Cross-sectional comparison of point-of-care with laboratory HbA1c in detecting diabetes in real-world remote Aboriginal settings.

OBJECTIVES: To determine if point-of-care (POC) glycated haemoglobin (HbA1c) is sufficiently accurate in real-world remote settings to predict or exclude the diagnosis of diabetes based on laboratory HbA1c measurements. DESIGN: Cross-sectional study comparing POC capillary HbA1c results with corresponding venous HbA1c levels measured in a reference laboratory. PARTICIPANTS: Aboriginal patients ≥15 years old who were due for diabetes screening at the participating clinics were invited to participate. Two hundred and fifty-five Aboriginal participants were enrolled and 241 were included in the analysis. SETTING: 6 primary healthcare sites in the remote Kimberley region of Western Australia from September 2011 to November 2013. MAIN OUTCOME MEASURES: Concordance and mean differences between POC capillary blood HbA1c measurement and laboratory measurement of venous blood HbA1c level; POC capillary blood HbA1c equivalence value for screening for diabetes or a high risk of developing diabetes; sensitivity, specificity and positive-predictive value for diagnosing and screening for diabetes; barriers to conducting POC testing. RESULTS: Concordance between POC and laboratory results was good (ρ=0.88, p<0.001). The mean difference was -0.15% (95% limits of agreement, -0.67% to 0.36%). POC HbA1c measurements ≥6.5%, 48 mmol/mol had a specificity of 98.2% and sensitivity of 73.7% for laboratory measurements ≥6.5%. The POC equivalence value for screening for diabetes or a high risk of developing diabetes was ≥5.7%, 39 mmol/mol (sensitivity, 91%; specificity, 76.7% for laboratory measurements ≥6.0%, 42 mmol/mol). Staff trained by other clinic staff 'on the job' performed as well as people with formal accredited training. Staff reported difficulty in maintaining formal accreditation. CONCLUSIONS: POC HbA1c testing is sufficiently accurate to be a useful component in screening for, and diagnosing, diabetes in remote communities. Limited local training is adequate to produce results comparable to laboratory results and accreditation processes need to reflect this.

Baseline investigations of folate status in Aboriginal and non-Aboriginal West Australians prior to the introduction of mandatory fortification.

OBJECTIVE: In September 2009, Australia implemented mandatory folic acid fortification of wheat flour for bread-making to reduce the incidence of neural tube defects. Our study aimed to establish baseline folate status data in Aboriginal and non-Aboriginal Western Australians. METHODS: Patients who presented at a health service or collection centre for blood tests were invited to participate. One hundred and ninety-one Aboriginals and 159 non-Aboriginals were recruited between April 2008 and September 2009. Participants completed a five-minute questionnaire and had blood taken for red blood cell (RBC) folate and serum vitamin B12. Data were analysed using SPSS (version 17.0.2, SPSS Inc., Chicago, IL, USA). RESULTS: Ten per cent (95% confidence intervals (CI): 5, 19) of the Aboriginal women participants and 26% (95% CI: 16, 40) of men had RBC folate concentrations below 250 ng/mL, the cut-off associated with folate deficiency. None of the non-Aboriginal women (95% CI: 0, 4) and 4% of the non-Aboriginal men (95% CI: 2, 12) had RBC folate concentrations below 250 ng/mL. All participants were vitamin B12 replete. None of the 96 Aboriginal and 8% of non-Aboriginal women aged 16-44 reported consumption of supplements with a daily intake of >400 µg folic acid during the previous week. CONCLUSIONS AND IMPLICATIONS: This study established a baseline of RBC folate, folate consumption and supplement use in Aboriginal and non-Aboriginal groups. We identified 10% of Aboriginal women and none of non-Aboriginal women participants with low folate concentrations. The higher prevalence of folate deficiency in Aboriginal participants suggests they are more likely to benefit from a universal program of folate fortification.

Point-of-care testing of capillary glucose in the exclusion and diagnosis of diabetes in remote Australia.

OBJECTIVES: To determine the utility of point-of-care (POC) capillary blood glucose measurements in the diagnosis and exclusion of diabetes in usual practice in primary health care in remote areas. DESIGN: Cross-sectional study comparing POC capillary glucose results with corresponding venous glucose levels measured in a reference laboratory. PARTICIPANTS: 200 participants aged 16-65 years enrolled: 198 had POC capillary glucose measurements; 164 also had acceptable venous glucose laboratory results. SETTING: Seven health care sites in the Kimberley region of Western Australia from May to November 2006. MAIN OUTCOME MEASURES: Concordance and mean differences between POC capillary blood glucose measurement and laboratory measurement of venous blood glucose level; POC capillary blood glucose equivalence values for excluding and diagnosing diabetes, and their sensitivity, specificity and positive-predictive value. RESULTS: The concordance between POC and laboratory results was high (rho=0.93, P<0.001). The mean difference in results was 0.48 mmol/L (95% CI, 0.23-0.73; limits of agreement, - 2.6 to 3.6 mmol/L). The POC capillary glucose equivalence values for excluding and diagnosing diabetes were < 5.5 mmol/L (sensitivity, 53.3%; specificity, 94.4%; positive-predictive value, 88.9%; for a venous value of < 5.5 mmol/L) and >or= 12.2 mmol/L (sensitivity, 83.3%; specificity, 99.3%; positive-predictive value, 95.2%; for a venous value of >or= 11.1 mmol/L), respectively. While the choice of glucometer and whether or not patients were fasting altered these results, they did not have a significant influence on the diagnostic utility of POC glucose measurement in this setting. CONCLUSION: POC capillary blood glucose analysers can be used as part of the process of diagnosing and excluding diabetes in remote rural communities using these locally established capillary equivalence values.