Inpatient glycaemic management

Overview 
Theory 
Diagnosis 
Management 
Follow up 
Resources 

Please note that formulations/routes and doses may differ between drug names and brands, drug formularies, or locations. Treatment recommendations are specific to patient groups: see disclaimer

ACUTE

critically ill or unplanned surgery or in intensive care unit (ICU): hyperglycaemia (blood glucose levels >7.8 mmol/L [>140 mg/dL])

1st line – insulin + treatment of comorbid illness

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1st line –

insulin + treatment of comorbid illness

Inpatient hyperglycaemia is not merely a transient response to illness or stress, but a condition that requires active management. Effective management of hyperglycaemia is associated with a decreased length of ICU and hospital stay.[3][21]

Several large trials have investigated optimal glycaemic targets for critically ill patients, with mixed results. While early studies supported tight glycaemic control in the ICU, later research raised concerns about increased mortality and hypoglycaemia associated with intensive insulin therapy.[35][36][37]

Continuous intravenous insulin infusion is the recommended method for glycaemic management in critically ill patients, as endorsed by both the American Diabetes Association (ADA) and the American Association of Clinical Endocrinology (AACE).[1][3][21] This method is favoured for its ability to achieve and maintain target glucose levels while minimising the risk of hypoglycaemia.[1]

Subcutaneous insulin and oral antidiabetic drugs should be discontinued during intravenous insulin therapy. Reassessment should be performed once the patient is stable, tolerating oral intake, and transitioning off intravenous insulin.

Several intravenous insulin infusion protocols have been devised (e.g., Yale Insulin Infusion Protocol), and outcomes are generally comparable across systems.[35][46][47] Institutions should select protocols suited to their own workflows and resources.[1]

Once therapy for hyperglycaemia is initiated, the ADA recommends target glucose levels of 7.8 to 10.0 mmol/L (140-180 mg/dL) for most critically ill patients with diabetes, with more stringent individualised goals for selected critically ill individuals if achievable without significant hypoglycaemia.[1] The Canadian Diabetes Association and Joint British Diabetes Societies for Inpatient Care (JBDS-IP) recommend target glucose levels between 6.0 and 10.0 mmol/L (108 and 180 mg/dL) for acutely ill or critically ill hospitalised patients.[2][29]

When intravenous insulin therapy is used, frequent capillary blood glucose monitoring - typically every 30 minutes to 2 hours - is required to ensure safe and effective management.[1]

Patients receiving insulin infusions may require concurrent glucose infusion to maintain glucose balance and avoid hypoglycaemia. Close monitoring of blood glucose levels and appropriate insulin dose adjustments are critical.

Transition planning is important for patients receiving intravenous insulin; co-administration of a subcutaneous basal insulin analogue can ease the shift from intravenous to subcutaneous insulin, reducing the risk of rebound hyperglycaemia.[1] For transitioning, the total daily dose of subcutaneous insulin may be calculated based on the insulin infusion rate during the prior 6-8 hours when stable glycaemic goals were achieved, based on prior home insulin dose, or following a weight-based approach.[1]

A paediatric endocrinologist should be consulted for children.

Consult local protocols for guidance on suitable insulin doses and regimens.

Primary options

insulin neutral: intravenously

Plus – supportive care

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Plus –

supportive care

Treatment recommended for ALL patients in selected patient group

Supportive care should address electrolyte imbalances, nutritional needs, and fluid balance.

Electrolytes should be monitored and corrected as required. Potassium should be added to intravenous fluids according to local ward protocols to prevent or treat hypokalaemia.

In all patients, adequate nutrition and fluid replacement should be ensured. Enteral nutrition or total parenteral nutrition may be required in patients with diabetes who are not eating.[1]

Patients on intravenous insulin may require concurrent glucose infusion to maintain glucose balance and prevent hypoglycaemia, particularly if they are not eating or have limited glucose intake.

Plus – follow-up and optimisation of outpatient antidiabetic treatment

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Plus –

follow-up and optimisation of outpatient antidiabetic treatment

Treatment recommended for ALL patients in selected patient group

Measurement of haemoglobin A1c (HbA1c) is valuable in determining the plan at discharge. A high HbA1c indicates poor pre-existing control and suggests need for increased or modified antidiabetic therapy (e.g., starting insulin or maximising oral drugs).[3][33]

A wide range of therapy is available for long-term diabetes management. Some patients may need to continue taking insulin at home until complete recovery allows a transition to other therapies.[34]

Patients without known diabetes should receive outpatient follow-up to reassess glucose levels and determine the need for ongoing treatment or diagnostic evaluation.

