Pathmaja Paramsothy

Managing preexisting diabetes for pregnancy: Summary of evidence and consensus recommendations for care

This document presents consensus panel recommendations for the medical care of pregnant women with preexisting diabetes, including type 1 and type 2 diabetes. The intent is to help clinicians deal with the broad spectrum of problems that arise in management of diabetes before and during pregnancy, and to prepare diabetic women for treatment that may reduce complications in the years after pregnancy. A thorough discussion of the evidence supporting the recommendations is presented in the book, Management of Preexisting Diabetes and Pregnancy , authored by the consensus panel and published by the American Diabetes Association (ADA) in 2008 (1). A consensus statement on obstetrical and postpartum management will appear separately. The recommendations are diagnostic and therapeutic actions that are known or believed to favorably affect maternal and perinatal outcomes in pregnancies complicated by diabetes. The grading system adapted by the ADA was used to clarify and codify the evidence that forms the basis for the recommendations (2). Unfortunately there is a paucity of randomized controlled trials (RCTs) of the different aspects of management of diabetes and pregnancy. Therefore our recommendations are often based on trials conducted in nonpregnant diabetic women or nondiabetic pregnant women, as well as on peer-reviewed experience before and during pregnancy in women with preexisting diabetes (3–4). We also reviewed and adapted existing diabetes and pregnancy guidelines (5–10) and guidelines on diabetes complications and comorbidities (2,3,11–14). ### A. Organization of preconception and pregnancy care #### Recommendations

Free Fatty Acid Impairment of Nitric Oxide Production in Endothelial Cells Is Mediated by IKKβ

Objective—Free fatty acids (FFA) are commonly elevated in diabetes and obesity and have been shown to impair nitric oxide (NO) production by endothelial cells. However, the signaling pathways responsible for FFA impairment of NO production in endothelial cells have not been characterized. Insulin receptor substrate-1 (IRS-1) regulation is critical for activation of endothelial nitric oxide synthase (eNOS) in response to stimulation by insulin or fluid shear stress. Methods and Results—We demonstrate that insulin-mediated tyrosine phosphorylation of IRS-1 and serine phosphorylation of Akt, eNOS, and NO production are significantly inhibited by treatment of bovine aortic endothelial cells with 100 &mgr;mol/L FFA composed of palmitic acid for 3 hours before stimulation with 100 nM insulin. This FFA preparation also increases, in a dose-dependent manner, IKKβ activity, which regulates activation of NF- &kgr;B, a transcriptional factor associated with inflammation. Similarly, elevation of other common FFA such as oleic and linoleic acid also induce IKKβ activation and inhibit insulin-mediated eNOS activation. Overexpression of a kinase inactive form of IKKβ blocks the ability of FFA to inhibit insulin-dependent NO production, whereas overexpression of wild-type IKKβ recapitulates the effect of FFA on insulin-dependent NO production. Conclusions—Elevated levels of common FFA found in human serum activate IKKβ in endothelial cells leading to reduced NO production, and thus may serve to link pathways involved in inflammation and endothelial dysfunction.

Association of Combinations of Lipid Parameters With Carotid Intima-Media Thickness and Coronary Artery Calcium in the MESA (Multi-Ethnic Study of Atherosclerosis)

