J Neurosurg 120:1201–1211, 2014 ©AANS, 2014
Incidence and predictors of 30-day readmission for patients discharged home after craniotomy for malignant supratentorial tumors in California (1995–2010) Clinical article Logan P. Marcus, M.S.,1 Brandon A. McCutcheon, M.P.P.,1 Abraham Noorbakhsh, B.S.,1 Ralitza P. Parina, M.P.H.,1 David D. Gonda, M.D., 2 Clark Chen, M.D., Ph.D., 2 David C. Chang, Ph.D., M.P.H., M.B.A.,1 and Bob S. Carter, M.D., Ph.D. 2 1
Department of Surgery and 2Division of Neurosurgery, University of California, San Diego, California
Object. Hospital readmission within 30 days of discharge is a major contributor to the high cost of health care in the US and is also a major indicator of patient care quality. The purpose of this study was to investigate the incidence, causes, and predictors of 30-day readmission following craniotomy for malignant supratentorial tumor resection. Methods. The longitudinal California Office of Statewide Health Planning & Development inpatient-discharge administrative database is a data set that consists of 100% of all inpatient hospitalizations within the state of California and allows each patient to be followed throughout multiple inpatient hospital stays, across multiple institutions, and over multiple years (from 1995 to 2010). This database was used to identify patients who underwent a craniotomy for resection of primary malignant brain tumors. Causes for unplanned 30-day readmission were identified by principle ICD-9 diagnosis code and multivariate analysis was used to determine the independent effect of various patient factors on 30-day readmissions. Results. A total of 18,506 patients received a craniotomy for the treatment of primary malignant brain tumors within the state of California between 1995 and 2010. Four hundred ten patients (2.2%) died during the index surgical admission, 13,586 patients (73.4%) were discharged home, and 4510 patients (24.4%) were transferred to another facility. Among patients discharged home, 1790 patients (13.2%) were readmitted at least once within 30 days of discharge, with 27% of readmissions occurring at a different hospital than the initial surgical institution. The most common reasons for readmission were new onset seizure and convulsive disorder (20.9%), surgical infection of the CNS (14.5%), and new onset of a motor deficit (12.8%). Medi-Cal beneficiaries were at increased odds for readmission relative to privately insured patients (OR 1.52, 95% CI 1.20–1.93). Patients with a history of prior myocardial infarction were at an increased risk of readmission (OR 1.64, 95% CI 1.06–2.54) as were patients who developed hydrocephalus (OR 1.58, 95% CI 1.20–2.07) or venous complications during index surgical admission (OR 3.88, 95% CI 1.84–8.18). Conclusions. Using administrative data, this study demonstrates a baseline glioma surgery 30-day readmission rate of 13.2% in California for patients who are initially discharged home. This paper highlights the medical histories, perioperative complications, and patient demographic groups that are at an increased risk for readmission within 30 days of home discharge. An analysis of conditions present on readmission that were not present at the index surgical admission, such as infection and seizures, suggests that some readmissions may be preventable. Discharge planning strategies aimed at reducing readmission rates in neurosurgical practice should focus on patient groups at high risk for readmission and comprehensive discharge planning protocols should be implemented to specifically target the mitigation of potentially preventable conditions that are highly associated with readmission. (http://thejns.org/doi/abs/10.3171/2014.1.JNS131264)
H
Key Words • brain tumor • readmission • neurosurgical outcomes
readmission within 30 days of discharge is a major contributor to the high cost of health care in the US. Medicare payments for unplanned 30-day readmission episodes were responsible for $17.4 billion or roughly 17% of the total Medicare hospital payospital
Abbreviations used in this paper: DVT = deep venous thrombosis; LOS = length of stay; OSHPD = Office of Statewide Health Planning & Development; PE = pulmonary embolism.
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ments for 2004.10,14 As a result, 30-day readmissions have become an important metric for measuring the quality of patient care. The Patient Protection and Affordable Care Act of 2010 authorized Medicare to use financial penalties to incentivize hospitals to reduce 30-day readmissions. Institutions have begun implementing programs to This article contains some figures that are displayed in color online but in black-and-white in the print edition.
