Question 3:

Instruction : Read the following abstract and answer the questions below

Context

Diabetes mellitus (DM) has been associated with an increased risk of fractures. However, the effect of glycemic control on the risk of fracture is not well understood.

Objective

To evaluate the association between glycemic control and the risk of low-trauma fractures in patients with type 1 DM (T1DM) and type 2 DM (T2DM).

Design

Nested case-control analysis.

Setting

UK-based Clinical Practice Research Datalink.

Patients or Other Participants

The study population was patients whose T1DM or T2DM had been newly diagnosed between 1995 and 2015. The cases were patients with a low-trauma fracture after DM onset. We matched four controls to each case by age, sex, general practice, fracture date, and DM type and duration.

Statistical Analys

Conditional logistic regression analyses were performed, adjusted for covariates, including body mass index, smoking, DM complications and medications.

Results

The study population included 3329 patients with T1DM and 44,275 patients with T2DM. The median duration between DM onset and fracture date was 4.5 years for both T1DM and T2DM. The risk of fracture was increased in the patients with T1DM with a mean hemoglobin A1c >8.0% (adjusted OR, 1.39; 95% CI, 1.06 to 1.83) compared with those patients with T1DM and a mean hemoglobin A1c 7.0%. No such effect was found in the patients with T2DM. Independently of glycemic control, the risk of fracture was elevated in patients with T2DM and the current use of rosiglitazone and pioglitazone.

Conclusions

The effect of glycemic control on the risk of low-trauma fracture differs between patients with T1DM and T2DM. Poor glycemic control increased the risk of fractures in patients with T1DM but not in those with T2DM.

Based on the information from the Abstract above, please answer the following questions:

Question 3a: What is the objective of this study (2pts)?

Question 3b. What type of study design was used (2pts)?

Question 3c: What is the primary exposure of interest (2pts)?

Question 3d: What is the primary outcome of interest (2pts)?

Question 3e.i.: Is age a confounder in this study (0.5pts)? _______

3e.ii. Briefly explain why you gave the answer in 3.e.i. above (1.5pts)?