OBJECTIVES The purpose of this study was to determine the association of combinations of lipid parameters with subclinical atherosclerosis. BACKGROUND Carotid intima-media thickness (CIMT) and coronary artery calcium (CAC) are significantly associated with incident cardiovascular disease (CVD). The association between common dyslipidemias (combined hyperlipidemia, [simple] hypercholesterolemia, dyslipidemia of metabolic syndrome, isolated low high-density lipoprotein cholesterol, and isolated hypertriglyceridemia) compared with normolipemia, and CIMT and CAC has not been previously examined. METHODS The MESA (Multi-Ethnic Study of Atherosclerosis) participants were White, Chinese, African-American, or Hispanic adults without clinical CVD. Subjects with diabetes mellitus or who were receiving lipid-lowering therapy were excluded. Every participant was classified into only 1 of 6 groups defined by specific low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, or triglyceride cut points. Multivariate linear and relative risk regressions evaluated the cross-sectional associations with CIMT and CAC after adjusting for CVD risk factors. Interactions with race, sex, and high-sensitivity C-reactive protein were evaluated for CIMT and CAC outcomes. RESULTS Among 4,792 participants, only those with combined hyperlipidemia and hypercholesterolemia demonstrated both increased common CIMT (combined hyperlipidemia 0.048 mm thicker, 95% confidence interval [CI]: 0.016 to 0.080 mm; hypercholesterolemia 0.048 mm thicker, 95% CI: 0.029 to 0.067 mm) and internal CIMT (combined hyperlipidemia 0.120 mm thicker, 95% CI: 0.032 to 0.208 mm; and hypercholesterolemia 0.161 mm thicker, 95% CI: 0.098 to 0.223 mm) as well as increased risk for prevalent CAC (combined hyperlipidemia relative risk: 1.22, 95% CI: 1.08 to 1.38; hypercholesterolemia relative risk: 1.22, 95% CI: 1.11 to 1.34) compared with normolipemia. The interactions between lipid parameters and race, sex, or high-sensitivity C-reactive protein were not significant for any outcomes. CONCLUSIONS Combined hyperlipidemia and simple hypercholesterolemia were associated with increased CIMT and prevalent CAC in a relatively healthy multiethnic population.

Plasma sterol evidence for decreased absorption and increased synthesis of cholesterol in insulin resistance and obesity

BACKGROUND The rise in LDL with egg feeding in lean insulin-sensitive (LIS) participants is 2- and 3-fold greater than in lean insulin-resistant (LIR) and obese insulin-resistant (OIR) participants, respectively. OBJECTIVE We determined whether differences in cholesterol absorption, synthesis, or both could be responsible for these differences by measuring plasma sterols as indexes of cholesterol absorption and endogenous synthesis. DESIGN Plasma sterols were measured by gas chromatography-mass spectrometry in a random subset of 34 LIS, 37 LIR, and 37 OIR participants defined by the insulin sensitivity index (S(I)) and by BMI criteria selected from a parent group of 197 participants. Cholestanol and plant sterols provide a measure of cholesterol absorption, and lathosterol provides a measure of cholesterol synthesis. RESULTS The mean (±SD) ratio of plasma total absorption biomarker sterols to cholesterol was 4.48 ± 1.74 in LIS, 3.25 ± 1.06 in LIR, and 2.82 ± 1.08 in OIR participants. After adjustment for age and sex, the relations of the absorption sterol-cholesterol ratios were as follows: LIS > OIR (P < 0.001), LIS > LIR (P < 0.001), and LIR > OIR (P = 0.11). Lathosterol-cholesterol ratios were 0.71 ± 0.32 in the LIS participants, 0.95 ± 0.47 in the LIR participants, and 1.29 ± 0.55 in the OIR participants. After adjustment for age and sex, the relations of lathosterol-cholesterol ratios were as follows: LIS < OIR (P < 0.001), LIS < LIR (P = 0.03), and LIR < OIR (P = 0.002). Total sterol concentrations were positively associated with S(I) and negatively associated with obesity, whereas lathosterol correlations were the opposite. CONCLUSIONS Cholesterol absorption was highest in the LIS participants, whereas cholesterol synthesis was highest in the LIR and OIR participants. Therapeutic diets for hyperlipidemia should emphasize low-cholesterol diets in LIS persons and weight loss to improve S(I) and to decrease cholesterol overproduction in LIR and OIR persons.

Combined hyperlipidemia in relation to race/ethnicity, obesity, and insulin resistance in the Multi-Ethnic Study of Atherosclerosis.