stable non-critical illness: uncontrolled hyperglycaemia (blood glucose levels >7.8 mmol/L [>140 mg/dL])

1st line – insulin + treatment of comorbid illness

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1st line –

insulin + treatment of comorbid illness

For hospitalised patients with stable, non-critical illness and uncontrolled hyperglycaemia, subcutaneous insulin is typically the preferred treatment.[1] Oral anti-hyperglycaemic agents are usually discontinued, and insulin doses are adjusted based on blood glucose trends and nutritional intake. The same general principles apply whether the patient has newly detected hyperglycaemia or a known history of diabetes - namely, avoiding both hypo- and hyperglycaemia, which are associated with worse outcomes in some settings.[48]

For patients not already on insulin, both the Endocrine Society and American Diabetes Association (ADA) provide guidance on initiation thresholds.[1][4] The Endocrine Society recommends initiating either scheduled or correctional insulin when glucose levels exceed 7.8 mmol/L (140 mg/dL), with a target range of 5.6 to 10.0 mmol/L (100-180 mg/dL) for non-critically ill patients, including those with insulin-treated diabetes prior to admission.[4] The ADA advises initiating or intensifying insulin therapy if glucose levels are ≥10.0 mmol/L (≥180 mg/dL), confirmed on two separate occasions within 24 hours. In patients with poor oral intake or nil by mouth (NBM), either basal insulin alone or basal plus bolus correctional insulin may be used.[1]

Evidence supports a basal-bolus insulin regimen over sliding scale insulin alone for non-critically ill patients, due to improved glucose control and reduced glycaemic variability.[49][50] Sliding scale insulin alone is strongly discouraged in the inpatient setting, as it is less effective than basal-bolus insulin and is associated with greater glucose variability.[1] The authors of this topic do not recommend the use of sliding scale insulin alone in the majority of clinical circumstances. However, sliding scales may be used on occasion for 24 hours to determine the insulin requirements in some patients. Additionally, sliding scales alone can be considered for patients hospitalised with non-critical illness and no history of diabetes with only mild hyperglycaemia (7.8 to 10.0 mmol/L [140-180 mg/dL]).[4]

For adults without known diabetes who develop hyperglycaemia during hospitalisation, the Endocrine Society advises initiating correctional insulin alone (i.e., insulin given only in response to raised glucose) to maintain glucose targets between 5.6 and 10.0 mmol/L (100 and 180 mg/dL).[4] If hyperglycaemia persists - defined as two or more capillary blood glucose (CBG) readings ≥10.0 mmol/L (≥180 mg/dL) within 24 hours - scheduled insulin therapy should be added.[4]

In adults with diabetes previously treated with diet or non-insulin anti-hyperglycaemic agents, initial therapy may also begin with either correctional insulin or scheduled insulin.[4] However, for patients showing persistent hyperglycaemia (≥2 CBG blood glucose readings ≥10.0 mmol/L [≥180 mg/dL] in 24 hours) while on correctional insulin alone, scheduled insulin should be initiated.[4] Scheduled insulin is also recommended for patients who present with admission blood glucose ≥10.0 mmol/L (≥180 mg/dL).[4]

For adults with insulin-treated diabetes prior to admission, the Endocrine Society recommends continuation of the home insulin regimen, modified based on nutritional intake and illness severity, with the goal of maintaining blood glucose levels within the 5.6 to 10.0 mmol/L (100-180 mg/dL) range.[4] Reductions in the dose of basal insulin (by 10% to 20%) at time of hospitalisation may be required for patients on basal-heavy insulin regimens (defined as doses of basal insulin ≥0.6 to 1 unit/kg/day), in which basal insulin is being used inappropriately to cover meal-related excursions in blood glucose.[4]

The ADA similarly recommends initiating or intensifying insulin or other glucose-lowering therapy for persistently elevated blood glucose levels ≥10.0 mmol/L on two separate occasions within 24 hours.[1]

The ADA and the Endocrine Society recommend blood glucose targets of 5.6 to 10.0 mmol/L (100-180 mg/dL) for non-critically ill patients who are being treated for hyperglycaemia, if this is achievable without significant hypoglycaemia.[1][4]

