Development and evaluation of a computer-based system for dietary management of hyperlipidemia.

Objective: To describe the development of a computer-based system for dietary management of hyperlipidemia and to evaluate its efficacy for lowering plasma cholesterol level.

Design: Using a stepwise approach, we developed and tested a three-part self-management system in five consecutive clinical studies. Each study assessed plasma cholesterol levels before and after dietary intervention using the system. These studies enabled progressive refinement of (a) a food frequency questionnaire used to assess food intake in the preceding month; (b) computer-generated progress reports, based on questionnaire responses, offering dietary change subgoals and strategies for change; and (c) a dietary workbook providing detailed information on how to achieve goals.

Subjects/setting: Persons with hyperlipidemia (n=814) were enrolled from worksite and clinical settings in the San Francisco Bay area of California. The attrition rate after randomization was 5%.

Intervention: Elements of the dietary intervention evolved in response to the results of five clinical studies. In each study, patients underwent a form of baseline assessment of dietary intake followed by counseling/instruction by various means. Follow-up dietary assessments were provided at specific intervals to facilitate subjects' progress toward their dietary goals. A dietary workbook provided the detailed instruction required to implement the recommendations contained in the periodic progress reports.

Statistical Analyses Performed: Changes in plasma cholesterol level were measured by paired and unpaired t tests. The relationship between the reported reduction in dietary fat and cholesterol level assessed by food frequency questionnaires and the directly measured change in plasma cholesterol level was measured by multiple linear regression.

Results: The three major elements of the final computerized system (food frequency questionnaires, computer-generated progress reports, and dietary workbook) were developed and refined in the course of the five clinical studies. Reductions in total plasma cholesterol level of 5.0% to 6.5% achieved by participants in all five studies were consistent with self-reported reductions in intake of dietary saturated fat and cholesterol. Therefore, the computerized self-management system appears to be an effective tool for reducing plasma cholesterol levels.

Applications/conclusions: A computer-based system for dietary self-management of hyperlipidemia, implemented by mail, was effective in short-term studies. This self-management system can potentially provide health-promoting services to large numbers of people at low cost.