Elena V. Kuklina

Prevalence of Cardiovascular Disease Risk Factors Among US Adolescents, 1999−2008

OBJECTIVE: Overweight and obesity during adolescence are associated with an increased risk for cardiovascular disease (CVD) risk factors. The objective of this study was to examine the recent trends in the prevalence of selected biological CVD risk factors and the prevalence of these risk factors by overweight/obesity status among US adolescents. METHODS: The NHANES is a cross-sectional, stratified, multistage probability sample survey of the US civilian, noninstitutionalized population. The study sample included 3383 participants aged 12 to 19 years from the 1999 through 2008 NHANES. RESULTS: Among the US adolescents aged 12 to 19 years, the overall prevalence was 14% for prehypertension/hypertension, 22% for borderline-high/high low-density lipoprotein cholesterol, 6% for low high-density lipoprotein cholesterol (<35 mg/dL), and 15% for prediabetes/diabetes during the survey period from 1999 to 2008. No significant change in the prevalence of prehypertension/hypertension (17% and 13%) and borderline-high/high low-density lipoprotein cholesterol (23% and 19%) was observed from 1999–2000 to 2007–2008, but the prevalence of prediabetes/diabetes increased from 9% to 23%. A consistent dose-response increase in the prevalence of each of these CVD risk factors was observed by weight categories: the estimated 37%, 49%, and 61% of the overweight, obese, and normal-weight adolescents, respectively, had at least 1 of these CVD risk factors during the 1999 through 2008 study period. CONCLUSIONS: The results of this national study indicate that US adolescents carry a substantial burden of CVD risk factors, especially those youth who are overweight or obese.

Severe Maternal Morbidity Among Delivery and Postpartum Hospitalizations in the United States

OBJECTIVES: To propose a new standard for monitoring severe maternal morbidity, update previous estimates of severe maternal morbidity during both delivery and postpartum hospitalizations, and estimate trends in these events in the United States between 1998 and 2009. METHODS: Delivery and postpartum hospitalizations were identified in the Nationwide Inpatient Sample for the period 1998–2009. International Classification of Diseases, 9th Revision codes indicating severe complications were used to identify hospitalizations with severe maternal morbidity and related in-hospital mortality. Trends were reported using 2-year increments of data. RESULTS: Severe morbidity rates for delivery and postpartum hospitalizations for the 2008–2009 period were 129 and 29, respectively, for every 10,000 delivery hospitalizations. Compared with the 1998–1999 period, severe maternal morbidity increased by 75% and 114% for delivery and postpartum hospitalizations, respectively. We found increasing rates of blood transfusion, acute renal failure, shock, acute myocardial infarction, respiratory distress syndrome, aneurysms, and cardiac surgery during delivery hospitalizations. Moreover, during the study period, rates of postpartum hospitalization with 13 of the 25 severe complications examined more than doubled, and the overall mortality during postpartum hospitalizations increased by 66% (P<.05). CONCLUSIONS: Severe maternal morbidity currently affects approximately 52,000 women during their delivery hospitalizations and, based on current trends, this burden is expected to increase. Clinical review of identified cases of severe maternal morbidity can provide an opportunity to identify points of intervention for quality improvement in maternal care. LEVEL OF EVIDENCE: III

Trends in postpartum hemorrhage: United States, 1994–2006

OBJECTIVE The purpose of this study was to estimate the incidence of postpartum hemorrhage (PPH) in the United States and to assess trends. STUDY DESIGN Population-based data from the 1994-2006 National Inpatient Sample were used to identify women who were hospitalized with postpartum hemorrhage. Data for each year were plotted, and trends were assessed. Multivariable logistic regression was used in an attempt to explain the difference in PPH incidence between 1994 and 2006. RESULTS PPH increased 26% between 1994 and 2006 from 2.3% (n = 85,954) to 2.9% (n = 124,708; P < .001). The increase primarily was due to an increase in uterine atony, from 1.6% (n = 58,597) to 2.4% (n = 99,904; P < .001). The increase in PPH could not be explained by changes in rates of cesarean delivery, vaginal birth after cesarean delivery, maternal age, multiple birth, hypertension, or diabetes mellitus. CONCLUSION Population-based surveillance data signal an apparent increase in PPH caused by uterine atony. More nuanced clinical data are needed to understand the factors that are associated with this trend.

