Teacher:Given a passage, construct a question on the basis of the information present in the passage. Construct the question in such a way that (i) it is unambiguous, (ii) it is answerable from the passage, (iii) its answer is unique (iv) it answer uses text phrases from the passage. Avoid creating questions that (i) can't be answered correctly without actually understanding the passage and (ii) uses the same words or phrases given in the passage.
Teacher: Now, understand the problem? Solve this instance: Visit-to-visit variability in low-density lipoprotein-cholesterol (LDL-C) was found to be a novel predictor of adverse cardiac events. Obstructive sleep apnea (OSA), an emerging cardiovascular risk factor, is characterized by sympathetic activation and increased oxidative stress which are regulators of LDL-C metabolism. We hypothesized that OSA was associated with LDL-C variability.', 'We prospectively recruited 190 patients with coronary artery disease for an overnight sleep study. Statin was prescribed upon discharge for 186 patients. Serum LDL-C levels were measured at clinic every 3 to 6months. Severity of OSA (on the basis of apnea-hypopnea index (AHI)) was correlated with visit-to-visit LDL-C variability (on the basis of variation independent of mean (VIM)) in outpatient clinic.', "The mean AHI was 21.918.9. Using an AHI cut-off of 5-14.9, 15-29.9, and 30, the prevalence of mild, moderate, and severe OSA was 26.3, 18.9, and 27.4%, respectively. After 53.225.3months, LDL-C was recorded over 8.14.2 measurements. VIM positively correlated with AHI (Pearson's r=0.183, p=0.016), but not body mass index, baseline and mean follow-up LDL-C levels, and number of LDL-C measurements. In multiple linear regression analysis, AHI remained an independent predictor of VIM after adjusting for diabetes mellitus and hyperlipidemia. A 10-unit rise in AHI led to a 3.8% increase in VIM (95% CI 0.1 to 7.4%; p=0.044).
Student:
Is obstructive sleep apnea associated with visit-to-visit variability in low-density lipoprotein-cholesterol in patients with coronary artery disease?