Transition from intravenous to subcutaneous insulin: effectiveness and safety of a standardized protocol and predictors of outcome in patients with acute coronary syndrome

OBJECTIVE

The study objectives were 1) to assess the effectiveness and safety of a standardized protocol for the transition to subcutaneous insulin and oral feeding in diabetic or hyperglycemic patients with acute coronary syndrome (ACS) who were receiving intravenous insulin and glucose at the time of the transfer from the intensive cardiac care unit to a general ward and 2) to identify predictors of transition outcome.

RESEARCH DESIGN AND METHODS

This was a prospective observational study. The protocol specifies that patients receive a 100% of their daily subcutaneous insulin requirement from the first day of oral feeding, calculated from the intravenous insulin rate during the final 12 h divided into two: 50% basal and 50% prandial.

RESULTS

In 142 patients (93 male, 49 female, age range 47–88 years, 135 with known diabetes) the first day after transition, 44.8% of blood glucose (BG) measurements were within the strict range of 100–140 mg/dL before meals and 100–180 mg/dL after meals, and 70.8% were within the broader ranges of 80–160 mg/dL and 80–200 mg/dL, respectively. Pre- or postprandial hypoglycemia (BG <70 mg/dL) occurred in 11 patients (7.7%) on the first day and in 38 patients (26.8%) on the first 3 days after transition. Old age, high doses of intravenous insulin, and wide BG variations in the 24 h before insulin infusion was stopped were predictive of poor BG control after transition.

CONCLUSIONS

This study shows the effectiveness and safety of a standardized protocol for the transition from intravenous to subcutaneous insulin in patients with ACS when regular oral feeding was resumed.In critically ill patients with diabetes or hyperglycemia who are admitted to intensive care units, intravenous infusion of insulin is the recommended treatment (1–6). During the postacute phase, many guidelines and recommendations suggest switching to subcutaneous insulin when patients begin eating regular meals and are moved to a lower-intensity care setting (1–6).There are few observational and intervention studies on the procedure for the transition from intravenous to subcutaneous insulin, and almost all concerned patients who had undergone operation and took little if any food (7–11). The transition is delicate because of the patients’ clinical condition and the organizational context in which they are transferred from an intensive care unit to a general ward. The few studies that have examined the course of blood glucose (BG) after interruption of intravenous insulin have documented inadequate control in the absence of a standardized transition protocol (9,12). In addition, the literature reporting the predictors of optimal transition is scarce and refers mainly to patients postsurgery (7,9,10).The objectives of this prospective observational study were to

1. assess the effectiveness and safety of a standardized protocol for conversion from intravenous to subcutaneous insulin therapy in patients with acute coronary syndrome (ACS) during the transfer from the intensive cardiac care unit (ICCU) to the general ward; and
2. identify predictive factors of transition outcome.