Continuity of care can improve patient outcomes.28,29
To our knowledge, this is the only study to explore whether the dissemination of patient-specific information alters the risk of hospital readmission. After controlling for important factors, we found a trend toward a lower likelihood of readmission for patients who were seen in follow-up by a physician who had received the discharge summary. Our data suggest that discharge summary dissemination could be more successful at decreasing hospital readmission than case managers.30,31
Further study is required to determine whether ‘continuity of information,’ in addition to continuity of care, can improve patient outcomes.
We were surprised by two of our findings. First, only a small number of follow-up physicians had received the discharge summary at the time of the patient visit. Although this may have occurred because patients consulted new physicians after discharge from hospital, we believe that it more likely results from hospital physicians failing to systematically identify all physicians involved in a patient's care and ensuring that summaries were sent to each. Since discharge summaries can only help patient care if they are received by their physicians, we must pursue methods to improve the timely dissemination of discharge summaries.
We also found that patients who had a regular family physician had a significantly higher risk of readmission. This is probably because patients with a family physician were sicker. Such patients were significantly older (66.6 vs 55.5 years; P < .001) and were more likely to have coronary artery disease (20.2% vs 8.3%; P = .01), chronic renal failure (9.3% vs 1.4%; P = .02), diabetes (20.7% vs 9.7%; P = .03), or any significant chronic medical condition (91.8% vs 77.8%; P < .001). Therefore, we believe that having a regular family physician is a marker of underlying chronic illness and comorbidity that increases the risk of readmission and was not controlled for in our model.
If the association between the receipt of discharge summaries and decreased readmission is true, this would be one of the most dramatic effects of interphysician communication yet documented. Previous studies have found that improved interphysician communication decreased waiting time in the emergency room,10
repetition of laboratory tests,10
and glycosylated hemoglobin levels,8
and increased cancer screening rates.7,32
One other study, by Williams and Fitton,33
found that communication between the hospital and the primary care physician was significantly less likely to occur in elderly patients who were readmitted to hospital. However, this study was susceptible to recall bias, given its case-control design, and did not use a multivariate analysis to determine the independent association of communication with readmission.
This study has a number of strengths including a large and well-defined sample of patients. We combined primary data with population-based administrative databases to collect enough information on each patient that we could adjust for factors that have been associated with readmission to hospital. These include demographic factors (such as age,34–38
nursing home status,37,42
and socioeconomic status43,44
), prehospitalization health service utilization (including emergency department use,45
and physician visits35
), baseline medical conditions (such as diabetes,35,51
coronary artery disease,35
congestive heart failure,47,52,53
and chronic renal failure41,52
) and hospital factors (including length of stay34,37
). Follow-up was sufficiently long and was, given the population-based status of the administrative databases used to follow patients, complete. Our outcome, emergent readmission to hospital, was objective and was measured without some of the common pitfalls often encountered when measuring hospital readmissions.54
This is because we were able to document readmissions to all Ontario hospitals (not just the original hospital, as is sometimes used in studies) and we censored people who died during the observation period. We also completely determined whether follow-up physicians received the discharge summary, using both mail and phone surveys.
However, this study had some weaknesses that need to be addressed in future research to truly determine the effect that continuity of information has upon patient outcomes. While the discharge summary is the most common media of communication following discharge from hospital,19
we did not document information flow using other methods such as interim discharge reports, faxes, phone calls, and patient knowledge about their hospitalization. We could not determine whether the summary was actually read by the receiving physician. Although hospital readmission is a very important outcome, many readmissions are due to progression of disease rather than medical errors. Therefore, future studies should explore the effect of postdischarge communication on outcomes such as avoidable adverse events and avoidable readmissions. We did not control for whether physicians seeing patients after discharge had also seen them prior to the hospitalization. Physician continuity could importantly influence patient outcomes. Although we studied 888 patients, they were all from 1 service in a single teaching hospital. Furthermore, we had notably poor dissemination of our discharge summaries to follow-up physicians. More studies are needed to determine if our observations are reproduced in a variety of hospital care systems.
The final 3 weaknesses of this study could be addressed simultaneously by a trial in which patients are randomized to routine care versus exemplary dissemination of patient information to follow-up physicians. Although we controlled for many important factors, our observational study could not control for all potential confounders. For example, patients whose follow-up physicians received a discharge summary may be systematically different from other patients. Also, readmission to hospital might be associated with poor care during the initial hospitalization,55–58
which itself could be associated with poor dissemination of discharge summaries. These and other unmeasured confounding factors, such as quality of care by the primary care physician, would be controlled in a properly conducted randomized clinical trial. Finally, our study was unable to determine how the dissemination of discharge summaries to follow-up physicians might avoid readmission to hospital. Ideally, one would want to document how information in the summary affected the decision making that influenced outcomes.
Our finding that dissemination of patient-specific hospital information to follow-up physicians may influence important outcomes is important for both physicians and health policy makers. Recent advances have resulted in a rapid proliferation of information and communication technologies that could extensively integrate health information as never before. However, the costs of adopting these technologies into exisiting health systems will be considerable. We believe that further research to determine the effects that continuity of patient information have upon important health outcomes is essential for appropriate decision making regarding these technologies.