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Vaccine effectiveness studies are subject to biases due to depletion-of-persons at risk of infection, or at especially high risk of infection, at different rates from different groups (depletionof-susceptibles bias), a problem that can also lead to biased estimates of waning effectiveness, including spurious inference of waning when none exists. An alternative study design to identify waning is to study only vaccinated persons, and compare for each day the incidence in persons with earlier or later dates of vaccination to assess waning in vaccine protection as a function of vaccination time (namely whether earlier vaccination would result in lower subsequent protection compared to later vaccination). Prior studies suggested under what conditions this alternative would yield correct estimates of waning. Here we define the depletion-ofsusceptibles process formally and show mathematically that for influenza vaccine waning studies, a randomised trial or corresponding observational study that compares incidence at a specific calendar time among individuals vaccinated at different times before the influenza season begins will not be vulnerable to depletion-of-susceptibles bias in its inference of waning as a function of vaccination time under the null hypothesis that none exists, and will – if waning does actually occur – underestimate the extent of waning. Such a design is thus robust in the sense that a finding of waning in that inference framework reflects actual waning of vaccine-induced immunity. We recommend such a design for future studies of waning, whether observational or randomised. [ABSTRACT FROM AUTHOR]

Objective: Although evidence suggests that patients with depression use more medical services than those without depression, few studies have examined whether specific subgroups of patients with depression have higher utilization than others. The study compared costs for general medical care with and without psychiatric care for patients with major depression and disabling chronic pain (reference group) with costs for five other groups: those with depression and nondisabling chronic pain, those with major depressive disorder alone, those with no depression who had disabling chronic pain, those with depression who had chronic pain that was not disabling, and those who had neither pain nor depression. Costs for the group with major depressive disorder alone were compared to costs for the three groups without depression.Methods: A questionnaire assessing major depressive disorder, chronic pain, and pain-related disability was mailed to a random sample of Kaiser Permanente patients who visited a primary care clinic. A total of 5,808 patients responded (54% participation rate). Costs for a two-year period were obtained from Kaiser Permanente's Cost Management Information System. Analyses were adjusted for presence of any of four major chronic medical illnesses.Results: Total costs for patients in the reference group were significantly higher than costs for the other five subgroups. Regression analyses indicated that continuous measures of severity of pain and severity of depression were associated with increased costs, but no statistically significant interaction of depression and pain on total cost was observed.Conclusions: Patients with major depressive disorder and comorbid disabling chronic pain had higher medical service costs than other groups of patients with and without depression. However, findings suggest that the increases in cost from having both pain and depression are additive and not multiplicative. [ABSTRACT FROM AUTHOR]

BACKGROUND: E-health services may improve the quality and efficiency of care; however, there is little quantitative data on e-health use. OBJECTIVE: The objective of this study was to examine trends in e-health use and user characteristics. RESEARCH DESIGN: This was a longitudinal study of e-health use (1999-2002) within an integrated delivery system (IDS). We classified 4 e-health services into transactional (drug refills and appointment scheduling) and care-related (medical and medication advice) services. SUBJECTS: Approximately 3.3 million members of a large, prepaid IDS. MEASUREMENTS: Amount and frequency of e-health use over time and characteristics of users. RESULTS: The number of members registered for access to e-health increased from 20,617 (0.7% of all members) in Q1 1999 to 270,987 (8.6%) in Q3 2002. Between Q1 and Q3 2002, 42,845 members (1.3%) used the drug refill service and 55,901 (1.7%) used the appointment scheduling service compared with 10,756 members (0.3%) who used the medical advice service and 3069 (0.1%) who used the medication advice service. Over the same period, transactional service users averaged 3.5 uses/user versus 1.6 uses/user among care-related service users. Members most likely to use e-health services had a high level of clinical need, a regular primary care provider, were 30 to 64 years old, female, white, and lived in a nonlow socioeconomic status neighborhood. These findings were consistent across e-health service types. CONCLUSIONS: Although use of all e-health services grew rapidly, use of care-related services lagged significantly behind use of transactional services. Subjects with greater clinical need and better ties to the health system were more likely to use both types of e-health services. [ABSTRACT FROM AUTHOR]

Background: Patients are increasingly paying for more of their medical care through cost-sharing, yet little is known about how patients change the ways that they seek care in response.Objective: We sought to assess how patients change their care-seeking behavior in response to emergency department (ED) copayments.Research Design: Telephone interviews with a stratified random sample of adult members of a large integrated delivery system.Subjects: There were 932 respondents (72% response rate).Measures: We examined participants' knowledge of their copayment level for ED services, and measures of how the cost-sharing affected their decisions about where or when to seek care.Results: Overall, 82% of participants faced a copayment for ED services (ranging between 5 US dollars and 100 US dollars), and 41% correctly reported the amount of this copayment. In response to the perceived copayment amount, 19% reported changing their care-seeking behavior within the previous 12 months: 12% sought care from an alternate delivery site, 12% contacted a provider by telephone or the Internet, 9% delayed going to the ED, and 2% avoided medical care altogether. In multivariate models, the ED cost-sharing amount was significantly associated with reporting changes in care-seeking behavior.Conclusions: When faced with an ED copayment, patients in the health system most commonly shifted toward seeking care from other available alternatives, and rarely avoid medical care altogether. [ABSTRACT FROM AUTHOR]

