|Pneumococcal disease||J13, A40.3, G00.1|
|Bone and cartilage||C40–C41|
|Acute lymphocytic leukaemia||C91.0|
|Complications of pregnancy||O01–O99|
|Complications of the perinatal period||P02–P94|
|Congenital heart disease (subset)||Q21|
|Valvular heart disease||I01, I05–I09, I33–I37|
|Peptic ulcer disease||K25–K26|
|Road traffic accidents||V01–V79, V87, V89, V99|
|Adverse health care events (subset)||T80–T88|
# fractured neck of femur
|Angina and chest pain||I20, R07.2–R07.4|
|Cellulitis||H00.0, H01.0, J34.0, L01–L04, L08, L98.0|
|Congestive heart failure||I50, J81|
|Dental conditions||K02, K04, K05|
|Dermatitis & eczema||L20–L30|
|Epilepsy||G40–G41, O15, R56.0, R56.8|
|GORD (Gastro-oesphageal reflux disease)||K21|
|Hypertensive disease||I10–I15, I67.4|
|Kidney/urinary infection||N10, N12, N13.6, N30.9, N39.0|
|Myocardial infarction||I21–I23, I24.1|
|Nutrition deficiency and anaemia||D50–D53, E40–E46, E50–E64, M83.3*|
|Other ischaemic heart disease||I240, I24.8,I24.9, I25|
|Respiratory infections – Pneumonia||J13–J16, J18|
|Rheumatic fever/heart disease||I00–I02, I05–I09|
|Sexually transmitted infections||A50–A59,A60, A63, A64, I980, M02.3, M03.1, M73.0, M73.1, N29.0, N34.1|
|Upper respiratory tract and ENT infections||J00–J04, J06, H65–H67|
|Vaccine-preventable disease – Meningitis, Whooping cough, Hepatitis B, Pneumococcal disease, Other||A33–A37, A40.3, A80, B16, B18|
|Vaccine-preventable disease – MMR||B05, B06,B26, M01.4, P35.0**|
*Adult only (15+ years)
|Total cardiovascular disease||I00–I99|
|Ischaemic heart disease||I20–I25|
|Other forms of heart disease||I30–I52|
|Rheumatic heart disease||I05–I09|
|Chronic obstructive pulmonary disease (COPD)||J40–J44|
|All revascularisation (CABG and angioplasty) heart disease procedures||3530400, 3850500, 9022100, 3530500, 3531000, 3531002, 3849700, 3849701, 3849702, 3849703, 3850000, 3850300, 3849704|
|Diabetes complications with renal failure||E102, E112, E122, E132, E142|
|Lower limb amputation with concurrent diabetes||E10–E14 together with
4433800, 4435800, 9055700, 4436100, 4436400, 4436401, 4436101, 4437000, 5023600, 4437300, 5023300, 4436700, 5023602, 4436701, 4436702
|Breast cancer (female only)||C50|
|Unintentional injuries (Accidents)||V01–X59|
|Motor vehicle traffic||V20–V59|
|All other transport||V60–V99|
|Drownings and submersions||W65–W74|
|Fires/hot objects or substances||X00–X19|
|Suicide and self-harm||X60–X84|
|Assault and homicide||X85–Y09|
2001 Census total Māori population
|Age group (Years)||Number||Weighting|
Ethnicity: Adjusters for the analysis of hospitalisation data
This appendix describes the method used to create the adjusters used in the analysis of hospital discharge data*. These ethnicity adjusters were created and used to calculate hospitalisation rates in Tatau Kahukura: Māori Health Chart Book 2010, 2nd edition (Ministry of Health 2010d).
High-quality ethnicity data are essential for monitoring health trends by ethnicity. Such data are also needed to provide Māori with high-quality information about Māori health and disparities for planning, for the development and evaluation of policies, and for interventions (Cormack and Harris 2009). However, official health data sets have still been shown to undercount Māori in cancer registrations and hospital admissions, and there is a need to improve ethnicity data in health information systems. The Ministry of Health has ethnicity data protocols for the health and disability sector that outline the procedures that are to be used for the standardised collection, recording and output of ethnicity data for the sector (see Ministry of Health 2004).
