Author + information
- Received February 21, 2018
- Revision received March 14, 2018
- Accepted March 20, 2018
- Published online July 16, 2018.
- Chun Shing Kwok, MBBS, MSc, BSca,b,
- Malcolm Bell, MDc,
- H. Vernon Anderson, MDd,
- Khaled Al Shaibi, MBChBe,
- Rajiv Gulati, MDc,
- Jessica Potts, MSca,
- Muhammad Rashid, MBBSa,
- Evangelos Kontopantelis, PhDf,
- Rodrigo Bagur, MDa and
- Mamas A. Mamas, BMBCh, DPhila,b,∗ ()
- aKeele Cardiovascular Research Group, Keele University, Stoke-on-Trent, United Kingdom
- bDepartment of Cardiology, Royal Stoke Hospital, Stoke-on-Trent, United Kingdom
- cDepartment of Cardiology, Mayo Clinic, Rochester, New York
- dDepartment of Cardiology, University of Texas Health Science Center, Houston, Texas
- eDepartment of Cardiology, King Fahd Armed Forces Hospital, Saudi Arabia
- fDivision of Population Health, Health Services Research and Primary Care, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
- ↵∗Address for correspondence:
Prof. Mamas A. Mamas, Keele Cardiovascular Research Group, Keele University, Stoke-on-Trent, United Kingdom.
Objectives This study aimed to evaluate discharge against medical advice (DAMA) in percutaneous coronary intervention (PCI) and how DAMA affects readmissions.
Background DAMA is infrequent but associated with poor patient outcomes. DAMA in the context of PCI has not been described in the published reports.
Methods The authors analyzed patients in the Nationwide Readmission Database between 2010 and 2014 with a PCI procedure who were either discharged home or against medical advice. The primary endpoint was all-cause 30-day readmissions and their causes. Descriptive statistics were used to compare DAMA with patients discharged home, and multiple logistic regressions were used to determine patient characteristics associated with DAMA and readmission.
Results Among the 2,021,104 patients in the analysis, the proportion of patients who DAMA was 0.5% (n = 10,049). The 30-day readmission rate for patients who were DAMA and those discharged home was 16.8% and 8.5%, respectively (p < 0.001). Important predictors of DAMA included diagnosis of acute myocardial infarction (odds ratio [OR]: 1.37; 95% confidence interval [CI]: 1.25 to 1.51; p < 0.001), smoking (OR: 1.71; 95% CI: 1.57 to 1.86; p < 0.001), drug abuse (OR: 1.82; 95% CI: 1.60 to 2.06; p < 0.001), and alcohol misuse (OR: 1.53; 95% CI: 1.32 to 1.78; p < 0.001). DAMA was the strongest predictor for readmission (OR: 1.89; 95% CI: 1.71 to 2.08; p < 0.001). DAMA patients were more likely to have neuropsychiatric reasons for noncardiac causes of readmission (8.3% vs. 2.4%) and acute myocardial infarction for cardiac causes of readmission (39.4% vs. 19.5%) compared with patients discharged home.
Conclusions DAMA occurs in approximately 0.5% of patients following PCI and is strongly associated with readmission within 30 days. Interventions should be developed to reduce DAMA in high-risk groups and initiate interventions to avoid complications and readmission when it occurs.
Discharge against medical advice (DAMA) refers to patients who leave the hospital before the treating physician’s recommendation for discharge. It poses a problem for physicians treating hospitalized patients and has been noted to occur in 1% to 2% of all medical admissions (1). Some groups within the general population, such as those with mental health problems, are more likely to DAMA (2). Other factors that predict DAMA include self-financing health care, having Medicaid insurance, and being young and male (2). Because patients who DAMA have been shown to be at higher risk of adverse outcomes, it has been suggested that these patients should be targeted for post-discharge interventions (3).
Historically, the published reports related to DAMA originated from cohorts with psychiatric illnesses (4) and substance misuse (5). A variety of factors precipitate DAMA, including problems related to their illness such as substance-seeking behavior or other factors such as financial problems, family pressure on returning home, and dissatisfaction with the hospital routine and treatment (6). DAMA is commonly seen in emergency departments and is associated with higher likelihood of worse outcomes and medicolegal consequences. There is a growing body of published reports suggesting that patients with cardiac problems also choose to DAMA (7–9). No previous study has evaluated DAMA in patients who undergo percutaneous coronary intervention (PCI). In this study, we examine rates, trends, and predictors of DAMA, and evaluate causes of and rates of readmission for patients who DAMA compared with those with discharge home in the Nationwide Readmission Database (NRD).
