blinding (synonym: masking)

Keeping secret group assignment (e.g., to treatment or control) from the study participants or investigators. Blinding is used to protect against the possibility that knowledge of assignment may affect patient response to treatment, provider behaviors (performance bias), or outcome assessment (detection bias). Blinding is not always practical (e.g., when comparing surgery to drug treatment). The importance of blinding depends on how objective the outcome measure is; blinding is more important for less easily measurable and quantifiable outcome measures such as pain or quality of life.

carriers

Private insurance companies that process Medicare Part B claims under contract to HCFA. They apply the Medicare coverage rules to determine the appropriateness of claims and issue payments to providers for the government.

clinical trial

A formal study carried out according to a prospectively defined protocol that is intended to discover or verify the safety and effectiveness in human beings of interventions to promote well-being, or to prevent, diagnose, or treat illness. The term may refer to a controlled or uncontrolled trial. In a strict sense, the modifier "clinical" could be reserved for trials carried out in a clinical setting involving clinical disease, but in practice, its use has been extended to include other types of trials, such as health promotion and disease prevention, and trials carried out in the community. "Trials," without a modifier, is used synonymously with "clinical trials" in this report.

diagnosis-related group (DRG)

A set of related diagnoses, generally requiring similar treatment and length of stay for necessary procedures, used as

the basis for inpatient payment under the Medicare prospective payment system (PPS).

effectiveness

Effectiveness describes the extent to which a specific intervention, when used under ordinary circumstances, does what it is intended to do. Effectiveness, therefore, takes into account the fact that, in any group of individuals, some will not take the intervention as prescribed, or will take other actions that may compromise the effect of the intervention (e.g., take drugs that might interact with the test intervention).

efficacy

Efficacy is defined as the extent to which an intervention produces a beneficial result under ideal conditions.

end-stage renal disease (ESRD)

Irreversible kidney failure. To survive, the patient must either receive a kidney transplant or periodic kidney dialysis. Individuals with ESRD are eligible for Medicare benefits.

fiscal intermediaries (FI)

Private insurance companies that process Medicare Part A claims under contract to HCFA. They apply the Medicare coverage rules to determine the appropriateness of claims and issue payments to providers for the government.

HCFA

The Health Care Financing Administration, an agency within the U.S. Department of Health and Human Services that administers the Medicare and Medicaid programs.

institutional review board (IRB)

A committee or board associated with a specific institution, constituted according to rules set by the U.S. Department of Health and Human Services, responsible for reviewing, approving, and monitoring research studies involving human beings to be carried out in that institution. Review focuses mainly on the ethics of the proposed research, the informed consent process, and other issues related to study participants.

intention-to-treat (analysis)

An intention-to-treat analysis is one in which outcomes for all the participants in a trial are analyzed according to the intervention to which they were allocated, whether they received it or not. Intention-to-treat analyses mirror the noncompliance and treatment changes that are likely to occur when the intervention is used in practice, and eliminate the potential effect introducing attrition bias by excluding some participants from the analysis.

Investigational Device Exemption (IDE)

An exemption given by the FDA to the manufacturer of a new medical device or to an independent investigator permitting evaluation of the device in human beings in specified studies under specified conditions. The studies are intended to produce information required for approval of the device for marketing.

Investigational New Drug Exemption (IND)

An exemption given by the FDA to the manufacturer of a new drug or to an independent investigator

permitting evaluation of the drug in human beings in specified studies under specified conditions. In some cases, INDs may also be needed to allow study of already-approved drugs for new (''unlabelled") indications. The studies are intended to produce information required for approval of the device for marketing.

managed care plan

A general term applied to a wide range of insurance plans, including HMOs, where choice of providers is limited and administrative measures control utilization of services. The types of Medicare managed care plans include health maintenance organizations (HMOs), competitive medical plans (CMPs), and health care prepayment plans (HCPPs). The Balanced Budget Act of 1997 expands the types of managed care plans that can participate in Medicare.

medical device

Diagnostic or therapeutic equipment that does not interact chemically with a person's body. Includes, for example, diagnostic tests, kits, pacemakers and other heart rhythm devices, arterial grafts, stents, intraocular lenses, and artificial heart valves and joints. eta-analysis The use of statistical techniques in a systematic review to integrate the results of the included studies. Also used to refer to systematic reviews that use meta-analysis.

