Evolution of the HALT-C Trial: pegylated interferon as maintenance therapy for chronic hepatitis C in previous interferon nonresponders

The Hepatitis C Antiviral Long-term Treatment against Cirrhosis (HALT-C) Trial was designed to determine whether maintenance interferon therapy could slow disease progression in patients who had failed to eradicate hepatitis C virus (HCV) during prior interferon treatment (nonresponders). Ten clinical sites, a virological testing center, and a data coordinating center (DCC) were selected to collaborate in the design and implementation of the final protocol. Eligible patients had been treated previously with interferon for at least 12 weeks, with or without another antiviral, ribavirin, but still had persistent viremia. Because patients had received a variety of prior treatments, and as a perceived benefit of enrollment, we incorporated a Lead-in period of treatment with long-acting pegylated interferon alfa-2a plus ribavirin into the study design, a combination believed to be more effective but not approved by the Food and Drug Administration at the Trial's inception. If patients failed to achieve clearance of virus from the blood after 20 weeks of this Lead-in therapy, they were entered into the main trial at week 24 and randomized to receive either a lower dose of pegylated interferon weekly alone or no further therapy for an additional 3 1/2 years. The original protocol was amended later in three respects to improve enrollment and to adapt to Food and Drug Administration approval of the Lead-in therapy, including allowing patients to proceed directly to the randomized part of the study if treatment resembling the Lead-in had been completed. The protocol changes enhanced enrollment while upholding the original goals of the study and its integrity.

Serum leptin concentrations and body adipose measures in older black and white adults

BACKGROUND

Among US adults, serum leptin concentrations are higher in women than in men and are higher in blacks than in whites independent of anthropometric measures of body fatness.

OBJECTIVE

Using radiographic measures of body fat, we determined the best correlates of leptin and whether adiposity can explain sex and race differences in leptin concentrations in older adults.

DESIGN

This was a cross-sectional analysis of fasting serum leptin concentrations and body fat measured by dual-energy X-ray absorptiometry (DXA), abdominal computed tomography, and standard anthropometry in 3026 well-functioning 70-79-y-old participants (42% black, 51% women) of the Health, Aging, and Body Composition Study.

RESULTS

Geometric mean (+/-SE) leptin concentrations (ng/mL) were higher in the women than in the men (16.5 +/- 0.3 and 5.7 +/- 0.1, respectively) and in the black women than in the white women (20.2 +/- 0.6 and 13.9 +/- 0.4, respectively), but did not differ significantly between the white and black men (5.8 +/- 0.2 and 5.5 +/- 0.2, respectively). Percentage fat estimated from DXA showed the highest correlation with leptin (R(2) = 0.56 for both sexes). Addition of abdominal visceral fat minimally increased the correlation. In the multivariate analysis, the association with sex was eliminated after adjustment for percentage fat and visceral fat in both whites (P = 0.051) and blacks (P = 0.34). Among women, higher leptin concentrations in blacks remained after adjustment for percentage fat and visceral fat (mean race difference = 4.95 ng/mL; P < 0.001). Among men, an association with black race emerged after adjustment for these factors (mean race difference = 1.42 ng/mL; P < 0.001).

CONCLUSIONS

Among older adults, higher serum leptin concentrations in women are explained by a greater percentage of body fat. Higher leptin concentrations in blacks are not explained by percentage of body fat.

Epidemiology of nonalcoholic fatty liver

Nonalcoholic fatty liver (NAFL) is increasingly recognized as an important and common public health problem that can lead to cirrhosis and hepatic failure. Because it is often asymptomatic,many people may not know that they have it. NAFL is closely linked to obesity, which in the United States and other developed countries is becoming more common. Consequently, the proportion of the population affected by NAFL will likely increase. Despite the growing importance of this condition, knowledge of the epidemiology of NAFL is limited by the lack of an accurate,noninvasive measure for use in screening of the general population. This article reviews information available from studies with relatively unselected samples with regard to prevalence, demographics,and risk factors for NAFL.

Peginterferon alfa-2a and ribavirin in patients with chronic hepatitis C who have failed prior treatment

BACKGROUND & AIMS

The most effective therapy currently available for treatment of chronic hepatitis C virus (HCV) is the combination of peginterferon and ribavirin. This study evaluated the effectiveness of this treatment in patients who were nonresponders to previous interferon-based therapy.

METHODS

The first 604 patients enrolled in the Hepatitis C Antiviral Long-Term Treatment Against Cirrhosis (HALT-C) Trial were evaluated. All were HCV RNA positive, previous nonresponders to interferon, with or without ribavirin, and had bridging fibrosis or cirrhosis on liver biopsy (Ishak fibrosis stage 3-6). Patients were retreated with peginterferon alfa-2a 180 microg/wk plus ribavirin 1000-1200 mg/day. Those with no detectable HCV RNA in serum at week 20 continued treatment for a total of 48 weeks and were then followed for an additional 24 weeks.