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L. P. Marcus et al. reduce hospital readmissions in both medical and surgical specialties. Despite coordinated efforts from physicians, nurses, pharmacists, and lower-level care providers, many hospitals have struggled to understand and improve upon the factors that underlie high readmission rates.15 Few studies have examined the rehospitalization of patients after the neurosurgical care of brain malignancy. The purpose of this study was to determine the 30-day readmission rate for patients undergoing the resection of primary brain tumors and to identify which factors predispose certain patient groups to rehospitalization. Data Source
Methods
The data source for this study was the California Office of Statewide Health Planning & Development (OSHPD) longitudinal inpatient-discharge administrative database for the years 1995 to 2010, obtained from the State of California OSHPD (http://www.oshpd.ca.gov/HID/ Products/PatDischargeData/PublicDataSet/). The California inpatient discharge database is an administrative, longitudinal database that represents a 100% sample of all inpatient discharges from California licensed hospitals. Each patient within the database is given a unique, masked patient identifier so that each patient may be followed throughout multiple inpatient hospital stays, across multiple institutions, and over multiple years within the state of California during the study period.
Inclusion and Exclusion Criteria and Definition of End Points
An index admission for surgical treatment of a primary brain tumor was defined using a combination of ICD-9-CM diagnosis and procedure codes. Patients were included in this study if they were given both a diagnosis of supratentorial malignant brain tumor (191.0–191.5, 191.8, 198.9) while also receiving a procedure code for lobectomy (01.53), excision or destruction of tissue or lesion of brain (01.59), or open brain biopsy (01.14) during the same hospital stay.2,4 Patients who received a previous craniotomy for any diagnosis prior to their index craniotomy for supratentorial malignant brain tumor were excluded from this study. The primary end point examined in this study was an unplanned hospital readmission less than or equal to 30 days after inpatient discharge for surgical treatment of a primary brain tumor. Within the OSHPD longitudinal inpatient-discharge administrative database, unplanned hospital readmissions are defined as inpatient stays that are unscheduled at the hospital 24 hours prior to patient admission (http://www.oshpd.ca.gov/HID/Products/PatDischarge Data/PublicDataSet/). Planned rehospitalizations were excluded from our analysis of readmission. Patients who were discharged to a location other than home after surgery or readmitted to the hospital from a location other than home were not included in our readmission analysis so as to eliminate the effect of inter- and/or intrahospital transfer on 30-day readmissions. However, all patients undergoing an index admission regardless of discharge location were included in our analysis of index surgical episode outcomes (Table 1).
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Patient Characteristics
Patient age, self-declared race/ethnicity, sex, expected primary payer (Medicare, Medi-Cal, private insurance, or uninsured), admission source (home, residential care facility, jail/prison, and others), type of admission (elective or nonelective), discharge disposition (home, died, residential care facility, jail/prison, and others), and calendar year were coded in the California inpatient discharge database. Due to a small sample size of certain ethnic groups within the database, patients of Native American race/ethnicity were combined with “other” race/ethnicity to avoid unstable coefficients in the multivariate model. To assess the effect of general medical comorbidities, the Charlson comorbidity index was calculated for each patient using the method described by Romano and colleagues.17 The medical history for each patient was defined using ICD-9-CM diagnosis and procedure codes. A patient was determined to have a specific condition if he or she carried a specified ICD-9-CM code on the index surgical admission or during any inpatient episode prior to the index surgical admission episode from 1995 to 2010 (Table 2).
Hospital Characteristics
Hospital identifier, county location of each hospital, and total charges for each inpatient episode were coded within the California inpatient discharge database. The teaching status of each hospital was determined according to whether the hospital was affiliated with a neurosurgical residency training program (http://www.societyns. org/match_information.html). Pediatric hospitals were defined as those hospitals solely dedicated to the treatment of pediatric patients.
Reasons for 30-Day Readmission
To identify the reasons for readmission, a cross-sectional analysis of ICD-9-CM principal diagnosis codes present on readmission was conducted for all patients readmitted within 30 days of discharge. Each ICD-9-CM principal diagnosis code with more than 1% prevalence in readmitted patients was placed into 1 of 15 disease categories (Table 2). The ICD-9-CM codes comprising each of the 15 disease categories were used to tabulate the number of readmitted patients who belonged in each disease category. Because of the longitudinal nature of the data used in this study, we were able to determine which diagnoses were present on both discharge and readmission for each patient. We established the reason for each patient’s readmission as a diagnosis that was not present on discharge but was present as a primary diagnosis on readmission.
