Capillary blood glucose monitoring, inpatient hypoglycaemia and quality of care

Abstract

Aims: Hypoglycaemia confers excess morbidity and mortality. UK guidelines recommend capillary blood glucose (CBG) measurement is repeated 15 minutes following identification and treatment of CBG <4mmol/l. We assessed adherence to this guidance, influence of initial CBG on time to repeat (TTR), and the impact of a quality improvement intervention on TTR.

Methods: We identified CBG readings (Abbott-PrecisionWeb) of 18,118 inpatients with recorded hypoglycaemic CBG between January 2009 and September 2013. TTR and associations with initial CBG were investigated. A single ward was targeted with an intervention (National Health Service Scotland Quality Improvement Hub ThinkGlucose pilot) during 2012. TTR was identified and compared before, during and after intervention.

Results: Of 90,935 CBGs <4mmol/l, 4.4% had no recorded repeat CBG. Of the 83,484 repeated CBGs, median TTR was 80 minutes, with 8.9% repeated within 15 minutes and only 42.2% within 60 minutes. TTR was proportional to initial CBG with median 22 minutes (IQR 10-47) for initial CBG 1-1.9 mmol/l, median 48 minutes (IQR 24-104) for 2-2.9 mmol/l, median 112 minutes (IQR 52-309) for 3-3.9 mmol/l(p=0.05). On the vascular unit, TTR improved post intervention from a median 77 minutes (IQR 37-281, n=843) to 29 minutes (IQR 19-55, n = 1041), and improvement persisted with median 20 minutes (IQR 15-28, n=268) in the nine months after the project ended.

Conclusions: TTR is a marker of treatment quality in hypoglycaemia and is suboptimal. TTR reduces with worsening initial degree of hypoglycaemia. We have shown a quality improvement package can produce sustained reduction of TTR.