Missouri started collecting hospital discharge data in 1963 using a key sort card system. These data were converted to tape but were never adequately edited. The Cooperative Health Statistics System contract made it possible for the Missouri Center for Health Statistics (MCHS) to update the hospital discharge collection procedures in 1975 by instituting a fully computerized data system called the Missouri Hospital Discharge Data Program. The new system collected the Uniform Hospital Discharge Data set.

From 1975 to 1977, about 41 percent of the 165 short-term, non-federal hospitals in Missouri participated in the Missouri Hospital Discharge Data Program. To augment the program data file, MCHS contracted with another 21 percent of the state hospitals that participated in a Professional Activities Study program operated by the Commission on Professional and Hospital Activities at Ann Arbor, Michigan. Data available from the Missouri Hospital Discharge Data Program's combined sources represented about half of the total yearly patient discharges from Missouri hospitals.

In January 1977, the Missouri Hospital Discharge Data Program system became fully operational within MCHS. During this time MCHS contracted with the Iowa Hospital Association to produce patient discharge reports for the participating hospitals. These reports are generated monthly, semi-annually and annually were based on data collected from hospitals on their discharged patients and served an important management function by providing the hospitals with information about the age, sex, diagnosis, procedure and length of stay characteristics of their patients.

In 1978, operation of the discharge program was assumed by the Missouri Health Data Corporation. The Missouri Health Data Corporation operated both the Professional Standards Review Organization data system and its own hospital discharge data collection system. In addition, it purchased data from the Commission on Professional and Hospital Activities, from other commercial data collection agencies and from hospitals capable of producing their own electronic data tapes. MCHS obtained from the Missouri Health Data Corporation the data from the various abstracting systems.

The Hospital Industry Data Institute, a unit of the Missouri Hospital Association, replaced Missouri Health Data Corporation in 1985. Hospital Industry Data Institute collected the hospital discharge data through 1992. The data were loaned to MCHS for research purposes. Requests for 1985-1992 data must be addressed to the Hospital Industry Data Institute, Missouri Hospital Association.

In 1993, following the enactment of 192.665-192.667, RSMo, the Patient Abstract System was implemented. It includes outpatient data as well as inpatient data. The outpatient data include emergency room patients, observation patients, and patients receiving invasive procedures on an outpatient basis, as well as patients receiving certain specified diagnostic procedures. The data collected since 1993 are maintained by the Department of Health and Senior Services. Since January 1, 1994, ambulatory surgical centers have also been required to report.