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Adult Intensive Care Unit and Hypothesis Testing

The following information is referenced in questions 9 through 11:
A random sample of 200 patients admitted to an adult intensive care unit (ICU) was collected to examine factors associated with death during hospital stay for ICU patients. Data was also collected on patient's age (in years), whether the patient had an infection at the time of ICU admission, and whether the patient had CPR administered prior to the hospital admission. Of specific interest is whether or not infection at the time of admission is associated with increased probability of death during hospital stay. Logistic regression was employed to estimate the unadjusted and adjusted relationships between death and patient characteristics. The results from these analyses appear in the table below:

Predictor Unadjusted Odds Ratio (95% CI) Adjusted Odds Ratio (95% CI)
Infection (1=Yes, 0=No) 2.50 (1.23, 5.13) 2.00 (0.96, 4.21)
CPR (1=Yes, 0=No) 5.44 (1.72, 17.25) 5.11 (1.53, 17.06)
Age (Years) 1.03 (1.01, 1.05) 1.03 (1.01, 1.05)

9. Which statement best describes the unadjusted association between death and infection status as estimated by the above regression model?
a. Patients with an infection have a higher (increased) risk of death as compared to patients without an infection (p < .05)
b. Patients with an infection have a higher (increased) risk of death as compared to patients without an infection (p > .05)
c. Patients with an infection have a lower (decreased) risk of death as compared to patients without an infection (p < .05)
d. Patients with an infection have a lower (decreased) risk of death as compared to patients without an infection (p > .05)

10. Use the unadjusted model to estimate the odds ratio of death comparing a group of 50 year old patients to a group of 40 years old patients.

a. 1.03
b.0.97
c.1.34
d. 0.75
f. 5.44
e. Cannot be estimated using given results.

11. Use the adjusted model results to estimate the odds ratio of death for 50 year old patients who have an infection and CPR administered at the time of ICU admission, compared to 50 year old patients who do not have an infection and do not have CPR administered at the time of ICU admission.

a. 2.00
b. 5.11
c. 7.11
d. 10.22
e. 3.11
f. 2.55

See attached file for full problem description.

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Solution Summary

This solution conducts a regression analysis on the predictor model by assuming a binomial variable to calculate if the effect of the infection is significant. It also compares and contrasts the odds ratio of two age groups to predict a patient's odds ratio with infection.

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