Primary health care: A review of the literature through 1972

The descriptive literature on primary health care reveals an abundance of articles, without documentation, extolling or disparaging different forms of primary care. Experimental studies have measured the effects of making a clinic setting more comprehensive. Making a clinic more comprehensive decreases hospitalization after about one year. Differences in utilization of pre- ventive vs. illness-related visits may explain the failure to decrease outpatient utilization with increasing comprehensiveness of care. Unconfirmed studies found decreased emergency room visits, fewer multiple hospitalizations, fewer broken appointments, and increased return to referring physician. End result studies are sparse and inconclusive. Present data is insufficient to show supe- rior quality for any one kind of primary care. Age, sex, race, martial status, family size, education, socioeconomic status, symptomatology, tendency to use services, university clinic setting vs. solo private practice, and sick vs. general population samples are variables which affect utilization and have not been controlled for adequately in past studies. Future studies should have more adequate control groups and more objective variables.