RESULTS

Thirty-five percent of patients had no detectable HCV RNA in serum at treatment week 20, and 18% achieved sustained virologic response (SVR). Factors associated with an SVR included previous treatment with interferon monotherapy, infection with genotypes 2 or 3, a lower AST:ALT ratio, and absence of cirrhosis. Reducing the dose of ribavirin from > or =80% to < or =60% of the starting dose during the first 20 weeks of treatment was associated with a decline in SVR from 21% to 11% (P < or = 0.05). In contrast, reducing the dose of peginterferon or reducing ribavirin after week 20, when HCV RNA was already undetectable, did not significantly affect SVR.

CONCLUSIONS

Selected nonresponders to previous interferon-based therapy can achieve SVR following retreatment with peginterferon alfa-2a and ribavirin.

Water turnover in 458 American adults 40-79 yr of age

Despite recent interest in water intake, few data are available on water metabolism in adults. To determine the average and range of usual water intake, urine output, and total body water, we administered 2H oxide to 458 noninstitutionalized 40- to 79-yr-old adults living in temperate climates. Urine was collected in a subset of individuals ( n = 280) to measure 24-h urine production using p-aminobenzoic acid to ensure complete collection. Preformed water intake was calculated from isotopic turnover and corrected for metabolic water and insensible water absorption from humidity. Preformed water intake, which is water from beverages and food moisture, averaged 3.0 l/day in men (range: 1.4-7.7 l/day) and 2.5 l/day in women (range: 1.2-4.6 l/day). Preformed water intake was lower in 70- to 79 (2.8 l/day)- than in 40- to 49-yr-old men and was lower in 70- to 79 (2.3 l/day)- than in 40- to 49- and 50- to 59-yr-old women. Urine production averaged 2.2 l/day in men (range: 0.6-4.9 l/day) and 2.2 l/day in women (0.9-6.0 l/day). There were no age-related differences in results in women, but 60- to 69-yr-old men had significantly higher urine output than 40- to 49- and 50- to 59-yr-old men. Only the 70- to 79-yr-old group included sufficient blacks for a racial analysis. Blacks in this age group showed significantly lower preformed water intake than did whites. Whites had significantly higher water turnover rates than blacks as well. Multivariate regression indicated that age, weight, height, and body mass index explained <12% of the gender-specific variance in water input or urine output, yet repeat measures indicated that within-individual coefficient of variation was 8% for preformed water intake ( n = 22) and 9% for 24-h urine production ( n = 222). These results demonstrate that water turnover is highly variable among individuals and that little of the variance is explained by anthropometric parameters.

Energy requirements in the eighth decade of life

BACKGROUND

Knowledge of energy requirements among relatively healthy elderly is limited.

OBJECTIVES

The objectives of the study were to measure total energy expenditure (TEE)-derived energy requirements in a biracial population of older adults without limitations to daily life and to test these empirical measures against national and international recommendations.

DESIGN

TEE (measured by the doubly labeled water method), resting metabolic rate (RMR), activity-related energy expenditure (AEE), and body composition were measured in 288 persons aged 70-79 y selected from the Health, Aging, and Body Composition Study.

RESULTS

TEE was lower in women (approximately 530 kcal/d; P < 0.0001) than in men because of the women's lower RMR and AEE. Fat-free mass explained the sex difference in RMR, but body weight failed to account for the women's lower AEE (approximately 1 kcal x kg(-1) x d(-1); P = 0.007). Blacks had lower TEE than did whites (approximately 100 kcal/d, P = 0.03), and that was explained by blacks' lower RMR. Physical activity level (TEE/RMR) did not differ significantly between sexes and races (1.70 +/- 0.23). The World Health Organization (WHO) recommendations overestimated TEE by 10 +/- 15% (P < 0.0001) in women but not in men, and the dietary reference intakes (DRIs) were accurate to 0 +/- 14% (P = 0.1). Both WHO and DRI recommendations are based on an underestimated physical activity level, and WHO recommendations are based on overestimated RMR.

CONCLUSIONS

This study of well-functioning older adults confirms the racial difference in energy metabolism and supports the use of the 2002 DRIs. Because the DRIs and WHO recommendations underestimated PAL, new predictive equations of energy requirements are proposed.

Diabetes increases the risk of chronic liver disease and hepatocellular carcinoma

BACKGROUND & AIMS

An association between diabetes and chronic liver disease has been reported. However, the temporal relationship between these conditions remains unknown.

