DIABETES SCREENING AS AN ADJUNCT TO THE HEPATITIS B SCREENING PROGRAMME

Transcription

1 I-Jealth Funding Authority DIABETES SCREENING AS AN ADJUNCT TO THE HEPATITIS B SCREENING PROGRAMME STACK; WK 810 [QI DUM 1999 Dr Felicity Dumble Public Health Medicine Registrar Public Health Operating Group Health Funding Authority Oct 1999 ISBN: MOH Library Information Centie Ministry of Health Wellington M

2 ACKNOWLEDGEMENTS The Author of this report would like to thank those who contributed their time, knowledge and experience to this work. Richard Hoskins Sandy Dawson Martin Entwhistle Chris Bullen Peter Moore Prof. Bob Elliot Health Funding Authority Health Funding Authority Health Funding Authority Auckland/Northland Hepatitis B Consortium New Zealand Society for Study of Diabetes Diatranz 2

3 CONTENTS Executive Summary Introduction The Hepatitis B Screening Programme The Proposed Diabetes Screening Programme Background The Government's Medium Term Strategy Ministry of Health Strategies HFA Decision Making Principles Choosing a Screening Method Choosing a Screening Tool The Impact of Diabetes on New Zealand's Population The Social Cost of Diabetes... g 3.2 The Economic Cost of Diabetes The Cost of Screening Direct Costs Downstream Effects Discussion The HFA Decision Making Principles Effectiveness Cost Equity Maori Health Acceptability The Screening Principles Other Options Screening in General Practice Why Screen? Conclusion Recommendations...21 References

4 EXECUTIVE SUMMARY Type 2 diabetes is a disease which has a significant impact on the health of a growing number of New Zealanders. The Hep B screening programme is already identifying, contacting and screening a population which is also at risk of developing diabetes. It was proposed by the Hepatitis Foundation that the blood sample taken could be tested for indicators of glucose intolerance. This proposal is currently being piloted in the East Cape. An accurate prediction as to the total costs incurred and avoided by this proposed diabetes screening programme is not possible. Estimations as to the current prevalence of type 2 diabetes (diagnosed and undiagnosed) vary substantially. The number of 'new cases' found will also vary according to the diagnostic parameters used in the screening test, and the type of test used. Down stream costs would be substantial. Providing the screening as an adjunct to another programme has some attraction due to 'shared costs and convenience'. There are fundamental differences, however, between the conditions. The Hep B screening programme is a 'one-off initiative to identify and manage carriers of an infectious disease. Diabetes screening is generally considered to be an on-going initiative to prevent the progression towards, or limit the impact of, diabetes. It is recommended that diabetes screening be targeted towards those at highest risk. The MoH advises the same management of all at risk regardless of test result. However, those who test positive could receive additional benefits through closer monitoring and possibly increased motivation to comply with treatment and modify lifestyle. This would be dependent on effective referral, monitoring and freatment strategies. The proposed screening appears to lack defined linkages with ongoing treatment providers. RECOMMENDATIONS 1). Screening those 'at-risk' is supported. Evidence does not indicate that an adjunct to the Hep B screening initiative would be the most effective use of resources targeting diabetes. 2). The adjunct screening could be more effective provided: targeting those who receive the diabetes screening was more explicit clear and appropriate referral processes were outlined and followed downstream diabetes disease management services were appropriately managing all diabetics already known and managed diabetics were identified and excluded from screening there was wider consultation and agreement in the field regarding methods and process the initiative was developed with a view to maintenance as an ongoing programme funds were adequate to support the screening and enhanced downstream services. 3). Review and facilitation of current initiatives through primary health may increase motivation, improve continuity and maximise effectiveness as an alternative to, or in conjunction with, the adjunct screening. 4). Resource directed into disease management in conjunction with opportunistic screening of those at risk could lead to: Active and effective monitoring of those with diabetes in a provider setting Improved communication between providers working in complimentary fields of expertise and collaboration in health education activities, sharing of knowledge and resources, avoidance of unproductive duplication, and the increased likelihood of positive outcomes. An approach targeting BP, cholesterol and signs of complications such as retinopathy. Targeting the factors associated with the development of complications would be 'outcome' focused but still be preventive. Development of registers can also contribute to improving the information available regarding the impact of diabetes in the community. This would be expensive and require evaluation in its own right. 5). As the pilot programme as an adjunct to the Hep B programme is undertaken, it should be evaluated independently. This will provide helpful information when considering future proposals and additional information regarding prevalence. 4

