Neuman MD, Wirtalla C, Werner RM. Association Between Skilled Nursing Facility Quality Indicators and Hospital Readmissions. JAMA. 2014;312(15):1542-1551. doi:10.1001/jama.2014.13513
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Hospital readmissions are common, costly, and potentially preventable. Little is known about the association between available skilled nursing facility (SNF) performance measures and the risk of hospital readmission.
To measure the association between SNF performance measures and hospital readmissions among Medicare beneficiaries receiving postacute care at SNFs in the United States.
Design and Participants
Using national Medicare data on fee-for-service Medicare beneficiaries discharged to a SNF after an acute care hospitalization between September 1, 2009, and August 31, 2010, we examined the association between SNF performance on publicly available metrics (SNF staffing intensity, health deficiencies identified through site inspections, and the percentages of SNF patients with delirium, moderate to severe pain, and new or worsening pressure ulcers) and the risk of readmission or death 30 days after discharge to a SNF. Adjusted analyses controlled for patient case mix, SNF facility factors, and the discharging hospital.
Main Outcomes and Measures
Readmission to an acute care hospital or death within 30 days of the index hospital discharge.
Of 1 530 824 patients discharged, 357 752 (23.3%; 99% CI, 23.3%-23.5%) were readmitted or died within 30 days; 72 472 died within 30 days (4.7%; 99% CI, 4.7%-4.8%), and 321 709 were readmitted (21.0%; 99% CI, 20.9%-21.1%). The unadjusted risk of readmission or death was lower at SNFs with better staffing ratings. SNFs ranked lowest (19.2% of all SNFs) had a 30-day risk of readmission or death of 25.5% (99% CI, 25.3%-25.8%) vs 19.8% (99% CI, 19.5%-20.1%) among those ranked highest. SNFs with better facility inspection ratings also had a lower risk of readmission or death. SNFs ranked lowest (20.1% of all SNFs) had a risk of 24.9% (99% CI, 24.7%-25.1%) vs 21.5% (99% CI, 21.2%-21.7%) among those ranked highest . Adjustment for patient factors, SNF facility factors, and the discharging hospital attenuated these associations; we observed small differences in the adjusted risk of readmission or death according to SNF facility inspection ratings (lowest vs highest rating: 23.7%; 99% CI: 23.7%, 23.7%; vs 23.0%; 99% CI: 23.0%, 23.1%). Other measures did not predict clinically meaningful differences in the adjusted risk of readmission or death.
Conclusions and Relevance
Among fee-for-service Medicare beneficiaries discharged to a SNF after an acute care hospitalization, available performance measures were not consistently associated with differences in the adjusted risk of readmission or death.
Quiz Ref IDOne in 5 Medicare beneficiaries is readmitted to the hospital within 30 days of discharge.1 Under traditional fee-for-service reimbursement, hospitals had few incentives to invest in reducing readmission rates. However, with Medicare’s Hospital Readmission Reduction Program2 and the increasing prevalence of bundled payments and shared-savings programs since the passage of the Patient Protection and Affordable Care Act,3- 6 hospitals have increased incentives to improve postdischarge management. One commonly discussed way to do so is through more effective use of postacute care.7,8
Quiz Ref IDSkilled nursing facilities (SNFs) represent the most common setting for postacute care in the United States. Rates of readmission from SNFs are high. One in 4 patients discharged to a SNF is readmitted within 30 days,9 and two-thirds of these readmissions may be preventable.10 Because readmission rates vary across SNFs,11 preferential discharge of postacute care patients to high-quality SNFs may be one strategy by which hospitals could decrease the likelihood of readmission among these patients. Information about SNF performance on common quality metrics is widely available through Medicare’s Nursing Home Compare website. However, little is known about whether performance on these metrics is associated with differences in performance that could predict the likelihood of readmission. To address this, we examined the association between available indicators of SNF quality and hospital readmission among Medicare beneficiaries receiving postacute care at US SNFs.
This study was approved by the Perelman School of Medicine Institutional Review Board, which waived the requirement for participant informed consent. Data sources included the 2008-2010 100% Medicare Provider Analysis and Review files, which include records of inpatient care for all fee-for-service Medicare beneficiaries; the 2009 and 2010 Nursing Home Minimum Data Set, which includes detailed clinical data on all patients in Medicare-certified SNFs; the 2009 and 2010 Medicare Beneficiary Summary files, which record vital status and health maintenance organization enrollment; the 2009 and 2010 Medicare Online Survey, Certification, and Reporting files, which compile data on SNF facility characteristics; and SNF performance data published on the Nursing Home Compare website in 2009 and 2010.
We based our inclusion criteria on methods used to calculate risk-adjusted hospital-wide readmission rates by the Hospital Readmission Reduction Program.12 Our starting sample included all Medicare discharges from nonfederal acute care hospitals between September 1, 2009, and August 31, 2010, to Medicare-certified SNFs for postacute care, as indicated by an appropriate Nursing Home Minimum Data Set admission assessment within 7 days of discharge.