METHODS

We identified all patients with a hospital discharge diagnosis of diabetes between 1985 and 1990 using the computerized records of the Department of Veterans Affairs. We randomly assigned 3 patients without diabetes for every patient with diabetes. We excluded patients with concomitant liver disease. The remaining cohort was followed through 2000 for the occurrence of chronic nonalcoholic liver disease (CNLD) and hepatocellular carcinoma (HCC). Hazard rate ratios (HRR) were determined in Cox proportional hazard survival analysis.

RESULTS

The study cohort comprised 173,643 patients with diabetes and 650,620 patients without diabetes. Most were men (98%). Patients with diabetes were older (62 vs. 54 years) than patients without diabetes. The incidence of chronic nonalcoholic liver disease was significantly higher among patients with diabetes (incidence rate: 18.13 vs. 9.55 per 10,000 person-years, respectively, P < 0.0001). Similar results were obtained for HCC (incidence rate: 2.39 vs. 0.87 per 10,000 person-years, respectively, P < 0.0001). Diabetes was associated with an HRR of 1.98 (95% CI: 1.88 to 2.09, P < 0.0001) of CNLD and an HRR of 2.16 (1.86 to 2.52, P < 0.0001) of hepatocellular carcinoma. Diabetes carried the highest risk among patients with longer than 10 years of follow-up.

CONCLUSIONS

Among men with diabetes, the risk of CNLD and HCC is doubled. This increase in risk is independent of alcoholic liver disease, viral hepatitis, or demographic features.

Maintenance therapy with ribavirin in patients with chronic hepatitis C who fail to respond to combination therapy with interferon alfa and ribavirin

To assess the efficacy and safety of maintenance therapy with ribavirin alone in chronic hepatitis C, 108 patients were treated with the combination of interferon alfa and ribavirin for 24 weeks; those who failed to have a virologic response were offered enrollment in a randomized, double-blind, controlled trial of ribavirin (1,000-1,200 mg daily) versus placebo for the subsequent 48 weeks. Patients were monitored at regular intervals with symptom questionnaires, serum aminotransferase levels, hepatitis C virus (HCV) RNA levels, and complete blood counts and underwent liver biopsy at the completion of therapy. Among 108 patients, 50 were still HCV RNA positive after 24 weeks of treatment, of whom 34 agreed to be randomized to continue either ribavirin monotherapy or placebo. Among 17 patients who received placebo, there was no overall improvement in symptoms, serum alanine aminotransferase (ALT) levels, HCV RNA levels, or hepatic histology. Among the 17 patients who received ribavirin, serum ALT levels and necroinflammatory features of liver histology were improved, whereas symptoms, HCV RNA levels, and hepatic fibrosis scores were not changed significantly from baseline. Responses to ribavirin seemed to be categorical, such that 8 patients (47%) had definite improvement in liver histology. Patients with improved histology had improvements in serum ALT levels both on combination therapy and after switching to ribavirin monotherapy. In conclusion, continuation of ribavirin monotherapy may maintain serum biochemical improvements that occur during interferon-ribavirin combination therapy in some patients and that these improvements are often associated with decreases in necroinflammatory changes in the liver. Whether these improvements will ultimately result in prevention of progression of hepatitis C requires further study.

Liver transplantation with hepatitis C virus-infected graft: interaction between donor and recipient viral strains

Superinfection of different viral strains within a single host provides an opportunity for studying host-virus and virus-virus interactions, including viral interference and genetic recombination, which cannot be studied in infections with single viral strains. Hepatitis C virus (HCV) is a positive single-strand RNA virus that establishes persistent infection in as many as 85% of infected individuals. However, there are few reports regarding coinfection or superinfection of HCV. Because of the lack of tissue culture systems and small animal models supporting efficient HCV replication, we explored these issues in the setting of liver transplantation where both recipient and donor were infected with different HCV strains and therefore represent a distinct model for HCV superinfection. Serial serum samples collected at multiple time points were obtained from 6 HCV-positive liver donor/recipient pairs from the National Institute of Diabetes and Digestive and Kidney Diseases liver transplantation database. At each time point, HCV genotype was determined by both restriction fragment length polymorphism analysis and phylogenetic analysis. Furthermore, we selectively sequenced 3 full-length HCV isolates at the earliest time points after liver transplantation, including both 5' and 3' ends. Detailed genetic analyses showed that only one strain of HCV could be identified at each time point in all 6 cases. Recipient HCV strains took over in 3 cases, whereas donor HCV strains dominated after liver transplantation in the remaining 3 cases. In conclusion, in all 6 cases studied, there was no genetic recombination detected among HCV quasispecies or between donor and recipient HCV strains.

