of one’s own HbA1c may be a consequence of good glycaemic control and not Significantly, the participants that had not reported HbA1cSK (almost 50%) were excluded in the secondary analysis analyses, reducing the sample size and power of the study. Future studies to evaluate what characterized this particular population (non-participation bias) could yield answers for the causal factors of HbA1cSK, for example awareness of HbA1c goal and of guidelines. In conclusion, this large study of self-knowledge of HbA1c across eight countries showed that almost half of the study population had knowledge of their last HbA1c value and that accurately reported self-knowledge HbA1c was associated with better glycaemic control. On average, the mean reported value for accurately reported HbA1cSK was found to be 7.0%, which corresponded with the safer target set recently by international bodies, suggesting that the effort to educate health care providers and patients may have had a beneficial effect. Nonetheless this study shows association and not causality and it is well recognised that patients with accurate self-knowledge of their HbA1c may have represented a biased group of participants who are more motivated and compliant, resulting in better managed diabetes care rather than due to their self-knowledge of HbA1c alone. However, despite the increased levels of awareness and education over the past 10 years, this study found that the proportion of the population with reported self-knowledge of HbA1c had not increased significantly. Therefore, the authors propose to study self-knowledge of one’s own HbA1c further as an intervention in our endeavour to improve glycaemic control. Acknowledgements SS, HT, LJG, MJD and KK acknowledge support from the National Institute for Health Research knowledge
Tables and Figures Table1: Comparison of the characteristics of participants of the participants who reported HbA1cSK and those who did not Reported HbA1cSK [N1] Had not reported HbA1cSK [N2] Levene’s Test For Equality of Variance (F) p t –test (df) Mean difference between the two groups (95% Confidence Intervals) P Eta –squared (eta 2) Mean age in years (SD) 66.0 (10.5) [3745] 66.9 (11.1) [3499] F = 8.29 p = 0.05 -3.55 (7062) - 0.91 (-1.41 to -0.41) p < 0.05 eta 2 = 0.002 Mean duration of T2DM in years (SD) 9.5 (7.5) [3485] 8.0 (6.6) [3133] F = 43.78 p < 0.05 8.65 (6612) 1.50 (1.16 to 1.84) p < 0.05 eta 2 = 0.011 Mean BMI kg/m2 (SD) 29.8 (5.6) [3069] 30.8 (5.8) [2630] F = 1.98 p = 0.164 -6.32 (5697) -0.96 (-1.25 to -0.66) p < 0.05 eta 2 = 0.007
Table 2: Comparison of mean HbA1cSK and mean HbA1cLAB between the participants who reported HbA1cSK and those who did not Reported HbA1cSK [N1] Had not reported HbA1cSK [N2] Levene’s Test For Equality of Variance (F) p t –test (df) Mean difference between the two groups (95% Confidence Intervals) P Eta –squared (eta 2) Mean HbA1cSK in % (SD) 7.5 (14.4) [3753] Not applicable Not applicable Not applicable Not applicable Not applicable Mean recorded HbA1cLAB in % (SD) 7.1 (1.1) [3722] 7.2 (1.3) [3316] F = 33.90 p <0.0001 -4.31 (6554) -0.12 (-0.18 to - 0.07) p < 0.05 eta 2 = 0.003
Table 4: A comparison of the participants with accurately reported HbA1cSK and inaccurately reported HbA1cSK Accurately reported HbA1cSK N1 Inaccurately reported HbA1cSK N2 Analysis: t-test/chi-squared with degrees of freedom (df) Mean difference and 95% confidence intervals (CI) Eta squared (eta 2) P Eta 2/ phi Mean HbA1c in % (SD) 7.0 (1.0) 2921 6.8 (1.5) 810 t = 2.76 (1033) 0.16 (0.04 to 0.27) p = 0.05 eta 2 = 0.002 Mean recorded HbA1c in % (SD) 7.0 (1.0) 2921 7.3 (1.2) 810 t = -6.88 (1152) -0.33 (-0.42 to -0.23) p < 0.05 eta 2 = 0.01