A full description of the methods is available in the Online Appendix.
Study design and participants
The NRD is a publicly available database of all-payer hospital inpatient stays, which was developed by the Agency for Healthcare Research and Quality as a part of the Healthcare Cost and Utilization Project in the United States. The data are drawn from 21 states that are geographically dispersed, and account for approximately 49% of the total U.S. resident population and approximately 49% of hospitalizations.
In the current study, we included men and women 18 years of age or older who underwent first PCI between 2010 and 2014, and were either DAMA or discharged home. First PCI was defined by first procedure of PCI within a calendar year. DAMA was defined from the variable “DISPUNIFORM,” which represents the disposition of patient at discharge. We excluded patients who died during their index admission for PCI, those who had an elective readmission, and those who were not discharged home or against medical advice.
Variables and outcomes
The data collected are described in the Online Appendix. We used International Classification of Disease-Ninth Revision-Clinical Modification and Clinical Classification Software of diseases codes to determine comorbidities, in-hospital procedures, and outcomes. The cost of clinical care was determined by the claims change multiplied by the cost-to-charge ratio. Thirty-day readmissions were defined as first rehospitalization after discharge within 30 days from admission for PCI. The causes of readmissions were determined from the principle diagnosis based on Clinical Classification Software codes as outlined in Online Table 1. The primary endpoint was all-cause 30-day readmissions and reasons for readmissions.
Statistical analysis was performed using Stata 14.0 (StataCorp, College Station, Texas). A flow diagram was used to determine the proportion of patients at each stage of the analysis and those who were readmitted as well as those who died on readmission. Descriptive statistics were used to compare patients who were DAMA compared with those who were discharged home, with further stratification depending on whether or not they were readmitted. Statistical differences between groups for continuous variables were tested using the t test and for categorical variables the chi-square test. For all analyses, the survey estimation commands were used (e.g., svy: logistic for multiple logistic regression), following the recommendations from Agency for Healthcare Research and Quality for analysis of survey data to account for the complex survey design of the NRD database. Multiple logistic regressions were used to determine independent variables associated with DAMA and 30-day readmission. We performed sensitivity analysis in the subgroup of patients in which elective cases were excluded. The major cardiac and noncardiac causes of readmission for the DAMA and discharged home groups are presented in the tables.
A total of 2,021,104 participants were included in the analysis after exclusion of patients who died after first PCI (n = 49,913), had an elective readmission (n = 26,690), or were discharged to other places of care (n = 276,410) (Figure 1). The overall proportion of patients who DAMA over the whole study period was 0.5% (n = 10,049). Figure 2 illustrates the temporal trends for DAMA at the index PCI procedure, increasing from 0.44 in 2010 to 0.59 in 2014 (p < 0.001 for trend). The 30-day readmission rate for patients who DAMA and those who were non-DAMA was 16.8% and 8.5%, respectively.
The participant characteristics and in-hospital outcomes for the index PCI admission for patients stratified by whether they DAMA are shown in Table 1. Patients who DAMA were younger (57.2 vs. 63.7 years), less likely to be women (18.9% vs. 30.6%), less likely to be admitted electively (8.2% vs. 17.3%), and in the lowest quartile of income (36.5% vs. 27.8%). Those who DAMA were more likely to be admitted on a weekend (35.6% vs. 28.8%) and receive Medicaid (19.8% vs. 7.7%). Significant differences were observed for most comorbidities, as well as smoking (65.6% vs. 42.7%; p < 0.001), alcohol misuse (8.4% vs. 2.6%) and drug abuse (10.7% vs. 2.1%; p < 0.001). A longer length of stay (3.2 vs. 3.0 days) and cost of index PCI ($20,441 vs. $19,732) was observed in patients who DAMA.