Relation of elevated serum alanine aminotransferase activity with iron and antioxidant levels in the United States

BACKGROUND & AIMS

Oxidative stress is thought to play a role in liver injury. Hepatic iron may promote liver injury, whereas antioxidant vitamins and minerals may inhibit it, but few clinical studies have examined such relationships. We analyzed the associations of serum iron measures and antioxidant concentrations with abnormal serum alanine transaminase (ALT) activity in a large, national, population-based study.

METHODS

A total of 13,605 adult participants in the third U.S. National Health and Nutrition Examination Survey (NHANES III), 1988-1994, underwent phlebotomy. Exclusions included excessive alcohol consumption, hepatitis B and C, and iron overload.

RESULTS

Elevated ALT levels were found in 3.1% of the population. In univariate analysis, factors associated with abnormal ALT levels (P < 0.05) included higher transferrin saturation and iron and selenium concentrations, and lower vitamin C, alpha and beta carotene, and lutein/zeaxanthin concentrations. In multivariate logistic regression analyses, elevated ALT level was associated positively with increasing deciles of transferrin saturation (odds ratio [OR] per decile, 1.10; 95% confidence interval [CI], 1.03-1.18) and iron concentration (OR, 1.13; 95% CI, 1.06-1.21). Abnormal ALT level was associated negatively with increasing deciles of alpha carotene (OR, 0.82; 95% CI, 0.72-0.94), beta carotene (OR, 0.91; 95% CI, 0.86-0.96), beta cryptoxanthin (OR, 0.91; 95% CI, 0.84-0.99), lutein/zeaxanthin (OR, 0.90; 95% CI, 0.84-0.96), and a variable combining the 5 carotenoid measures (OR, 0.89; 95% CI, 0.83-0.95). Vitamin C was associated inversely, but only at the highest concentrations.

CONCLUSIONS

In this large, national, population-based study, the risk for apparent liver injury was associated with increased iron and decreased antioxidants, particularly carotenoids.

A cohort study of the incidence of serious acute liver injury in diabetic patients treated with hypoglycemic agents

BACKGROUND

The incidence of acute liver failure or serious liver injury in diabetic patients is needed to evaluate the safety of hypoglycemic drug therapy.

METHODS

We conducted a retrospective cohort study of 5 health maintenance organizations. Study patients were 171,264 health plan members 19 years or older when they received oral hypoglycemic drugs or insulin between April 1, 1997, and June 30, 1999. We searched for hospital discharge diagnoses and procedures potentially indicative of acute liver injury and reviewed the full-text medical records. Acute liver failure was defined as acute liver disease and (1) hepatic encephalopathy, (2) prothrombin time prolongation greater than 3 seconds or international normalized ratio greater than 1.5, and (3) a total bilirubin level greater than 3.0 mg/dL (>51 micro mol/L). Acute liver injury was diagnosed in individuals who did not meet 1 or more of the criteria for acute liver failure but had alanine transaminase or aspartate transaminase levels greater than 500 U/L.

RESULTS

We identified 35 cases of acute liver failure or injury not clearly attributable to a known cause other than use of hypoglycemic agents. The age- and sex-standardized incidence per 1000 person-years was 0.15 for insulin users, 0.08 for sulfonylurea users, 0.12 for metformin users, and 0.10 for troglitazone users. The incidence was higher (on the order of 0.3 per 1000) during the first 6 months of exposure to all hypoglycemic agents.

CONCLUSIONS

Acute liver failure or injury not clearly attributable to other known causes occurred on the order of 1 per 10,000 person-years among diabetic patients treated with oral hypoglycemic drugs or insulin.

A survey of liver transplantation from living adult donors in the United States

BACKGROUND

The transplantation of the right lobe of a liver from a living adult donor into an adult recipient has been performed increasingly frequently in the United States. Although the use of grafts from living donors is standard practice in transplantation in children, their use in adults remains controversial.

METHODS

To study the use of liver transplantation from a living donor, we sent a 24-item questionnaire to all liver-transplantation programs in the United States. Data on indications, evaluation, and outcomes were analyzed with the use of univariate and multivariate methods. Data on recent transplantations were gathered from the Scientific Registry of Transplant Recipients and directly from the transplantation programs.

RESULTS

Questionnaires were returned by 84 of the 122 programs (69 percent) describing the results of 449 adult-to-adult transplantations of partial livers from living donors that were performed in 42 centers. Fourteen centers had performed more than 10 such transplantations each and together accounted for 80 percent of such transplantations. Centers that performed such transplantations also performed more transplantations of livers from cadaveric donors and more transplantations from living donors in children than centers that did not perform the adult-to-adult procedure (P=0.002 and P=0.001, respectively). A total of 45 percent of potential donors who were evaluated eventually donated a lobe of their liver; 99 percent of these donors were genetically or emotionally related to the recipient. Complications in the donor were more frequent in the centers performing the fewest transplantations from living donors in adults and included biliary complications requiring intervention (in 6.0 percent), reoperation (in 4.5 percent), and death (in one donor [0.2 percent]). Among the recipients, 1.6 percent did not meet criteria for receipt of a cadaveric transplant; cancer, retransplantation, and acute liver failure were uncommon indications for transplantation from a living donor. Biliary complications occurred in 22.0 percent of recipients, and vascular complications occurred in 9.8 percent.

