Context The Internet has attracted considerable attention as a means to improve health and health care delivery, but it is not clear how prevalent Internet use for health care really is or what impact it has on health care utilization. Available estimates of use and impact vary widely. Without accurate estimates of use and effects, it is difficult to focus policy discussions or design appropriate policy activities.

Objectives To measure the extent of Internet use for health care among a representative sample of the US population, to examine the prevalence of e-mail use for health care, and to examine the effects that Internet and e-mail use has on users' knowledge about health care matters and their use of the health care system.

Design, Setting, and Participants Survey conducted in December 2001 and January 2002 among a sample drawn from a research panel of more than 60,000 US households developed and maintained by Knowledge Networks. Responses were analyzed from 4764 individuals aged 21 years or older who were self-reported Internet users.

Main Outcome Measures Self-reported rates in the past year of Internet and e-mail use to obtain information related to health, contact health care professionals, and obtain prescriptions; perceived effects of Internet and e-mail use on health care use.

Results Approximately 40% of respondents with Internet access reported using the Internet to look for advice or information about health or health care in 2001. Six percent reported using e-mail to contact a physician or other health care professional. About one third of those using the Internet for health reported that using the Internet affected a decision about health or their health care, but very few reported impacts on measurable health care utilization; 94% said that Internet use had no effect on the number of physician visits they had and 93% said it had no effect on the number of telephone contacts. Five percent or less reported use of the Internet to obtain prescriptions or purchase pharmaceutical products.

Conclusions Although many people use the Internet for health information, use is not as common as is sometimes reported. Effects on actual health care utilization are also less substantial than some have claimed. Discussions of the role of the Internet in health care and the development of policies that might influence this role should not presume that use of the Internet for health information is universal or that the Internet strongly influences health care utilization.

The economic importance of innovation brings with it an active debate on the impact public policy has on the innovation process. This annual series, sponsored by the National Bureau of Economic Research, brings the work of leading academic researchers to the broader policy community. This volume considers such topics as the implications of software outsourcing for American technology leadership; the complementary roles of large corporations and entrepreneurs in developing innovative technology; city-level policy and planning that establishes a "jurisdictional advantage" in the value of local resources; the effect of taxes on entrepreneurship; and how to incorporate innovation into the analysis of business mergers. These papers highlight the role economic theory and empirical analysis can play in evaluating policies and programs regarding research, innovation, and the commercialization of new technologies.

Diabetes mellitus is a leading cause of morbidity and death in the United States. Type 2 diabetes mellitus accounts for the majority of affected persons (90% to 95%) and affects older adults, particularly those older than 50 years of age. It affects an estimated 16 million Americans, 11 million of whom have both diabetes and hypertension. Most adverse diabetes outcomes are a result of vascular complications. These complications are generally classified as microvascular, such as retinopathy, nephropathy, and neuropathy (although neuropathy may not be entirely a microvascular disease), or macrovascular, such as coronary artery disease, cerebrovascular disease, and peripheral vascular disease.

In order to prevent, or diminish the progression of, microvascular and macrovascular complications, recommended diabetes management necessarily encompasses both metabolic control and cardiovascular risk factor control. The need for good glycemic control is supported by the Diabetes Control and Complications Trial in type 1 diabetes mellitus and, more recently, the United Kingdom Prospective Diabetes Study (UKPDS) in type 2 diabetes mellitus. In these studies, tight blood sugar control reduced microvascular complications, such as nephropathy and retinopathy, but had little effect on macrovascular outcomes. Up to 80% of patients with type 2 diabetes mellitus will develop or die of macrovascular disease, underscoring the importance of preventing macrovascular complications.

In an effort to provide internists and other primary care physicians with effective management strategies for diabetes care, the American College of Physicians decided to develop guidelines on the management of hypertension in people with type 2 diabetes mellitus. The target audience for this guideline is all clinicians who provide care to patients with type 2 diabetes. The target patient population is all persons with type 2 diabetes who have hypertension, defined as systolic blood pressure of at least 140 mm Hg or diastolic blood pressure of at least 90 mm Hg. This target patient population includes those who already have some form of microvascular complication and, of particular importance, premenopausal women with diabetes. We will attempt to answer the following questions: 1) What are the benefits of tight blood pressure control in type 2 diabetes? 2) What should the target levels of systolic blood pressure and diastolic blood pressure be for patients with type 2 diabetes? and 3) Are certain antihypertensive agents more effective or beneficial in patients with diabetes?

When analyzing benefit or effectiveness for this review, we included only studies that measured clinical end points. The four major classes of clinical end points were all-cause mortality, cardiovascular mortality, cardiovascular events (myocardial infarction, stroke, or congestive heart failure), and microvascular complications (photocoagulation, nephropathy, neuropathy, or amputation).

The review was divided into two categories. The first included studies that evaluated the effects of blood pressure control if the comparison examined an antihypertensive drug versus placebo or the effects of different target blood pressure levels. The second category evaluated the effect of different classes of drugs. A discussion of this evidence follows.

