CI: Blood Glucose Control (2009)

Citation:

Krinsley JS. Association between hyperglycemia and increased hospital mortality in a heterogeneous population of critically ill patients? Mayo Clin Proc. 2003. Dec;78(12):1472-8.

PubMed ID: 14661676
 
Study Design:
Cross-Sectional Study
Class:
D - Click here for explanation of classification scheme.
Quality Rating:
Positive POSITIVE: See Quality Criteria Checklist below.
Research Purpose:
Research Question: Is there a correlation between hyperglycemia in the ICU and mortality?
Inclusion Criteria:
  • admission to intensive care unit
Exclusion Criteria:
  • no plasma glucose values obtained during ICU stay
  • incomplete records of final ICD9 codes
Description of Study Protocol:

Recruitment 

Not recruited: ICU director identified ICU patients for whom plasma glucose values and complete record of final ICD-9 codes were available.

Design

Retrospective CrossSectional Database Study

Blinding used (if applicable)

not used/not applicable

Intervention (if applicable)

No intervention.

Statistical Analysis

  • mean and range compared between survivors and nonsurvivors with use of Wilcoxon test for populations without normal distribution
  • X2 used to test trend of increasing hospital mortality with increasing mean glucose levels and to assess differences in mortality rates among groups of patients
  • Multiple stepwise logistic regression analysis to assess effect on hospital mortality of APACHE II scores
  • level of significance was alpha = .05 for all analyses
Data Collection Summary:

Timing of Measurements

not applicable - these patients were sequentially admitted to ICU

Dependent Variables

  • mortality

Independent Variables

  • glucose values measured by finger stick or plasma glucose level

Control Variables

  • length of stay: measured in increments of 0.1 hr in the ICU
  • need for mechanical ventilation
  • age
  • diagnosis: ICD 9 code
Description of Actual Data Sample:

Initial N: 988 males, 838 females

Attrition (final N): n/a

Age: ranged from 13 to 100 years

Ethnicity: not reported

Other relevant demographics:

Anthropometrics not reported

Location: The Stamford Hospital, Stamford, CT

Summary of Results:

 

Mean glucose (mg/dL)

Mortality Rate (%)

N

80-99

9.6    

264

100-119    

12.2

491

120-139 15.1 338
140-159 18.8 202
160-179 28.4 141
180-199 29.4 102
200-249 37.5 144
250-299 32.9 70

>300

42.5

40

Other Findings

Increasing APACHE scores and increased mean glucose values were independent predictors of hospital mortality.

Author Conclusion:

Even a modest degree of hyperglycemia during the ICU stay was associated with increased hospital mortality. Differences in mean glucose values between survivors and nonsurvivors were greater among nondiabetic patients than among diabetic patients.

Multiple Stepwise Logistic Regression Analysis of Factors Associated with Hospital Mortality

Factor

Regression correlation

P value

APACHE II

-.396

<.001
Mechanical Ventilation

-.130

<.001
Age

-.100

<.001
Mean glucose

-.081

<.001

Funding Source:
University/Hospital: Stamford Hospital
Reviewer Comments:
This was a descriptive paper. Kinsley followed up with another study in 2004 in which a protocol to keep glucose values < 140 was initiated.
Quality Criteria Checklist: Primary Research
Relevance Questions
  1. Would implementing the studied intervention or procedure (if found successful) result in improved outcomes for the patients/clients/population group? (Not Applicable for some epidemiological studies) N/A
  2. Did the authors study an outcome (dependent variable) or topic that the patients/clients/population group would care about? Yes
  3. Is the focus of the intervention or procedure (independent variable) or topic of study a common issue of concern to dieteticspractice? Yes
  4. Is the intervention or procedure feasible? (NA for some epidemiological studies) N/A
 
