National probability samples in studies of low-prevalence diseases. Part I: Perspectives and lessons from the HIV cost and services utilization study.

OBJECTIVE: To examine the trade-offs inherent in selecting a sample design for a national study of care for an uncommon disease, and the adaptations, opportunities and costs associated with the choice of national probability sampling in a study of HIV/AIDS. SETTING: A consortium of public and private funders, research organizations, community advocates, and local providers assembled to design and execute the study. DESIGN: Data collected by providers or collected for administrative purposes are limited by selectivity and concerns about validity. In studies based on convenience sampling, generalizability is uncertain. Multistage probability sampling through households may not produce sufficient cases of diseases that are not highly prevalent. In such cases, an attractive alternative design is multistage probability sampling through sites of care, in which all persons in the reference population have some chance of random selection through their medical providers, and in which included subjects are selected with known probability. DATA COLLECTION AND PRINCIPAL FINDINGS: Multistage national probability sampling through providers supplies uniquely valuable information, but will not represent populations not receiving medical care and may not provide sufficient cases in subpopulations of interest. Factors contributing to the substantial cost of such a design include the need to develop a sampling frame, the problems associated with recruitment of providers and subjects through medical providers, the need for buy-in from persons affected by the disease and their medical practitioners, as well as the need for a high participation rate. Broad representation from the national community of scholars with relevant expertise is desirable. Special problems are associated with organization of the research effort, with instrument development, and with data analysis and dissemination in such a consortium. CONCLUSIONS: Multistage probability sampling through providers can provide unbiased, nationally representative data on persons receiving regular medical care for uncommon diseases and can improve our ability to accurately study care and its outcomes for diseases such as HIV/AIDS. However, substantial costs and special circumstances are associated with the implementation of such efforts.

The care of HIV-infected adults in the United States. HIV Cost and Services Utilization Study Consortium.

BACKGROUND AND METHODS: In order to elucidate the medical care of patients with human immunodeficiency virus (HIV) infection in the United States, we randomly sampled HIV-infected adults receiving medical care in the contiguous United States at a facility other than military, prison, or emergency department facility during the first two months of 1996. We interviewed 76 percent of 4042 patients selected from among the patients receiving care from 145 providers in 28 metropolitan areas and 51 providers in 25 rural areas. RESULTS: During the first two months of 1996, an estimated 231,400 HIV-infected adults (95 percent confidence interval, 162,800 to 300,000) received care. Fifty-nine percent had the acquired immunodeficiency syndrome according to the case definition of the Centers for Disease Control and Prevention, and 91 percent had CD4+ cell counts of less than 500 per cubic millimeter. Eleven percent were 50 years of age or older, 23 percent were women, 33 percent were black, and 49 percent were men who had had sex with men. Forty-six percent had incomes of less than $10,000 per year, 68 percent had public health insurance or no insurance, and 30 percent received care at teaching institutions. The estimated annual direct expenditures for the care of the patients seen during the first two months of 1996 were $5.1 billion; the expenditures for the estimated 335,000 HIV-infected adults seen at least as often as every six months were $6.7 billion, which is about $20,000 per patient per year. CONCLUSIONS: In this national survey we found that most HIV-infected adults who were receiving medical care had advanced disease. The patient population was disproportionately male, black, and poor. Many Americans with diagnosed or undiagnosed HIV infection are not receiving medical care at least as often as every six months. The total cost of medical care for HIV-infected Americans accounts for less than 1 percent of all direct personal health expenditures in the United States.

A national survey of physician-assisted suicide and euthanasia in the United States.

BACKGROUND: Although there have been many studies of physician-assisted suicide and euthanasia in the United States, national data are lacking. METHODS: In 1996, we mailed questionnaires to a stratified probability sample of 3102 physicians in the 10 specialties in which doctors are most likely to receive requests from patients for assistance with suicide or euthanasia. We weighted the results to obtain nationally representative data. RESULTS: We received 1902 completed questionnaires (response rate, 61 percent). Eleven percent of the physicians said that under current legal constraints, there were circumstances in which they would be willing to hasten a patient's death by prescribing medication, and 7 percent said that they would provide a lethal injection; 36 percent and 24 percent, respectively, said that they would do so if it were legal. Since entering practice, 18.3 percent of the physicians (unweighted number, 320) reported having received a request from a patient for assistance with suicide and 11.1 percent (unweighted number, 196) had received a request for a lethal injection. Sixteen percent of the physicians receiving such requests (unweighted number, 42), or 3.3 percent of the entire sample, reported that they had written at least one prescription to be used to hasten death, and 4.7 percent (unweighted number, 59), said that they had administered at least one lethal injection. CONCLUSIONS: A substantial proportion of physicians in the United States report that they receive requests for physician-assisted suicide and euthanasia, and about 7 percent of those who responded to our survey have complied with such requests at least once.

Effects of HIV infection, perceived health and clinical status on a cohort at risk for AIDS.

Data from a general population sample of 621 healthy homosexual men are used to evaluate the social and emotional effects of HIV antibody status, clinical signs detected by medical examination, and subjectively perceived symptoms. Participants are unaware of their serologic status at the time of data collection, thus allowing the effects of the virus to be separated from reactions to the knowledge of serologic status. The data show that seropositivity for HIV is not associated with elevated levels of social or emotional impairment. Clinical signs lead to impairment in baseline data, but these effects do not persist at a second wave. This weakening suggests that the effects are mediated by psychological pathways rather than biologic ones. This suspicion is confirmed in further analyses, which show that the effects of clinical signs are mediated by subjectively perceived symptoms. These results show that neither social nor emotional impairment is likely to be a prodromal sign of HIV infection in otherwise healthy homosexual men. The substantial levels of distress found among these men is more directly influenced by psychological determinants than biologic ones. This suggests that physicians should be aware of the psychological toll imposed on gay men who develop health problems in the current atmosphere of uncertainty regarding risk of AIDS.

A comparison of the symptoms of medical and psychiatric patients matched on the Beck Depression Inventory.

The goals of this study were to examine, in greater detail, the experience of depression in the medically ill, and to compare their experience with that of depressed psychiatric patients. Medical and psychiatric inpatients were matched in terms of total scores on the Beck Depression Inventory (BDI). In addition to the BDI, all patients completed a self-report symptom battery. No difference was found between the two groups in terms of total BDI scores, but psychiatric patients scored significantly higher on the affective BDI items, and medical patients scored significantly higher on the somatic BDI items. Discriminant analysis was used to compare their responses to the symptom battery. Depression in the psychiatric patients was characterized primarily by suicidal ideation and loss of interest, whereas in medical patients a lack of energy and worry were the predominant symptoms. The implications of these findings for assessing depression in the medically ill are discussed.

The effect of an educational intervention on the rate of neonatal circumcision.

Despite the absence of verifiable indications, routine circumcision of the male neonate remains one of the most common surgical procedures in the United States. A sample of obstetric clinic patients in a large urban hospital was tested to determine whether spoken educational intervention would reduce the rate of circumcision. The results showed that the rate was lowered significantly (94.4% circumcised in the control group versus 72% circumcised in the study group). Nevertheless, the majority of the study mothers requested circumcision for their sons despite the educational intervention, suggesting the presence of strong social motives. The authors conclude that many mothers in this population chose circumcision because of inadequate medical information or strong social motives. Both must be addressed if the rate of elective circumcision is to be reduced.