Adherence to (or compliance with) a medication regimen is generally defined as the extent to which patients take medications as prescribed by their health care providers. The word "adherence" is preferred by many health care providers, because "compliance" suggests that the patient is passively following the doctor's orders and that the treatment plan is not based on a therapeutic alliance or contract established between the patient and the physician. Both terms are imperfect and uninformative descriptions of medication-taking behavior. Unfortunately, applying these terms to patients who do not consume every pill at the desired time can stigmatize these patients in their future relationships with health care providers. The language used to describe how patients take their medications needs to be reassessed, but these terms are still commonly used.1 Regardless of which word is preferred, it is clear that the full benefit of the many effective medications that are available will be achieved only if patients follow prescribed treatment regimens reasonably closely.

If rational individuals pay the full costs of their decisions about food intake and exercise, economists, policy makers, and public health officials should treat the obesity epidemic as a matter of indifference. In this paper, we show that, as long as insurance premiums are not risk rated for obesity, health insurance coverage systematically shields those covered from the full costs of physical inactivity and overeating. Since the obese consume significantly more medical resources than the non-obese, but pay the same health insurance premiums, they impose a negative externality on normal weight individuals in their insurance pool.

To estimate the size of this externality, we develop a model of weight loss and health insurance under two regimes——(1) underwriting on weight is allowed, and (2) underwriting on weight is not allowed. We show that under regime (1), there is no obesity externality. Under regime (2), where there is an obesity externality, all plan participants face inefficient incentives to undertake unpleasant dieting and exercise. These reduced incentives lead to inefficient increases in body weight, and reduced social welfare.

Using data on medical expenditures and body weight from the National Health and Interview Survey and the Medical Expenditure Panel Survey, we estimate that, in a health plan with a coinsurance rate of 17.5%, the obesity externality imposes a welfare cost of about $150 per capita. Our results also indicate that the welfare loss can be reduced by technological change that lowers the pecuniary and non-pecuniary costs of losing weight, and also by increasing the coinsurance rate.

Concern about health care expenditures is not a new phenomenon. Seventy-five years ago, President Herbert Hoover appointed a committee to investigate the cost of medical care under the chairmanship of Ray Lyman Wilbur, MD, president of Stanford University. Thirty-eight years ago, John Gardner, Secretary of Health, Education, and Welfare, convened a national conference on medical care costs. Since then, not a year has passed without professional and lay periodicals addressing this subject. Most recently, Annals has published 4 articles by Thomas Bodenheimer on health care costs, the last of which, coauthored by Alicia Fernandez, appears in this issue. These articles provide valuable background material and address several key questions about expenditures from many different perspectives. Possible approaches to cost containment are discussed, with special emphasis on the potential role of physicians and with the caveat that this is "an overview of a complex topic, written by a noneconomist for noneconomists."

This editorial, written by an economist for physicians, emphasizes some critical distinctions and offers a somewhat different set of questions and answers. It differentiates sharply between levels of expenditures and their rates of growth, addresses the question of why either should be of concern for public policy, and discusses strategies for containing expenditures.

BACKGROUND:

Idiopathic pulmonary fibrosis (IPF) profoundly affects the quality of patients' lives. A systematic review was performed to evaluate critically the published literature and to examine what is known about health-related quality of life (HRQL) in patients with IPF.

METHODS:

The MEDLINE, EMBASE, Health and Psychosocial Instruments, and Cochrane Library databases were searched to 1 April 2004. Abstracts and bibliographies of published articles were scanned and contact was made with investigators. Included studies analysed HRQL (or quality of life) in at least 10 patients with IPF. Two reviewers independently selected studies, evaluated their quality according to predetermined criteria, and abstracted data on study design, patients' demographic and clinical characteristics, and quality of life outcome measures.

RESULTS:

Seven studies met the inclusion criteria. The studies enrolled 512 patients with IPF and used three different instruments to measure HRQL. All studies had important limitations in methodological quality; none measured longitudinal changes in HRQL over time. Patients reported substantially impaired HRQL, especially in domains that measured physical health and level of independence. Patients with IPF appear to have similar impairments in HRQL to those with chronic obstructive pulmonary disease. Measures of dyspnoea were moderately correlated with scores from domains that measured physical health (R2 = 0.03-0.66) and energy/fatigue/pep (R2 = 0.19-0.55), but measures of pulmonary function and gas exchange did not correlate as strongly with these and other domains.

CONCLUSION:

Studies of HRQL in patients with IPF suggest that, in addition to the obvious effect on physical health, general health, energy level, respiratory symptoms, and level of independence are also impaired. Variability in HRQL among patients is not fully explained by measures of dyspnoea or pulmonary function, suggesting that HRQL measures provide unique information. More research is needed to identify or design appropriate measurement instruments for patients with IPF and to examine changes in HRQL over time or in response to specific treatments.

This issue of CHP/PCOR's quarterly newsletter covers developments from the spring 2005 quarter. It includes articles about:

• research on HIV/AIDS in Russia -- presented in May at an international conference -- which shows that in order to contain the country's rapidly expanding HIV/AIDS epidemic, Russia must aggressively treat HIV-positive injection drug users;
• a CHP/PCOR-hosted discussion session with Edward Sondik, director of the National Center for Health Statistics;
• an ongoing CHP/PCOR study that examines older adults' preferences about health states in which they would need help with basic tasks like bathing or eating;
• a panel discussion on "International Responses to Infectious Diseases," led by CHP/PCOR at the Stanford Institute for International Studies' first annual conference, featuring the World Health Organization's chief of infectious diseases;
• a widely publicized study by CHP/PCOR researchers which found that obese workers are paid less than non-obese workers in similar jobs, but only when they have employer-sponsored health insurance -- a finding suggesting that the wage gap is due to obese workers' higher medical costs, rather than outright prejudice; and
• an update on the Center on Advancing Decision Making for Aging, including two new seed projects and a lecture given by economics and psychology professor George Loewenstein.