In hospitalised patients with diabetes who are eating, CBG monitoring should be conducted before meals. For those who are not eating, glucose monitoring is recommended every 4-6 hours.[1] Although CBG remains the standard for inpatient glucose monitoring, emerging research has explored the use of ambulatory continuous glucose monitoring (CGM) in non-critically ill hospital patients. Initial studies on one such device suggest that it may help to reduce both hyperglycaemia and hypoglycaemia in non-intensive care unit settings.[38] Several CGM devices have been approved for hospital use in Europe (most sample glucose through the intravascular route, and one through the subcutaneous route) and in the US (intravascular route). Real-time CGM has been shown to lower the incidence of hypoglycaemia, although it may increase nursing workload.[39] During the coronavirus disease 2019 (COVID-19) pandemic, there was increasing utilisation of ambulatory CGM devices in the hospital setting. Inpatient data suggest that CGM devices offer accuracy comparable to CBG testing in many situations, with the added benefit of enhanced detection and prevention of glycaemic excursions.[40][41][42][43]

According to the Endocrine Society, CGM initiation in the inpatient setting is recommended for select patients at high risk of hypoglycaemia, using a hybrid approach that combines CGM with periodical confirmatory CBG testing to validate CGM accuracy.[4][44] Patients at high risk for hypoglycaemia who might benefit from the initiation of inpatient CGM include those with impaired awareness of hypoglycaemia, individuals aged 65 years and older, and those with a body mass index ≤27 kg/m².[4] Additional risk factors include a total daily insulin dose ≥0.6 units/kg and a history of significant comorbidities such as stage ≥3 chronic kidney disease (estimated glomerular filtration rate <60 mL/min/1.73 m²), liver failure, cerebrovascular accident, active malignancy, pancreatic disorders, congestive heart failure, or infection.[4] Individuals with a history of hypoglycaemia prior to admission or those who have experienced hypoglycaemia during a recent or current hospitalisation are also considered high-risk.[4]

For patients already using personal CGM devices, the Endocrine Society recommends continuing their use during hospitalisation.[4][44] This continuation should also follow the hybrid approach, combining CGM with periodical CBG testing to ensure accuracy.[4][44] The ADA also supports the continued use of CGM during hospitalisation alongside confirmatory CBG testing, provided that adequate resources and staff training are available.[1] However, it does not recommend initiating CGM use during hospitalisation, noting that the initiation of new CGM devices in this setting has not received US Food and Drug Administration (FDA) approval.[1]

Both the Endocrine Society and ADA also encourage the continued use of closed-loop insulin pumps (automated insulin delivery systems) during hospitalisation, provided the patient is capable of independent device management and the institution has established protocols, supplies, training, and competency assessments in place.[1][44] Patient Safety Learning: diabetes - what the tech? poster (June 2024) Opens in new window

Subcutaneous rapid- or short-acting insulin should be given before meals in patients with sufficient oral intake. In patients who are NBM or with poor oral intake, continue basal insulin and use correctional doses as needed.

For patients who were already on insulin at home, their total daily home dose can be used as a starting point for inpatient insulin dosing.

Basal insulin can either be long-acting (e.g., insulin glargine, insulin degludec) or intermediate-acting (e.g., insulin neutral protamine Hagedorn [NPH]).

Long-acting regimens: half the total daily dose as basal insulin (once or twice daily) and the other half divided into premeal rapid-acting doses. Withhold rapid-acting insulin if the patient is not eating; basal insulin should still be continued.[49]

Intermediate-acting regimens: two-thirds of the total daily dose in the morning (two-thirds insulin NPH + one-third rapid-acting), and one-third in the evening (split into half insulin NPH and half rapid-acting insulin at the evening meal or bedtime).[49]

Second-generation basal insulins, such as insulin glargine (300 units/mL) and insulin degludec (100 units/mL and 200 units/mL), have lower peak-to-trough ratios, have longer duration of action than the first-generation basal insulins, and provide less glycaemic variability. Patients who use these preparations can be continued on them while in the hospital.[51][52]

Based on the findings of one randomised controlled trial that compared basal-bolus insulin with and without supplemental short-acting insulin at bedtime to correct hyperglycaemia, the use of fast-acting insulin at bedtime to correct hyperglycaemia is not recommended for inpatients with type 2 diabetes.[53]

Hypoglycaemia should be avoided by regular monitoring of blood glucose and changes in therapy as needed (e.g., reducing insulin).

A paediatric endocrinologist should be consulted for children.

Consult local protocols for guidance on suitable insulin doses and regimens.

Primary options

insulin aspart: subcutaneously before each meal

insulin glulisine: subcutaneously before each meal

insulin lispro: subcutaneously before each meal

-- AND --

insulin isophane human (NPH): subcutaneously twice daily, preferably in the morning and at bedtime

insulin glargine: subcutaneously once daily, preferably at bedtime

insulin degludec: subcutaneously once daily

Plus – supportive care

Back

Plus –

supportive care

Treatment recommended for ALL patients in selected patient group

Supportive care should address electrolyte imbalances, nutritional needs, and fluid balance.