5 1. INTRODUCTION Type 2 diabetes (Non insulin dependent diabetes NIDDM) is a disease which has a significant impact on the health of a growing number of New Zealanders. It becomes more prevalent with increasing age. The population considered to be at risk of contracting Hepatitis B is also a population with a high prevalence and incidence of diabetes. It has been suggested that it may be appropriate to screen this population for diabetes at the time they are screened for Hepatitis B. 1.1 The Hepatitis B Screening Programme This programme was initiated as a result of a Cabinet decision whereby the HFA were required to implement a National Hepatitis B screening and surveillance programme. Maori, Pacific Island and Asian populations within the North Island were identified as the target populations for the programme. It is to be provided by the Hepatitis Foundation and the Auckland Hepatitis Consortium, with independent evaluation. 1.2 The Proposed Adjunct Diabetes Screening Programme The Hep B screening programme is already identifying, contacting and screening a population which is also has a comparatively high degree of risk for developing diabetes. The screening process involves the taking of a blood sample and an element of health education. It was proposed that the blood could be tested for indicators of impaired glucose tolerance (IGT). This would seem to be an opportunity to achieve health gain by taking advantage of another screening programme. Advantages of this "piggy back" type screening could be: Reduced administration costs Reduced service provider costs e.g. staff, overheads The target population is already identified The target population is already attending a health service provider for a screening test resulting in... An opportunity for a diabetes screening test as a blood sample is already being taken An opportunity for diabetes education Advice about a healthy lifestyle to reduce the risk of developing diabetes may also reduce the risk of the development of other health problems Multiplicity of screening and education targets is consistent with the multifactorial nature of health status and integrated nature of health The New Zealand First Party leader Winston Peters strongly supported this screening initiative saying to the media on 25th May 1999 that it would have been included if NZ First had got its way while in coalition government with the National Party. Diabetes New Zealand figures were quoted as showing that $1 in every $12 spent on publicly funded health care went toward diabetes treatment. One in ten hospital admissions were said to be diabetes related. 5

6 Sandor Mime of the Hepatitis Foundation, delivery part of the national Hep B programme, has initiated a 'pilot' in the East Cape adding HBAIc screening to the test regimen for Hep B. This is being undertaken in collaboration with Diatranz. Funding has been obtained through charitable trusts. Individuals found to have high glycated haemoglobin, at a level that puts them at risk, are re-tested and examined by a screening team and referred to their GP or Public Health Nurse. A registration process is being undertaken through the initiative and reassessment is planned at 12 months. As at 22/9/99, initial findings indicate that the prevalence of Type 2 diabetes has been significantly underestimated. As a result, predicted costs and extent of downstream services are inadequate. There is no distinction between those already known to be diabetics and new cases. It has been suggested that the addition of diabetes screening has enhanced participation in the Hep B screening programme. Currently this adjunct diabetes screening has not been given HFA or Ministry endorsement or funding. 2. BACKGROUND Population screening is a health initiative aimed to prevent the development and/or reduce the impact of disease conditions. There is potential for significant impact on health status of the population with respect to reducing morbidity and mortality. The decision to undertake such an initiative will involve multiple stakeholders. These include the Health Ministry (M0H), the Minister of Health and other politicians, the Health Funding Authority (HFA), providers, clinicians, health groups and the public. 2.1 The Government's Medium Term Strategy The Government's Medium Term Strategy identifies the Government's aim to give equity of health status to all New Zealanders, and to maximise the benefits of early intervention and health promotion. The health goals include decreasing long-standing disparities in health status (in particular those experienced by Maori and Pacific Island peoples), and placing a greater emphasis on population health approaches. These approaches include screening, but also healthier lifestyles and better diets. Diabetes is specifically identified as a health issue requiring special attention. The strategy also determines that the public organisations in the health sector should be focussed on getting the most benefit for the public from the available resources from Vote: Health. 2.2 Ministry of Health Strategies The Ministry of Health (M0H) has produced a Background Paper and Strategies regarding the prevention and control of Diabetes in New Zealand (1997). These documents provide statistical data regarding diabetes and identify the Ministry's approach to this health issue.

7 M0H Identified key strategies: Opportunistic screening based on risk factor profile Intra/intersectoral collaboration to promote and increase physical activity and healthy nutrition, and reduce obesity Prevention strategies encompassing a holistic approach The MoH does indicate support for screening those at high risk of developing diabetes. The Ministry also supports health promotion activities aiming to decrease the risk factors associated with the development of Type II Diabetes. They did not advocate general population based screening. 2.3 HFA Decision making principles Prior to establishing an opportunistic screening programme, several issues need to be considered to ensure the HFA principles of evidence based decision making are followed. These principles are: Effectiveness Cost Equity Maori Health Acceptability The HFA is instructed by Government to fund health services with the goal of achieving maximum health gain and independence for New Zealanders. As resources are limited, the decision making process regarding which services to fund, and to what level, needs to be transparent, consistent and based on evidence. 2.4 Choosing a Screening Method The New Zealand Society for the Study of Diabetes (1995) refer to the criteria that can be used to determine whether a programme screening asymptomatic individuals should be introduced. 1. The condition screened for should be a significant problem within the community. 2. The natural history of the disorder is known, and there is a recognisable presymptomatic or latent stage 3. Effective and acceptable treatments are available once a disorder is diagnosed. 4. The screening tests need to be safe, simple and reliable with no important side effects. 5. The screening programme needs to reach those who need it most. 6. The screening programme needs to be adequately resourced and managed. 7. Downstream services are in place to deal with those screened. 8. Screening should do more good than harm. VA

