Other targets will be set as data become available and the NBCSP is established.

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1 Target revision No revision of the target is required at this stage. Trends will need to be monitored with the change in ethnicity coding as there may be a need to set separate targets for Mäori. Other targets will be set as data become available and the NBCSP is established. Diabetes Key points Diabetes was the primary cause of death in an average of 530 deaths per year from 1994 to The mortality rate was slightly higher for males than females. In 1996 Mäori rates exceeded non-mäori rates by four-and-a-half times. Between 2 and 5 percent of New Zealanders are estimated to have diabetes. In 1997 there were 3289 hospitalisations where diabetes was the primary diagnosis, and where diabetes was an other diagnosis. The Mäori hospitalisation rate for any diagnosis is more than three times that of non-mäori (1884 and 576 per respectively). Genetic factors affect diabetes risk. Modifiable risk factors for adverse outcomes include poor glucose, blood pressure and blood fat control, delayed treatment, smoking, and poor foot care. Appropriate nutrition and weight control assist in the control of these risk factors. Strategies to prevent adverse outcomes in those with diabetes depend upon the delivery of quality, timely and appropriate diabetes care, including patient education and the promotion of patient empowerment, physical activity, appropriate nutrition and a smokefree lifestyle. TARGETS To reduce the age-standardised diabetes mortality rate among the total New Zealand population to eight per or less by the year To reduce the age-standardised diabetes mortality rate among Mäori to 38 per or less by the year Target derivation The current targets were set as interim targets in 1997 (Ministry of Health 1997o), and represent a 10 percent reduction (25 percent for Mäori) in the average mortality rate from diabetes by the target period of , relative to the baseline period of Mäori mortality targets have been scaled up from the original target of 30 per due to changes in ethnicity coding (see Use of Ethnicity Data section). It was assumed that without significant improvements in control strategies the mortality rates from diabetes would increase over the next five years. This target is the only one able to be set at present due to inadequate data to monitor other diabetes indicators (see Target revision section below). 212 Progress on Health Outcome Targets 1998

2 Indicator Age-standardised mortality rate for diabetes (ICD-9-CM code 250). Data source Mortality data held on the NZHIS National Minimum Dataset. The most recent data available are provisional for Related targets Food and nutrition Physical activity Tobacco Ischaemic heart disease Health impact Diabetes mellitus is characterised by raised blood glucose (hyperglycaemia). There are two main types of diabetes: Type 1 diabetes, caused by destruction of insulin-producing cells, leading to insulin deficit; and Type 2 diabetes, caused by a combination of resistance to insulin and a relative insulin deficit (Ministry of Health 1997a). Mortality Using New Zealand mortality data for , diabetes was the primary cause of death in an average of 530 cases per year (an age-standardised rate of 9.8 per population). The mortality rate was slightly higher in males than females (11.2 versus 8.8 per ). Mäori rates were four-and-a-half times higher than for non-mäori in 1996 (49.3 and 10.5 per respectively). A recently submitted paper in New Zealand indicated that Mäori have some of the highest death rates for diabetes in the world; the major causes of death were renal disease, heart disease and infections (personal communication, D Simmons). Morbidity It has been estimated that the prevalence of diabetes in New Zealand is in the range of 2 to 4 percent for Europeans, 5 to 10 percent for Mäori and 4 to 8 percent for Pacific peoples (Ministry of Health 1996j). In 1997 there were 3289 hospitalisations where diabetes was the primary diagnosis. When diabetes was indicated as any other diagnosis, the number of hospitalisations rose to Mäori hospitalisation rates for diabetes as any diagnosis exceeded non-mäori by 3.3 times (1884 and 576 per respectively). Hospitalisation data based on primary diagnosis have been found to underestimate the true incidence of hospitalisations of those with diabetes by 25 to 75 percent (Simmons 1996). Including all diagnosis may also not provide a true estimate as diabetes will not always be diagnosed, and when it is it may not have been directly related to the admission. It is estimated that diabetes accounts for approximately 5 percent of surgical and 15 percent of medical inpatient admissions (Simmons 1996). GOAL: Health of Adults/Pakeke/Mätua 213

