Selection bias from requiring patients to give consent to examine data for health services research.

BACKGROUND: New rulings nationwide require health services researchers to obtain patient consent before examining personally identifiable data. A selection bias may result if consenting patients differ from those who do not give consent. OBJECTIVE: To compare patients who consent, refuse, and do not answer. DESIGN: Patients completing an in-office survey were asked for permission to be surveyed at home and for their records to be reviewed. Survey responses and practice billing data were used to compare patients by consent status. SETTING: Urban family practice center. PATIENTS: Of 2046 eligible patients, 1106 were randomly selected for the survey, were approached by staff, and agreed to participate. Approximately 87% of the nonparticipants were eliminated through a randomization process. MAIN OUTCOME MEASURE: Consent status. RESULTS: A total of 33% of patients did not give consent: 25% actively refused, and 8% did not answer. Consenting patients were older, included fewer women and African Americans, and reported poorer physical function than those who did not give consent (P<.05). Patients who did not answer the question were older, included more women and African Americans, and were less educated than those who answered (P<.02). Visits for certain reasons (eg, pelvic infections) were associated with lower consent rates. On multivariate analysis, older age, male sex, and lower functional status were significant predictors of consent. CONCLUSIONS: Patients who release personal information for health services research differ in important characteristics from those who do not. In this study, older patients and those in poorer health were more likely to grant consent. Quality and health services research restricted to patients who give consent may misrepresent outcomes for the general population. Arch Fam Med. 2000;9:1111-1118

Evaluating the administration of an office-based health survey in a primary care practice.

Self-administered waiting room questionnaires are popular tools for gathering health information from patients, but these data cannot be used for research purposes without confirming adequate sampling of the practice population and assessing the completeness and accuracy of patients' responses. Long-term data collection also requires avoiding an imposition on clinic operations. We developed a protocol to test these questions in a 9-week pilot study of 884 survey-eligible patients visiting a family practice clinic. We found an adequate proportion of eligible patients were approached (74%) and participated (89%), they provided relatively complete (82-98%) and accurate responses, and the impact on office operations was minimal (<2 min of staff time per participant). Some demographic differences in participation and survey item completion were identified. A systematic process for testing survey performance allowed us to not only document these findings, but also to rapidly identify problems and introduce solutions while the survey was in progress.

Is cigarette smoking associated with impaired physical and mental functional status? An office-based survey of primary care patients.

OBJECTIVE: To examine the relationship between cigarette smoking and self-reported physical and mental functional status. DESIGN: Cross-sectional survey of 837 patients visiting 2 family-practice centers. Patients completed a self-administered survey about functional status, tobacco use, and demographic characteristics while waiting to be called back for their appointments. SETTING: An inner-city family practice clinic in Richmond, Virginia, and a more affluent suburban practice outside Washington, DC. MAIN OUTCOME MEASURES: Physical and mental functional status, as measured by the SF-36 (Medical Outcomes Trust, Boston, MA); current and former cigarette use; and demographic variables (age, gender, education, income). RESULTS: Among current smokers, self-reported functional status scores were significantly lower than those of nonsmokers in all SF-36 domains (p < or = 0.02), a pattern that was more dramatic for mental functional status domains (social function, vitality, emotional role limitations, mental health). In several SF-36 domains, a dose-response relationship between smoking and functional status was noted. After multivariate adjustment for demographic confounders and practice site, the statistical significance of these differences diminished considerably, but it remained significant for certain domains and for the overall difference across all domains (MANCOVA p = 0.017). CONCLUSIONS: Current smokers report lower functional status than nonsmokers, in physical and especially in mental domains. The meaning of this cross-sectional relationship is unclear without further longitudinal study. Smoking may be associated with other variables that have a causal role.

Screening for prostate cancer: the roles of science, policy, and opinion in determining what is best for patients.

Controversy over screening for prostate cancer involves both scientific and policy considerations. The principal scientific questions are whether tumors detected by screening are clinically significant, whether screening generates too many false-positive results, and whether early detection lowers morbidity or mortality. Both screening and treatment of prostate cancer can be harmful, making the tradeoff between benefits and risks especially relevant. Studies suggest that this judgment is highly personal, depending on the relative importance that individuals assign to potential outcomes. Opinions and policy considerations also influence views about the appropriateness of screening. Chief among these are personal beliefs about benefits and harms, medicolegal concerns, patient expectations, resource constraints, and opportunity costs. Appropriate policy must discriminate between what is best for populations and for individual patients. The lack of evidence of benefit and the potential harms argue against a societal policy of routine screening. Individual patients who could benefit from screening should be informed about the potential benefits and harms and invited to make a personal choice based on their priorities and concerns.

The functional status of inner-city primary care patients. Diminished function in a family practice population and its potential determinants.

BACKGROUND: Research on health care quality and effectiveness often relies on global health status measures, such as functional status, but little is known about the functional status of patients in the primary care setting (without limitation to specific diseases) and even less about the function of the poor or ethnic minorities. In preparation for a planned practice-based research network, we administered a functional-status survey to patients visiting an inner-city family practice center. METHODS: Over 9 weeks, 555 established patients older than 18 years, as well as adolescents accompanied by a parent or guardian, completed a survey that included the SF-36 Health Survey and questions about demographic variables and cigarette use. The survey was self-administered in the waiting area and examination room, and patients received no assistance from staff. RESULTS: Functional-status scores reported by this primary care cohort were significantly lower than those of the general population (P < .001) and comparable with those reported nationally for patients with chronic diseases (e.g., congestive heart failure, diabetes). Functional-status scores were associated with age, sex, and, most strikingly, socioeconomic status. For example, patients with a yearly income of less than $15,000 had lower mean physical function scores than those reported nationally for patients with hypertension, diabetes, depression, recent myocardial infarction, or hypertension (P < .05). Patients who currently smoked reported lower physical function (P = .004) and strikingly lower mental function (P < .001) than nonsmokers. CONCLUSIONS: Although patients completing the survey included healthy persons seeking preventive care and sick patients with acute and chronic illnesses, their overall functional status resembled that reported nationally for patients with chronic disease, perhaps reflecting the influence of poverty. Few studies have reported the association we observed between smoking and lower functional status. Further longitudinal studies in the primary care setting are necessary to fully interpret these associations and to evaluate the true impact of interventions on outcomes.