A cluster-controlled implementation project of intensive insulin therapy: effects on blood glucose control and incidence of severe hypoglycemia

Introduction

Intensive insulin therapy (IIT) is a complex intervention involving several steps that may all contain potential sources of variability. Changing practice in complex multidisciplinary environments is difficult. In addition, it is undecided whether IIT should be applied by nurses and physicians, or nurses alone. We implemented IIT using a conceptual implementation framework and compared overall blood glucose control and incidence of severe hypoglycemia (SH) (blood glucose level (BGL) <40 mg/dl) before and after implementation.

Methods

Three ICUs developed and implemented an evidence-based guideline for IIT; three ICUs with no change in blood glucose control served as control ICUs. In the guideline ICUs, the IIT practice change comprised two periods: in the first year after implementation of the guideline, physicians and nurses used the guideline together; in the second year the guideline was applied solely by nurses. BGL collection and analysis included the 1 year before implementation of the guideline. Analysis was performed using statistical process control.

Results

IIT guideline: the new guideline emphasized fast correction of high BGLs, acceptance of low BGLs and frequent BGL measurements (up to one/hour). Blood glucose control: BGLs of approximately 8,000 patients were collected and analyzed. The case mix was similar in guideline and control ICUs, and did not change over time. No change in overall blood glucose control or incidence of SH was observed in the control ICUs during the study duration. In the guideline ICUs, the median number of daily blood glucose measurements increased from 4 (3 to 7) per patient to 9 (5 to 12) per patient (P < 0.001). Median morning BGL declined in guideline ICUs, from 114 (96 to 139) mg/dl to 100 (85 to 123) mg/dl (P < 0.001). The change in blood glucose control was accompanied by a rise in the incidence of SH, from 7% to 13% (P < 0.001). SH, however, did never cause short-term harm (no death or coma). Nurses alone performed equally well with regard to overall blood glucose control, and even showed a decline of incidence of SH.

Conclusions

Implementation of an evidence-based IIT guideline improves blood glucose control, with results comparable with the original studies on IIT in Leuven. The increase of incidence of SH is temporary, and improves when IIT is applied by nurses alone.