Sodium and Potassium Intake and Mortality Among US Adults: Prospective Data From the Third National Health and Nutrition Examination Survey

BACKGROUND Several epidemiologic studies suggested that higher sodium and lower potassium intakes were associated with increased risk of cardiovascular diseases (CVD). Few studies have examined joint effects of dietary sodium and potassium intake on risk of mortality. METHODS To investigate estimated usual intakes of sodium and potassium as well as their ratio in relation to risk of all-cause and CVD mortality, the Third National Health and Nutrition Examination Survey Linked Mortality File (1988-2006), a prospective cohort study of a nationally representative sample of 12,267 US adults, studied all-cause, cardiovascular, and ischemic heart (IHD) diseases mortality. RESULTS During a mean follow-up period of 14.8 years, we documented a total of 2270 deaths, including 825 CVD deaths and 443 IHD deaths. After multivariable adjustment, higher sodium intake was associated with increased all-cause mortality (hazard ratio [HR], 1.20; 95% confidence interval [CI], 1.03-1.41 per 1000 mg/d), whereas higher potassium intake was associated with lower mortality risk (HR, 0.80; 95% CI, 0.67-0.94 per 1000 mg/d). For sodium-potassium ratio, the adjusted HRs comparing the highest quartile with the lowest quartile were HR, 1.46 (95% CI, 1.27-1.67) for all-cause mortality; HR, 1.46 (95% CI, 1.11-1.92) for CVD mortality; and HR, 2.15 (95% CI, 1.48-3.12) for IHD mortality. These findings did not differ significantly by sex, race/ethnicity, body mass index, hypertension status, education levels, or physical activity. CONCLUSION Our findings suggest that a higher sodium-potassium ratio is associated with significantly increased risk of CVD and all-cause mortality, and higher sodium intake is associated with increased total mortality in the general US population.

Hypertensive disorders and severe obstetric morbidity in the United States.

OBJECTIVE: To examine trends in the rates of hypertensive disorders in pregnancy and compare the rates of severe obstetric complications for delivery hospitalizations with and without hypertensive disorders. METHODS: We performed a cross-sectional study using the 1998–2006 Nationwide Inpatient Sample of the Healthcare Cost and Utilization Project. Logistic regressions and population-attributable fractions were used to examine the effect of hypertensive disorders on severe complications. RESULTS: The overall prevalence of hypertensive disorders among delivery hospitalizations increased significantly from 67.2 per 1,000 deliveries in 1998 to 81.4 per 1,000 deliveries in 2006. Compared with hospitalizations without any hypertensive disorders, the risk of severe obstetric complications ranged from 3.3 to 34.8 for hospitalizations with eclampsia/severe preeclampsia and from 1.4 to 2.2 for gestational hypertension. The prevalence of hospitalizations with eclampsia/severe preeclampsia increased moderately from 9.4 to 12.4 per 1,000 deliveries (P for linear trend <0.001) during the period of study. However, these hospitalizations were associated with 38% of hospitalizations with acute renal failure and 19% or more of hospitalizations with ventilation, disseminated intravascular coagulation syndrome, pulmonary edema, puerperal cerebrovascular disorders, and respiratory distress syndrome. Overall, hospitalizations with hypertensive disorders were associated with 57% of hospitalizations with acute renal failure, 27% of hospitalizations with disseminated intravascular coagulation syndrome, and 30% or more of hospitalizations with ventilation, pulmonary edema, puerperal cerebrovascular disorders, and respiratory distress syndrome. CONCLUSION: The number of delivery hospitalizations in the United States with hypertensive disorders in pregnancy is increasing, and these hospitalizations are associated with a substantial burden of severe obstetric morbidity. LEVEL OF EVIDENCE: III

Trends in stroke hospitalizations and associated risk factors among children and young adults, 1995–2008

The aim of this study was to determine acute stroke hospitalization rates for children and young adults and the prevalence of stroke risk factors among children and young adults hospitalized for acute stroke.