Electrolytes should be monitored and corrected as required. Potassium should be added to intravenous fluids according to local ward protocols to prevent or treat hypokalaemia.

In all patients, adequate nutrition and fluid replacement should be ensured. Enteral nutrition or total parenteral nutrition (TPN) may be required in patients who are not eating.[1]

If TPN is used, insulin can be added directly to the TPN solution - particularly if more than 20 units of correctional insulin have been needed in the previous 24 hours - or administered as a separate intravenous infusion.[1] A starting insulin dose of 1 unit of neutral human insulin per 10 g of glucose is recommended, with daily adjustments as needed.[1]

For individuals receiving enteral nutrition, insulin orders should address basal, prandial, and correctional needs. Most adults already receiving basal insulin should continue their usual dose.[1] The prandial insulin component can be estimated at 1 unit per 10-15 g of carbohydrate delivered by the feeding formula.[1] Insulin selection and timing should match the feeding schedule: for continuous enteral feeds, options include insulin neutral protamine Hagedorn every 8-12 hours or neutral insulin every 6 hours, given their longer duration of action. For bolus enteral feedings, rapid-acting or neutral insulin should be administered before each feed, with correctional insulin added as needed.[1]

Because continuous enteral or parenteral feeding creates a constant postprandial state, attempting to lower glucose below 7.8 mmol/L (140 mg/dL) significantly increases the risk of hypoglycaemia.[1] Frequent insulin dose adjustments are necessary, and correctional insulin may be given every 6 hours (neutral insulin) or every 4 hours (rapid-acting insulin), depending on the regimen.[1] In the event of enteral nutrition interruption, glucose-containing intravenous fluids should be started immediately, particularly in individuals with type 1 diabetes, to prevent hypoglycaemia and reduce the risk of diabetic ketoacidosis.[1]

Plus – follow-up and optimisation of outpatient antidiabetic treatment

Back

Plus –

follow-up and optimisation of outpatient antidiabetic treatment

Treatment recommended for ALL patients in selected patient group

Measurement of HbA1c is valuable in determining the plan at discharge. A high HbA1c indicates poor pre-existing control and suggests need for increased or modified antidiabetic therapy (e.g., starting insulin or maximising oral drugs).[3][33]

A wide range of therapy is available for long-term diabetes management. Some patients may need to continue taking insulin at home until complete recovery allows a transition to other therapies.[34]

Patients without known diabetes should receive outpatient follow-up to reassess glucose levels and determine the need for ongoing treatment or diagnostic evaluation.

stable non-critical illness: well-controlled known diabetes

eating normally

1st line – continuation of usual anti-diabetic regimen + treatment of comorbid illness

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1st line –

continuation of usual anti-diabetic regimen + treatment of comorbid illness

For hospitalised patients with diabetes who are clinically stable, have well-controlled blood glucose levels, and maintain consistent oral intake, continuation of their usual outpatient antidiabetic regimen may be appropriate.[34] However, inpatient management should be individualised based on comorbid conditions, risk of hypoglycaemia, and the potential for fasting (nil by mouth [NBM]) status. Insulin remains the preferred form of treatment for most inpatients, particularly those with hyperglycaemia or unpredictable oral intake.

Type 1 diabetes: patients admitted to the hospital who have well-controlled blood glucose levels can continue taking their usual insulin regimen if meal consumption remains similar to home intake. The American Diabetes Association (ADA) recommends a basal and correction insulin regimen for all hospitalised patients with type 1 diabetes, regardless of oral intake status, with prandial insulin added if the patient is eating.[1] Mealtime insulin doses may need to be adjusted depending on food intake.

Type 2 diabetes: there is no strong evidence to suggest whether patients with type 2 diabetes should continue oral antidiabetic drugs during hospitalisation (when able). Most patients are switched to a basal-bolus insulin regimen, especially in the presence of hyperglycaemia or unpredictable oral intake. However, for patients with well-controlled glycaemic levels who are eating consistently and have no contraindications, continuation of oral agents may be considered if it is unlikely that the patient will be made NBM.