According to previous research findings from the New Zealand Census − Mortality Study (NZCMS), the ethnicity records in the death registrations for the years 2001–2004 showed no net undercount of Māori deaths (Fawcett 2008). However, cancer registration data sets in the years 1981–2004 have been shown to undercount Māori cancer registrations (Harris et al 2007; Shaw et al 2009).
In 2009 the methodology used to assign ethnicity to cancer registrations changed. Ethnicity is assigned to cancer registrations by looking at the ethnicity recorded on each of the corresponding death registrations, hospitalisation records and National Health Indexes (NHIs). A cancer registration is automatically assigned the ethnicity(s) on death registrations and NHIs (unless the ethnicity is not stated, or is identified as ‘Other’). In addition, if a particular ethnicity is recorded on at least 20 percent of hospitalisation records, the ethnicity is assigned to the cancer registration.
This means that when there are different ethnic groups on the different source data sets, multiple ethnicities are recorded on the cancer register. This chart book does not adjust for an undercount, so cancer registration rates for Māori could still be underestimated. Further information about the current methodology used to assign ethnicity to cancer registrations can be obtained from the Ministry of Health by emailing [email protected].
The ‘ever Māori’ method of ethnicity classification was used in the previous edition of Tatau Kahukura to adjust for the undercount in death records, cancer registration and hospitalisation data**. However, concerns with potential over-counting using this method for more recent time periods has prompted the recommendation that new ethnicity adjusters be developed to address the continued undercount of Māori in hospital discharge data (Harris et al 2007).
Death registration ethnicity was assumed to be a reliable count of Māori ethnicity data. Using encrypted NHIs, public hospital event records were linked to death registrations among those people who had both been admitted to hospital and died in the period 2003–2006. Death records were only available up to 2006, whereas hospitalisation data were available up to 2008. The time period 2003–2006 was chosen because it was the closest period to the period of interest for hospitalisations (2006–2008), and it was wide enough to provide enough data to calculate reliable adjusters. The number of Māori hospitalisations using hospital event ethnicity was compared to the number of Māori hospitalisations using death registration ethnicity. Anyone recorded as Māori (either alone or in combination with another ethnic group or groups) was classified as Māori. Everyone else was classified as non-Māori.
Ratios of Māori hospitalisations (death ethnicity/hospital event ethnicity) by age are presented in Table A3.1 below. A ratio greater than 1 indicates more Māori hospitalisations using death ethnicity for that age group compared with Māori hospitalisations using hospital event ethnicity and therefore suggests an undercount of Māori in the hospitalisation data.
Undercounting of Māori tends to be higher in younger and older age groups. However, the data in younger age groups may be less reliable due to the smaller numbers of deaths, and therefore fewer linkages.
Age-specific smoothed hospital adjusters were created using local regression with the LOESS procedure in SAS (version 9.1, SAS Institute Inc, Cary NC). Smoothing the ratios accounts for the effect of low numbers in younger age groups and the potential unreliability. The smoothed ratios (adjusters) are all above 1 and increase with age.
|Age group (Years)||Māori recorded at 2003–2006 death registration||Māori recorded at 2003–2006 public filtered hospital admission||Ratio (death/hospital)||Smoothed ratio^||Linked hospital and mortality data 2000–2004 (from Hauora IV)^^|
^The ratios were smoothed using local regression with LOESS procedure in SAS.
^^Robson and Harris 2007
Table A3.1 shows the public hospital adjusters developed for Hauora IV for comparison. The pattern and magnitude of the ratios for this edition of Tatau Kahukura are generally similar to those found in Hauora IV.
The standard error for the smoothed adjusters was also calculated. This standard error was incorporated into the 95 percent CIs for the hospitalisation rates and ratios.
For the purposes of this chart book, these hospital adjusters are likely to improve the counts for Māori hospitalisations, assuming that death registration data records ethnicity data accurately for Māori.
*This linkage method was developed in Hauora: Māori Standards of Health IV (Robson and Harris 2007), and we would like to acknowledge the authors’ contribution to this report.
**For information on the ‘ever Māori’ method, please see Appendix 3 in the first edition of Tatau Kahukura: Māori Health Chart Book (Ministry of Health 2006).