Diabetes Trends Among Delivery Hospitalizations in the U.S., 1994–2004

OBJECTIVE To examine trends in the prevalence of diabetes among delivery hospitalizations in the U.S. and to describe the characteristics of these hospitalizations. RESEARCH DESIGN AND METHODS Hospital discharge data from 1994 through 2004 were obtained from the Nationwide Inpatient Sample. Diagnosis codes were selected for gestational diabetes mellitus (GDM), type 1 diabetes, type 2 diabetes, and unspecified diabetes. Rates of delivery hospitalization with diabetes were calculated per 100 deliveries. RESULTS Overall, an estimated 1,863,746 hospital delivery discharges contained a diabetes diagnosis, corresponding to a rate of 4.3 per 100 deliveries over the 11-year period. GDM accounted for the largest proportion of delivery hospitalizations with diabetes (84.7%), followed by type 1 (7%), type 2 (4.7%), and unspecified diabetes (3.6%). From 1994 to 2004, the rates for all diabetes, GDM, type 1 diabetes, and type 2 diabetes significantly increased overall and within each age-group (15–24, 25–34, and ≥35 years) (P < 0.05). The largest percent increase for all ages was among type 2 diabetes (367%). By age-group, the greatest percent increases for each diabetes type were among the two younger groups. Significant predictors of diabetes at delivery included age ≥35 years vs. 15–24 years (odds ratio 4.80 [95% CI 4.72–4.89]), urban versus rural location (1.14 [1.11–1.17]), and Medicaid/Medicare versus other payment sources (1.29 [1.26–1.32]). CONCLUSIONS Given the increasing prevalence of diabetes among delivery hospitalizations, particularly among younger women, it will be important to monitor trends in the pregnant population and target strategies to minimize risk for maternal/fetal complications.

Sodium Intake and Blood Pressure Among US Children and Adolescents

OBJECTIVE: To assess the association between usual dietary sodium intake and blood pressure among US children and adolescents, overall and by weight status. METHODS: Children and adolescents aged 8 to 18 years (n = 6235) who participated in NHANES 2003–2008 comprised the sample. Subjects’ usual sodium intake was estimated by using multiple 24-hour dietary recalls. Linear or logistic regression was used to examine association between sodium intake and blood pressure or risk for pre-high blood pressure and high blood pressure (pre-HBP/HPB). RESULTS: Study subjects consumed an average of 3387 mg/day of sodium, and 37% were overweight/obese. Each 1000 mg per day sodium intake was associated with an increased SD score of 0.097 (95% confidence interval [CI] 0.006–0.188, ∼1.0 mm Hg) in systolic blood pressure (SBP) among all subjects and 0.141 (95% CI: –0.010 to 0.298, ∼1.5 mm Hg) increase among overweight/obese subjects. Mean adjusted SBP increased progressively with sodium intake quartile, from 106.2 mm Hg (95% CI: 105.1–107.3) to 108.8 mm Hg (95% CI: 107.5–110.1) overall (P = .010) and from 109.0 mm Hg (95% CI: 107.2–110.8) to 112.8 mm Hg (95% CI: 110.7–114.9; P = .037) among those overweight/obese. Adjusted odds ratios comparing risk for pre-HBP/HPB among subjects in the highest versus lowest sodium intake quartile were 2.0 (95% CI: 0.95–4.1, P = .062) overall and 3.5 (95% CI: 1.3–9.2, P = .013) among those overweight/obese. Sodium intake and weight status appeared to have synergistic effects on risk for pre-HBP/HPB (relative excess risk for interaction = 0.29 (95% CI: 0.01–0.90, P < .05). CONCLUSIONS: Sodium intake is positively associated with SBP and risk for pre-HBP/HPB among US children and adolescents, and this association may be stronger among those who are overweight/obese.