Patients on metformin should be closely monitored given its contraindications (including renal impairment, heart failure, and contrast imaging), and it is often discontinued during hospitalisation. However, recent large observational studies suggest it may be safely continued in select, clinically stable patients.[54][55]

Sodium-glucose cotransporter-2 (SGLT2) inhibitors should be discontinued on admission due to the risk of euglycaemic diabetic ketoacidosis, particularly in surgical patients; they should be stopped 3 days prior to elective procedures (4 days for ertugliflozin).[1][56] Despite these concerns, the use of SGLT2 inhibitors in the hospital setting remains a subject of active investigation, with emerging data suggesting benefit in select populations.[57] The ADA recommends that patients with type 2 diabetes hospitalised with heart failure be started or continued on an SGLT2 inhibitor after recovery from the acute illness, provided there are no contraindications.[1]

Thiazolidinediones are not recommended in patients presenting with fluid overload or heart failure due to their risk of exacerbating volume retention.

In select patients with type 2 diabetes and mild hyperglycaemia, the Endocrine Society suggests that a dipeptidyl peptidase-4 (DPP-4) inhibitor with correctional insulin or scheduled insulin therapy can be used.[4] This approach is appropriate for patients with recent haemoglobin A1c <58 mmol/mol (<7.5%), blood glucose consistently <10.0 mmol/L (<180 mg/dL), and, if previously insulin-treated, a total daily dose <0.6 units/kg/day.[4] Patients whose blood glucose levels remain persistently raised while on a DPP-4 inhibitor should be transitioned to scheduled insulin.[4] These recommendations do not apply to patients with type 1 diabetes or insulin-dependent forms of diabetes.[4] For any new therapy initiated during hospitalisation with plans for outpatient continuation, clinicians should discuss cost and patient preference before discharge.[4]

Drugs with hypoglycaemic effects (e.g., sulfonylureas, meglitinides) may be difficult to dose appropriately with changes in the patient's feeding status and are generally not recommended.

Use of insulin on the general ward should be based on a basal-bolus approach.[49]

For subcutaneous insulin, basal insulin can either be long-acting (insulin glargine, insulin degludec) or intermediate-acting (insulin neutral protamine Hagedorn [NPH]). Second-generation basal insulins, such as insulin glargine (300 units/mL) and insulin degludec (100 units/mL and 200 units/mL), have lower peak-to-trough ratios, have longer duration of action than the first-generation basal insulins, and provide less glycaemic variability. Patients who use these preparations can be continued on these while in the hospital.[51][52]

For regimens using long-acting insulin, one half of the total daily dose is given as long-acting insulin and one half as rapid-acting insulin. Long-acting insulin should be given once or twice daily. Rapid-acting insulin should be given in divided doses before each meal (and held if the patient is not eating, although basal insulin should always be continued).[49]

For regimens using intermediate-acting insulin, two-thirds of the total daily dose is given in the morning (further divided into two-thirds insulin NPH and one-third fast-acting insulin), and the remaining one-third in the evening (further divided into half fast-acting with the evening meal and half insulin NPH at bedtime).

The use of sliding scale insulin alone is not recommended, although it may be used on occasion for 24 hours to determine the insulin requirements in some patients.

The ADA and the Endocrine Society recommend blood glucose targets of 5.6 to 10.0 mmol/L (100-180 mg/dL) for non-critically ill patients, if achievable without significant hypoglycaemia.[1][4]

In hospitalised patients with diabetes who are eating, capillary blood glucose (CBG) monitoring should be conducted before meals.[1] Although CBG remains the standard for inpatient glucose monitoring, emerging research has explored the use of ambulatory continuous glucose monitoring (CGM) in non-critically ill hospital patients. Initial studies on one such device suggest that it may help to reduce both hyperglycaemia and hypoglycaemia in non-intensive care unit settings.[38] Several CGM devices have been approved for hospital use in Europe (most sample glucose through the intravascular route, and one through the subcutaneous route) and in the US (intravascular route). Real-time CGM has been shown to lower the incidence of hypoglycaemia, although it may increase nursing workload.[39] During the coronavirus disease 2019 (COVID-19) pandemic, there was increasing utilisation of ambulatory CGM devices in the hospital setting. Inpatient data suggest that CGM devices offer accuracy comparable to CBG testing in many situations, with the added benefit of enhanced detection and prevention of glycaemic excursions.[40][41][42][43]

Nutrition status, comorbidities, and procedures requiring fasting (NBM) should be considered in treatment planning.

Consult local protocols for guidance on suitable insulin doses and regimens.