Statistical Analysis
Bivariate analysis of mean patient age, surgical length of stay (LOS), Charlson score, and readmission status was performed using the Welch t-test. Bivariate analysis of patient factors and readmission status was performed using the Pearson chi-square test. Multivariate analyses were performed using logistic regression models to determine the odds of hospital readmission within 30 days of surgical discharge while adjusting for age, demographics, surgical admission LOS, race/ethnicity, sex, expected primary J Neurosurg / Volume 120 / May 2014
Incidence and predictors of 30-day readmission after craniotomy TABLE 1: Patient characteristics and surgical episode outcome among 18,506 patients undergoing craniotomy for primary malignant brain tumor in California (1995–2010)
TABLE 1: Patient characteristics and surgical episode outcome among 18,506 patients undergoing craniotomy for primary malignant brain tumor in California (1995–2010) (continued)
Variable
Value
Variable
Value
mean age in yrs (median) race/ethnicity (%) non-Hispanic white African American Hispanic Asian Native American/other sex (%) male female medical history prior to surgical episode (%) hypertension tobacco use disorder seizure & convulsive disorder cerebrovascular disease chronic pulmonary disease diabetes mellitus lipid disorder obesity & overweight speech & language disorder motor deficit moderate or severe liver disease myocardial infarction congestive heart failure cerebral edema & compression of the brain hydrocephalus gait & coordination dysfunction peripheral vascular disease vision & optic disorder malaise & fatigue peptic ulcer disease renal disease mild liver disease mean Charlson comorbidity index (median) expected primary payer (%) Medicare Medi-Cal private insurance uninsured hospital teaching status (%) neurosurgical residency program no neurosurgical residency program hospital pediatric status (%) nonpediatric hospital pediatric hospital mean LOS on surgical admission in days (median)
51.6 (54.0) n = 18,324 13,546 (74.0) 626 (3.4) 2772 (15.1) 931 (5.1) 449 (2.5) n = 18,506 10,684 (57.7) 7822 (42.3) n = 18,506 5988 (32.4) 3513 (19.0) 2449 (13.2) 2160 (11.7) 1771 (9.6) 1672 (9.0) 1118 (8.0) 1061 (5.7) 893 (4.8) 857 (4.6) 779 (4.2) 598 (3.2) 474 (2.6) 432 (2.3) 375 (2.0) 372 (2.0) 220 (1.2) 186 (1.0) 171 (0.9) 110 (0.6) 61 (0.3) 55 (0.3) 2.7 (2.0) n = 15,996 3903 (24.4) 1562 (9.8) 10,132 (63.3) 369 (2.3) n = 18,506 5881 (31.8) 12,625 (68.2) n = 18,506 17,918 (96.8) 588 (3.2) 8.2 (6.0)
mean charges for surgical admission in $ (median) surgical admission mortality (%) patients discharged home (%)
95,906 (72,029) 410 (2.2) 13,586 (73.4)
(continued)
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payer, hospital teaching status, California county, calendar year of surgery, medical history prior to surgical admission, and complications arising during surgical admission. Expected 30-day readmission rates were calculated for each patient using a multivariate logistic regression model for 30-day readmission. The expected likelihoods of 30-day readmission were then aggregated by hospital, and the ratio of observed to expected readmissions for each hospital was calculated. Statistical analysis was performed using commercially available software (STATA/ AMP 10, Stata Corp. LP). All tests were 2-sided, and p values < 0.05 were considered statistically significant.
Results
There were 18,506 inpatient admissions for resection of primary brain tumors in California between 1995 and 2010. Four hundred ten patients (2.2%) died during the index surgical admission, 13,586 patients (73.4%) were discharged home, and 4510 patients (24.4%) were transferred to another facility (Table 1). Among the home discharge patients, 1790 (13.2%) had at least 1 unplanned readmission within 30 days of discharge, and 483 (27%) of these readmitted patients were readmitted to a different hospital than the hospital from which they were discharged following the index surgical episode (Table 3). There were also 377 patients excluded from our analysis who had a planned readmission within 30 days of discharge. A majority of these planned readmissions were for brain excision (28.6%), chemotherapy (22.0%), and radiotherapy (9.3%). Index Admission Episodes
The median age of patients undergoing tumor resection was 54 years. The majority of patients were privately insured non-Hispanic white patients who received neurosurgical care at nonacademic medical centers (Table 1). The median LOS for index surgical admission was 6 days, and the median total charges per index surgical admission were $72,029 (Table 1). The most prevalent diseases in patients’ medical histories prior to surgery were hypertension (32.4%), tobacco use disorder (19.0%), and seizure and convulsive disorder (13.2%).