Table 2 shows the patient variables according to 30-day readmission status stratified by DAMA status. Among patients who were not readmitted, patients who DAMA were more likely to be smokers (66.0% vs. 42.8%), abuse alcohol (7.9% vs. 2.6%), abuse drugs (10.3% vs. 2.0%), have a previous myocardial infarction (MI) (19.5% vs. 14.2%), have a previous PCI (25.6% vs 21.2%), and have chronic lung disease (20.9% vs. 14.8%), and were less likely to receive a drug-eluting stent (60.2% vs. 76.3%). For patients who were readmitted, those who DAMA were more likely to be smokers (63.7% vs. 41.4%), misuse alcohol (10.7% vs. 2.8%), abuse drugs (10.7% vs. 2.8%), have chronic lung disease (28.0% vs. 22.2%), and have fluid and electrolyte disorders (21.8% vs. 14.8%), and less likely to receive a drug-eluting stent (54.4% vs. 70.9%). A greater proportion of DAMA patients were uninsured and from the lowest median household income irrespective of readmission status. Table 3 shows the readmissions outcomes for patients according to whether or not the patient DAMA. DAMA was associated with greater death (3.2% vs. 2.0%), in-hospital major adverse cardiac events (6.1% vs. 2.4%), and DAMA in the readmission (13.9% vs. 1.1%). Similar increases were observed for both in the whole cohort of patients undergoing PCI and the subgroup of patients who were admitted with a diagnosis of acute MI.
The predictors of DAMA are shown in Table 4. Predictors of DAMA included smoking (odds ratio [OR]: 1.71; 95% confidence interval [CI]: 1.57 to 1.86), alcohol misuse (OR: 1.53; 95% CI: 1.32 to 1.78), and dementia (OR: 1.52; 95% CI: 1.03 to 2.24), whereas female sex (OR: 0.58; 95% CI: 0.53 to 0.63) and elective admissions (OR: 0.66; 95% CI: 0.57 to 0.76) were independently associated with reduced odds of DAMA. Among patients with acute MI, the strongest predictor of DAMA was acute kidney injury (OR: 2.51; 95% CI: 1.53 to 4.13), although drug (OR: 1.83; 95% CI: 1.57 to 2.13) and alcohol (OR: 1.28; 95% CI: 1.07 to 1.53) abuse and smoking (OR: 1.77; 95% CI: 1.59 to 1.97) remained independent predictors of DAMA (Online Table 2).
Table 5 shows the independent predictors of 30-day readmission. DAMA was the strongest predictor of 30-day unplanned readmissions (OR: 1.89; 95% CI: 1.71 to 2.08) for all patients and for patients with admission for acute MI (OR: 1.96; 95% CI: 1.73 to 2.22) (Online Table 2).
The causes of unplanned 30-day readmissions were subsequently studied in patients who DAMA and those who were discharged home. Table 6 shows that the proportion of patients with noncardiac readmissions was higher in patients who were discharged home (54.5% vs. 45.5%) whereas the rates of cardiac and noncardiac readmission were similar for the DAMA group (50.2% vs. 49.8%).
Table 6 shows the most common noncardiac and cardiac causes for readmission according to whether patients were DAMA or non-DAMA. Nonspecific chest pain was the commonest noncardiac cause for readmission for both patients who DAMA and those who discharge home (19.7% and 20.2%, respectively). For noncardiac readmissions, patients who DAMA were more likely to have neuropsychiatric causes for readmission (8.3%, fourth-most-common cause of readmission) compared with those patients discharged home (2.4%, 10th-most-common cause). The specific causes of psychiatric readmissions in the DAMA group were mainly due to depression, bipolar and mood disorders (43.3%), and paranoid schizophrenia, schizoaffective disorder, and psychosis (16.7%) (Online Table 3). In terms of cardiac readmissions, acute MI was the most common diagnosis code for both cohorts, although patients who DAMA were twice as likely to be readmitted with the diagnosis code of acute MI (39.4% vs. 19.5%) compared with those discharged home. For patients presenting with acute MI at their index admission, DAMA was associated with increase rates of cardiac readmissions (56.6% vs. 49.2%) (Online Table 2). Noncardiac chest pain was the most common reason for noncardiac readmissions. The most frequent reasons for cardiac readmission for both DAMA and not DAMA in the acute MI groups were diagnosis of acute MI and coronary artery disease, including angina.
DAMA is a rare occurrence among patients who undergo PCI, and is strongly related to smoking and alcohol misuse and is less likely to occur among patients who are women, are privately insured, have a higher quartile of income, or are admitted for elective PCI. Whereas the rates of DAMA appear to be rising, it is still a relatively rare occurrence. We show that patients who DAMA are a high-risk cohort. They have a 2-fold increased risk of readmission and are twice as likely to be readmitted with the diagnosis code of acute MI and 4 times as likely to be readmitted with an acute neuropsychiatric episode. To the best of our knowledge, we show, for the first time, that DAMA is one of the strongest predictors of unplanned 30-day readmission after PCI. Our results provide evidence that patients who DAMA should be considered to be at high risk. Our findings support the need for a greater understanding of patients who DAMA to further develop interventions to either reduce it or the development of pathways that allow follow-up of patients that DAMA.