We have asked whether the prevalence of combined hyperlipidemia (CHL) differs by race/ethnicity, obesity, and insulin resistance in a contemporary, multiethnic, US cohort. We determined the prevalence and adjusted odds of CHL in a cohort of 5923 men and women free of clinically recognized cardiovascular disease and diabetes according to race/ethnicity (white, Chinese, African American, and Hispanic), obesity, and insulin resistance. Untreated lipid values were imputed for those on lipid-lowering therapy. Combined hyperlipidemia was defined using age- and sex-specific greater than or equal to 75th percentile cut points for low-density lipoprotein cholesterol and triglycerides obtained from a predominantly white North American population study. Compared with whites, adjusted odds ratios for CHL were 0.48 in African Americans (95% confidence interval [CI], 0.30-0.75), 1.33 in Hispanics (95% CI, 0.93-1.91), and 1.06 in Asians (95% CI, 0.62-1.82). Within the entire population, the adjusted odds of CHL were over 2-fold higher in overweight and obese participants compared with normal-weight participants and more than 4-fold higher in quartiles 2 through 4 of insulin resistance compared with quartile 1. African Americans had lower odds for CHL than whites despite higher body mass index and abdominal adiposity. Hispanics had a nonsignificantly higher trend, and Asians had no significantly different odds than whites. Modest increases in weight and insulin resistance were associated with significantly higher odds of CHL in a multiethnic US population. Further research is needed to determine the most efficacious diet, exercise, and drug management to decrease the risk of CHL and coronary heart disease among racial/ethnic groups in the United States.

Comprehensive Lipid Management Versus Aggressive Low-Density Lipoprotein Lowering to Reduce Cardiovascular Risk

Five lines of evidence justify comprehensive lipoprotein management over aggressive low-density lipoprotein (LDL) lowering alone in most cases of cardiovascular disease (CVD) prevention. First, lipoprotein lipid transport consists of a single, recycling system involving very-low-density lipoprotein, LDL, and high-density lipoprotein (HDL). Single lipid interventions affect all lipoprotein classes to varying degrees. These effects can be expanded by using different drug classes in combination. Second, observational studies support the unitary nature of lipoprotein risk. A family of curves describes increasing CVD risk from increasing LDL as other risk factors are present. Conversely, a family of curves describes increasing CVD risk from decreasing levels of HDL in mirror image to LDL. The LDL and HDL risks are additive. Third, clinical trials that raise HDL and lower triglyceride ameliorate CVD, as does lowering LDL. Lowering LDL prevents heart disease, but by only 22%-36% with 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor therapy. Studies indicate that better CVD prevention is obtained when drugs for triglyceride and HDL reduction are combined with LDL reduction. Fourth, HDL and its apolipoprotein (apo), apo A-I, as well as apo A-I analogues, decrease atherosclerosis. Each modality decreases atherosclerosis in animal models, and apo A-I Milano acutely decreases human coronary luminal stenosis. Apo A-I analogues have similar promise. Fifth, combined hyperlipidemia is the most common lipid disorder, has the strongest risk for CVD, and combines elevated LDL, hypertriglyceridemia, and low HDL. This condition requires the comprehensive treatment approach described above. In conclusion, 5 lines of evidence justify comprehensive diet and drug treatment for combined hyperlipidemia and, at lesser LDL elevations, the atherogenic dyslipidemias of obesity, diabetes mellitus, and the metabolic syndrome.

Age-modification of lipoprotein, lipid, and lipoprotein ratio-associated risk for coronary artery calcium (from the Multi-Ethnic Study of Atherosclerosis [MESA]).

