We describe 3 categories of medical errors caused by failure to implement the intended discharge plans for recently hospitalized patients. Specifically, the medical errors defined in this study are best termed continuity of information7,10
errors in that relevant information concerning the intended discharge plan was not adequately transmitted from the hospital-based provider to the outpatient PCP. To our knowledge, this is the only study to investigate the prevalence of these types of medical errors and their potential association with adverse patient outcomes.
Almost half of all patients in our study sample had at least 1 medical error related to the discontinuity of care from the inpatient to the outpatient setting, with a significant association between the presence of a work-up error and an increased likelihood of rehospitalization within 3 months after the first postdischarge PCP visit.
Our study was not powered to investigate how work-up errors potentially affect rehospitalizations. Ideally, one would want to document a causal relationship between the work-up errors that we found and the subsequent rehospitalizations. The inter-rater reliability among physicians using medical record review to identify adverse events caused by medical errors has been found to be poor to moderate; and researchers therefore should use caution when interpreting these data.11,12
Given the aforementioned caveat, we hypothesize that the increased risk of rehospitalization for patients who experience work-up errors may, in part, be due to patients' intended outpatient work-ups not being implemented. For example, a 60-year-old woman in our study with a history significant for asthma and hypertension was hospitalized with the diagnosis of asthma exacerbation. Her symptoms of dyspnea and wheezing began improving on a steroid taper and she was subsequently discharged home with a planned outpatient work-up for an abnormal admission chest radiograph significant for a diffuse reticular nodular pattern consistent with an interstitial process. The outpatient work-up that was to include a computed tomography (CT) scan of the chest and an appointment with a pulmonologist was not implemented, and the planned work-up was never mentioned in the chart by the outpatient PCP who evaluated the patient 2 weeks after discharge. The patient was rehospitalized approximately 1 month later complaining of worsening shortness of breath. During the rehospitalization, a CT tomography scan of the chest was obtained and the results were significant for bilateral hilar adenopathy and numerous apical nodular densities consistent with sarcoidosis, although a neoplastic process could not be excluded. In this example, it is unclear if the rehospitalization would have been prevented if the patient had been diagnosed and treated during the planned outpatient work-up; therefore, a determination of any causal relationship is clearly subject to interpretation. In reviewing the medical records of patients in our study who had both a work-up error and a rehospitalization, we found that in 3 of 6 cases, the work-up error may have contributed directly to the rehospitalization. Once again, our sample size was extremely small and our methods for determining causality were not rigorous. Future research with a large sample size and use of high confidence scores to indicate the presence of an adverse event caused by a work-up error is needed to establish a possible causal relationship.
We did not find an association between medication continuity errors or test follow-up errors with rehospitalizations. However, many of the medication continuity errors and test follow-up errors in our study were likely not severe enough to result in a rehospitalization. For example, 50% of the cardiovascular medication continuity errors involved antihypertensive medications. While this sort of error may cause an elevation in the patient's blood pressure, it is not likely to result in a rehospitalization; thus, the study may not have been powered to detect such an association. Ghandi et al. showed that 48% of patients reporting outpatient drug complications sought medical help.13
These complications may be associated with emergency room or urgent care visits, but do not necessarily lead to rehospitalizations.
A limitation of this study is that we relied on documentation in the outpatient chart in order to establish the presence or absence of a medical error related to the discontinuity of care from the inpatient to the outpatient setting. This methodology potentially overestimated the prevalence of medical errors in that a given PCP may have been aware of a patient's discharge regimen, tests pending at discharge, or suggested outpatient work-ups, and not have documented this fact in the outpatient chart, or (perhaps for good reason) may have chosen not to follow the intended discharge plan. One way of addressing this deficiency is to modify the medical error definitions to allow for exceptions when the documented outpatient management can be reasonably justified given the findings documented at the postdischarge visit. For example, if a patient is discharged from the hospital on an antihypertensive medication and is subsequently found to be normotensive at the postdischarge PCP visit despite being nonadherent with the medication, it should not be considered a medical error if the PCP does not restart the antihypertensive. However, the tradeoff for using clinical judgment to improve the specificity of the algorithms used to determine the existence of these discontinuity errors is likely a decrease in inter-rater reliability, since physician reviewers will likely have varying thresholds for the outpatient managements that they consider “reasonably justified.”
The prevalence of medication continuity errors in our sample (42%) is similar to the percentage of patients found to be nonadherent with their intended discharge medication regimens by other investigators (approximately 50%).14,15
Therefore, the PCPs in our study may be accurately documenting what the patient is currently taking, while being unaware that the current regimen is a significant departure from the intended discharge regimen.
Although we controlled for many important factors, our observational study could not control for all potential confounders. For example, physicians whose patients had a work-up error may be systematically different in the way they manage their patients compared with physicians whose patients did not have a work-up error.
Another limitation of our study is that it was done at a single institution with a hospitalist model for inpatient physician care and with outpatient PCPs who had no access to patients' discharge summaries. Despite this limitation, our findings have important implications given the growing prevalence of the hospitalist model as a recent organizational innovation in health care.10,16
Studies have shown significant improvement in outcomes with implementation of the hospitalist model.17–24
However, some investigators have expressed concern that this comes at the expense of inpatient-to-outpatient continuity of care and that, as a result, patient care during the immediate postdischarge period may suffer.10,25–28
We believe that the hospitalist model combined with the poor dissemination of discharge information to outpatient PCPs create an environment in which the discontinuity errors described in this article become relatively common. This is consistent with the Institute of Medicine's assessment that poor processes of care, and not the actions of individual providers, are primarily responsible for medical errors.3
Our patient population was overwhelmingly black and Hispanic (85%) with largely Medicaid and Medicare insurance coverage (96%). Factors influencing the prevalence of medical errors related to the discontinuity of care from the inpatient to the outpatient setting may differ for other populations. For example, there are racial, ethnic, and sociodemographic differences in the use of teaching hospitals,29
outpatient PCP continuity,30
and preventable hospitalizations,31
all of which may influence the prevalence of the medical errors described in this study. We believe that further research is warranted in order to determine if there are racial, ethnic, and sociodemographic differences in the prevalence of these errors.
Finally, the severity of the medical errors identified in the study was not described. As a result, no distinction was made between a medication continuity error involving a drug prescribed to treat a relatively benign ailment, and one prescribed to treat a disease with a high morbidity and mortality. Future efforts should concentrate on developing a reproducible measure of medical error severity based on the potential of the error to result in an adverse event, which could then be applied to determine if there is an association between moderate-to-severe medical errors and adverse patient outcomes.
Our findings linking the discontinuity of care from the inpatient to the outpatient setting to adverse outcomes has important implications for clinicians. Historically, the hospital discharge summary has been the most common method for the dissemination of patient-specific information from hospital-based providers to outpatient PCPs32
and its receipt by PCPs may be linked to improved patient outcomes.7
Future studies should focus on investigating how receipt of discharge summaries by PCPs influence the discontinuity errors described in this study. If an association is shown, interventions focused on improving the timely dissemination of hospital discharge summaries to outpatient PCPs may be designed specifically to decrease discontinuity errors and improve the quality of patient care.