Blood Sugar Refer to Exercise 1 on tight glycemic control, and answer the questions asked in Exercise 2 in the Guided Exercises.

Exercise 1

Tight Control of Blood Sugar "Tight glycemic control" means that the blood sugar is kept within a narrow range. Read the abstract below, and then answer the questions that follow it.

"Methods: In this two-center, prospective, randomized trial, we enrolled 980 children, 0 to 36 months of age, undergoing surgery with cardiopulmonary bypass. Patients were randomly assigned to either tight glycemic control . . . targeting a blood glucose level of 80 to 110 mg per deciliter . . . or standard care in the cardiac intensive care unit.

Results: A total of 444 of the 490 children assigned to tight glycemic control (91%) received insulin versus 9 of 490 children assigned to standard care (2%). . . . [T]ight glycemic control was not associated with a significantly decreased rate of health care-associated infections (8.6 vs. 9.9 per 1000 patient-days, P = 0.67).

Conclusions: Tight glycemic control can be achieved with a low hypoglycemia rate after cardiac surgery in children, but it does not significantly change the infection rate . . . as compared with standard care."

a. Identify the treatment variable and the response variable.

b. Was this a controlled experiment or an observational study? Explain.

c. What does the p-value show?

d. Can you conclude that the use of tight glycemic control affects the rate of infections? Why or why not?

(Source: Agus, Michael et al. 2012. Tight glycemic control versus standard care after pediatric cardiac surgery. New England Journal of Medicine 367, 1208-1219.)

Exercise 2

Drug for Asthma

Eosinophils are a form of white blood cell that is often present in people suffering from allergies. People with asthma and high levels of eosinophils who used steroid inhalers were given either a new drug or a placebo. Read extracts from the abstract of this study that appear below, and then evaluate the study.

"Methods: We enrolled patients with persistent, moderateto- severe asthma and a blood eosinophil count of at least 300 cells per microliter . . . who used medium-dose to highdose inhaled glucocorticoids. . . . We administered dupilumab (300 mg) or placebo subcutaneously once weekly. The primary end point was the occurrence of an asthma exacerbation [worsening].

Results: A total of 52 patients were [randomly] assigned to the dupilumab group, and 52 patients were [randomly] assigned to the placebo group. . . . Three patients had an asthma exacerbation with dupilumab (6%) versus 23 with placebo (44%), corresponding to an 87% reduction with dupilumab (odds ratio, 0.08; 95% confidence interval, 0.02 to 0.28; P<0.001).

Conclusions: In patients with persistent, moderate-tosevere asthma and elevated eosinophil levels who used inhaled glucocorticoids and LABAs, dupilumab therapy, as compared with placebo, was associated with fewer asthma exacerbations [worsenings]."

(Source: Sally Wenzel et al. 2013. Dupilumab in persistent asthma with elevated eosinophil levels. New England Journal of Medicine 368, 2455-2466.)