CONCLUSIONS

Adult-to-adult liver transplantation from a living donor is increasingly performed in the United States but is concentrated in a few large-volume centers. Mortality among donors is low, but complications in the donor are relatively common.

Determinants of the association of overweight with elevated serum alanine aminotransferase activity in the United States

BACKGROUND & AIMS

In the absence of other causes, overweight and obesity increase the risk of liver disease. We examined whether central adiposity and metabolic markers explain the association of body mass index (BMI as kg/m(2)) with abnormal serum alanine aminotransferase (ALT) activity in a national, population-based study.

METHODS

Adult participants (5724) in the third U.S. National Health and Nutrition Examination Survey (1988-1994) underwent anthropometric measures and phlebotomy after an overnight fast. Participants with excessive alcohol consumption, hepatitis B, hepatitis C, iron overload, or known diabetes were excluded.

RESULTS

Elevated ALT levels were found in 2.8% of the population. In univariate analysis, factors associated with elevated ALT levels (P < 0.05) included younger age, male sex, Mexican-American ethnicity, and higher BMI, waist-to-hip circumference ratio (WHR), and fasting serum leptin, triglyceride, insulin, and glucose concentrations. The proportion of elevated ALT activity due to overweight and obesity (BMI > or =25 kg/m(2)) was 65%. In multivariate logistic regression analysis, control for WHR, demographic factors, and glucose concentration diminished but did not eliminate the association of higher BMI with elevated ALT activity. After adding leptin and insulin concentrations, abnormal ALT activity was most strongly associated with higher WHR (odds ratio [OR], 1.32; 95% confidence interval [CI], 1.12-1.56) and leptin (OR, 1.12; 95% CI, 1.01-1.24) and insulin (OR, 1.27; 95% CI, 1.01-1.60) concentrations, whereas BMI was not independently related.

CONCLUSIONS

In this large, national, population-based study, central adiposity, hyperleptinemia, and hyperinsulinemia were the major determinants of the association of overweight with elevated serum ALT activity.

Neutropenia during combination therapy of interferon alfa and ribavirin for chronic hepatitis C

Interferon therapy of hepatitis C causes a decrease in neutrophil counts, and neutropenia is a common reason for dose adjustment or early discontinuation. However, it is unclear whether neutropenia caused by interferon is associated with an increased rate of infection. In this study, we assessed factors associated and clinical consequences of neutropenia before and during interferon therapy of chronic hepatitis C. A total of 119 patients with chronic hepatitis C treated with the combination of interferon alfa and ribavirin were analyzed. In these studies, neutropenia was not used as an exclusion or dose modification criterion. In multivariate analysis, only black race was associated with baseline neutropenia. During treatment, neutrophil counts decreased by an average of 34%. Among 3 blacks with baseline neutropenia without cirrhosis or splenomegaly, there was little or no decrease in neutrophil counts (despite typical decreases in platelet and lymphocyte counts). Documented or suspected bacterial infections developed in 22 patients (18%), but in no patient with neutropenia. United States population estimates suggest that 76,000 blacks with hepatitis C have neutrophil counts below 1,500 cells/microL and might be denied therapy if this exclusion criterion was generally applied. In conclusion, neutropenia is frequent during treatment of hepatitis C with interferon and ribavirin, but it is not usually associated with infection. Constitutional neutropenia, which is common among blacks, should not exclude patients from therapy with interferon as these patients usually have minimal further decreases in neutrophil counts on therapy and are not excessively prone to bacterial infections.

Relationship of serum leptin concentration with bone mineral density in the United States population

Overweight is associated with both higher bone mineral density (BMD) and higher serum leptin concentrations. In humans, little is known about the relationship of leptin concentration and bone density. We studied this relationship in a large, national population-based sample. Participants included 5815 adults in the Third U.S. National Health and Nutrition Examination Survey (NHANES III; 1988-1994) who underwent DXA of the proximal femur and measurement of fasting serum leptin. Mean +/- SE BMD (gm/cm2) of the total hip was 1.01 +/- 0.005 in men, 0.94 +/- 0.004 in premenopausal women, and 0.78 +/- 0.007 in postmenopausal women. Bone density increased with increasing leptin concentration in men (p = 0.003), premenopausal women (p < 0.001), and postmenopausal women (p < 0.001). However, after adjusting for body mass index (BMI) and other bone density-related factors, an inverse association emerged in men (p < 0.001), being most evident among men < 60 years old. There was no association of leptin and BMD in premenopausal women (p = 0.66) or postmenopausal women (p = 0.69) in multivariate analysis. Controlling for leptin had no effect on the strong positive association of BMI and BMD in either men or women. Serum leptin concentration did not appear to affect directly BMD. If present, the association appeared to be limited to younger men who are at lower risk of osteoporosis.

