Kaiser Permanente Medical Care Program

KAISER PERMANENTE MEDICAL CARE PROGRAM

The Kaiser Permanente Medical Care Program is the largest and one of the oldest pre-paid group model health care systems in the United States (Selby et al., 2005). With more than eight million members in nine states, the programme is divided into eight administra-tive regions, seven of which have their own research centers. Each research center operates as a distinct entity, using only its own regional databases. The two oldest research centres, in operation since the 1960s, are the Division of Research of Kaiser Perma-nente Northern California and the Center for Health Research of Kaiser Permanente Northwest (KPNW). Both centres have made major contributions to phar-macoepidemiology, including developing strategies for dealing with methodological issues endemic to the use of clinical data for research, and developing approaches to overcoming biases present in clinical databases, at least as applied to Kaiser Permanente databases (Selby et al., 2005). Four of the Kaiser HMOs participate in the HMO Research Network (see below).

KAISER PERMANENTE NORTHERN CALIFORNIA

Kaiser Permanente’s largest and oldest regional entity is in Northern California, and now serves approx-imately 3.1 million enrollees in a 14-county area that includes the Oakland–San Francisco Bay and Sacramento metropolitan areas (Selby et al., 2005). About 30% of the population in the area covered by this region of Kaiser Permanente is enrolled, mainly through employment; 13% receive some Medicare coverage, bringing the proportion of members 65 and older close to the proportion in the general population (Selby et al., 2005). Race/ethnicity information is not collected routinely, but special member surveys and other sources show a close similarity to the distri-bution of the general population, based on census data (Selby et al., 2005). Comparisons of household income of the membership with census data show a slight under-representation at the highest and lowest income levels (Krieger, 1992; Selby et al., 2005). After the first year or two of membership, during which there is a relatively high turnover, enrollees tend to stay with the programme for relatively long periods of time. A unique medical record number is used for all encounters with the Kaiser Perma-nente program, making possible the linking of vari-ous records. Computerized membership files contain records of all members at a given point in time.

The Pharmacy Information Management System has been operational in Kaiser pharmacies since 1994, recording information on approximately 15 million prescriptions per year. Information on each prescrip-tion is entered into the database prior to its being dispensed, and includes patient and prescribing physi-cian identification numbers, drug name, National Drug Code (NDC), dose, therapeutic class, date dispensed and prescription cost. Nearly all prescrip-tions are captured for the 94% of members who have the drug benefit (Selby et al., 2005).

Other databases include hospitalizations, avail-able since 1971; laboratory, pathology and radiol-ogy/diagnostic imaging data, stored since 1992; and information on outpatient visits, stored since 1994. Review of medical records has not been obviated, however, and is recommended for validation of certain computerized data.