Primary options

insulin aspart: subcutaneously before each meal

insulin glulisine: subcutaneously before each meal

insulin lispro: subcutaneously before each meal

-- AND --

insulin isophane human (NPH): subcutaneously twice daily, preferably in the morning and at bedtime

insulin glargine: subcutaneously once daily, preferably at bedtime

insulin degludec: subcutaneously once daily

not eating

1st line – insulin + treatment of comorbid illness

Back

1st line –

insulin + treatment of comorbid illness

For patients who are not taking anything by mouth the American Diabetes Association (ADA) recommends an insulin schedule with basal and correction components.[1]

Hypoglycaemia should be avoided by regular monitoring of blood glucose and changes in therapy as needed (e.g., reducing insulin).

In hospitalised patients with diabetes who are not eating, glucose monitoring is recommended every 4-6 hours.[1] Although capillary blood glucose (CBG) remains the standard for inpatient glucose monitoring, emerging research has explored the use of ambulatory continuous glucose monitoring (CGM) in non-critically ill hospital patients. Initial studies on one such device suggest that it may help to reduce both hyperglycaemia and hypoglycaemia in non-intensive care unit settings.[38] Several CGM devices have been approved for hospital use in Europe (most sample glucose through the intravascular route, and one through the subcutaneous route) and in the US (intravascular route). Real-time CGM has been shown to lower the incidence of hypoglycaemia, although it may increase nursing workload.[39] During the Coronavirus disease 2019 (COVID-19) pandemic, there was increasing utilisation of ambulatory CGM devices in the hospital setting. Inpatient data suggest that CGM devices offer accuracy comparable to CBG testing in many situations, with the added benefit of enhanced detection and prevention of glycaemic excursions.[40][41][42][43]

Patients at high risk for hypoglycaemia who might benefit from the initiation of inpatient CGM include those with impaired awareness of hypoglycaemia, individuals aged 65 years and older, and those with a body mass index ≤27 kg/m².[4] Additional risk factors include a total daily insulin dose ≥0.6 units/kg and a history of significant comorbidities such as stage ≥3 chronic kidney disease (estimated glomerular filtration rate <60 mL/min/1.73 m²), liver failure, cerebrovascular accident, active malignancy, pancreatic disorders, congestive heart failure, or infection.[4] Individuals with a history of hypoglycaemia prior to admission or those who have experienced hypoglycaemia during a recent or current hospitalisation are also considered high-risk.[4]

It is important to note that inpatient CGM use is not currently FDA-approved but is allowed under enforcement discretion and was utilised with emergency use authorisation during the COVID-19 pandemic.[44] Both the Endocrine Society and ADA also encourage the continued use of closed-loop insulin pumps (automated insulin delivery systems) during hospitalisation, provided the patient is capable of independent device management and the institution has established protocols, supplies, training, and competency assessments in place.[1][44] Patient Safety Learning: diabetes - what the tech? poster (June 2024) Opens in new window

Consult local protocols for guidance on suitable insulin doses and regimens.

Primary options

insulin isophane human (NPH): subcutaneously twice daily, preferably in the morning and at bedtime

insulin glargine: subcutaneously once daily, preferably at bedtime

insulin degludec: subcutaneously once daily

-- AND --

insulin aspart: subcutaneously before each meal

insulin glulisine: subcutaneously before each meal

insulin lispro: subcutaneously before each meal

hypoglycaemia (blood glucose <3.9 mmol/L [<70 mg/dL])

able to take orally

1st line – oral carbohydrate + adjustment of diabetic regimen

Back

1st line –

oral carbohydrate + adjustment of diabetic regimen

Mild hypoglycaemia in patients capable of oral intake can be managed with oral glucose or fruit juice.

Patients at increased risk of hypoglycaemia include those with reduced nutritional intake, malnutrition, renal or hepatic impairment, heart failure, malignancy, infection, sepsis, older age, and cognitive impairment.[1][3][21]

Compared with sliding scale insulin, basal-bolus insulin is more frequently associated with hypoglycaemia.[26][34] Insulin-induced hypoglycaemia can lead to neuroglycopenia. Hypoglycaemia is associated with worse outcomes, especially in intensive care unit (ICU) patients. Sedation or beta-blocker use may mask symptoms of neuroglycopenia, and counter-regulatory responses can be impaired. Additionally, changes in corticosteroid dosing, reductions in intravenous glucose or parenteral nutrition, or alterations in oral nutritional intake may contribute to hypoglycaemia. Oral insulin secretagogues (sulfonylureas or meglitinides) may also precipitate hypoglycaemia.

The American Diabetes Association (ADA) and the American Association of Clinical Endocrinology (AACE) recommend reassessing the insulin regimen when a patient's blood glucose falls below 5.6 mmol/L (100 mg/dL), and modifying the regimen if glucose drops below 3.9 mmol/L (70 mg/dL).[1][3][21]

To prevent hypoglycaemia, frequent glucose monitoring and timely treatment modifications - such as promptly reducing insulin infusion rates - are essential.