Diabetes increases the risk of acute hepatic failure

BACKGROUND & AIMS

It is unclear whether patients with diabetes are at an increased risk of developing acute liver failure (ALF). We performed a large cohort study to examine the occurrence of ALF by using the databases of the Department of Veterans Affairs.

METHODS

We identified all patients with a hospital discharge diagnosis of diabetes (ICD-9 codes: 250 [1-9][0-4]) from 1985 to 1990 and randomly assigned patients without diabetes for comparison (3:1 ratio). We excluded patients with concomitant liver disease as far back as 1980. After excluding the first year of follow-up, the remaining patients were observed through 2000 for the occurrence of ALF (ICD-9 570). The cumulative risk and the relative risk of ALF were determined by Kaplan-Meier and Cox Proportional Hazard survival analysis, respectively.

RESULTS

We included 173,643 patients with diabetes and 650,620 patients without diabetes. Patients with diabetes were significantly older (62 vs. 54 years) and were less likely to be white (28% vs. 24%). The cumulative risk of ALF was significantly higher among patients with diabetes (incidence rate, 2.31 per 10,000 vs. 1.44 per 10,000 person-years; P < 0.0001). In the Cox proportional hazard model, diabetes was associated with a relative risk of 1.44 (95% CI, 1.26-1.63; P < 0.0001) for ALF while controlling for comorbidity index, age, sex, ethnicity, and period of service. This risk remained significantly increased after excluding patients with liver disease or viral hepatitis recorded during follow-up or those with ALF recorded after the introduction of troglitazone (relative risk = 1.40; P < 0.0001).

CONCLUSIONS

Diabetes increases the risk of ALF. The increase in ALF is independent of recognized underlying chronic liver disease or viral hepatitis.

Prevalence of gallbladder disease in American Indian populations: findings from the Strong Heart Study

American Indians are believed to be at high risk of gallbladder disease (GBD), but there has been no systematic evaluation of its prevalence among diverse groups of American Indians. Therefore, we determined the prevalence of GBD and associated risk factors among specified American Indian populations using ultrasonography of the gallbladder and standardized diagnostic criteria. Enrolled members, aged 47 years and older, of 13 American Indian tribes or communities in Arizona, Oklahoma, and South and North Dakota who participated in the Strong Heart Study were analyzed. GBD was the sum of gallstones (determined by ultrasound examination) and cholecystectomy (determined by ultrasound and self-report). The proportion of American Indian heritage was based on the heritage of the grandparents of participants. GBD prevalence was determined among 3,296 participants at the 3 sites. Among women, 17.8% had gallstones, and 46.3% had evidence of a cholecystectomy, for a total of 64.1% with GBD. Among men, 17.4% had gallstones, and 12.1% had evidence of a cholecystectomy, for a total of 29.5% with GBD. When figures were adjusted for age and Indian heritage, there was no significant difference in GBD prevalence across the 3 geographical areas. In multivariate logistic regression analysis, age, American Indian heritage, and waist circumference were associated with GBD among men, and age, American Indian heritage, diabetes, and parity were associated with GBD among women. Body mass index was not independently associated with GBD in either sex. In conclusion, GBD was found in epidemic proportions in diverse American Indian populations.

The burden of selected digestive diseases in the United States

BACKGROUND & AIMS

Gastrointestinal (GI) and liver diseases inflict a heavy economic burden. Although the burden is considerable, current and accessible information on the prevalence, morbidity, and cost is sparse. This study was undertaken to estimate the economic burden of GI and liver disease in the United States for use by policy makers, health care providers, and the public.

METHODS

Data were extracted from a number of publicly available and proprietary national databases to determine the prevalence, direct costs, and indirect costs for 17 selected GI and liver diseases. Indirect cost calculations were purposefully very conservative. These costs were compared with National Institutes of Health (NIH) research expenditures for selected GI and liver diseases.