Thirty-Day Outcomes and 30-Day Readmissions
Three hundred sixteen patients (2.3%) died within 30 days of home discharge (Table 3). A total of 1790 patients were rehospitalized within 30 days of discharge, and the median time to first readmission was 11 days. Although a majority of readmitted patients had only 1 readmission episode, 11.8% of readmitted patients had multiple read1203
L. P. Marcus et al. TABLE 2: Diagnosis and procedure codes (ICD-9-CM) used to define patient comorbidities and complications Category
Code*
hypertension tobacco use disorder seizure & convulsive disorder cerebrovascular disease
401.0, 401.1, 401.9 305.1, V15.82 345.10, 345.11, 345.2, 345.3, 345.40, 345.41, 345.50, 345.51, 345.70, 345.71, 345.8, 345.9, 780.39 430, 431, 432.0, 432.1, 432.9, 433.00, 433.01, 433.10, 433.11, 433.20, 433.21, 433.30, 433.31, 433.80, 433.81, 433.90, 433.91, 434.00, 434.01, 434.10, 434.11, 434.90, 434.91, 435.0, 435.1, 435.2, 435.3, 435.8, 435.9, 436, 437.0, 437.1, 437.2, 437.3, 437.7, 437.8, 437.9, 438.0, 438.89, 438.9 chronic pulmonary disease † lipid disorder 272.0, 272.1, 272.2 diabetes mellitus † obesity & overweight 278.00, 278.01, 278.02, V85.36, V85.37, V85.38, V85.39, V85.4 speech & language disorder 784.3, 784.41, 784.42, 784.5, 784.51, 784.52, 784.59, 784.60, 784.61, 784.69, 937.5,‡ 937.2,‡ 438.10, 438.11, 438.12, 438.19 moderate or severe liver disease † motor deficit 342.0, 342.1, 342.8, 342.9, 344.0, 344.1, 344.3, 344.4, 344.6, 344.81, 344.89, 344.9, 781.4, 781.94, 799.3, 438.20, 438.30, 438.40, 438.50, 438.82, 438.83 myocardial infarction † cerebral edema & compression of brain 348.4, 348.5 hydrocephalus 331.3, 331.4, 02.2,‡ 02.34‡ congestive heart failure † gait & coordination dysfunction 781.2, 438.81, 438.84, 781.3, 93.22‡ peripheral vascular disease † vision & optic disorder 368.46, 368.47, 377.49, 377.75, 378.81, 379.50, 379.56, 438.7 malaise & fatigue 780.7, 780.71, 780.79 peptic ulcer disease † renal disease † mild liver disease † nonspecific CNS surgical complication 996.2, 996.75, 997.00, 997.01, 997.09 general infection 039.1, 039.8, 041.00, 041.01, 041.02, 041.03, 041.04, 041.09, 041.10, 041.11, 041.12, 041.19, 041.2, 041.3, 041.4, 041.5, 041.6, 041.7, 041.81, 041.82, 041.83, 041.84, 041.85, 041.86, 041.89, 041.9, 999.31, 999.39 sepsis & septicemia 003.1, 038.0, 038.10, 038.11, 038.12, 038.19, 038.2, 038.3, 038.40, 038.41, 038.42, 038.43, 038.44, 038.49, 038.8, 038.9, 790.7, 995.91, 995.92 urinary tract infection 590.10, 590.11, 590.80, 595.0, 595.3, 595.4, 599.0, 997.5 DVT, PE, & venous complications 415.10, 415.11, 415.19, 416.2, 451.0, 451.11, 451.19, 451.2, 451.82, 451.83, 451.84, 451.89, 451.9, 453.1, 453.2, 453.40, 453.41, 453.42, 453.51, 453.52, 453.6, 453.80, 453.81, 453.82, 453.9 surgical infection of the CNS 324.0, 326, 998.51, 998.59, 01.31,‡ 01.25,‡ 01.24,‡ 01.59,‡ 03.4,‡ 036.0, 047.9, 049.9, 320.0, 320.1, 320.2, 320.3, 320.7, 320.81, 320.82, 320.89, 320.9, 321.0, 321.1, 321.2, 322.0, 322.1, 322.2, 322.9, 323.01, 323.02, 323.9, 324.1, 324.9 * All codes are ICD-9-CM codes unless otherwise indicated. † ICD-9 code categorical classification from Romano and colleagues.17 ‡ ICD-9 procedure code.
