Dilemmas in Inpatient Diabetes Management

  • Admission A1c Interpretation
  • Inpatient Glucose Goals
  • Medications to Use and Avoid
  • Enteral and Parenteral Feedings
  • Glucocorticoid Use
Why do glucose levels go up in the hospital?
  • GH, cortisol, catecholamines and glucagon all increase under physiologic stress.
  • This increases gluconeogenesis, glycogenolysis, and insulin resistance increases.
Do higher glucoses impair outcomes?
  • Glucose > 180 impairs PMN function
  • Impaired protein synthesis/healing
  • Dehydration due to fluid shifts and glucose-related diuresis
  • Impaired myocardial metabolism
  • Increased inflammatory cytokines
References:  Moghissi E, Diabetes Care 2009; 32:1119ff. and Umpierrez G, J Clin Endocrinol Metab 2012; 97:16
Hypoglycemia can also be an issue in the hospital:
  • They’re NPO
  • Medication errors (insulin dosing errors are common)
  • Liver dysfunction (most important glucose-producing organ in the body)
  • Renal dysfunction (second most important glucose-producing organ, and metabolizes insulin)
  • Diet changes in the hospital
  • Low glucose causes a catecholamine spike, and then myocardial O2 demand and arrhythmia risk.
  • If A1c < 5.7% and inpatient glucose high = stress hyperglycemia but no DM.
  • A1c 5.7-6.4% and inpatient glucose high = stress hyperglycemia AND pre-diabetes.
  • A1c 6.5-8.0% and inpatient glucose high = stress hyperglycemia and well-controlled diabetes.
  • A high A1c on admission means you need to address their outpatient regimen at discharge!  
  • Goal is fasting < 140, random < 180.
  • Insulin should be initiated if any blood glucose readings are > 180.
  • Non-critically ill pts:  fasting goal 90-140, all BGs < 180.
  • Critically ill patients:  140-180.
  • Metformin and glipizide should be stopped on admission; basal and CF insulin should be substituted.
  • Type I diabetes:  Insulin only
    • Basal – bolus insulin regimen
    • Basal insulin should be given whether they are NPO or not!  Give 75-100% of home dose depending on:
      • home control (A1c) – if well-controlled at home, drop the dose to 75%; if poor control, may need 100%.
      • eating or NPO status
      • if no records or not sure where to start:  0.1-0.2 U/kg weight; approx 50% of total daily dose of insulin.
    • Best time to give meal-time CF insulin is about 15 mins prior to a meal, but this is not always practical even in the hospital.  It’s okay to give the CF right after the meal for safety – at least you know they ate something.
    • Home mealtime (prandial) dose continued, or…C:I ratio (carbohydrate:insulin) of 15 g CHO: 1 unit insulin.
    • Correction component – with the CF or alone.
      • use home correction factor or CF of 50:1 – 1 unit per 50 mg/dL over 150 mg/dL.
  • Type II diabetes:  more variation – lifestyle only, PO meds, insulin regimens…
    • Insulin is the preferred agent for achieving glucose control in hospitalized patients.
    • Non-insulin therapies should be discontinued in most patients.
      • SUs:  stop almost always (risk of no meal)
      • meglitinides:  stop almost always (risk of no meal)
      • metformin:  usually stop (chance of AKI)
      • TZDs:  usually stop (risk of HF or edema)
      • new agents – usually stop as well
    • Situation 1:  Lifestyle management only, A1c well-controlled
      • POC glucose measurement QID x 24-48h, continue if hyperglycemia
      • If BG > 180 – correction doses with short-acting insulin (50:1 correction factor, 1 unit per 50 mg/dL above target)
      • Start basal insulin if 3+ correction doses are needed per day.  Start at 0.2-0.3 U/kg/d.
      • If postprandial sugars high despite the above, start prandial/nutritional insulin too with a C:I ratio of 15:1.
    • Situation 2:  Uncontrolled on lifestyle mgmt or on non-insulin treatment (PO agents)
      • QID testing
      • Start basal right away 0.2-0.3 U/kg/day
      • Correction insulin if glucoses > 180 at ratio of 25:1 above target 150 mg/dL
      • Add mealtime insulin if post-prandial sugars are still high.
    • Situation 3:  Basal insulin +/- PO agents
      • Start basal insulin (home dose usually okay or 0.2-0.3 U/kg/d)
      • Correction dose if sugars > 180 (25:1 ratio)
      • Mealtime insulin if post-prandial sugars high (C:I ratio of 15:1)
    • Situation 4:  Basal / Bolus insulin therapy
      • Basal insulin at all times – if you stop it, they’ll get ketotic
      • Treat this a lot like T1DM
      • Use 75-100% of their home dose depending on their A1c (lower doses if well-controlled)
      • Mealtime insulin and correction factors:  home doses or C:I 10:1 (mealtime)
  • BG testing every 4-6 hours for 24-48h in ALL patients on EN/PN.
  • Start scheduled insulin if BG > 140 and needing persistent correction doses.
  • Use an insulin that has a duration of action consistent with the duration of feeding!
    • Aspart, lispro – bolus feedings
    • Glargine or 70/30 BID-TID – continuous feedings
  • C:I ratio is 15:1 – CHO 15 gram for each unit of insulin if pt diabetic (25:1 if non-DM hyperglycemia).  CHO content should be available from the chart or dietician.
  • Correction doses q 6 hours:  CF 50:1 (1 unit for every 50 mg/dL above target 150 mg/dL).
  • 70/30 or NPH BID to TID is appropriate for continuous tube feeding.  This is preferred to glargine or detemir because tube feeds are sometimes stopped!
    • Dose is C:I ratio of 15:1 (DM) or 25:1 (non-DM).
    • Correction dose q 6 hours CF 50:1 to target of 150 mg/dL
  • Example:
    • Pt getting TF with 282 g CHO/day
    • At ratio of 15:1, he needs 18 units of insulin daily
    • So, give NPH 6 units TID.
  • Short-acting insulin can be given in TPN!  Use C:I ratio of 15:1.
  • If EN/PN is stopped (inadvertently or purposefully), be aware of when you gave your last insulin and what kind of insulin – will need to cover that insulin with D5 or D10 (try to give same CHO content as EN/PN).
  • Typical pattern with QD prednisone or methylprednisolone:  fasting glucose is okay, but post-lunch and post-dinner levels very high.  Usually starts to decrease again after 14 hours or so.
  • A nice way to correct this is:  morning NPH and as-needed pre-meal correction insulin.
  • BG testing QID x 24-48 hours after starting glucocorticoid therapy REGARDLESS of their hx of diabetes!
  • Start by giving CF 25:1 to target 150 mg/dL
  • If needing persistent CF, then start basal insulin (consider NPH with the morning dose).
  • NPH dose 10 U (sensitive) or 20 U (resistant) per 40mg of prednisone/methylprednisolone
  • Give NPH BID if they’re getting BID steroids.
  • This can be added even if the patient is on an insulin pump or as an add-on to an existing insulin regimen!
  • Intra-articular steroids will also raise sugar (obviously), but the rise is all day long, not the kinetics seen with PO prednisone.
  • Reference:  Seggelke S, J Hosp Med 2011; 6:175-6
 – From Rocky Mountain Hospital Medicine, 2016, McDermott

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