3 The overall cost of diabetes to the New Zealand public health sector is difficult to gauge. Recent work by the Ministry of Health estimates that the total direct cost for diabetes-related public hospital care in New Zealand in was around $95 million (Ministry of Health 1997a). This does not take into account any indirect cost to society in terms of lost productivity. A recent study on health care costs of obesity estimated that the cost of noninsulin-dependent diabetes (NIDDM) in New Zealand could be as high as $200 $300 million (Swinburn, Gillespie et al 1997). These data are also an underestimate as they exclude many other diabetes-related direct costs, like increased length of stay and readmission for other related conditions. Risk factors Genetic factors: NIDDM has a significant genetic component, and some population groups have a heightened susceptibility in the context of rapid lifestyle changes (Anonymous 1992). This may be true in New Zealand for Pacific peoples. In New Zealand, there has been work showing the importance of genetics on the risk of NIDDM in all ethnic groups (Simmons et al 1995). Genetic susceptibility to insulin-dependent diabetes mellitus (IDDM) is well known (Brown 1993). Obesity and diet: There is evidence for an association between obesity and NIDDM (Colditz et al 1990). In New Zealand, the increased prevalence of diabetes among Mäori and Pacific peoples (but not Asians) was considered in one study to be partly attributable to increased obesity, compared with Europeans (Scragg et al 1991). Nevertheless, the role of obesity as a risk factor for NIDDM is a complex one and it may involve interactions with various genetic risk factors (Morris et al 1989). A number of studies suggest that the adoption of a Western -style diet is associated with increased prevalence of diabetes (WHO Study Group on Diabetes Mellitus 1985). In particular, it has been suggested that dietary fat and dietary protein may be specific risk factors (Tsunehara et al 1990; Marshall et al 1991). Physical inactivity: There is reasonably good evidence that lack of physical exercise results in an increased risk of developing NIDDM (Helmrich et al 1991; Manson, Eric et al 1991). The effect remains, although less strongly, when obesity is accounted for. Diabetes complications: Diabetes complications include blindness, kidney failure, nerve damage (leading to impotence and foot problems), circulatory problems, heart disease and early death. Diabetes complications are largely preventable through regular screening and good diabetes care (Ministry of Health 1997a). Progress toward the target Mortality from diabetes has fluctuated over the years but has been steadily increasing over the past five years (8.1 per in 1991, 10.3 per in 1996). No trend is shown for Mäori rates due to changes in ethnicity coding. Figure 76 shows data for 1996 but no interpretation can be given until more data are available. The at-risk population for diabetes is growing and therefore absolute numbers of the population with diabetes will also be increasing. 214 Progress on Health Outcome Targets 1998

4 Figure 75: Diabetes (primary cause) mortality rate, Age-standardised rate per Target Year Source of data: New Zealand Health Information Service Figure 76: Diabetes (primary cause) mortality rate, for total and Mäori population, Age-standardised rate per Mäori Target Total Target Total Mäori Source of data: New Zealand Health Information Service GOAL: Health of Adults/Pakeke/Mätua 215

5 Assessment Data quality Mortality data presented here may underestimate the true impact of diabetes mortality. For example, an Australian study found that diabetes was not mentioned on one-third of death certificates of persons known to have diabetes (Whittall et al 1990). Work in the US attempting to identify the true impact of diabetes on mortality estimated that 6.8 percent of all deaths in the US are due to diabetes (Huse et al 1989). In New Zealand just 1.8 percent of deaths in 1996 had a principal diagnosis of diabetes. Recent work in New Zealand reports that diabetes was recorded on death certificates in just 60 percent of cases (Personal communication, D Simmons). Limitations of indicator Targets based only on mortality data do not capture the important non-fatal health outcomes associated with diabetes (eg, disability from heart disease, blindness, renal failure and limb amputations). See Target revision section. Interpretation of trend Mortality rates over the past five years have been rising away from the target, but given the possibility that improvements in mortality coding may have occurred, it is difficult to interpret the trend. No interpretation of the Mäori trends are possible until more data are available (see Use of Ethnicity Data section). Strategies Preventing diabetes Prevention and control strategies Promotion of physical activity Promotion of healthy nutrition In 1997 the Ministry of Health published Strategies for the Prevention and Control of Diabetes in New Zealand (Ministry of Health 1997o), based on an earlier discussion document. See the section on Physical Activity. Preventing adverse outcomes in those with diabetes Diabetes management provided by primary and secondary health care services Promotion of physical activity See the section on Food and Nutrition. A recent review article describes the current community-based approaches for primary prevention of NIDDM, and identifies control of obesity through a population approach as the most likely to succeed (Simmons et al 1997). Management of diabetes is part of standard primary and secondary health care in New Zealand. However, the extent to which current care might be suboptimal, due to barriers to access or inadequate service delivery, is unclear. The National Health Committee has released three guidelines which can be found at Key components of diabetes management include tight control of blood glucose, serum lipids and blood pressure. Screening for and early treatment of diabetes-related damage should also be part of standard diabetes management. This is provided (largely to an unknown extent) as part of personalised advice from health care workers. Green Prescriptions have recently been promoted to encourage physical activity in patients. continued/ Progress on Health Outcome Targets 1998

6 Promotion of smokefree lifestyles Promotion of healthy diets to prevent or reduce obesity Promotion of patient education and empowerment Smoking cessation is provided as part of personalised advice from health care workers. Dietitians and diabetes nurse specialists (among other health care workers) provide personalised advice for those with diabetes. The National Health Committee has developed a simple explanation of the care that people with diabetes should expect in This can be viewed at ( The National Diabetes Forum members are also active in supporting education for those with diabetes. Target revision The mortality target is the only target able to be monitored at the present time. The need to monitor other targets is recognised but not possible due to a lack of relevant information systems. The New Zealand Declaration on Diabetes Mellitus identified the following fiveyear targets based on the St Vincent Declaration (Diabetes Care and Research in Europe 1990): to reduce new blindness due to diabetes by one-third or more to reduce numbers of people entering end-stage diabetic renal failure by at least one-third to reduce by one-half the rate of limb amputations for diabetic gangrene to cut morbidity and mortality from coronary heart disease in people with diabetes by vigorous programmes or risk factor reduction to achieve pregnancy outcome in women with diabetes that approximates that of nondiabetic women. GOAL: Health of Adults/Pakeke/Mätua 217