Objectives: To use a natural experiment to identify patient factors associated with the decision to follow one's primary care provider (PCP) to a more distant location after the closure of a medical practice. Study Design: Case-control study. Methods: Eight months after the closure of a practice in Dundalk, Maryland, we randomly selected 140 patients older than 60 years from each of the following groups: those who followed their PCP (continuity group) and those who transferred to a closer clinic (proximity group). We designed a survey instrument to collect information about demographics, duration of the patient-PCP relationship, transportation, self-assessed driving proficiency, and patients' estimates of the distance in miles and the driving time in minutes from their homes to both practices. chi(2) Tests and logistic regression analyses were used to determine differences between the groups. Results: The response rate to the survey was 64%. More than 85% of patients in both groups had been with their original PCP for longer than 2 years. In multivariable analysis, the following 3 factors were associated with being a patient in the proximity group: living alone (adjusted odds ratio [ OR], 3.14; 95% confidence interval [ CI], 1.35-7.26), having greater physical disability (physical component summary score <= 40; OR, 2.14; 95% CI, 1.04-4.39), and perceiving that travel time from home to the farther clinic would require at least 10 minutes longer than the MapQuest estimate (OR, 4.08; 95% CI, 1.97-8.43). Conclusion: Older patients who live alone and are weaker seem to be more likely to forgo continuity with their PCP for the sake of convenience when a barrier to access occurs such as relocation of the physician to a more distant office.