Talk to the Veterans Crisis Line now
U.S. flag
An official website of the United States government

VA Health Systems Research

Go to the VA ORD website
Go to the QUERI website

HSR Citation Abstract

Search | Search by Center | Search by Source | Keywords in Title

What patient population does visit-based sampling in primary care settings represent?

Lee ML, Yano EM, Wang M, Simon BF, Rubenstein LV. What patient population does visit-based sampling in primary care settings represent? Medical care. 2002 Sep 1; 40(9):761-70.

Dimensions for VA is a web-based tool available to VA staff that enables detailed searches of published research and research projects.

If you have VA-Intranet access, click here for more information

VA staff not currently on the VA network can access Dimensions by registering for an account using their VA email address.
   Search Dimensions for VA for this citation
* Don't have VA-internal network access or a VA email address? Try searching the free-to-the-public version of Dimensions


BACKGROUND: Evaluations of outpatient interventions often rely on consecutive sampling of clinic visitors, and assume that study results generalize to the population of patients cared for. OBJECTIVE: The representativeness of such visit-based sampling compared with the population of patients seen during the same year, in terms of sociodemographic and clinical characteristics of the user groups that visit-based sampling yielded were assessed. METHODS: One thousand five hundred forty-six continuing patients visiting the primary care firms in an urban VA medical center were consecutively sampled, and visit frequencies were compared for these patients with subsets of the patient population. Administrative and survey data was then used to describe the types of patients visit-based sampling most represented compared with the types of patients sampled less frequently. RESULTS: The average sampled patient visited the firms significantly more often than patients in the reference population (18.7 vs. 9.5). Sampled patients were significantly older ( > 55 years), in poorer health (higher prevalence of cancer, stroke, hypertension), less likely to smoke, and more likely to be single than the average patient visiting the firms (P < 0.05). Adjusting for age and sickness, frequent visitors were more apt to have experienced continuity of care during the prior year, to prefer VA care, and to be unemployed. CONCLUSIONS: Consecutive visit-based sampling actually selected patients with a visit pattern more typical of the patient population visiting four or more times a year. Studies using sampling of consecutive visitors will typically under-represent low users of care and should account for the degree to which results may not generalize to the broader practice population.

Questions about the HSR website? Email the Web Team

Any health information on this website is strictly for informational purposes and is not intended as medical advice. It should not be used to diagnose or treat any condition.