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A position statement on screening andmanagement of prediabetes in adults in primarycare in Australia - Brett A. Gordon- Holsworth Research Initiative, La Trobe University, VIC, Australia

Brett A. Gordon

 Prediabetes has a high prevalence, with early detection essential to facilitate optimal man-agement to prevent the development of conditions such as type 2 diabetes and cardiovas-cular disease. Prediabetes can include impaired fasting glucose, impaired glucose toleranceand elevated HbA1c. This position statement outlines the approaches to screening andmanagement of prediabetes in primary care.There is good evidence to implement intensive, structured lifestyle interventions forindividuals with impaired glucose tolerance. The evidence for those with impaired fastingglucose or elevated HbA1c is less clear, but individuals should still be provided with gener-alised healthy lifestyle strategies. A multidisciplinary approach is recommended to imple-ment healthy lifestyle changes through education, nutrition and physical activity.Individuals should aim to lose weight (5–10% of body mass) using realistic and sustainabledietary approaches supported by an accredited practising dietitian, where possible. Physi-cal activity and exercise should be used to facilitate weight maintenance and reduce bloodglucose. Moderate-vigorous intensity aerobic exercise and resistance training should beprescribed by an accredited exercise physiologist, where possible. When indicated, phar-macotherapy, metabolic surgery and psychosocial care should be considered, in order toenhance the outcomes associated with lifestyle change. Individuals with prediabetesshould generally be evaluated annually for their diabetes status This position statement has been developed to provideconsensus-based clinical recommendations for the screeningand management of prediabetes in adults in the Australianprimary care setting, with a focus on practical implementa-tion.  This  statement  provides  general  information  andadvice, and does not explicitly address populations withspecific needs including prediabetes in children or adoles-cents, disability or mental health. The reference list maynot be exhaustive as the position statement is not a system-atic  literature  review,  rather  a  review  of  pertinentpublications. Imbalances in glucose homeostasis without intervention,increase the risk of progression from prediabetes to type 2diabetes. Women with prediabetes before pregnancy have ahigher  risk  of  developing  gestational  diabetes  mellitus(GDM)[6,7]. GDM affects 9% of pregnancies in Australia[8],with rates as high as 30% in high-risk ethnically-diverseregions of Australia[9]. Women with a history of GDM alsohave an increased risk of progressing to type 2 diabetes laterin life[10]. Children born to mothers diagnosed with GDMduring their pregnancies also have a much higher risk offuture prediabetes and type 2 diabetes[11].Prediabetes increases the risk of CVD by approximately20%[12].Ameta-analysis of 53 prospective cohort studies,including >1.5 million individuals from general populations,identified that prediabetes was associated with an increasedrisk of CVD, with IGT posing the highest risk (18). However,health risks were observable in people with an IFG level aslow as 5.6 mmol/L (19). Further, the AusDiab study reportedthat IFG was an independent predictor for CVD mortality(hazard ratio 2.5 (95% CI: 1.2–5.1) when compared to normalglucose tolerance, although IGT was not (1.2 (0.7–2.2)) The AUSDRISK is a short questionnaire, designed to estimatethe risk of progression to type 2 diabetes over five years[14],using the risk factors for prediabetes and type 2 diabetes(Table 1). Adults in the ‘intermediate risk’ (scoring 6–11) or‘high risk’ category (scoring 12 and above) should be testedfor prediabetes (Fig. 1). Re-screening or testing should occurevery 1–5 years, depending on the risk score.4.2.   Pathology screeningPrediabetes can be identified by fasting blood glucose, HbA1cor an OGTT. Each test has benefits and limitations, and there-fore the most appropriate test should be tailored to the indi-vidual. Each test will identify a slightly different group ofindividuals, such that each person may fall into one or multi-ple prediabetes states, i.e. IFG, IGT and elevated HbA1c. Sincethe clearest evidence of benefit for structured, intensive life-style intervention is among people with IGT, and much lesscertain in IFG or elevated HbA1c, it is recommended that anOGTT is performed before referral into a structured, intensivelifestyle program. Those with IFG or elevated HbA1c, but notIGT, should still be provided with general lifestyle advice.4.2.1.  Fasting venous blood testA fasting venous blood test can be used to identify those withIFG, but not IGT. A fasting blood glucose of 6.1–6.9 mmol/L isindicative of IFG (Fig. 1)[15]. A fasting glucose of 7.0 mmol/Lor above is indicative of type 2 diabetes[15].4.2.2.  HbA1cHbA1c can be used to identify those at high risk of progress-ing to diabetes, but there is uncertainty about the preciserange of HbA1c that should be used to identify prediabetes.The American Diabetes Association recommends 5.7–6.4%(39–46 mmol/mol) (23), while the International Expert Com-mittee recommended 6.0–6.4% (42–46 mmol/mol)[16]

 

This position statement considered and synthesised theavailable evidence to inform treatment recommendationsand the coordination of care services. However, this was notgathered through a systematic review. The following recom-mendations are made:Individuals with clinical risk factors for prediabetes arerecommended to receive formal screening using theAustralian Type 2 Diabetes Risk Assessment (AUS-DRISK) screening tool. For those at high risk, pathologyscreening is recommended (fasting venous blood glu-cose test, HbA1c or oral glucose tolerance test).An oral glucose tolerance test is recommended beforereferral to a structured, intensive lifestyle program, asthe clearest evidence for benefit of these programs isamong people with IGT.The management of prediabetes should be multi-faceted, including lifestyle interventions, diet, physicalactivity,  psychological  support  and with  pharma-cotherapy as appropriate.Education is best provided on diagnosis, and as fre-quently as needed or desired to support behaviouralor pharmacological interventions.Care  needs  to  be  person-centred,  treating  theindividual as an active participant in their health careteam.