Background: In 1996, the Minnesota legislature passed a medical data privacy act requiring patient authorization for the use of medical records in research. Other state legislatures and Congress are considering similar legislation. The impact of this statute on a researcher's ability to obtain complete and representative data is unknown.
Methods: This was a cross-sectional study of all patients visiting the outpatient clinic, emergency department, or hospital of the Olmsted Medical Center (OMC), for an appointment or admission during January 1997 or February 1997. Patients were asked to give consent for the use of their medical records for research. Our objective was to gather information on the number and characteristics of patients who refused authorization.
Results: Of the 15,997 patients: 90.6% granted authorization; 3.6 refused authorization; 4.5% were undecided; and 1.3% were not asked for authorization. Refusal rates were highest among patients visiting the center for mental health concerns, trauma, or eye care, and among women aged 39 years or older. Undecided rates were highest in women presenting for pregnancy care.
Conclusions: Refusal rates were low for this community practice. However, higher refusal rates in some subgroups, such as older women or patients with mental health concerns, may increase the chance of selection bias in studies involving these patients.