Dai, Qi

Abstract Objectives Drug repurposing, which finds new indications for existing drugs, has received great attention recently. The goal of our work is to assess the feasibility of using electronic health records (EHRs) and automated informatics methods to efficiently validate a recent drug repurposing association of metformin with reduced cancer mortality. Methods By linking two large EHRs from Vanderbilt University Medical Center and Mayo Clinic to their tumor registries, we constructed a cohort including 32 415 adults with a cancer diagnosis at Vanderbilt and 79 258 cancer patients at Mayo from 1995 to 2010. Using automated informatics methods, we further identified type 2 diabetes patients within the cancer cohort and determined their drug exposure information, as well as other covariates such as smoking status. We then estimated HRs for all-cause mortality and their associated 95% CIs using stratified Cox proportional hazard models. HRs were estimated according to metformin exposure, adjusted for age at diagnosis, sex, race, body mass index, tobacco use, insulin use, cancer type, and non-cancer Charlson comorbidity index. Results Among all Vanderbilt cancer patients, metformin was associated with a 22% decrease in overall mortality compared to other oral hypoglycemic medications (HR 0.78; 95% CI 0.69 to 0.88) and with a 39% decrease compared to type 2 diabetes patients on insulin only (HR 0.61; 95% CI 0.50 to 0.73). Diabetic patients on metformin also had a 23% improved survival compared with non-diabetic patients (HR 0.77; 95% CI 0.71 to 0.85). These associations were replicated using the Mayo Clinic EHR data. Many site-specific cancers including breast, colorectal, lung, and prostate demonstrated reduced mortality with metformin use in at least one EHR. Conclusions EHR data suggested that the use of metformin was associated with decreased mortality after a cancer diagnosis compared with diabetic and non-diabetic cancer patients not on metformin, indicating its potential as a chemotherapeutic regimen. This study serves as a model for robust and inexpensive validation studies for drug repurposing signals using EHR data.

BackgroundDiabetes is a risk factor for mild cognitive impairment (MCI) and dementia. However, the association between high normal fasting blood glucose (FBG) and dementia has not been studied.MethodsPolytomous logistic regression was used to assess the association of dementia and MCI with FBG in an age‐ and sex‐matched sample of 32 dementia patients, 27 amnestic MCI (aMCI) patients, and 31 normal controls (NC). Analyses were repeated for those with normal FBG. Correlations between FBG and cognitive test scores were obtained.ResultsControlling for age, gender, education, body mass index, Hachinski Ischemic Score, magnetic resonance imaging (MRI) stroke, and normalized brain, hippocampal, and white matter hyperintensity MRI volumes; higher FBG was associated with dementia versus aMCI status (OR = 3.13; 95% CI, 1.28–7.69). This association remained (OR = 7.75; 95% CI, 1.10–55.56) when analyses were restricted to subjects with normal FBG. When dementia patients were compared with NC adjusting for age, gender, and education, a significant association with FBG also was seen (OR = 1.83; 95% CI, 1.09–3.08), but it was lost when vascular covariates were added to the model. FBG was not associated with aMCI status versus NC. Higher FBG was correlated with poorer performance on the Trailmaking Test Part B (P = .003). The percentage of dementia patients with high normal FBG (90%) was significantly higher than that of aMCI patients with high normal FBG (32.9%) (χ2 = 13.9, P < .001).ConclusionsHigher FBG was associated with dementia (vs. aMCI) independent of vascular risk factors and MRI indicators of vascular disease, and remained a significant risk factor when analyses were restricted to subjects with normal FBG. The results of this cross‐sectional study suggest that a high normal level of FBG may be a risk factor for dementia.

Objective: To determine apolipoprotein E (APOE)-ε4 and -ε2 frequencies and risk of mild cognitive impairment (MCI) and dementia in Shanghai, China. Methods: A total of 34 MCI and 34 dementia cases were recruited from an urban Memory Disorders Clinic and 32 controls were recruited from a residential community served by the clinic. Apolipoprotein E was genotyped using standard methods. Results: Among controls, frequencies were ε2, 0.11; ε3, 0.84; and ε4, 0.05; among MCI, 0.05, 0.77, and 0.18; and for dementia, 0.02, 0.84, and 0.15, respectively. In education-adjusted models, the odds ratio (OR) = 5.6 for dementia (95% CI = 1.09-29.3) and 4.7 for MCI (95% CI = 0.90-25.2) associated with any ε4 allele. The ε2 allele was inversely associated with dementia (OR = 0.12, 95% CI = 0.013-0.997) and MCI (OR = 0.38, 95% CI = 0.08-1.61). Conclusions: APOE-ε4 increases and -ε2 decreases the risk of dementia vs normal cognition. Similar trends were observed for amnestic mild cognitive impairment (aMCI).