Although abnormal lipoproteins and lipoprotein ratios are powerful risk factors for clinical cardiovascular events, these associations are stronger in younger than in older subjects. Whether age modifies the relation of lipoproteins and lipoprotein ratios to the relative risk of subclinical cardiovascular disease (CVD), as assessed by coronary artery calcium (CAC) scores, has not been examined in a contemporary, multiethnic cohort. We performed multivariate relative risk regression analyses to determine the relative risks for associations of lipoproteins and lipoprotein ratios with prevalent CAC in participants in Multi-Ethnic Study of Atherosclerosis (MESA). The participants were community-dwelling adults aged 45 to 84 years without clinically apparent CVD at baseline. We excluded those taking lipid-lowering therapy (15%) and stratified the results by decades of age. A total of 5,092 participants met the inclusion criteria. In the fully adjusted models, per SD of low-density lipoprotein, the age-stratified, adjusted relative risk for CAC was 1.17 (95% confidence interval [CI] 1.07 to 1.28) for those aged 45 to 84 years but was 1.05 (95% CI 1.01 to 1.10) for those aged 75 to 84 years (p-interaction = 0.12). The relative risk per SD of total/high-density lipoprotein cholesterol ratio was 1.20 (95% CI 1.12 to 1.29) for those aged 45 to 54 years but only 1.04 (95% CI 1.00 to 1.09) for those aged 75 to 84 years (p-interaction <0.001). The lipoproteins levels and lipoprotein ratios were associated with increased relative risks for CAC across all age categories. However, these associations were markedly attenuated by age. In conclusion, abnormal lipoprotein levels in middle age are a powerful risk factor for early atherosclerosis, as manifested by prevalent CAC.

Types of Myocardial Infarction Among Human Immunodeficiency Virus-Infected Individuals in the United States

Importance The Second Universal Definition of Myocardial Infarction (MI) divides MIs into different types. Type 1 MIs result spontaneously from instability of atherosclerotic plaque, whereas type 2 MIs occur in the setting of a mismatch between oxygen demand and supply, as with severe hypotension. Type 2 MIs are uncommon in the general population, but their frequency in human immunodeficiency virus (HIV)–infected individuals is unknown. Objectives To characterize MIs, including type; identify causes of type 2 MIs; and compare demographic and clinical characteristics among HIV-infected individuals with type 1 vs type 2 MIs. Design, Setting, and Participants This longitudinal study identified potential MIs among patients with HIV receiving clinical care at 6 US sites from January 1, 1996, to March 1, 2014, using diagnoses and cardiac biomarkers recorded in the centralized data repository. Sites assembled deidentified packets, including physician notes and electrocardiograms, procedures, and clinical laboratory tests. Two physician experts adjudicated each event, categorizing each definite or probable MI as type 1 or type 2 and identifying the causes of type 2 MI. Main Outcomes and Measures The number and proportion of type 1 vs type 2 MIs, demographic and clinical characteristics among those with type 1 vs type 2 MIs, and the causes of type 2 MIs. Results Among 571 patients (median age, 49 years [interquartile range, 43-55 years]; 430 men and 141 women) with definite or probable MIs, 288 MIs (50.4%) were type 2 and 283 (49.6%) were type 1. In analyses of type 1 MIs, 79 patients who underwent cardiac interventions, such as coronary artery bypass graft surgery, were also included, totaling 362 patients. Sepsis or bacteremia (100 [34.7%]) and recent use of cocaine or other illicit drugs (39 [13.5%]) were the most common causes of type 2 MIs. A higher proportion of patients with type 2 MIs were younger than 40 years (47 of 288 [16.3%] vs 32 of 362 [8.8%]) and had lower current CD4 cell counts (median, 230 vs 383 cells/µL), lipid levels (mean [SD] total cholesterol level, 167 [63] vs 190 [54] mg/dL, and mean (SD) Framingham risk scores (8% [7%] vs 10% [8%]) than those with type 1 MIs or who underwent cardiac interventions. Conclusions and Relevance Approximately half of all MIs among HIV-infected individuals were type 2 MIs caused by heterogeneous clinical conditions, including sepsis or bacteremia and recent use of cocaine or other illicit drugs. Demographic characteristics and cardiovascular risk factors among those with type 1 and type 2 MIs differed, suggesting the need to specifically consider type among HIV-infected individuals to further understand MI outcomes and to guide prevention and treatment.