RESULTS

The most prevalent diseases were non-food-borne gastroenteritis (135 million cases/year), food-borne illness (76 million), gastroesophageal reflux disease (GERD; 19 million), and irritable bowel syndrome (IBS; 15 million). The disease with the highest annual direct costs in the United States was GERD ($9.3 billion), followed by gallbladder disease ($5.8 billion), colorectal cancer ($4.8 billion), and peptic ulcer disease ($3.1 billion). The estimated direct costs for these 17 diseases in 1998 dollars were $36.0 billion, with estimated indirect costs of $22.8 billion. The estimated direct costs for all digestive diseases were $85.5 billion. Total NIH research expenditures were $676 million in 2000.

CONCLUSIONS

GI and liver diseases exact heavy economic and social costs in the United States. Understanding the prevalence and costs of these diseases is important to help set priorities to reduce the burden of illness.

A prospective study of dyspepsia in primary care

Dyspepsia is a common complaint, but its course and associated resource utilization have not been well described. In this study, 288 adult, primary care patients with dyspepsia treated at ambulatory clinics were followed prospectively for one year. Medical chart, utilization, and baseline and one-year follow-up survey data were collected. These patients had 13.3 medical visits (sex- and age-standardized) during the follow-up period, 55% above standardized mean visits for a comparison group of nondyspepsia patients. Standardized mean charges of $3542 for dyspeptics was 126% above nondyspepsia patient charges. Over half had gastrointestinal-related follow-up visits; 61% used gastrointestinal drugs; and 43% had gastrointestinal procedures. NSAID users had higher gastrointestinal-related utilization than did nonusers, recording an additional gastrointestinal visit (P < 0.001) and $678 more in charges (P = 0.03). Eighty-six percent of the 189 follow-up survey respondents experienced gastrointestinal symptoms at some time during the follow-up year. This study showed that most primary care dyspepsia patients remained symptomatic after one year and were intensive users of medical care.

Reliability of Helicobacter pylori and CagA serological assays

Background serological assays for Helicobacter pylori are commonly used without knowledge of reliability. This information is needed to define the ability of serological tests to determine either new cases of infection or loss of infection in longitudinal studies. We evaluated the reproducibility and the interrelationships of serological test results for H. pylori and cytotoxin-associated gene product A (CagA) enzyme-linked immunoassays within a subset of participants in a population-based study. Stored samples from 1,229 participants in the third U.S. National Health and Nutrition Examination Survey were replicate serologically tested for H. pylori and CagA. Overall disagreement was 3.4% between duplicate tests for H. pylori (or 2.3% if equivocal results were disregarded). Six percent of samples positive on the first test had an immune serum ratio at least 30% lower on repeat testing. The odds ratio for H. pylori seropositivity on retesting was 2.8 (95% confidence interval [CI] = 1.8 to 4.5) when CagA serology was positive versus when it was negative. CagA antibody was found among 47.8% of H. pylori-equivocal and 7.0% of H. pylori-negative samples. CagA-positive yet H. pylori-negative samples were more likely to occur among Mexican Americans (odds ratio, 5.2; 95% CI = 2.4 to 11.4) and non-Hispanic blacks (odds ratio, 5.5; 95% CI = 2.3 to 13.0) than among non-Hispanic whites. Relying on repeated H. pylori serological tests over time to determine infection rates may result in misinterpretation due to limits in test reproducibility. CagA testing may have a role in verifying infection.

Influence of delayed isotopic equilibration in urine on the accuracy of the (2)H(2)(18)O method in the elderly

Isotopic determination of total energy expenditure (TEE) by the doubly labeled water (DLW) method may be affected by urine retention in the elderly. The isotopic enrichments in urine and plasma sampled simultaneously 4 h post-DLW dose were compared in a subset of 281 subjects [139 women, 142 men, 75 +/- 3 (SD) yr] of the 3,075 participants in the Health, Aging, and Body Composition study. Based on analytic precisions, a +/- 2% urine-plasma difference was set as the cut-off value. Ten percent of the population presented a difference lower than -2%, suggesting a delay in urine isotopic equilibration. This -13 +/- 10% urine-plasma difference was not linked to analytic errors, illnesses, the sampling time, or the time and quantity of water intake, suggesting that urine retention may be the main factor. The consequences are an 18 +/- 13 and 21 +/- 16% overestimation of the total body water and the TEE, respectively. Unexpectedly, 21% of the population presented a urine-plasma difference higher than +/- 2% that resulted, however, in a nonsignificant TEE underestimation of -3 +/- 5%. In conclusion, the delayed isotopic equilibration observed in urine reduces the accuracy of the DLW method in the elderly. It is recommended, when blood sampling is impossible, to adopt the intercept method with urine sampling 24 h postdose.