PDQ

The Physician Data Query system of the National Cancer Institute, which consists of a registry of most NCI-sponsored clinical trials as well as some other trials (industry-sponsored, foreign-sponsored). Other components of PDQ are site-and stage-specific descriptions of cancers and state-of-the-art treatment options. PDQ is accessible to the public as well as physicians, via internet or telephone requests.

phases of trials

Clinical trials are classified by phase most commonly for drugs, biologics, and devices in the FDA approval process for marketing (although the trials themselves may extend beyond the date of approval). NIH also describes trials by phase, for example, trials in cancer and AIDS, which are listed in their respective registries by phase. Clear lines do not necessarily demarcate one phase from another, however, and trials may be denoted as "phase 1/2" or "phase 3/4." In trials undertaken other than for marketing approval, a trial designated as phase 2 or 3 does not necessarily imply the completion of earlier phases: a phase 3 trial may be the first undertaken for a specific intervention.

phase 1 trial

First studies in people, to evaluate chemical action, appropriate dosage, and safety. Usually enrolls small numbers of participants and typically has no comparison group.

phase 2 trial

Provides preliminary information about how well the new drug works and generates more information about safety and benefit. Usually includes comparison group; patients may be assigned to groups by randomization.

phase 3 trial

Compares intervention with the current standard or placebo to assess dosage effects, effectiveness, and safety. Almost always uses random allocation to assign treatment. Typically involves many people (hundreds or thousands) but may be smaller.

phase 4 trial

Compares intervention with control intervention (with assignment to groups by randomization or some other scheme) with long-term follow-up focusing on specific clinical events related to safety and efficacy. For drugs, phase 4 trials may be required by FDA after approval for marketing has been granted.

placebo

An inactive substance or procedure administered to a patient, usually to compare its effects with those of a real drug or other intervention, but sometimes for the psychological benefit to the patient through a belief that s/he is receiving treatment. Placebos are used in clinical trials to blind people to their treatment allocation. Placebos should be indistinguishable from the active intervention to ensure adequate blinding.

principal investigator (PI)

The individual responsible for directing a research project.

protocol-induced costs

Patient care costs incurred in a clinical trial for services necessary solely to satisfy data collection needs of the clinical trial, such as monthly CT scans for a condition usually requiring only a single scan. Care that would be required under standard treatment—even if it also is required by the trial protocol—would not be considered protocol-induced.

randomization (random assignment)

A method that uses the play of chance to assign participants to comparison groups in a trial, by using a random numbers table or a computer-generated random sequence. Random allocation implies that each individual or unit being entered into a trial has the same chance of receiving each of the possible interventions. It also implies that the probability that an individual will receive a particular intervention is independent of the probability that any other individual will receive the same intervention.

routine patient care

Care that would be received by a patient undergoing "standard treatment." This would include such items as room and board for patients who are hospitalized, diagnostic and laboratory tests and monitoring appropriate to the patient's condition, post-surgical care when indicated, office visits, and so on.

standard treatment

An accepted mode of treatment for a given condition.

AAHP

American Association of Health Plan

AHCPR

Agency for Health Care Policy and Research

AMC

Academic Medical Center

ASCO

American Society of Clinical Oncology

CDC

Centers for Disease Control and Prevention

CFR

Code of Federal Regulations

CMP

competitive medical plan

CT

computerized tomography

DHHS

Department of Health and Human Services

DoD

Department of Defense

DRG

diagnosis-related group

FDA

Food and Drug Administration

GAO

General Accounting Office

GCRC

General Clinical Research Center

GHC

Group Health Cooperative of Puget Sound

HCFA

Health Care Financing Administration

HCPP

health care prepayment plan

HHA

Home Health Agency

HMO

health maintenance organization

IDE

Investigational Device Exemption

IND

Investigational New Drug Exemption

IOM

Institute of Medicine

IRB

institutional review board

KPNC

Kaiser Permanente of Northern California

LVRS

lung volume reduction surgery

MRA

magnetic resonance angiography

NCI

National Cancer Institute

NHLBI

National Heart, Lung and Blood Institute

NIDDK

National Institute of Diabetes and Digestive and Kidney Diseases

NIH

National Institutes of Health

NLM

National Library of Medicine

OIG

Office of the Inspector General

ONDS

optic nerve decompression surgery

OPRR

Office of Protection from Research Risks

PDQ

Physician Data Query

PET

positron-emission tomography

PI

principal investigator

PPS

prospective payment system

PRO

Peer Review Organization

ProPAC

Prospective Payment Assessment Commission

PTCA

percutaneous transluminal coronary angioplasty

SNF

skilled nursing facility

SPN

solitary pulmonary nodule

VA.

Department of Veterans Affairs