Use of Lipoprotein Particle Measures for Assessing Coronary Heart Disease Risk Post-American Heart Association/American College of Cardiology Guidelines

Objective—The American College of Cardiology and American Heart Association have issued guidelines indicating that the contribution of apolipoprotein B-100 (ApoB) to cardiovascular risk assessment remains uncertain. The present analysis evaluates whether lipoprotein particle measures convey risk of coronary heart disease (CHD) in 4679 Multi-Ethnic Study of Atherosclerosis (MESA) participants. Approach and Results—Cox regression analysis was performed to determine associations between lipids or lipoproteins and primary CHD events. After adjustment for nonlipid variables, lipoprotein particle levels in fourth quartiles were found to convey significantly greater risk of incident CHD when compared to first quartile levels (hazard ratio [HR]; 95% confidence interval [CI]): ApoB (HR, 1.84; 95% CI, 1.25–2.69), ApoB/ApoA-I (HR, 1.91; 95% CI, 1.32–2.76), total low-density lipoprotein-particles (LDL-P; HR, 1.77; 95% CI, 1.21–2.58), and the LDL-P/HDL-P (high-density lipoprotein-P) ratio (HR, 2.28; 95% CI, 1.54–3.37). Associations between lipoprotein particle measures and CHD were attenuated after adjustment for standard lipid panel variables. Using the American Heart Association/American College of Cardiology risk calculator as a baseline model for CHD risk assessment, significant net reclassification improvement scores were found for ApoB/ApoA-I (0.18; P=0.007) and LDL-P/high-density lipoprotein-P (0.15; P<0.001). C-statistics revealed no significant increase in CHD event discrimination for any lipoprotein measure. Conclusions—Lipoprotein particle measures ApoB/ApoA-I and LDL-P/high-density lipoprotein-P marginally improved net reclassification improvement scores, but null findings for corresponding c-statistic are not supportive of lipoprotein testing. The attenuated associations of lipoprotein particle measures with CHD after the adjustment for lipids indicate that their measurement does not detect risk that is unaccounted for by the standard lipid panel. However, the possibility that lipoprotein measures may identify CHD risk in a subpopulation of individuals with normal cholesterol, but elevated lipoprotein particle numbers cannot be ruled out.

Use of Lipoprotein Particle Measures for Assessing Coronary Heart Disease Risk Post-American Heart Association/American College of Cardiology Guidelines: The Multi-Ethnic Study of Atherosclerosis

Objective—The American College of Cardiology and American Heart Association have issued guidelines indicating that the contribution of apolipoprotein B-100 (ApoB) to cardiovascular risk assessment remains uncertain. The present analysis evaluates whether lipoprotein particle measures convey risk of coronary heart disease (CHD) in 4679 Multi-Ethnic Study of Atherosclerosis (MESA) participants. Approach and Results—Cox regression analysis was performed to determine associations between lipids or lipoproteins and primary CHD events. After adjustment for nonlipid variables, lipoprotein particle levels in fourth quartiles were found to convey significantly greater risk of incident CHD when compared to first quartile levels (hazard ratio [HR]; 95% confidence interval [CI]): ApoB (HR, 1.84; 95% CI, 1.25–2.69), ApoB/ApoA-I (HR, 1.91; 95% CI, 1.32–2.76), total low-density lipoprotein-particles (LDL-P; HR, 1.77; 95% CI, 1.21–2.58), and the LDL-P/HDL-P (high-density lipoprotein-P) ratio (HR, 2.28; 95% CI, 1.54–3.37). Associations between lipoprotein particle measures and CHD were attenuated after adjustment for standard lipid panel variables. Using the American Heart Association/American College of Cardiology risk calculator as a baseline model for CHD risk assessment, significant net reclassification improvement scores were found for ApoB/ApoA-I (0.18; P=0.007) and LDL-P/high-density lipoprotein-P (0.15; P<0.001). C-statistics revealed no significant increase in CHD event discrimination for any lipoprotein measure. Conclusions—Lipoprotein particle measures ApoB/ApoA-I and LDL-P/high-density lipoprotein-P marginally improved net reclassification improvement scores, but null findings for corresponding c-statistic are not supportive of lipoprotein testing. The attenuated associations of lipoprotein particle measures with CHD after the adjustment for lipids indicate that their measurement does not detect risk that is unaccounted for by the standard lipid panel. However, the possibility that lipoprotein measures may identify CHD risk in a subpopulation of individuals with normal cholesterol, but elevated lipoprotein particle numbers cannot be ruled out.