Context Low-carbohydrate diets have been popularized without detailed evidence of their efficacy or safety. The literature has no clear consensus as to what amount of carbohydrates per day constitutes a low-carbohydrate diet.

Objective To evaluate changes in weight, serum lipids, fasting serum glucose, and fasting serum insulin levels, and blood pressure among adults using low-carbohydrate diets in the outpatient setting.

Data Sources We performed MEDLINE and bibliographic searches for English-language studies published between January 1, 1966, and February 15, 2003, with key words such as low carbohydrate, ketogenic, and diet.

Study Selection We included articles describing adult, outpatient recipients of low-carbohydrate diets of 4 days or more in duration and 500 kcal/d or more, and which reported both carbohydrate content and total calories consumed. Literature searches identified 2609 potentially relevant articles of low-carbohydrate diets. We included 107 articles describing 94 dietary interventions reporting data for 3268 participants; 663 participants received diets of 60 g/d or less of carbohydrates—of whom only 71 received 20 g/d or less of carbohydrates. Study variables (eg, number of participants, design of dietary evaluation), participant variables (eg, age, sex, baseline weight, fasting serum glucose level), diet variables (eg, carbohydrate content, caloric content, duration) were abstracted from each study.

Data Extraction Two authors independently reviewed articles meeting inclusion criteria and abstracted data onto pretested abstraction forms.

Data Synthesis The included studies were highly heterogeneous with respect to design, carbohydrate content (range, 0-901 g/d), total caloric content (range, 525-4629 kcal/d), diet duration (range, 4-365 days), and participant characteristics (eg, baseline weight range, 57-217 kg). No study evaluated diets of 60 g/d or less of carbohydrates in participants with a mean age older than 53.1 years. Only 5 studies (nonrandomized and no comparison groups) evaluated these diets for more than 90 days. Among obese patients, weight loss was associated with longer diet duration (P = .002), restriction of calorie intake (P = .03), but not with reduced carbohydrate content (P = .90). Low-carbohydrate diets had no significant adverse effect on serum lipid, fasting serum glucose, and fasting serum insulin levels, or blood pressure.

Conclusions There is insufficient evidence to make recommendations for or against the use of low-carbohydrate diets, particularly among participants older than age 50 years, for use longer than 90 days, or for diets of 20 g/d or less of carbohydrates. Among the published studies, participant weight loss while using low-carbohydrate diets was principally associated with decreased caloric intake and increased diet duration but not with reduced carbohydrate content.

The United States, physicians insert more than 5 million central venous catheters every year. Central venous catheters allow measurement of hemodynamic variables that cannot be measured accurately by noninvasive means and allow delivery of medications and nutritional support that cannot be given safely through peripheral venous catheters. Unfortunately, the use of central venous catheters is associated with adverse events that are both hazardous to patients and expensive to treat. More than 15 percent of patients who receive these catheters have complications. Mechanical complications are reported to occur in 5 to 19 percent of patients,5,6,8 infectious complications in 5 to 26 percent,5,7,9 and thrombotic complications in 2 to 26 percent. In this review, we explain methods for reducing the frequency of complications in adult patients.

OBJECTIVE: The prevalence of type 2 diabetes, especially in developing countries, has grown over the past decades. We performed a controlled clinical study to determine whether a community-based, group-centered public health intervention addressing nutrition and exercise can ameliorate glycemic control and associated cardiovascular risk factors in type 2 diabetic patients in rural Costa Rica.

RESEARCH DESIGN AND METHODS: A total of 75 adults with type 2 diabetes, mean age 59 years, were randomly assigned to the intervention group or the control group. All participants received basic diabetes education. The subjects in the intervention group participated in 11 weekly nutrition classes (90 min each session). Subjects for whom exercise was deemed safe also participated in triweekly walking groups (60 min each session). Glycosylated hemoglobin, fasting plasma glucose, total cholesterol, triglycerides, HDL and LDL cholesterol, height, weight, BMI, and blood pressure were measured at baseline and the end of the study (after 12 weeks).

RESULTS: The intervention group lost 1.0 +/- 2.2 kg compared with a weight gain in the control group of 0.4 +/- 2.3 kg (P = 0.028). Fasting plasma glucose decreased 19 +/- 55 mg/dl in the intervention group and increased 16 +/- 78 mg/dl in the control group (P = 0.048). Glycosylated hemoglobin decreased 1.8 +/- 2.3% in the intervention group and 0.4 +/- 2.3% in the control group (P = 0.028).

CONCLUSIONS: Glycemic control of type 2 diabetic patients can be improved through community-based, group-centered public health interventions addressing nutrition and exercise. This pilot study provides an economically feasible model for programs that aim to improve the health status of people with type 2 diabetes.