8 Further, effectiveness of the screening programme would require that there would be an effective response to cases identified through the programme and that health gain could be achieved. The M0H define their criteria for a screening programme: Benefit to individuals detected early is clear cut and significant Harm from false positives and negatives is significantly less than the benefit Costs (direct and indirect) are lower than benefits 2.5 Choosing a Screening Tool Any diabetes screening test used would need to be effective, and the sensitivity and specificity of the test would need to be identified and acceptable. Screening can result in 'false positives' where an individual is incorrectly identified as being at risk of developing or having a disease. This can result in negative consequences for that person such as adverse psychological factors, stigmatisation and the risk and discomfort of additional tests. 'False negatives' can result in inappropriate reassurance and those at risk failing to receive treatment. The test and the screening process would also need to be cost effective. 3. THE IMPACT OF DIABETES ON NEW ZEALAND'S POPULATION Diabetes data can be obtained from national and community surveys, diabetes registers and national hospitalisation and mortality lata. However, the information on the prevalence and incidence of diabetes i New Zealand is not precise or complete. Wilson et al (1999) reported that currently these data sources were inadequate to provide this information an recommended further development of diabetes registers to address this. - hey suggested that these registers should be developed at both general prac Use and district levels, properly configured and used consistently. The costs associated with the care of people with diabetes are difficult to quantify. The disease manifests itself in damage to multiple organ systems. The resultant care may be undertaken through multiple providers and therefore the aetiology of the problem may be unclear or unknown. The direct and indirect costs of the disease would be expected to be substantial due to the morbidity, as well as premature mortality, resulting from the illness. Incapacity resulting from diabetic complications will, impact on individuals, but also families and communities. 8

9 3.1 The Social Cost of Diabetes In this report, the social cost refers to the impact of a disease on the community in terms of illness and disability. Available information on the current impact of diabetes on New Zealanders: Prevalence 2-5 % New Zealanders (M0H) or 4-10% (Dawson) The majority have type 2 diabetes and half thought to be undiagnosed (Lawrenson et al 1993) Prevalence of diabetes in adults 3.7% (1996/97 Health Survey) 30-50% people with diabetes undiagnosed (M0H) Underreported morbidity, hospitalisation and mortality (M0H) Prevalence is reported to be growing rapidly (South Auckland Diabetes Group, 1992) Expected to rise with ageing population Higher in those older, Maori (5-10%) and Pacific Islander (4-8%) and Asians 7-8%.(M0H).. Maori and Pacific people more than twice as likely to be diagnosed, and at a younger age (M0H) Diabetes a Maori Health priority (HFA) 43,341 hospital admissions in 1997 with diabetes as primary or secondary diagnosis. Diabetics account for % of hospital bed occupancy according to three published studies of New Zealand tertiary hospitals (Dawson) Rising diabetes age-standardised death rate rising by 6% per year during (Dawson) Health care and personal costs, suffering, disability and death (M0H) Burden of disease; Blindness, renal failure, amputation, CVD (M0H) Retinopathy present in 10-29% and proteinuria present in 10-37% of patients at the time of diagnosis of NIDDM (WHO 1994) There are a number of risk factors for Type II Diabetes, including a positive family history of NIDDM, obesity, age greater than 50 years, previously abnormal glucose tolerance, hypertension ethnic predisposition (Welborn et al 1997). Obesity (having a body mass index of 30 or more where BMI is weight in kg divided by height in metres squared) is a modifiable risk factor through alterations in exercise and food intake. A person with a BMI of more than 35 has a 6.61 times greater risk than a person with a BMI of under 25, of developing Type II Diabetes (Rubin, R 1999). In New Zealand, 27% of Maori males and 27.9% of Maori females are obese (BMI ^: 32) compared with 26.2% and 47.2% for Pacific people (BMI ^: 32) and 12.6% and 16.7% for NZ European and others (BMI ^ 30) respectively (1997 National Nutrition survey).