Relationship of serum leptin concentration and other measures of adiposity with gallbladder disease

Obesity increases the risk of gallstones, especially in women. Most gallbladder disease studies have used body mass index (BMI) as a measure of overall adiposity, although BMI does not distinguish between fat and lean body mass. Central adiposity may also increase gallstone risk, although this is less well studied. Leptin is a peptide whose serum concentration is highly correlated with total body fat mass. We examined the relationship of gallbladder disease with anthropometric measures and serum leptin concentration in a large, national, population-based study. A total of 13,962 adult participants in the Third National Health and Nutrition Examination Survey underwent gallbladder ultrasonography and anthropometric measurements of BMI, body circumferences, and skinfold thicknesses, and a random subgroup of 5,568 had measures of fasting serum leptin concentrations. Gallstone-associated gallbladder disease was defined as ultrasound-documented gallstones or evidence of cholecystectomy. When controlling for BMI and other gallbladder disease risk factors in multivariate analysis, a test for trend for increasing waist-to-hip circumference ratio and risk of gallbladder disease was statistically significant among women (P =.043) and men (P =.007). BMI remained strongly associated with gallbladder disease among women (P <.001), but was unrelated among men (P =.46). Leptin concentration was associated with gallbladder disease in both sexes (P <.001), but not after controlling for BMI and waist-to-hip circumference in either women (P =.29) or men (P =.65). In conclusion, waist-to-hip circumference ratio was related to gallbladder disease among women and men. Serum leptin concentration was not a better predictor of gallbladder disease than anthropometry.

Hospitalization with respiratory disease following hiatal hernia and reflux esophagitis in a prospective, population-based study

PURPOSE

Hiatal hernia and reflux esophagitis have been associated with respiratory manifestations, though the temporal sequence of this relationship is uncertain. This study examined prospectively the relationship of hiatal hernia and reflux esophagitis with respiratory outcomes in a representative sample of the United States population.

METHODS

6928 participants in the first National Health and Nutrition Examination Survey, a population-based sample initially examined in 1971-1975, who were hospitalized during follow-up through 1992-1993 composed the study population. The relationship between hiatal hernia and reflux esophagitis hospitalization and a subsequent hospitalization with respiratory outcomes was measured in persons free of respiratory disease at baseline and at first hospitalization.

RESULTS

Multivariable survival analysis showed higher rates of hospitalization with any respiratory diagnosis [rate ratio (RR) = 1.4, 95% confidence interval (CI) 1.2-1.7] in persons with preceding hiatal hernia or reflux esophagitis hospitalization. Individually, rate ratios of pharyngitis (RR = 5.6, CI 2.0-15.7), tonsillitis (RR = 8.0, CI 2.5-25.8), bronchitis (RR = 1.8, CI 1.2-2.7), pneumonia (RR = 1.3, CI 1.0-1.7), emphysema (RR = 2.9, CI 1.5-5.5), asthma (RR = 2.1, CI 1.1-4.2), bronchiectasis (RR = 6.2, CI 1.1-34.3), and empyema or abscess (RR = 7.4, CI 1.3-42.3) were all higher following hiatal hernia and reflux esophagitis. Rate ratios were similar when reflux esophagitis and hiatal hernia were examined separately.

CONCLUSIONS

A prior hiatal hernia or reflux esophagitis hospitalization increased risk of respiratory disease hospitalization.

Leptin concentrations in the United States: relations with demographic and anthropometric measures

BACKGROUND

Leptin is a peptide that is strongly correlated with adiposity and is a potential determinant of obesity and its complications.

OBJECTIVE

Leptin concentrations from a representative sample of the US population were examined in relation to demographic and anthropometric measures.

DESIGN

Fasting serum leptin concentrations were measured in 6303 women and men aged > or =20 y in the third National Health and Nutrition Examination Survey. Anthropometric measures included body mass index, 4 skinfold thicknesses, and 4 body circumferences. Ethnic groups included non-Hispanic whites and blacks and Mexican Americans.

RESULTS

The mean serum leptin concentration was much higher in women (12.7 microg/L) than in men (4.6 microg/L). In a multivariate analysis, leptin concentrations were associated with the sum of 4 skinfold thicknesses, waist and hip circumferences, ethnicity, and age. These measures explained most of the variance in leptin concentrations in women (R2 = 0.69) and in men (R2 = 0.67). Triceps skinfold thickness, when substituted for the sum of skinfold thicknesses, performed nearly as well in women (R2 = 0.68) and men (R2 = 0.67). Leptin concentrations were slightly but significantly higher in non-Hispanic blacks than in non-Hispanic whites of both sexes when these anthropometric measures and age were controlled for; Mexican Americans had concentrations that were intermediate compared with the concentrations of non-Hispanic whites and blacks.

CONCLUSIONS

In this large, representative sample of the US population, demographic and anthropometric measures predicted serum leptin concentrations in women and men.