BACKGROUND: There exists substantial evidence that individuals with alcohol and drug disorders have heightened comorbidities and health care costs. However, little is known about the larger population of 'hazardous' drinkers (those whose consumption increases their 'risk of physical and psychological harm') and drug users. METHODS: A sample of 1,419 patients from HMO primary care clinics was screened for hazardous drinking and drug use. Health plan databases were used to examine medical conditions and health care costs of hazardous drinkers and drug users in the year prior to screening, in comparison to 13,347 patients from the same clinics, excluding those screened. RESULTS: We found a prevalence of 7.5% for hazardous drinking and 3.2% for drug use in primary care (10% had at least one of the two problems). Hazardous drinkers and drug users had heightened prevalences for eight medical conditions, including costly conditions such as injury and hypertension, and psychiatric conditions. Medical costs for the year examined were not higher, except for those who also had psychiatric conditions. CONCLUSIONS: The prevalence of hazardous drinking and drug use was similar to hypertension and diabetes. Hazardous drinkers and drug users' heightened medical conditions, especially those related to alcohol and drug abuse, indicate that screening and brief intervention at this lower threshold of hazardous drinking and drug use will detect individuals with health risks sooner. Optimal treatment and prevention of some medical disorders may require identification and intervention of underlying hazardous alcohol or drug use. [ABSTRACT FROM AUTHOR]

OBJECTIVE: To evaluate the patterns of e-Health use over a four-year period and the characteristics of users. DESIGN: Longitudinal, population-based study (1999-2002) of members of a prepaid integrated delivery system. Available e-Health services included ordering prescription drug refills, scheduling appointments, and asking medical questions. MEASUREMENTS: Rates of known access to e-Health services, and of e-Health use each quarter. RESULTS: The number of members with known e-Health access increased from 51,336 (1.6%) in 1999 to 324,522 (9.3%), in 2002. The percentage of households in which at least one person in the household had access increased from 2.7% to 14.1%. Among the subjects with known access, the percentage of subjects that used e-Health at least once increased from 25.7% in 1999 to 36.2% in 2002. In the multivariate analysis, subjects who had a low expected clinical need, were nonwhite, or lived in low socioeconomic status (SES) neighborhoods were less likely to have used e-Health services in 2002. Disparities by race/ethnicity and SES persisted after controlling for access to e-Health and widened over time. CONCLUSION: Access to and use of e-Health services are growing rapidly. Use of these services appears to be greatest among persons with more medical need. The majority of subjects, however, do not use any e-Health services. More research is needed to determine potential reasons for disparities in e-Health use by race/ethnicity and SES as well as the implications of these disparities on clinical outcomes. [ABSTRACT FROM AUTHOR]

Disease management (DM) promises to achieve cost savings by improving the quality of care for chronic diseases. During the past decade the Permanente Medical Group in Northern California has implemented extensive DM programs. Examining quality indicators, utilization, and costs for 1996-2002 for adults with four conditions, we find evidence of substantial quality improvement but not cost savings. The causal pathway--from improved care to reduced morbidity to cost savings--has not produced sufficient savings to offset the rising costs of improved care. We conclude that the rationale for DM programs, like the rationale for any medical treatments, should rest on their effectiveness and value. [ABSTRACT FROM AUTHOR]

Background: The use of cost-sharing to control healthcare expenditures is increasing, but there is scant information about patients' knowledge of cost-sharing or its influence on behavior.Objective: The objective of this study was to evaluate what patients know about their individual levels of cost-sharing and how it influences decisions to seek care.Study Design: We conducted a cross-sectional telephone survey with a 69% response rate.Subjects: We studied a stratified random sample of 695 adult patients in an integrated delivery system: 266 subjects > or =65 years, 218 low-income subjects, and 211 subjects from the overall membership.Measures: We used perceived and actual levels of copayments for emergency department (ED) visits, office visits, and prescription drugs; and self-reports of copayment-related behavior changes.Results: One third of subjects correctly reported their ED copayment, whereas three fourths correctly reported their prescription drug and office visit copayments. Over half of the subjects (57%) underestimated their ED copayment by $20 or more. Among patients who reported having any copayment, 11% described changing their behavior because of the copayment, ie, delayed or avoided emergency care. The perceived copayment level was strongly associated with behavior change (odds ratio, 3.9). Other significant factors included having more ED visits in the past 12 months and having a low health status.Conclusions: Patients have less knowledge of their ED cost-sharing levels than for other services. The perceived copayment amount was strongly associated with avoidance of or delays in emergency care. Further research is needed to determine whether these responses reflect greater efficiency or harmful decisions. [ABSTRACT FROM AUTHOR]