In hospitalised patients with diabetes who are not eating, glucose monitoring is recommended every 4-6 hours.[1] Although capillary blood glucose (CBG) remains the standard for inpatient glucose monitoring, emerging research has explored the use of ambulatory continuous glucose monitoring (CGM) in non-critically ill hospital patients. Initial studies on one such device suggest that it may help to reduce both hyperglycaemia and hypoglycaemia in non-ICU settings.[38] Several CGM devices have been approved for hospital use in Europe (most sample glucose through the intravascular route, and one through the subcutaneous route) and in the US (intravascular route). Real-time CGM has been shown to lower the incidence of hypoglycaemia, although it may increase nursing workload.[39] During the coronavirus disease 2019 (COVID-19) pandemic, there was increasing utilisation of ambulatory CGM devices in the hospital setting. Inpatient data suggest that CGM devices offer accuracy comparable to CBG testing in many situations, with the added benefit of enhanced detection and prevention of glycaemic excursions.[40][41][42][43]

See Diabetic hypoglycaemia.

2nd line – glucose or glucagon

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2nd line –

glucose or glucagon

If hypoglycaemia is severe or refractory to oral treatment, glucose should be given intravenously and blood glucose monitored closely for the next hour. Alternatively, glucagon can be given intramuscularly.

See Diabetic hypoglycaemia.

Primary options

glucose: (50%) 25-50 mL intravenously as a single dose

glucagon: 1 mg intramuscularly as a single dose, may repeat in 20 minutes as needed

unable to take orally

1st line – glucose or glucagon + adjustment of diabetic regimen

Back

1st line –

glucose or glucagon + adjustment of diabetic regimen

If patients are unable to take treatment orally, glucose should be given intravenously and blood glucose monitored closely for the next hour. Alternatively, glucagon can be given intramuscularly.

To prevent hypoglycaemia, frequent glucose monitoring and timely treatment modifications - such as promptly reducing insulin infusion rates are essential.

In hospitalised patients with diabetes who are not eating, glucose monitoring is recommended every 4-6 hours.[1] Although capillary blood glucose (CBG) remains the standard for inpatient glucose monitoring, emerging research has explored the use of ambulatory continuous glucose monitoring (CGM) in non-critically ill hospital patients. Initial studies on one such device suggest that it may help to reduce both hyperglycaemia and hypoglycaemia in non-ICU settings.[38] Several CGM devices have been approved for hospital use in Europe (most sample glucose through the intravascular route, and one through the subcutaneous route) and in the US (intravascular route). Real-time CGM has been shown to lower the incidence of hypoglycaemia, although it may increase nursing workload.[39] During the coronavirus disease 2019 (COVID-19) pandemic, there was increasing utilisation of ambulatory CGM devices in the hospital setting. Inpatient data suggest that CGM devices offer accuracy comparable to CBG testing in many situations, with the added benefit of enhanced detection and prevention of glycaemic excursions.[40][41][42][43]

See Diabetic hypoglycaemia.

Primary options

glucose: (50%) 25-50 mL intravenously as a single dose

glucagon: 1 mg intramuscularly as a single dose, may repeat in 20 minutes as needed

preoperative: minor elective surgery

1st line – management of diabetic regimen

Back

1st line –

management of diabetic regimen

For adults with diabetes scheduled to undergo elective surgery, the Endocrine Society recommends aiming for a preoperative haemoglobin A1c (HbA1c) of <63.9 mmol/mol (<8%) and maintaining blood glucose levels between 5.6 and 10.0 mmol/L (100 and 180 mg/dL).[4] These recommendations apply only to patients undergoing elective procedures where there is sufficient time to optimise glucose control in advance. Blood glucose levels should also be within the target range during the 1-4 hours prior to surgery.[4]

Clinicians should be aware that factors such as anaemia, haemoglobinopathies, chronic kidney disease, alcohol use, certain drugs, and significant glucose variability can affect HbA1c readings and should be considered when assessing glycaemic control.[4]

Patients admitted for minor elective surgery who take oral antidiabetic drugs may continue their oral drugs if the procedure is short and the patient is expected to resume eating later the same day.

For longer, more complicated procedures, oral drugs are usually discontinued in favour of starting basal-bolus insulin given subcutaneously starting on the day of surgery.