missions and there were a total of 2022 30-day readmission episodes. The median LOS during a readmission was 4 days, and the median hospital charges per 30-day readmission episode were $20,296. The diagnoses that were most often established as reasons of readmission were seizure and convulsive disorder (20.9%), surgical infection of the CNS (14.5%), and motor deficit (12.8%). Differences Between Readmitted and Nonreadmitted Patients
Patients readmitted within 30 days had a 2-day lon-
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ger median LOS on their index surgical episode than nonreadmitted patients. There were significant racial/ethnic differences noted between the 2 groups. Readmitted patients were more frequently African American or Hispanic than nonreadmitted patients. Patients with at least one 30-day hospital readmission were more often Medicare and Medi-Cal beneficiaries and less often privately insured. Other observed differences between readmitted and nonreadmitted patients are noted in Table 4. The results of the multivariate analyses are presented in Table 5. In the multivariate regression model, longer J Neurosurg / Volume 120 / May 2014
Incidence and predictors of 30-day readmission after craniotomy TABLE 3: Thirty-day outcomes among 13,586 patients discharged home following craniotomy for primary malignant brain tumor Variable
Value
30-day mortality (%) inpatient outpatient total 30-day readmission (%) patients w/ 1 readmission episode patients w/ 2 readmission episodes patients w/ 3 readmission episodes patients w/ 4 readmission episodes total 30-day readmission episodes patients w/ readmission occurring at a different hospital from surgical site (%) mean days to first 30-day readmission (median) mean LOS during 30-day readmission episode in days (median) mean charges ($) per 30-day readmission episode (median) reason for readmission by diagnosis (%) seizure & convulsive disorder surgical infection of the CNS motor deficit DVT, PE, & venous complications general infection cerebral edema & compression of the brain hydrocephalus speech & language disorder urinary tract infection cerebrovascular disorder nonspecific CNS surgical complication sepsis & septicemia malaise & fatigue gait & coordination dysfunction vision & optic disorder
LOSs were associated with greater odds of subsequent readmission. Medi-Cal beneficiaries were at an increased likelihood of readmission relative to the privately insured (OR 1.52, 95% CI 1.20–1.93) as were patients with histories of prior myocardial infarctions (OR 1.64, 95% CI 1.06–2.54). The development of hydrocephalus during the index surgical admission was associated with a higher likelihood of 30-day readmission (OR 1.58, 95% CI 1.20– 2.07) as was the development of a deep venous thrombosis (DVT), pulmonary embolism (PE), or other venous complication (OR 3.88, 95% CI 1.84–8.18). Urinary tract infections during the index surgical episode were associated with lower odds of 30-day readmission (OR 0.52, 95% CI 0.29–0.94). Readmission Rates by Hospital
Forty hospitals (20.7%) had higher than expected 30-day readmission rates after craniotomy for resection of primary malignant brain tumors during the study pe-
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81 (0.6) 235 (1.7) 316 (2.3) 1790 (13.2) 1577 196 15 2 2022 483 (27.0) 12.3 (11.0) 5.9 (4.0) 44,249 (20,296) 20.9 14.5 12.8 11.3 11.1 10.1 9.6 8.5 8.5 6.3 6.3 4.9 2.6 2.0 1.3
riod (Fig. 1). Among patients discharged home during the study period, 501 craniotomies were performed at a pediatric hospital within California and 133 (26.6%) of these patients had at least one 30-day readmission, while 13,085 craniotomies were performed at a nonpediatric hospital and 1657 (12.7%) of these patients had at least 1 readmission. Additionally, among home-discharged patients, 8885 craniotomies were performed at nonteaching hospitals with a readmission rate of 13.3%, while 4701 craniotomies were performed at teaching hospitals with a readmission rate of 12.9%.
Discussion Neurosurgical Cost Burden of 30-Day Readmission
In this study it was found that 13.2% of all patients discharged home after craniotomy for tumor resection were rehospitalized within 30 days of discharge. Each readmission represented an additional $20,296 in median 1205
L. P. Marcus et al. TABLE 4: Comparative analysis of nonreadmitted patients and patients with at least one 30-day readmission after home discharge 30-Day Readmissions Variable
None (%)
At Least 1 (%)
p Value*
mean age in yrs (median) mean LOS on surgical admission in days (median) mean Charlson comorbidity index (median) race/ethnicity non-Hispanic white African American Hispanic Asian Native American/other sex male female medical history hypertension tobacco use disorder cerebrovascular disease chronic pulmonary disease lipid disorder diabetes mellitus obesity & overweight moderate or severe liver disease myocardial infarction congestive heart failure peripheral vascular disease peptic ulcer disease renal disease mild liver disease complications during surgical admission seizure & convulsive disorder speech & language disorder motor deficit cerebral edema & compression of the brain hydrocephalus nonspecific CNS surgical complication gait & coordination dysfunction vision & optic disorder malaise & fatigue general infection sepsis & septicemia urinary tract infection DVT, PE, & venous complications cerebrovascular disorder surgical infection of the CNS expected primary payer Medicare Medi-Cal
48.4 (50.0) 6.2 (4.0) 2.4 (2.0)
47.2 (51.0) 9.2 (6.0) 2.6 (2.0)
0.031