10 3.2 The Economic Cost of Diabetes Problems determining the extent of the prevalence and incidence of Type II Diabetes also hinder the assessment of the financial costs of the disease. Inpatient costs have been estimated to be $95 million per year, and prescriptions are thought to cost $29 million per year (M0H). Professor Bevan (11/6/99) reported to the media that the Government was having to spend $220 million on treating complications caused by diabetes. In 1996, the estimated cost of inpatient, outpatient and primary sector care funded within the Midland region (excluding domiciliary and community services) was approximately $57 million (McNerney 1996). At that time, Simmons (1996) reported that the estimated direct costs of diabetes for the whole of New Zealand were $ million. This was thought to be consistent with the 5-6% of the total health budget thought to be spent on these services in the UK, USA and Finland. In contrast, Dawson reports 14.6% of USA healthcare expenditure is accounted for by diabetes. Medication for diabetes treatment costs $15.5 million pa and syringes, needles and test equipment cost $10 million pa. Costs to the HFA are thought to be $ million pa (Dawson). Professor Bevan (11/6/99) reported to the media that the rate of diabetes was rising and this was mainly due to lifestyle choices such as diet, lack of exercise and obesity. He proposed that a fingerprick test for every person over 50 years of age once a year to detect the early onset of diabetes could save money. During the 10 year window between a rise in blood glucose levels and the onset of symptoms, good clinical management could prevent costly complications. Following diagnosis a proposed annual check-up could ensure symptoms did not worsen. 4. THE COSTS OF SCREENING The costs of a screening programme need to be considered in relation to the benefits or costs avoided. Costs involved include direct costs of the screening programme such as materials and staff, indirect costs associated with the initiative and 'downstream' costs that will arise as a consequence of the programme. Opportunity costs also need to included within the decision making process, where, by funding this screening programme, those funds can not be used elsewhere in the health sector to achieve health gain through other initiatives and services. This applies, not only to funds sources from the HFA, but to funds provided through other sources such as charitable organisations. 10

11 4.1 Direct Costs Direct costs of the screening programme include materials used for the test, staff to administer the test, laboratory diagnostic services and follow up to inform individuals about test results. The costs would also be influenced by the choice of test used. There are also direct costs to the individual such as transport to the testing site. Attaching the diabetes to the Hep B screening programme would minimise some of these costs and some would already be incurred such as hireage of venues, phlebotomists, needles/syringes and the individual's transport costs. The screening initiative undertaken by Lawrenson et al (1993) resulted in costs to the Area Health Board estimated to be $87,000 over 2 years with $33,000 staff costs, $39,000 promotion and $5,000 equipment and support services. Costs were not detailed and it is not specified as to whether the latter included the cost of the tests (random capillary glucose estimation using a BM stix and a Reflolux meter; and if blood sugar ^:8 mmol/l, an oral glucose tolerance test). This equated to approximately $15 per patient tested and $1,500 per newly diagnosed person with diabetes. The test which has been chosen as the screening tool for the Hep B Foundation's pilot is HBA1c. It can be measured via a simple blood test and does not require fasting. The measurement of glycated haemoglobin in the form of HBAIc can provide an objective assessment of glucose control over the previous 6-8 weeks. However, no tool is perfect. Kilpatrick et al (1998) note that a meta-analysis of 34 studies indicated that a large number of subjects with either impaired glucose tolerance or diabetes can have HBA1c values within the non-diabetic range. They suggest this number of false negatives limit the value of HBAIc as a screening tool while supporting its use as a tool to assess the glycaemic control of diabetic patients. Further study was recommended. In 1995, the New Zealand Society for the Study of diabetes recommended the random glucose test as the screening tool. The authors stated that glycated haemoglobin was of low sensitivity and specificity. They also suggested that lifestyle advise should be offered to those at risk regardless of the test result. This would minimise the effect of false negatives. The testing would identify those in need of specific treatment. Providers who presented proposals for the Hep B programme were invited to comment on diabetes screening as a part of the programme. Other tests, methods and costs proposed included: Cholestech LDX to provide lipid profile on finger prick whole blood including cholesterol, HDL and $15 per test. Options of fructosamine or HbAIC (10% further tests), blood pressure and BMI at additional cost. Require $60,000 for equipment. Glucose testing for 70% screened target group. If greater than 6.5 mmol/l (15% of screened target group) then total $50,

12 Diabetes screening of those > 30 years via random blood sugar. Expect 50% to have RBS 7 mmol/l, recall for 2hr glucose tolerance test (GTT). Number expected to have abnormal GTT needing referral and/or default tracing 25% of latter. Total $30,610 is based on $9.60 per person screened or $73.75 per case of diabetes or IGT for referral. Random glucose tests were reported to be cheap and easy to perform but low predictive values in the range 5.5 to 11 mmol/l as time since last meal or glucose ingestion is critical. Raised fasting glucose test has reasonable specificity for diabetes detection but requires overnight fast, therefore probably unworkable in community setting. Gold standard for detecting early diabetes is GTT but expensive and requires high compliance. Glycated haemoglobin (HbAlc) can be performed without fasting. Free of interference's such as renal failure, haemoglobin variants and alcohol. Predictive value of a raised result (>7%) is very high. Predictive value of a modestly raised result ( %) is less well defined, but should be regarded with suspicion, definitely in the % range and justify followup glucose testing within 12 months. When reporting on the test type options for diabetes screening in 1998, Goldstein stated that it didn't so much matter what test was used but rather "that testing be performed". 4.2 Downstream Costs and Services Screening tests identify those with a high probability of having a disease. Further tests are generally required to confirm the diagnosis. The downstream costs of a screening programme would include: Information Systems to collect data for identification and monitoring the care of people with diabetes. (MoH) Information Technology (IT) for surveillance Additional testing False positives leading to unnecessary additional testing and personal stress False negatives leading to higher costs of future care where the progress of the disease has remained unchecked for longer Medical complications may also arise from the screening test and possibly from interventions after diagnosis (WHO 1994). 12