Trends in high levels of low-density lipoprotein cholesterol in the United States, 1999-2006.

CONTEXT Studies show that a large proportion of adults with high levels of low-density lipoprotein cholesterol (LDL-C) remain untreated or undertreated despite growing use of lipid-lowering medications. OBJECTIVE To investigate trends in screening prevalence, use of cholesterol-lowering medications, and LDL-C levels across 4 study cycles (1999-2000, 2001-2002, 2003-2004, and 2005-2006). DESIGN, SETTING, AND PARTICIPANTS The National Health and Nutrition Examination Survey (NHANES) is a cross-sectional, stratified, multistage probability sample survey of the US civilian, noninstitutionalized population. After we restricted the study sample to fasting participants aged 20 years or older (n = 8018) and excluded pregnant women (n = 464) and participants with missing data (n = 510), our study sample consisted of 7044 participants. MAIN OUTCOME MEASURE High LDL-C levels, defined as levels above the specific goal for each risk category outlined in guidelines from the National Cholesterol Education Program Adult Treatment Panel III (NCEP ATP III). All presented results are weighted and age-standardized to 2000 standard population estimates. RESULTS Prevalence of high LDL-C levels among persons aged 20 years or older decreased from 31.5% in 1999-2000 to 21.2% in 2005-2006 (P < .001 for linear trend) but varied by risk category. By the 2005-2006 study cycle, prevalence of high LDL-C was 58.9%, 30.2%, and 11.0% for high-, intermediate-, and low-risk categories, respectively. Self-reported use of lipid-lowering medications increased from 8.0% to 13.4% (P < .001 for linear trend), but screening rates did not change significantly, remaining less than 70% (P = .16 for linear trend) during the study periods. CONCLUSIONS Among the NHANES population aged 20 years or older, the prevalence of high LDL-C levels decreased from 1999-2000 to 2005-2006. In the most recent period, the prevalence was 21.2%.

Incidence and determinants of peripartum hysterectomy.

OBJECTIVE: Most studies of peripartum hysterectomy are conducted in single institutions, limiting the ability to provide national incidence estimates and examine risk factors. The objective of this study was to provide a national estimate of the incidence of peripartum hysterectomy and to examine factors associated with the procedure. METHODS: We used data for 1998–2003 from the Healthcare Cost and Utilization Project Nationwide Inpatient Sample, an annual nationally representative survey of inpatient hospitalizations. Peripartum hysterectomy was defined as a hysterectomy and delivery occurring during the same hospitalization. Odds ratios (ORs) and 95% confidence intervals (CIs) were adjusted for maternal and hospital characteristics using logistic regression. RESULTS: During 1998–2003, an estimated 18,339 peripartum hysterectomies occurred in the United States (0.77 per 1,000 deliveries). Compared with vaginal delivery without a previous cesarean delivery, the ORs of peripartum hysterectomy for other delivery types were as follows: repeat cesarean, 8.90 (95% CI 8.09–9.79); primary cesarean, 6.54 (95% CI 5.95–7.18); and vaginal birth after cesarean, 2.70 (95% CI 2.23–3.26). Multiple births were associated with an increased risk compared with singleton births (OR 1.41, 95% CI 1.16–1.71). CONCLUSION: Our results suggest that vaginal birth after cesarean, primary and repeat cesarean deliveries, and multiple births are independently associated with an increased risk for peripartum hysterectomy. These findings may be of concern, given the increasing rate of both cesarean deliveries and multiple births in the United States. LEVEL OF EVIDENCE: III