Validity Questions
1. Was the research question clearly stated? Yes
  1.1. Was (were) the specific intervention(s) or procedure(s) [independent variable(s)] identified? Yes
  1.2. Was (were) the outcome(s) [dependent variable(s)] clearly indicated? Yes
  1.3. Were the target population and setting specified? Yes
2. Was the selection of study subjects/patients free from bias? Yes
  2.1. Were inclusion/exclusion criteria specified (e.g., risk, point in disease progression, diagnostic or prognosis criteria), and with sufficient detail and without omitting criteria critical to the study? Yes
  2.2. Were criteria applied equally to all study groups? Yes
  2.3. Were health, demographics, and other characteristics of subjects described? Yes
  2.4. Were the subjects/patients a representative sample of the relevant population? Yes
3. Were study groups comparable? Yes
  3.1. Was the method of assigning subjects/patients to groups described and unbiased? (Method of randomization identified if RCT) N/A
  3.2. Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline? Yes
  3.3. Were concurrent controls or comparisons used? (Concurrent preferred over historical control or comparison groups.) N/A
  3.4. If cohort study or cross-sectional study, were groups comparable on important confounding factors and/or were preexisting differences accounted for by using appropriate adjustments in statistical analysis? Yes
  3.5. If case control study, were potential confounding factors comparable for cases and controls? (If case series or trial with subjects serving as own control, this criterion is not applicable.) Yes
  3.6. If diagnostic test, was there an independent blind comparison with an appropriate reference standard (e.g., "gold standard")? N/A
4. Was method of handling withdrawals described? N/A
  4.1. Were follow-up methods described and the same for all groups? N/A
  4.2. Was the number, characteristics of withdrawals (i.e., dropouts, lost to follow up, attrition rate) and/or response rate (cross-sectional studies) described for each group? (Follow up goal for a strong study is 80%.) N/A
  4.3. Were all enrolled subjects/patients (in the original sample) accounted for? N/A
  4.4. Were reasons for withdrawals similar across groups? N/A
  4.5. If diagnostic test, was decision to perform reference test not dependent on results of test under study? N/A
5. Was blinding used to prevent introduction of bias? N/A
  5.1. In intervention study, were subjects, clinicians/practitioners, and investigators blinded to treatment group, as appropriate? N/A
  5.2. Were data collectors blinded for outcomes assessment? (If outcome is measured using an objective test, such as a lab value, this criterion is assumed to be met.) Yes
  5.3. In cohort study or cross-sectional study, were measurements of outcomes and risk factors blinded? No
  5.4. In case control study, was case definition explicit and case ascertainment not influenced by exposure status? N/A
  5.5. In diagnostic study, were test results blinded to patient history and other test results? N/A
6. Were intervention/therapeutic regimens/exposure factor or procedure and any comparison(s) described in detail? Were interveningfactors described? Yes
  6.1. In RCT or other intervention trial, were protocols described for all regimens studied? N/A
  6.2. In observational study, were interventions, study settings, and clinicians/provider described? Yes
  6.3. Was the intensity and duration of the intervention or exposure factor sufficient to produce a meaningful effect? Yes
  6.4. Was the amount of exposure and, if relevant, subject/patient compliance measured? Yes
  6.5. Were co-interventions (e.g., ancillary treatments, other therapies) described? Yes
  6.6. Were extra or unplanned treatments described? N/A
  6.7. Was the information for 6.4, 6.5, and 6.6 assessed the same way for all groups? N/A
  6.8. In diagnostic study, were details of test administration and replication sufficient? N/A
7. Were outcomes clearly defined and the measurements valid and reliable? Yes
  7.1. Were primary and secondary endpoints described and relevant to the question? Yes
  7.2. Were nutrition measures appropriate to question and outcomes of concern? N/A
  7.3. Was the period of follow-up long enough for important outcome(s) to occur? Yes
  7.4. Were the observations and measurements based on standard, valid, and reliable data collection instruments/tests/procedures? Yes
  7.5. Was the measurement of effect at an appropriate level of precision? Yes
  7.6. Were other factors accounted for (measured) that could affect outcomes? Yes
  7.7. Were the measurements conducted consistently across groups? Yes
8. Was the statistical analysis appropriate for the study design and type of outcome indicators? Yes
  8.1. Were statistical analyses adequately described and the results reported appropriately? Yes
  8.2. Were correct statistical tests used and assumptions of test not violated? Yes
  8.3. Were statistics reported with levels of significance and/or confidence intervals? Yes
  8.4. Was "intent to treat" analysis of outcomes done (and as appropriate, was there an analysis of outcomes for those maximally exposed or a dose-response analysis)? N/A
  8.5. Were adequate adjustments made for effects of confounding factors that might have affected the outcomes (e.g., multivariate analyses)? Yes
  8.6. Was clinical significance as well as statistical significance reported? N/A
  8.7. If negative findings, was a power calculation reported to address type 2 error? N/A
9. Are conclusions supported by results with biases and limitations taken into consideration? Yes
  9.1. Is there a discussion of findings? Yes
  9.2. Are biases and study limitations identified and discussed? Yes
10. Is bias due to study's funding or sponsorship unlikely? No
  10.1. Were sources of funding and investigators' affiliations described? Yes
  10.2. Was the study free from apparent conflict of interest? Yes