Estimation of blood glucose levels by people with diabetes: a cross-sectional study.

BACKGROUND

Recommendations suggest that all patients with diabetes who use insulin should home test their blood glucose. Recommendations for those not using insulin remain contradictory. These recommendations are in part based upon the assumption that people with diabetes cannot make an accurate estimate.

AIM

To explore whether people with diabetes can accurately estimate their blood glucose levels and to assess which factors explain variability in these estimates.

DESIGN

A cross-sectional design.

SETTING

One general practice in Oxfordshire, UK.

PARTICIPANTS

One hundred and fifteen consecutive patients with diabetes attending a diabetic clinic were invited to estimate their blood glucose level prior to having it routinely measured.

RESULTS

One hundred and four patients made estimates. Of these, 45 (43.3%) underestimated their blood glucose, 18 (17.3%) overestimated, and 41 (39.4%) made guesses that fell into the range defined as accurate. Of those not using insulin (n = 85), 37 (43.5%) underestimated their blood glucose, 12 (14%) overestimated and 36 (42.3%) were accurate. Accuracy in the non-insulin users was associated with home testing, lower blood glucose levels, coming to the clinic in a fasting state, and reporting no symptoms when they felt that their blood glucose level was high. Overestimation was associated with having co-occurring illnesses and experiencing no symptoms when their blood glucose was low.

CONCLUSION

The majority of patients with diabetes in this study could not accurately estimate their blood glucose levels indicating that home testing may be a necessary part of diabetes self care. Home testing may also function as a form of biofeedback to facilitate an improved ability to estimate blood glucose levels.