x (excluding 719.2 & 719.3)	M23.x-M25.x
		721.x 727.1 728.4	M20.x-M22.x M47.x- M48.x K07.68

 

Table 4: CCI and CPP codes for joint replacement surgery used in Chapter 9

Category	Procedures (examples)	CPP codes	CCI codes
Hip Replacement	Total joint replacement (primary and revision)	9351 9352 9353 9359	VA.53.LAPN
Knee Replacement	Total or partial joint replacement (primary and revision)	9340 9341	VG.53.LAPN VG.53.LAPP
Other Joint Replacement	Joint replacement (primary and revision)	9331 9339 9348 9371 9381 9384 9385 9386 9387	TA TM UB UC UG UK VP WA W WM, 53

 

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¹ Statistics Canada. Canadian Community Health Survey (CCHS). 2007 Microdata File User Guide . Ottawa, Ontario: Health Statistics Division, Statistics Canada, June 2008. www.statcan.gc.ca/imdb-bmdi/document/3226_D7_T9_V4-eng.pdf

² St-Pierre M, Béland Y. Imputation of Proxy Respondents in the Canadian Community Health Survey. In: 2002 Proceedings of the Survey Methods Section , Statistical Society of Canada. Ottawa, ON: Statistical Society of Canada, 2002.

³ Yeo D, Mantel H, Liu T-P. Bootstrap Variance Estimation for the National Population Health Survey. American Statistics Association Conference . Ottawa, Ontario: Statistics Canada, 1999.

⁴ Wilkins K, Wysocki M, Morin C, Wood P. Multiple causes of death. Health Reports 1997;9(2)19-29.

⁵ Assembly of First Nations. The First Nations Regional Longitudinal Health Survey (RHS) 2002/ 03. Adult Questionnaire . Ottawa, ON: Assembly of First Nations, 2002. URL: www.rhs-ers.ca/english/pdf/rhs2002-03_files/questionnaires/rhs2002-03_adult_questionnaire.pdf

⁶ Assembly of First Nations. First Nations Regional Longitudinal Health Survey (RHS) 2002/03. Report on Process and Methods , Ottawa, ON: Assembly of First Nations, June 2006. URL: rhs-ers.ca/english/pdf/rhs2002-03reports/rhs2002-03-report_on_process_and_methods.pdf

 

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