GRAPEVINE, TEX. – There is no one-size-fits-all method of transitioning hospitalized diabetic patients off intravenous insulin to subcutaneous insulin.

A combination of a basal bolus of insulin, plus a sliding scale dictated by the patient’s blood sugar, is usually the way to go, although the process varies slightly depending on the before- and after-nutritional mode, Dr. John MacIndoe said at the annual meeting of the Society of Hospital Medicine.

"An important point to remember is that using sliding-scale insulin as a sole strategy for glucose control in someone who needs insulin every day is not a good idea," said Dr. MacIndoe of HealthPartners Medical Group and Clinics, Minneapolis.

There are no evidence-based guidelines to provide a framework for the process, he said. "There are several protocols with supportive data, but no head-to-head trials comparing one to the other. This is a fairly young area with much less evidence than we would really like."

The initial changeover is managed by a basal bolus insulin protocol. This consists of a single dose of basal insulin (usually glargine) given once per day, along with scheduled insulin according to meal pattern, and sliding-scale insulin given throughout the day as indicated by blood glucose.

"Generally speaking, half of the insulin one requires over 24 hours (half of the total daily dose) is a long-acting preparation which covers the continuous amount of glucose put out by the liver," Dr. MacIndoe said. "This is referred to as basal insulin. The other half is that which is needed to cover the carbohydrate ingested with meals. This is usually given in thirds, with each meal, as a rapid-acting insulin."

The subcutaneous insulin for the first 24 hours after transition is considered to be 80% of the total daily dose required on intravenous insulin, Dr. MacIndoe said. "The subcutaneous total daily dose (TDD) is also dependent on what kind of nutrition the patient was given during the time on IV insulin, and the [newly implemented] type of nutrition," he said. "We see three common patterns here: NPO to NPO; NPO to meals; and enteral to meals."

For the NPO patient who will remain NPO, "things are pretty straightforward. You give a dose of basal glargine that’s equal to the TDD calculated for the subcutaneous transition."

Because the patient isn’t eating, there’s no need for additional scheduled nutritional insulin. However, sliding-scale insulin will be given as needed every 4-6 hours, depending on whether the insulin is a rapid-acting analog or regular insulin.

For patients switching from NPO to meals, the basal insulin will also be equal to the dose-calculated TDD for subcutaneous transition. At mealtime, patients get additional rapid-acting insulin at a dose equal in amount to one-third of the basal insulin dose; thus, by the end of the day, 50% of all the insulin given will be the single dose of glargine and 50% will be a rapid-acting analog, divided into three doses.

These patients need a constant carbohydrate diet, "which is essential because we can then predict the amount of insulin they will need with every meal," Dr. MacIndoe said. "You’ll have a finger stick ordered at each meal and bedtime, and, until they’re stable, a 2-hour postprandial check and maybe even a 3 a.m. value if they receive bedtime sliding-scale [insulin]." The most commonly used scales call for insulin to be given if the blood sugar exceeds 150 mg/dL.

Patients switching from enteral to meals "are a little trickier," he said. "It is important to remember that half of the IV insulin was covering nutrition and half covering their true basal needs. So as you transfer to meals, the basal dose of glargine will be equal to half of the calculated TDD of subcutaneus insulin, and at each meal the patient receives rapid-acting insulin equivalent to one-third of the basal dose."

"One of the toughest things to gauge in a patient after transition is whether and how quickly they will begin to eat. The key point is that the patient should be getting blood sugar measurements at mealtime; if it’s above target, they should receive whatever sliding-scale dose is called for with the meal, even if they might not be hungry."

Hold the nutritional dose until after the patient has finished eating, Dr. MacIndoe said. "If they complete their full meal or at least 50%, they can get the full dose of insulin. But if they eat less than 50%, they should only get half of the nutritional dose. The assessment and the insulin dosing should occur within 15 minutes of the meal, if possible."

Dr. MacIndoe disclosed that he is on the speakers bureau of Sanofi-Aventis.

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