Regarding glucagon-like peptide-1 (GLP-1) receptor agonists, a 2024 multisociety clinical practice guidance, endorsed by the American Society of Anesthesiologists (ASA) and other specialty groups, recommends a shared decision-making approach between anaesthesia, surgical, and prescribing teams.[58] This includes assessing individual risk factors for delayed gastric emptying and aspiration, such as being in a dose escalation phase, use of higher-dose or weekly formulations, presence of gastrointestinal symptoms (e.g., nausea, vomiting, abdominal pain, constipation), or comorbidities like gastroparesis or Parkinson’s disease. For patients without elevated risk, GLP-1 receptor agonist therapy may be continued perioperatively.[58] In patients with increased risk, discontinuation should be considered, with the ASA recommending holding daily formulations on the day of surgery and weekly formulations at least 7 days prior to elective procedures.[58][59] Preoperative risk mitigation strategies - such as a 24-hour pre-procedure liquid diet, use of gastric ultrasound when available, or anaesthesia adjustments like rapid sequence induction - may further reduce aspiration risk.[58] The American Diabetes Association (ADA) similarly advises that perioperative decisions be individualised based on factors including the indication for therapy (e.g., diabetes vs. obesity), current glycaemic control, surgical urgency, type of anaesthesia, and institutional resources.[1] If withholding a GLP-1 receptor agonist (or dual glucose-dependent insulinotropic polypeptide [GIP]/GLP-1 receptor agonist) is expected to worsen glycaemic outcomes, the ADA recommends considering alternative perioperative glycaemic management, such as insulin therapy.[1]

For patients using insulin before hospitalisation, perioperative insulin adjustments may be required. The dose of intermediate-acting insulin is reduced by 30% to 50% the evening before surgery. True basal insulins such as insulin glargine or insulin degludec can usually be given at or close to their routine dose. Rapid-acting insulins are held while the patient is not eating.

Long and complicated surgical procedures may require intravenous insulin infusion to maintain optimal glucose control, with several established protocols available. Once patients are clinically stable postoperatively, a transition from intravenous to subcutaneous insulin is recommended. This typically involves reducing the total 24-hour intravenous insulin dose by 20%, then administering 50% of the adjusted total as basal insulin and the remaining 50% as prandial insulin divided over meals.

The ADA and the Endocrine Society recommend maintaining inpatient blood glucose targets of 5.6 to 10.0 mmol/L (100-180 mg/dL) for non-critically ill hospitalised adults with diabetes, provided these targets can be achieved safely without significant hypoglycaemia.[1][4]

To prevent hypoglycaemia, frequent glucose monitoring and timely treatment modifications - such as promptly reducing insulin infusion rates are essential. In hospitalised patients with diabetes who are not eating, glucose monitoring is recommended every 4-6 hours.[1] Although capillary blood glucose (CBG) remains the standard for inpatient glucose monitoring, emerging research has explored the use of ambulatory continuous glucose monitoring (CGM) in non-critically ill hospital patients. Initial studies on one such device suggest that it may help to reduce both hyperglycaemia and hypoglycaemia in non-intensive care unit settings.[38] Several CGM devices have been approved for hospital use in Europe (most sample glucose through the intravascular route, and one through the subcutaneous route) and in the US (intravascular route). Real-time CGM has been shown to lower the incidence of hypoglycaemia, although it may increase nursing workload.[39] During the coronavirus disease 2019 (COVID-19) pandemic, there was increasing utilisation of ambulatory CGM devices in the hospital setting. Inpatient data suggest that CGM devices offer accuracy comparable to CBG testing in many situations, with the added benefit of enhanced detection and prevention of glycaemic excursions.[40][41][42][43]

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Inpatient glycaemic management

Treatment algorithm

critically ill or unplanned surgery or in intensive care unit (ICU): hyperglycaemia (blood glucose levels >7.8 mmol/L [>140 mg/dL])

insulin + treatment of comorbid illness

Primary options

supportive care

follow-up and optimisation of outpatient antidiabetic treatment

stable non-critical illness: uncontrolled hyperglycaemia (blood glucose levels >7.8 mmol/L [>140 mg/dL])

insulin + treatment of comorbid illness

Primary options

supportive care

follow-up and optimisation of outpatient antidiabetic treatment

stable non-critical illness: well-controlled known diabetes

continuation of usual anti-diabetic regimen + treatment of comorbid illness

Primary options

insulin + treatment of comorbid illness

Primary options

hypoglycaemia (blood glucose <3.9 mmol/L [<70 mg/dL])

oral carbohydrate + adjustment of diabetic regimen

glucose or glucagon

Primary options

glucose or glucagon + adjustment of diabetic regimen

Primary options

preoperative: minor elective surgery

management of diabetic regimen