We conducted a systematic review to identify studies examining the relationship between SCOC and quality of care. We searched articles limited to the English language and human subjects, published from January 1, 1966, to January 1, 2002, using Medline, the Educational Resources Information Center (ERIC) and PSYCH INFO. Candidate articles were those with titles containing the medical subject heading (MeSH) descriptors “continuity of patient care” or “continuity of care.”
Additional titles were found in the bibliographies of articles accepted in our original search, through experts in primary care, health care management, and research, and in the bibliographies of relevant textbooks.
Two investigators (MDC, SHJ) screened titles and full bibliographic citations to identify candidate articles. We excluded letters, editorials, and practice guidelines. We accepted randomized controlled trials (RCT), cross-sectional, case-control, and cohort studies.
We excluded articles in which a significant percentage of providers were physicians in training. Our focus was SCOC in the outpatient setting; we excluded articles that analyzed inpatient or chronic care facility settings, or transitions to or from an outpatient setting (eg, post-hospitalization discharge care).
In many RCTs, implementation of SCOC was part of a multifaceted intervention (eg, multidisciplinary clinic and home care).17, 18 Although these studies examined quality of care, the effect of SCOC was indistinguishable from that of broader intervention. If the effect of SCOC could not be distinguished, we excluded the study. Finally, we excluded articles that did not measure SCOC in relation to a quality of care endpoint or a cost of care endpoint, defined below.
Quality-of-care and cost endpoints for analysis
The definition of quality of care was based on a framework described by Donabedian.19Structure is part of this framework for quality and includes resources (such as buildings, equipment, staff) available to provide health care that may or not promote SCOC. Since SCOC itself is a product of structure, we did not include structure in our analysis.
We defined 4 possible endpoints: process of care, outcomes, satisfaction, and cost of care. Process of care refers to differences in the delivery of care or differences in the receipt of care by patients. Outcome is any change in the health status of a patient. Satisfaction is an individual’s (eg, patient, caregiver, or provider) emotional or cognitive evaluation of the structure, process, or outcome of health care.20Cost of care encompasses direct and indirect costs to patient, payer, and society.
Determination of SCOC
Though there is no standard method to determine SCOC, we accepted only studies that fulfilled the criteria below.
The method had to (i) measure SCOC at the provider-level. We did not use a site-based measure, since it is possible for a patient to visit the same clinic multiple times and see different providers.
The method had to (ii) determine SCOC over a time frame longer than one visit. We did not include studies that used “did you see the physician at the last visit?” as a method for determining SCOC. Although this fulfills definition for continuity used in other studies,8 the purpose of the current analysis was to examine the effect of SCOC (ie, longitudinality) on quality.
The method had to (iii) be applied consistently to all patients. We did not accept studies that used “number of physicians seen” if the study did not standardize the observation period. Patients observed for longer periods would likely have seen more physicians in general, and have been at greater risk for lower SCOC, than would patients observed for shorter periods. Since it is not clear if the SCOC measure would be consistently applied, a study using this type of measure was excluded.
Finally, the method had to (iv) account for the possibility of more than one provider during the observed time period. We did not include studies that used “duration of time that the patient has seen the provider” as a measure of SCOC. Theoretically, any number of other providers could have seen the patient during this time and affected the SCOC.
Two investigators (MDC, SHJ) independentlyreviewed the full text to exclude articles not fulfilling criteria. Differences were resolved by informal consensus. We calculated a kappa score to measure the degree of agreement in the selection process.
Data extraction and analysis
We abstracted study design, location, population, method to calculate SCOC, and the association of SCOC with a study endpoint. We grouped articles in relation to endpoint measured. Simple counts and descriptive statistics of the articles were calculated. If 2 articles used data from the same study, we used the more recent article.