Our study provides novel insight into patients who DAMA after PCI, and temporal trends, predictors, and outcomes associated with DAMA in PCI have not been explored before. It is unclear whether the observed changes are a result of changes in the demographics of the patients that present for PCI or because of changes in the care delivered that may influence patient decisions. We show evidence that is consistent with published reports outside the PCI setting that being young and male are factors associated with DAMA. We also find that smokers and patients who misuse alcohol are at higher risk, and decisions to DAMA in these patients may be motivated by substance-seeking behavior.
Our findings suggest that patients undergoing elective procedures are less likely to DAMA, which suggests that there may be an element of selection bias for such procedures, with patients in which there may be issues around compliance or future engagement with health care less likely to be offered an elective PCI. By contrast, in PCI procedures undertaken in the short-term setting of an acute MI, selection based on future compliance or engagement with health care services is not feasible, which may explain the increased risk of DAMA associated with the readmission diagnosis code of MI.
We show, for the first time, the reasons for readmissions after DAMA in patients who undergo PCI. A key finding here is that patients who DAMA have a 4-fold increased rate of neuropsychiatric unplanned 30-day readmissions compared with patients discharged home. Our detailed analysis of specific causes of readmission suggests that depression, bipolar disorder, and mood disorders are the most common reasons for readmission, with previous published reports reporting that coronary artery intervention can increase patients’ anxiety and depression (10). In the current study, both smoking (11) and alcohol misuse (12) were independently associated with DAMA, and these 2 factors have also been linked to mental illness. We also report that patients who DAMA are twice as likely to be readmitted with the diagnosis code of acute MI. This is an important finding and may relate to failure to prescribe dual antiplatelet therapy (DAPT) to patients who DAMA, or failure for their continuing prescription once discharged which significantly increases the risk of stent thrombosis. It is unclear from this study whether patients who DAMA were prescribed medications such as antiplatelet agents before DAMA or whether these patients had any follow-up with medical services once discharged for continued receipt of pharmacotherapy. Interestingly, one study of general admissions suggests that only 21.4% of patients had medications prescribed when patients DAMA (13).
DAMA in the context of PCI are unlike DAMA in the emergency department and general hospital admissions that have been reported in the published reports (14–16). A patient who is seen at the emergency department may not receive treatment, and similarly, a patient admitted to hospital may be admitted for investigations and observation initially. By contrast, patients who undergo PCI have received a treatment that requires ongoing management and medical therapy to ensure optimal future outcomes. In patients who DAMA at some point after the procedure, there is a breakdown in the care relationship, and the patient chooses to discontinue care. This can have serious consequences because ongoing patient care is required after PCI, with prescription of DAPT to reduce the risk of stent thrombosis or an echocardiogram to assess for left ventricular function after an acute event enabling prescription of evidence-based therapies that reduce the risk of rehospitalization (17), or management of newly diagnosed diabetes mellitus and so forth. Furthermore, whereas a patient who DAMA in the emergency department and general hospital inpatient stay may carry the risks associated with the presenting condition, the patients who undergo PCI may carry the risks associated with their presenting condition but also those related to their treatment (PCI).
The need for interventions for DAMA patients
Our findings suggest that an evidence base around understanding reasons for DAMA in the context of PCI should be developed, with interventions developed to reduce DAMA or at least obviate the risks in situations where it does occur. A previous qualitative study proposed several strategies to reduce DAMA in cardiovascular disease (9). First, patients highlighted that communications needed to be improved, and health care providers should receive training in cultural diversity, interpersonal skills, and customer service and also be more truthful and accurate regarding wait times. Nurses further suggested that the quality of verbal communication needed to be improved to manage patient’s expectations to minimize false promises. The principles of these findings could potentially be applied to settings where PCI has been undertaken to potentially reduce rates of DAMA. Secondly, in cases in which DAMA has occurred, interventions need to be developed to obviate potential risks, particularly around the prescription of DAPT and other cardiac medications in this patient group. This may require the development of targeted interventions across health care providers spanning the secondary and primary care interface, or the development of pharmacy outreach programs that enable prescription or continuation of therapies in the community. Finally, given that neuropsychiatric causes are an important cause of unplanned 30-day readmissions in patients who DAMA, involvement of psychiatric services, particularly in those with a history of mental health conditions or a history of substance abuse, early on in the index admission for patients undergoing PCI particularly in the short-term setting, may decrease the risk of DAMA or at least provide an arena for safer “discharge” planning, even in those who do subsequently DAMA. Another area of future work should explore the care that patients are deprived of by choosing to DAMA. There is likely a portion of patients who require further treatment, and these patients may be at higher risk of adverse events, but also patients who have received PCI treatment and are recommended to stay in hospital for a period of observation.