13 A screening initiative should ideally also include health promotion components. The M0H key strategies promote: Development of resource services with a special focus for Maori and Pacific people. Recognition of community development for at risk. Funding for research re strategies for lifestyle change. Development of intra/intersectoral collaboration. 5. DISCUSSION Well intended health initiatives can prove to be ineffective and/or inefficient if they are not well considered. Screening programmes have a wide impact on the community, beyond simply the testing of those who are 'disease free'. Due to the multifactorial nature of health status an I well-being it is inappropriate to view a service or intervention in isolation A structured and transparent decision making process is required. 5.1 The HFA Decision Making Principles In an effort to achieve some degree of consistency and equity in decision making, the HFA has been instructed to follow the decision making principles as outlined above (2.3) Effectiveness The New Zealand Society for the Study of Diabetes (NZSSD) note that a proportion of diabetics present with tissue damage and that metabolic control and education can reduce the incidence of this damage. Recent evidence from the UK Prospective Diabetes Study (1998) indicates that good glycaemic control and management of blood pressure of those with type 2 diabetes can result in reduced rates of complications and risk of premature death. It is generally believed that early detection, and subsequent lifestyle change and glycaemic control, may reduce the progression of microvascular or macrovascular disease due to asymptomatic hyperglycaemia (de Courten and Zimmet 1997). While direct evidence was reported to link glycaemic control to the reduction of complications in patients with IDDM (insulin dependent diabetes mellitus), extrapolation of these findings to patients with NIDDM is unproven and thus requires confirmation and investigation. It has been reported that intensive control of blood sugar reduces microvascular complications and good control of diabetes and blood pressure in those with diabetes reduces macro-vascular complications (Dawson). As modifying risk can reduce cardiovascular events, Welborn et al (1997) believe this effect can apply for those with IGT and diabetes. Vijan et al (1997) recommend the prophylactic use of aspirin (if not contraindicated), control of hypertension and hyperlipidaemia and cessation of smoking for those with type II diabetes mellitus to prevent macrovascular 13

14 disease. They believe improved glycaemic control could prevent microvascular disease. Clinicians are encouraged to implement interventions, provide education and encourage self management. Action during the 10 year window" between the development of impaired glucose tolerance and the complications of diabetes, is widely recommended (Vijan et al 1997, Welborn et al 1997, Goyder and lrwig 1998, Meltzer et al 1998). In 1988, Singer et al reported that the evidence linking improved glucose control and the reduction of complications was weak. As a result, they did not recommend screening for diabetes in non-pregnant adults. More recently, a working party for the New Zealand Society for the Study of Diabetes (NZSSD) investigated the issues associated with the screening of asymptomatic individuals for diabetes. Interestingly they report (1995) that "there is no absolute evidence" that early diagnosis can reduce the risk of risk of tissue damage. This lack of evidence was also referred to by de Courten and Zimmet (1997) and Milborn et al (1997). The NZSSD does note that there is no absolute evidence that early diagnosis reduces the risk of diabetic tissue damage (Simmons 1995). However, as metabolic control and education can reduce the incidence of such damage, it is suggested that early detection, in combination with early management, may be effective. Potentially, the number who present with tissue damage at time of first diagnosis could be reduced. The NZSSD (1995) have developed recommendations for diabetes screening and advise that such a programme needs to be repeated regularly and be associated with well established support services. The Hep B screening programme is a 'one-off initiative with follow-up only planned for those who test positive for carriage, so would not fulfil this recommendation. In order for a programme to demonstrate its effectiveness, if initiated, the service should include an evaluation stream. An evaluation is most effective if considered in the initial planning stages. According to WHO (1994), an evaluation of a screening programme should include: Number of new cases detected Cost per case detected Actions taken if test positive Long-term benefits of early detection Cost Where health funding is finite, the opportunity cost associated with establishing this programme would need to be recognised. If this programme were to be funded, that money is prevented from being spent elsewhere. 14