Objective: To test the feasibility, acceptability, and potential efficacy of after-school dance classes and a family-based intervention to reduce television viewing, thereby reducing weight gain, among African-American girls.

Design: Twelve-week, 2-arm parallel group, randomized controlled trial.

Setting: Low-income neighborhoods.

Participants: Sixty-one 8-10-year-old African-American girls and their parents/guardians.

Interventions: The treatment intervention consisted of after-school dance classes at 3 community centers, and a 5-lesson intervention, delivered in participants' homes, and designed to reduce television, videotape, and video game use. The active control intervention consisted of disseminating newsletters and delivering health education lectures.

Main Outcome Measures: Implementation and process measures, body mass index, waist circumference, physical activity measured by accelerometry, self-reported media use, and meals eaten with TV.

Results: Recruitment and retention goals were exceeded. High rates of participation were achieved for assessments and intervention activities, except where transportation was lacking. All interventions received high satisfaction ratings. At follow up, girls in the treatment group, as compared to the control group, exhibited trends toward lower body mass index (adjusted difference = -.32 kg/m2, 95% confidence interval [CI] -.77, .12; Cohen's d = .38 standard deviation units) and waist circumference (adjusted difference = -.63 cm, 95% CI -1.92, .67; d = .25); increased after-school physical activity (adjusted difference = 55.1 counts/minute, 95% CI -115.6, 225.8; d = .21); and reduced television, videotape, and video game use (adjusted difference = -4.96 hours/week, 95% CI -11.41, 1.49; d = .40). The treatment group reported significantly reduced household television viewing (d = .73, P = .007) and fewer dinners eaten while watching TV (adjusted difference = -1.60 meals/week, 95% CI -2.99, -.21; d = .59; P = .03). Treatment group girls also reported less concern about weight (d = .60; P = .03), and a trend toward improved school grades (d = .51; P = .07).

Conclusions: This study confirmed the feasibility, acceptability, and potential efficacy of using dance classes and a family-based intervention to reduce television viewing, thereby reducing weight gain, in African-American girls.

Contemporary clinical trials commonly measure quality of life and medical costs to establish whether therapies are both effective and cost effective. Cost-effectiveness analysis, however, requires a measure of patient utility or preferences for various health states. Because utilities are not often measured directly, we sought to develop a method of translating standard quality-of-life scales into a patient utility measure.

Methods

Five hundred fifty-three patients enrolled in the Bypass Angioplasty Revascularization Investigation Study of Economics and Quality of Life completed a battery of quality-of-life measures and a time trade-off utility assessment an average of 7.3 years after random assignment.

Results

The mean time trade-off score was 8.54 (SD ? 2.53) out of a maximum of 10; median score was 9.95. The distribution of scores was skewed, with 12% of patients at the highest possible score of 10. Patients with recurrent angina had significantly lower time trade-off scores than patients without angina (mean 7.03 vs 8.70, P .05). Time trade-off scores were moderately correlated with each quality-of-life measure (Spearman coefficients 0.38-0.52). Time trade-off scores could be predicted by combinations of 4 (r² ? 0.29), 5 (r² ? 0.31), or 6 (r² ? 0.32) variables.

Conclusions

Time trade-off utility scores can be inferred from commonly used quality-of-life measures. Angina significantly reduces patient utility scores.

Objectives

To evaluate recent trends, we examined longitudinal national data on the outpatient use of warfarin in atrial fibrillation (AF), beta-blockers and aspirin in coronary artery disease (CAD), and angiotensin-converting enzyme inhibitors (ACEIs) in congestive heart failure (CHF).

Background

Previous studies indicate that specific cardiac medications are underutilized.

Methods

We used the National Disease and Therapeutic Index (NDTI) (produced by IMS HEALTH, Plymouth Meeting, Pennsylvania) for 1990 to 2002, and the National Ambulatory Medical Care Surveys (NAMCS) for 1990 to 2000 to follow nationally representative samples of outpatient visits. For visits by patients with AF (total N = 14,634 visits), CAD (n = 35,295), and CHF (n = 33,008), we examined trends in the proportion of visits with the selected medications reported.

Results

Warfarin use in AF increased from 12% in 1990, to 41% in 1995, to 58% in 2001 in NDTI; a similar moderation of recent increase was seen in NAMCS. For CAD in NDTI, beta-blocker use increased slowly from 19% in 1990, to 20% in 1995, then to 40% in 2001; NAMCS showed this same pattern. Aspirin use in CAD in NDTI increased from 18% in 1990, to 19% in 1995, to 38% in 2001; NAMCS, however, showed lower use rates. For NDTI, ACEI use in CHF increased from 24% in 1990 to 36% in 1996, but increased to only 39% by 2001, a general pattern also seen in NAMCS.

Conclusions

Both national datasets demonstrate continuing underutilization of these cardiac medications of proven benefit. Although use is increasing, it remains lower than expected, and some increases noted in earlier years have slowed. Substantial public health benefits would result from further adoption of these effective therapies.