Table 1—

Evidence for association of blood glucose level with clinical outcomes

Clinical settingThreshold BG levels [mg/dl, (mmol/l)]Outcomes and comments
General medicine and surgeryMortality, ICU admits, length of stay, and nursing home or transitional care admits correlated with BG and glucose tolerance status:Review of BG levels of patients on general medicine and surgery wards. Hyperglycemia defined as two or more measurements with fasting BG ≥126 (7) and/or random ≥200 (11.1). Hospital mortality for normoglycemic patients was 1.7%. With known diabetes mortality was 3% and with “new” hyperglycemia it was 16%. After adjustment for variables, the “new” hyperglycemia group had an 18.3-fold increased mortality rate compared with a 2.7-fold increase with known diabetes. Patients with new hyperglycemia also had an increased length of stay, were more likely to require ICU care, and were more likely to require transitional or nursing home care (Obs, n = 1,886) (1).
 Normoglycemia = 108 ± 10.8 (6 ± 0.6);
 New hyperglycemia = 189 ± 18 (10.5 ± 1);
 Known diabetes = 230.4 ± 18 (12.8 ± 1).
Infection rates correlated with BG above 220.5.9-fold increase in serious infections, including sepsis, pneumonia, and wound infections for BG over 220 (12.2), which was a sensitive (85%) predictor of nosocomial infection (Obs, n = 97) (191).
CVD and critical care
 Acute MIMortality, CHF, and cardiogenic shock risk correlated with BGLiterature review. Relative risk (RR) for inhospital mortality increased 3.9-fold in subjects without diabetes with BG at or above range of 109.8–144 (6.1–8), 95% CI 2.9–5.4; risk of CHF and cardiogenic shock was also increased. RR for moderate increase in mortality with known diabetes with was 1.7 (14 article review with meta-analysis) (192).
 Above 109.8 (6), in patients without known diabetes;
 At or above 124 (6.9), with diabetes diagnosis.
Admit BG, stratified according to WHO criteria and correlated with mortality:One-year mortality was 19.3% for BG <100.8 (5.6) at time of admission, compared with 44% when BG ≥199.8 (11). Mortality was higher in patients with diabetes than in those without (40 vs. 16%, P < 0.05) (Obs, n = 336) (193).
  I. BG less than 100.8 (5.6) to
  IV. BG greater than or equal to 199.8 (11)
Mortality correlated with BG in intensive insulin therapy group where mean BG = 172.8 ± 59.4 (9.6 ± 3.3) compared with conventional therapy group where mean BG = 210.6 ± 73.8 (11.7 ± 4.1).Intensive insulin therapy in patients with acute MI, followed by multishot regimen for 3 or more months, with 29% reduction in mortality at 1 year. Benefit extends to at least 3.4 years. One life saved for nine patients treated (Int, n = 620) (128).
 Cardiac surgeryMortality positively correlated with BG in a dose-dependent manner, with the lowest mortality in the group where mean postoperative BG <150 (8.3).Observational studies using historical controls. Both mortality and incidence of DSWIs were reduced to the nondiabetic range after implementing insulin infusion protocols with progressively lower BG targets over time (196,197).
 Critical careMortality and sepsis risk correlated with BG. Intensive insulin therapy arm with mean BG 103 ± 19 (5.7 ± 1.06); conventional treatment arm with mean BG 153 ± 33 (8.5 ± 1.8).Prospective randomized controlled study of adults admitted to surgical ICU and on mechanical ventilation. Sixty percent had had cardiac surgery, majority of others also surgical patients. IIT to maintain BG in 80–110 (4.4–6.1) range compared with conventional therapy (CT) to target BG to 180–200 (10–11.1). IIT reduced ICU mortality by 40% from 8.0 to 4.6%, P < 0.04. For each 20 mg/dl increase in BG, risk of death was increased by 30%. IIT also reduced incidence of sepsis by 46% and overall hospital mortality by 34%. A gradual decline in risk for ICU and hospital death with decline in BG level was observed, with no identifiable threshold below which there was no further risk reduction. Prolonged inflammation, defined as elevation in CRP above 150 mg/dl for over 3 days, was associated with mean BG level (per 20 mg/dl added) with or of 1.16 (95% CI 1.06–1.24), P = 0.0006. Threshold may be higher than 110 (6.1) (Int, n = 1,548) (2,200).