15 In 1998, the CDC Diabetes cost effectiveness group in the US investigated the cost effectiveness of early detection and treatment of diabetes. They reported that opportunistic screening of all persons over 24 years of age would result in the incremental cost of $236,449 per life year gained and $56,649 per quality adjusted life year (QALY) gained. This reduced to $2,219 and $822 respectively where screening targeted African Americans aged years. Direct non-medical and indirect costs were not included. Easton and Segal (1998) recommend opportunistic screening of high risk groups by GPs rather than the general population where the costs were estimated to be $1190 and $3,252 per new case respectively. The costs included were for consultation, test and follow-up Equity Such a service would need to be equitable. The goal is to achieve equity of health outcome for New Zealanders and reduce any discrepancies in health status. The NZSSD (1995) recommend that screening of asymptomatic individuals should only take place in the primary care setting or in organised clinics. This would be to ensure that adequate ongoing care would be provided and to ensure continuity of care. The NZSSD also made recommendations regarding the parameters of screening. They suggested that Europeans aged over 40 years and non-europeans aged over 30 years should be screened. The frequency of screening would be influenced by the presence of risk factors. As mentioned previously, obesity, a modifiable risk factor for Type II Diabetes, is not distributed evenly among the population. It is associated with ethnicity and deprivation (National Nutrition Survey 1997). The impact of Diabetes is also 'inequitably distributed' among the population. As the Hep B screening targets the populations also at increased risk of developing Type II Diabetes, this proposed screening could address this inequity in health status Maori Health The Hepatitis B screening programme is targeted to the Maori, Pacific Islander and Asian populations at higher risk of both Hepatitis B. The two former populations are also at higher risk of developing diabetes. The providers of the Hepatitis screening programme aim to produce a service which is acceptable to these populations. If behavioural change were to be promoted in conjunction with the diabetes screening, cultural factors influencing diet and behaviour would need to be considered. Consultation and partnership with Maori in accordance with the Treaty of Waitangi would be required. Vijan et al (1997) refer to the higher rates of diabetes related morbidity and mortality among minorities in the United States. They report that the disparities may be due to differences in disease severity, comorbidities or access to care. 15

16 In a discussion document (1996), the Public Health Group for the MoH identified some barriers to care faced by Maori and Pacific Island diabetics. These include problems with access to, and infrastructure of, diabetes services Acceptability Negative outcomes of screening for diabetes in asymptomatic individuals have been reported by de Courten and Zimmet (1997). These include factors associated with false positives and even true positives. Asymptomatic people may suffer adverse consequences due to "labelling effects". These effects may be social and emotional as well as economic (such as influences on obtaining health insurance). The screening programme does involve a blood test which may be unacceptable for some members of the target population. This type of intervention is also based on the traditional medical model. Acceptability may be influenced by the staff administering the test and the setting in which it takes place. As this proposed screening is an adjunct to another programme 'the strategies to deal with these issues should already be determined. Evaluation of the programme should include indicators of client satisfaction and acceptability. 5.2 The Screening Principles With reference to the principles outlined (2.4) 1). The condition screened for should be a significant problem within the community. Data available on the prevalence of Type II Diabetes in New Zealand indicates that this disease does make a significant impact on our communities. 2). The natural history of the disorder is known, and there is a recognisable presymptomatic or latent stage Information is available describing the progress of this disease and its aetiology. Some aspects are controversial with respect to definitions. Hazards associated with the definition of what is diabetes in terms of the threshold for diagnosis reflect the fact that glucose levels detected are on a continuum (de Courten and Zimmet,1997, Mannucci et al 1998). Roubicek et al felt a cut-off or threshold was appropriate and widely used to identify those at risk including inthe measurement of cholesterol and blood pressure. The level at which the 'cut-off is set will influence prevalence levels and downstream services. 16

17 3). Effective and acceptable treatments are available once a disorder is diagnosed. Interventions and treatments to reduce risk and improve glycaemic control are available. The effectiveness of advice to influence lifestyle change has not been universally acknowledged as being proven. A move from a medical model approach to a community based integrated approach has been recommended to be effective for the target population. As discussed in the effectiveness of early intervention to alter outcomes is under debate. 4). The screening tests need to be safe, simple and reliable with no important side effects. Some degree of controversy is also associated with the appropriate screening tool for determining most effectively those at risk of developing Type II Diabetes. The choice of screening test has been discussed in the literature. The appropriateness of the use of HBAIc as the screening tool was questioned by the NZSSD (1995), de Courten and Zimmet (1997) Mannucci et al (1998) and Kilpatrick et al (1998). Many recommend the use of the oral glucose tolerance test (OGTT) in a clinical setting for high risk groups. 5). The screening programme needs to reach those who need it most The population targeted by the Hep B programme includes those at risk of developing Type II Diabetes. However, it also includes those of ethnic groups and age groups not considered to be at high risk. 6). The screening programme needs to be adequately resourced and managed. An under-estimation of the costs associated with the Hepatitis Foundation Pilot, in particular down stream costs, has led to inadequacies of funding. This could impact negatively on the success of the programme. Any extension or expansion of the pilot must be adequately funded. 7). Downstream services are in place to deal with those screened. Expansion of down stream services to respond to those who test positive has not been clarified by those proposing the adjunct programme. 8). Screening should do more good than harm. Type II Diabetes is a significant health issue in New Zealand. Costs and suffering could be reduced with effective initiatives to decrease risk and improve treatment. From the information available it is not clear that a screening programme as an adjunct to another is sufficiently "purpose built" to maximise health gain for those in need. 53 Other Options Mass screening of the general population is currently not supported internationally (WHO 1994) or locally (Lawrenson et al 1993, M0H 1997). In IVA

