Information In Practice

Effect of electronic health records in ambulatory care: retrospective, serial, cross sectional study

BMJ 2005; 330 doi: (Published 10 March 2005) Cite this as: BMJ 2005;330:581
  1. Terhilda Garrido, senior director (terhilda.garrido{at},
  2. Laura Jamieson, senior business consultant1,
  3. Yvonne Zhou, project manager1,
  4. Andrew Wiesenthal, associate executive director, Permanente Federation1,
  5. Louise Liang, senior vice president for quality and clinical systems support, Kaiser Foundation Health Plan1
  1. 1 Clinical Systems Planning and Consulting, Kaiser Permanente, 2101 Webster Street, Oakland, CA 94612, USA
  1. Correspondence to: T Garrido
  • Accepted 31 January 2005


Objective To evaluate the effect of implementing comprehensive, integrated electronic health record systems on use and quality of ambulatory care

Design Retrospective, serial, cross sectional study.

Setting Colorado and Northwest regions of Kaiser Permanente, a US integrated healthcare delivery system.

Population 367 795 members in the Colorado region and 449 728 members in the Northwest region.

Intervention Implementation of electronic health record systems.

Main outcome measures Total number of office visits and use of primary care, specialty care, clinical laboratory, radiology services, and telephone contact. Health Plan Employer Data and Information Set to assess quality.

Results Two years after electronic health records were fully implemented, age adjusted rates of office visits fell by 9% in both regions. Age adjusted primary care visits decreased by 11% in both regions and specialty care visits decreased by 5% in Colorado and 6% in the Northwest. All these decreases were significant (P < 0.0001). The percentage of members making ≥ 3 visits a year decreased by 10% in Colorado and 11% in the Northwest, and the percentage of members with ≤ 2 visits a year increased. In the Northwest, scheduled telephone contact increased from a baseline of 1.26 per member per year to 2.09 after two years. Use of clinical laboratory and radiology services did not change conclusively. Intermediate measures of quality of health care remained unchanged or improved slightly.

Conclusions Readily available, comprehensive, integrated clinical information reduced use of ambulatory care while maintaining quality and allowed doctors to replace some office visits with telephone contacts. Shifting patterns of use suggest reduced numbers of ambulatory care visits that are inappropriate or marginally productive.


  • Contributors AW sponsored and facilitated the work. TG directed the study and drafting of the paper. LJ and YZ analysed the data. TG contributed to the conception and design of the study. LJ was involved in interviewing clinical and operations leaders. AW, TG, LJ, and YZ took part in planning the study, interpreting the data, and commented on the manuscript. AW and LL have sponsored the continuation, dissemination, and application of this work. TG is the guarantor.

  • Funding Kaiser Foundation Health Plan and Hospitals.

  • Competing interests None declared.

  • Ethical approval Not required.

  • Accepted 31 January 2005
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