Neurologic disorders
 Acute strokeMortality and functional recovery after acute ischemic stroke correlated with BG. Admission BG over 110 (6.1) for mortality; over 121 for functional recovery.Literature review (1966–2000). After ischemic stroke, admission glucose level >110–126 (>6.1–7) associated with increased risk of in hospital or 30-day mortality in patients without diabetes only (RR 3.8; 95% CI 2.32–4.64). Stroke survivors without diabetes and BG over 121–144 (6.7–8) had RR of 1.41 (1.16–1.73) for poor functional recovery (metaanalysis, 26 studies) (96).
Neurologic function after acute stroke correlated with admission BG.Controlled, randomized trial of molecular heparin in acute stroke. Mean admission BG 144 ± 68 (8 ± 3.8) associated with neurologic improvement at 3 months. In those without improvement, BG was 160 ± 84 (8.9 ± 4.7). As BG increased, odds for neurologic improvement decreased, with OR = 0.76 per 100-mg/dl increase in admission BG (95% CI 0.61–0.95, P = 0.01) (Obs, n = 1,259) (201).
 Odds for neurologic improvement decreased with OR of 0.76 for each 100 mg/dl BG increase.
Functional outcomes and return to work after stroke correlated with admission BG.Prospective data. Stroke-related deficits were more severe when admission glucose values were >120 (6.7). Only 43% of patients with an admission glucose value of >120 mg/dl able to return to work, whereas 76% of patients with lower glucose values regained employment (202).
 Admission BG under 120 (6.7) with positive relationship.
RtPA-induced hemorrhage into an infarct correlated with BG over 300 (16.7).Central collection of retrospective and prospective data on acute ischemic stroke treated in clinical practices with alteplase. BG >300 mg/dl an independent risk factor for hemorrhage into an infarct when treatment with recombinant RtPA is given (Obs, n = 1,205) (203).
Mortality, length of stay, and charges increased with admission BG ≥130 (7.2).Hospitalization for acute ischemic stroke. Hyperglycemia (random BG at or above 130) present in 40% at admission. Most remained hyperglycemic with mean BG values of 206 (11.4). Random admission serum glucose ≥130 (7.2) independently associated with increased risk of death at 30 days (HR 1.87) and 1 year (HR 1.75), both P ≤ 0.01. Other significant correlates with hyperglycemia, when compared with normal BG, were length of stay (7 vs. 6 days, P = 0.015) and charges ($5,262 vs. $6,611, P < 0.001) (Obs, n = 656) (205).
Hypoglycemia risk and 4 week mortality with BG targeted to 72–126 (4–7).Glucose-insulin infusion in acute stroke with mild-to-moderate hyperglycemia. Examined the safety of treating to a target glucose of 72–126 (4–7). Lowering BG was found to be without significant risk of hypoglycemia or 4-week excess mortality in patients with acute stroke and mild-to-moderate hyperglycemia (147).
Penumbral salvage, final infarct size, and functional outcome in patients with median acute BG ranging from 104.4 to 172.8 (5.8–9.6).Study of MRI and MRS in acute stroke. Prospective evaluation with serial diffusion-weighted and perfusion-weighted MRI and acute BG measurements. Median acute BG was 133.2 mg/dl (7.4 mmol/l), range 104.4–172.8 mg/dl (5.8–9.6 mmol/l). A doubling of BG from 5 to 10 mmol/l led to a 60% reduction in penumbral salvage and a 56- cm3 increase in final infarct size. In patients with acute perfusion-diffusion mismatch, acute hyperglycemia was also correlated with reduced salvage of mismatch tissue from infarction, greater final infarct size, and worse functional outcome, independent of baseline stroke severity, lesion size, and diabetic status (Obs, n = 63) (110).
  • BG, blood glucose; CT, conventional therapy; DM, diabetes mellitus; HR, hazard ratio; Int, interventional study; Obs, observational study; RtPA, recombinant tissue plasminogen activator; Rx, therapy.