18 1993, Lawrenson et al offered free diabetes screening to three rural communities. Although 5000 attended the screening initiative, only 34% of those in the communities in the at risk age group were tested. Therefore, it was reported that voluntary screening was ineffective, despite a major investment in promotion. They found 56 (1.2%) newly diagnosed cases of diabetes. It was concluded that this indiscriminate screening was "not effective as a population screening tool". The authors suggested that screening should be undertaken by GPs targeting all adults greater than 50 years of age and all adult Maori with obesity (BMI ^ 30). Generally, diabetes screening is recommended for those 'at risk' of diabetes (Lawrenson et al 1993, WHO 1994, WHO 1995, Goyder and Irwig 1998). These authors also state that early treatment for macrovascular risk factors may be more important than early treatment for diabetes itself. Selective screening was recommended by WHO in 1994 for those considered to be at risk. They identified those at risk as those from certain ethnic groups, those with a positive family history, obese (BMI 2: 27), age greater than 50 years for those of European origin, or greater than in high risk groups, and those with risk factors such as hypertension and macrovascular disease. Butler et al (1998) and Meltzer et al (1998) recommend screening asymptomatic persons over 45 years of age three yearly. However, they stress the importance of primary prevention and lifestyle change. Meltzer et al also identify the need for appropriate surveillance programmes for complications and management options. Beaven (1999), recommends mandatory annual blood sugar screening for those at high risk. Once diagnosed with IGT (impaired glucose tolerance), annual blood sugar testing would continue for monitoring purposes. This proposal is for targeted screening on an annual basis. This is not consistent with the population or the logistics of the Hep B screening programme. Opportunistic screening based on these risk factors has been undertaken in primary care settings Screening in General Practice "The New Zealand Society for the study of Diabetes (1995), the British Diabetic Association (Patterson 1993) and American Diabetes Association (1996) advocate regular opportunistic screening in general practice for those with one or more risk factors" (M0H 1997). However, information regarding the implementation or effectiveness of such a proposal is not consistent or complete. An additional screening programme could potentially lead to duplication. Those reporting on the prevalence of Type II Diabetes in the community indicate there are substantial numbers of those who are affected, going undiagnosed. This would suggest that the opportunistic screening in general practice as undertaken presently is insufficient to identify all those with glucose intolerance and diabetes. 18

19 This additional screening also would result in an increased workload for GPs through patient management and follow-up. 5.4 Why Screen? It is known that screening has its own associated hazards. Austoker (1999) refers to the harm and expense that can be incurred when screening. The importance of due consideration when proposing a screening initiative is also stressed. Initial reports from the pilot programme already indicate costs well exceed what was estimated and a substantial impact on downstream services. The MoH diabetes publications (1997) include the introduction of opportunistic screening based on a risk factor profile as a key strategy. Screening could not only identify those at risk of developing Type II Diabetes but also those with the disease who have not been diagnosed. When discussing screening Roubicek et al recommended those at high risk could be identified and appropriate counselling, further diagnostic testing and preventive measures could be offered, regardless of the test result. The Strategies for the Prevention and Control of Diabetes in New Zealand produced by the M0H (1997) includes the statement "Opportunistic screening of NIDDM for at-risk individuals is supported, but can only be justified as part of a lifestyle intervention programme which can reduce risk factors for individuals, whether they screen positive or not". This poses the question; why screen in the first place? Primary prevention may be more important than screening. Risk factors for NIDDM are also risk factors for other disease conditions such as heart disease. As the programme is targeted and those screened have the risk factors, all could benefit from lifestyle advice, regardless of test result. There is a potential for opportunistic prevention via education for healthy living linked with nutrition and physical activity promotion as currently provided by the Heart Foundation and the Cancer Society, as suggested in the National Plan of Action for Nutrition (1995). The National plan of action for diabetes refers to the work of Manson and Spelsberg (1994) where from epidemiological data it was suggested that increasing physical activity could decrease the risk of NIDDM developing by 50-75%. While it is difficult to influence lifestyle change such as improved diet and maintaining ideal weight, these are the interventions that are proposed to prevent the development of NIDDM, and to prevent or reduce the progression of diabetic complications in those who test positive during screening. Asymptomatic individuals may be less responsive to lifestyle and dietary advice (de Courten and Zimmet 1997). Exercise, prudent diet and weight loss are already recommended for the at risk groups regardless of test result. 19

