Issues in Data Analysis

Friedman, Lawrence M.; Furberg, Curt D.; DeMets, David L.

doi:10.1007/978-1-4419-1586-3_17

Cited by 5 publications

(1 citation statement)

References 160 publications

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“…(24) We had to omit lipid values measured after index hospital discharge because these values may have reflected intermediate, treated valuesthat could bias estimates of comparative effectiveness. (25) During the ‘transition period’ (see Figure 1), we collected data on important co-interventions including use of other medications (i.e., beta blockers, calcium channel blockers, ACE/ARB, and diuretics) and coronary revascularization (percutaneous coronary intervention and coronary artery bypass grafting). Because these variables are likely not intermediates , we controlled for them in the analysis using stratification (by estimating a separate baseline hazard).…”

Section: Methodsmentioning

confidence: 99%

Comparative Effectiveness of Statin Therapy in Chronic Kidney Disease and Acute Myocardial Infarction: A Retrospective Cohort Study

Smith

Johnson

Boudreau

et al. 2015

The American Journal of Medicine

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Background Whether there is a kidney function threshold to statin effectiveness in patients with acute myocardial infarction is poorly understood. Our study sought to help fill this gap in clinical knowledge. Methods We undertook a new-user cohort study of the effectiveness of statin therapy by level of estimated glomerular filtration rate (eGFR) in adults who were hospitalized for myocardial infarction (MI) between 2000 and 2008. Data came from the Cardiovascular Research Network. The primary clinical outcomes were one-year all-cause mortality and cardiovascular hospitalizations, with adverse outcomes of myopathy and development of diabetes mellitus. We calculated incidence rates, the number needed to treat (NNT) and used Cox proportional hazards regression with propensity score matching and adjustment to control for confounding, with testing for variation of effect by level of kidney function. Results Compared with statin non-initiators (n=5,583), statin initiators (n=5,597) had a lower propensity score-adjusted risk for death (HR, 0.79; 95% Confidence Interval [CI], 0.71, 0.88) and cardiovascular hospitalizations (HR, 0.90; 95% CI, 0.82, 1.00). We found little evidence of variation in effect by level of eGFR (p=0.86 for death; p=0.77 for cardiovascular hospitalization). Adverse outcomes were similar for statin initiators and statin non-initiators. The NNT to prevent one additional death over 1 year of follow-up ranged from 15 (95% CI 11, 28) for eGFR <30 ml/min/1.73 m2 requiring statin treatment over 2 years to prevent one additional death, to 67 (95% CI 49, 118) for patients with eGFR >90 ml/min/1.73m2. Conclusions Our findings suggest that there is potential for important public health gains by increasing the routine use of statin therapy for patients with lower levels of kidney function.

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Section: Methodsmentioning

confidence: 99%

Comparative Effectiveness of Statin Therapy in Chronic Kidney Disease and Acute Myocardial Infarction: A Retrospective Cohort Study

Smith

Johnson

Boudreau

et al. 2015

The American Journal of Medicine

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Relationship of Age, Sex, and Ethnicity With Myopia Progression and Axial Elongation in the Correction of Myopia Evaluation Trial

Hyman

Gwiazda²,

Hussein³

et al. 2005

Arch Ophthalmol

193

158

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To identify the baseline factors independently related to 3-year myopia progression and axial elongation in COMET.Methods: A total of 469 children were enrolled, randomly assigned to progressive addition lenses with aϩ2.00 diopter (D) addition or to single vision lenses and observed for 3 years. Eligible children were 6 to 11 years old, with spherical equivalent myopia of − 1.25 to−4.50 D, bilaterally. The primary and secondary outcomes, myopia progression by cycloplegic autorefraction and axial elongation by A-scan ultrasonography, were measured annually. Multiple linear regression was used to adjust for covariates, including treatment.Results: Younger baseline age (6-7 vs 11 years, 8 vs 11 years, and 9 vs 11 years, PϽ.001; 10 vs 11 years, P=.04), female sex (P=.01), and each ethnic group compared with African Americans (Asian, P = .02; Hispanic, P = .002; mixed, P=.002; white, P = .001) were independently as-sociated with faster 3-year progression. Children aged 6 to 7 years had the fastest progression of all age groups, progressing by a mean (±SD) of 1.31 D±0.13 more than children aged 11 years. Females progressed 0.16 D more than the males. Children of mixed, Hispanic, Asian, and white ethnicity progressed more than African American children by 0.49 D±0.16, 0.33 D±0.11, 0.32 D±0.13, 0.27 D±0.08, respectively. Age and ethnicity, but not sex, were independently associated with axial elongation. Among these myopic children, a 0.5 mm increase in axial length was associated with 1 D of myopia progression.Conclusions: Younger baseline age was the strongest factor independently associated with faster myopic progression and greater axial elongation at 3 years. African American children had less myopic progression and axial elongation than the other ethnic groups.

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