Study strengths and limitations
Our study has several strengths. First, this is the first study to evaluate DAMA in the context of PCI in a large cohort that has sufficient sample size to capture these uncommon events. Second, the data from the NRD are largely complete, which minimizes biases related to missing data. Finally, we were able to adjust for a variety of confounders in our models to predict DAMA and 30-day readmission, including many socioeconomic factors, comorbidities, hospital characteristics, procedural variables, and outcomes.
There are several limitations in the current study. First, the overall data are derived from 5 unique datasets corresponding to each year in the period between 2010 to 2014, and no linkage is possible between years. Second, the dataset does not capture pharmacotherapy data such as DAPT, and thus prescription fill rates and compliance are unknown in patients who DAMA. Third, although we report a 2-fold increased odds of readmission with diagnosis code of acute MI in patients who DAMA, there are no diagnostic codes for stent thrombosis, and so we were unable to determine whether this increased risk relates to stent thrombosis events, or reflects a worse cardiovascular risk factor profile in patients who self-discharge for de novo events. Fourth, the study is a retrospective analysis of an administrative database that was collected from administrative claims sampled from 21 states but may not be generalizable to all settings, because regional heterogeneity was not explored. In addition, we were unable to capture out-of-hospital deaths, so our results may underestimate the extent of poor outcomes associated with patients who DAMA. Also, we were not able to exclude the possibility that the same patient may appear in multiple years because the database is composed of 5 annual datasets, which cannot be linked across years. Furthermore, as with any such administrative database, coding errors are always a potential source of bias, as is underreporting of secondary and comorbid diagnoses. Finally, causes of readmission were identified using the primary discharge diagnosis codes, which may be subject to reporting biases.
DAMA occurs in 0.5% of patients who undergo PCI and is strongly associated with a greater risk of 30-day unplanned readmission with higher mortality. We identified that patients who have previous MI, are smokers, and misuse alcohol and drugs are most likely to DAMA. This information may be useful for clinicians to identify those patients upon admission or shortly after that are at high risk of DAMA, allowing clinicians to better tailor care so that the management is supported and agreed on by these patients, and there is no breakdown in the therapeutic relationship.
WHAT IS KNOWN? DAMA is associated with poor patient outcomes and DAMA in the context of PCI has not been described in the published reports.
WHAT IS NEW? Our analysis of 2,021,104 patients reveals that the proportion of patients who DAMA was 0.5%, and important predictors of DAMA included diagnosis of acute MI, smoking, and alcohol misuse. DAMA was the strongest predictor for unplanned 30-day readmission (OR: 1.89; 95% CI: 1.71 to 2.08; p < 0.001) and DAMA patients were more likely to have neuropsychiatric reasons for noncardiac causes of readmission and acute MI for cardiac causes of readmission compared with patients discharged home. DAMA following PCI is rare, but it is strongly associated with readmissions within 30 days.
WHAT IS NEXT? Interventions should be developed to reduce DAMA in high-risk groups and initiate interventions to avoid complications and readmission when it occurs.
The authors are grateful to the Healthcare Cost and Utilization Project (HCUP) and the HCUP Data Partners for providing the data used in the analysis.
The study was supported by a grant from the Research and Development Department at the Royal Stoke Hospital. This work is conducted as a part of Dr. Kwok’s PhD, which is supported by Biosensors International. The authors have reported that they have no relationships relevant to the contents of this paper to disclose.
- Abbreviations and Acronyms
- confidence interval
- discharge against medical advice
- dual antiplatelet therapy
- myocardial infarction
- Nationwide Readmission Database
- odds ratio
- percutaneous coronary intervention
- Received February 21, 2018.
- Revision received March 14, 2018.
- Accepted March 20, 2018.
- 2018 American College of Cardiology Foundation
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