20 Much of the impact of Diabetes is through the complications of micro and macro vascular disease. It has been noted that concentrating on markers of these complications such as high blood pressure may be effective in reducing the poor outcome due to Diabetes (UK PDSG, 1998). Additional screening initiatives would be unlikely to have a positive impact on health status if the management and treatment of those identified is not sufficient. Funds could be more effectively used in improving access, preventive care, and outpatient management. An advantage of targeting individuals on the basis of positive screening results would be that the blood glucose level can be used as a marker to monitor progress. Diet and exercise change reduce risk factors and improve glycaemic control. This could then reduce or slow progression of complications. A diagnosis of diabetes will also influence an individuals predicted risk profile as per predictive tables (New Ethicals catalogue, 1999). This may increase the motivation of clinicians and patients to modify risk factors. 6. CONCLUSION An accurate prediction as to the total costs incurred and avoided by this proposed screening programme is not possible. Direct costs can be estimated using the numbers to be screened as per the Hep B programme and the costs of the screening test. This does not include the indirect and downstream costs. Further the impact of the screening is difficult to judge as the estimations as to the current prevalence of Type II Diabetes (diagnosed and undiagnosed) vary substantially. The number of 'new cases' found will also vary according to the diagnostic parameters used. This will influence the estimation of costs that would be avoided. The success of a screening programme is dependent on the downstream services. If the management and care of known Diabetics is insufficient or inadequate it is difficult to justify directing resource into finding more cases. When commenting on diabetes screening in proposals for the Hep B programme, a provider questioned the ethics of screening to identify additional cases when the present caseload is inadequately catered for. It was suggested that patient education had not been demonstrated to improve compliance and complication rates especially among Pacific people. Late presentation and subsequent low utilisation of tertiary intervention have been demonstrated. This opinion supports the call for improved patient management services and initiatives such as screening for retinopathy in known diabetics. It also stresses the need for the provision of services acceptable to the target population. The proposed screening appears to lack linkages with national registration or monitoring. Once identified those at risk or requiring treatment would need to be referred on to appropriate and effective prevention and treatment services. 20

21 Screening can result in the identification of two groups - those without evidence of disease present - those with evidence of disease present who haven't sought treatment For the first group the intervention of choice is lifestyle education and alteration to increase activity, improve diet and reduce obesity (improved self management). This is also recommended for the second group (regardless of test result). The second group would also potentially gain from subsequent monitoring to pick up complications if/as they develop and allow for early intervention and improved glycaemic control. For the second group improved care may result through individualised education, co-ordination of care, improved monitoring, and more timely treatment. Strategies are already being developed within the HFA to improve disease management. It is recommended that any screening programme be targeted towards those at increased risk of developing type II diabetes. Therefore, the whole population screened would benefit from the same management as recommended by the MoH. However, those who test positive may also have increased motivation to comply. Providing the screening as an adjunct to another programme has some attraction due to 'shared costs and convenience'. There are fundamental differences, however, between the conditions. The Hep B screening programme is a 'one-off' initiative to identify carriers of an infectious disease and then treat for life. Diabetes is a non-infectious disease, the development of which is on a continuum. Diabetes screening is generally considered to be an on-going initiative to prevent the progression towards, or limit the impact of, the disease. While it is acknowledged that type 2 diabetes is a significant health issue, and that screening those at risk is recommended, specialists in the field, including those within New Zealand, are not unanimous in their opinions as to the best ways to manage this problem. Without consensus collaboration will be impeded. A balance needs to be struck between evidence based decision making and the avoidance of doing nothing, remaining at an impasse. 7. RECOMMENDATIONS From review of the information a diabetes screening initiative as an adjunct to the Hep B screening programme, as it currently stands, would not appear to be the best use of limited resources. Diabetes is a disease which has a significant impact on our population and correspondingly is identified as a key area of concern in the Government's strategy. While opportunistic screening is supported this initiative does not satisfy the criteria for acceptance as an effective strategy. Recommendations from this review are as follows. 1). Evidence does not indicate that an adjunct to the Hep B screening initiative would be the most effective use of resources targeting diabetes. Screening those 'at-risk' is supported. 21

22 2). The adjunct screening could be more effective provided: targeting those who receive the diabetes screening was more explicit regarding risk factors such as age and obesity clear and appropriate referral processes were outlined and followed downstream diabetes disease management services were appropriately managing all diabetics (see 4 below) already known and managed diabetics were identified and excluded from screening there was wider consultation and agreement in the field regarding methods and process the initiative was developed with a view to future maintenance as an ongoing screening programme funding was adequate to support the screening and the enhanced downstream services. 3). Diabetes services within the primary care setting have been reported to be incomplete with diabetics going unrecognised and untreated. Review and facilitation of current initiatives through primary health may increase motivation, improve continuity and maximise effectiveness as an alternative to, or in conjunction with, the adjunct screening. 4). Resource directed into disease management in conjunction with opportunistic screening of those at risk could lead to: Active and effective monitoring of those with diabetes in a provider setting improving the outcomes of individuals, but also contributing to the development of other initiatives to address the issue. Improved communication between providers working in complimentary fields of expertise. Many of the risk factors associated with diabetes are also significant with respect to other health issues such as heart disease, nutrition, and smoking. Collaboration in health education activities would lead to sharing of knowledge and resources, avoidance of unproductive duplication, and the increased likelihood of positive outcomes. An approach targeting BP, cholesterol and signs of complications such as retinopathy. Targeting the factors associated with the development of complications would be 'outcome' focused but still be preventive. Development of registers can also contribute to improving the information available regarding the impact of diabetes in the community. This could also enhance continuity of care and follow-up. This information collection and maintenance would be expensive and require evaluation in its own right. 5). As the pilot programme as an adjunct to the Hep B programme is undertaken it should be evaluated independently. This will provide helpful information when considering future proposals and additional information regarding prevalence. 22