Because we obtained patient comorbidity data from claims filed up to 12 months before the index discharge, we excluded beneficiaries who were younger than 66 years at hospital discharge or who were enrolled in a health maintenance organization during the 12 months before the index because their claims were unavailable in our data. We also excluded patients who were enrolled in a health maintenance organization in the 30 days after hospital discharge because we could not identify readmissions among them; those who were discharged against medical advice or discharged to hospice (as recorded in the Medicare Provider Analysis and Review discharge status field); those for whom the primary reason for hospitalization was a psychiatric condition, rehabilitation, or medical cancer treatment, following Hospital Readmission Reduction Program definitions,12 because readmissions after hospitalizations for these indications are likely to occur for different reasons than readmissions after other acute care hospitalizations; and those who received postacute care at SNFs that were excluded from Nursing Home Compare at the index discharge for 1 or more of the 5 performance measures we examined because of low case volumes or an insufficient duration of participation in the Nursing Home Compare program.
For consistency with Hospital Readmission Reduction Program methods, if a patient had more than 1 eligible discharge during the study period, all discharges meeting the above criteria were used in our regression analyses. In other words, our analysis was at the discharge level rather than the patient level.12 However, we also conducted a supplementary patient-level analysis that included only the first eligible discharge for each patient in our sample. The sample definition used International Classification of Diseases, Ninth Revision (ICD-9) diagnosis and procedure codes for each discharge, grouped by Agency for Healthcare Research and Quality Clinical Classification Software.12
Our primary outcome was a composite end point of unplanned readmission or death from any cause within 30 days of hospital discharge. To allow a uniform window for outcomes assessment for each discharge, we did not distinguish between patients who were directly readmitted from a SNF and those who were discharged home from one and subsequently readmitted, as long as this readmission occurred within 30 days of the index discharge. Death within 30 days was included in our primary outcome to prevent inappropriate censoring of observations13,14; however, for purposes of comparison, we conducted a secondary analysis using an end point of readmission at 30 days, rather than a combined end point of readmission or death.
We considered a readmission to be unplanned if it involved an admission to an acute care hospital that occurred within 30 days of hospital discharge and the reason for admission was not bone marrow or solid organ transplant, maintenance chemotherapy, rehabilitation, or a potentially planned procedure not performed to treat an acute condition or a complication of previous care.12
We obtained 5 indicators of SNF performance from Medicare’s Nursing Home Compare website, using data listed there as of the date of hospital discharge. Performance indicators included 3 clinical measures for postacute care residents (the percentage of SNF residents with delirium, with new or worsening pressure ulcers, and reporting moderate to severe pain15,16), a categorical summary rating of staffing intensity that ranged from 1 to 5 stars,17 and a categorical summary rating based on health deficiencies identified through site inspections that also ranged from 1 to 5 stars.17
Information on other SNF facility characteristics came from the Online Survey, Certification, and Reporting survey closest in time to hospital discharge. Facility characteristics included nursing home size (50 beds or fewer; 51-100 beds; 101-150 beds; or 151 beds or more),18- 20 the percentage of patients covered by Medicare and Medicaid within each facility,21- 24 occupancy rate,20,25 chain membership,26- 28 location in a hospital,20,29 and ownership (not for profit, for profit, or government owned).28,30- 32
We obtained data on patient age, race,33 sex, and the indication for the index hospitalization from Medicare Provider Analysis and Review files. We categorized indications for hospitalization into 5 broad groups based on ICD-9,Clinical Modification diagnosis and procedure codes, using Hospital Readmission Reduction Program algorithms12: surgical and gynecologic conditions, respiratory conditions and heart failure, cardiac and noncardiac vascular conditions, neurologic conditions, and other general medical conditions. We also obtained Hospital Readmission Reduction Program–defined variables on 31 risk factors and 173 admission diagnosis categories, using hospital discharge claims from the index discharge and all hospitalizations occurring in the 12 months before the index.12
We used χ2 tests and the Wilcoxon rank-sum test to assess differences in the baseline characteristics of patients according to outcomes at 30 days. We used linear probability models to test the association between SNF factors and risk of readmission or death within 30 days of discharge. Models evaluated the association between risk of readmission or death and the 5 SNF performance measures, SNF facility characteristics, and the combination of available SNF performance measures and facility characteristics. All regression models adjusted for age, sex, and race; the indication for the index hospitalization; and all 204 risk factor and admission diagnosis variables. Because observed differences in rates of readmission or death across SNFs could reflect differences in quality of the discharging hospital, our regression models included hospital fixed effects to account for time-invariant hospital characteristics. In other words, each regression was a “within-hospital” analysis that compared outcomes among patients who were discharged from the same hospital to different SNFs. We handled missing data via listwise deletion (ie, omitting from each model all observations with missing data on a variable included in that model); of our sample of 1 530 824 discharges, 4 (<0.001%) were omitted because of missing data on race. Models used robust standard errors that adjusted for clustering of observations within SNFs.
We used these regressions to generate predicted risks for readmission or death within 30 days of hospital discharge for patients treated at SNFs that differed across available performance measures and facility characteristics, holding all other factors (including other quality and facility characteristics) at their means. For categorical variables (eg, staffing and survey ratings, chain status, location in a hospital, size, ownership), we compared the adjusted risk of readmission or death across categories; for continuous variables (eg, percentages of patients with delirium, pain, and pressure ulcers; occupancy; percentage receiving Medicare and Medicaid), we used the regression coefficient to calculate predicted risk values for a discharge to a hypothetical SNF at the 25th percentile to a discharge to a hypothetical SNF at the 75th percentile. We generated 99% CIs based on the distribution of predicted risks across 500 block-bootstrapped samples that used the individual SNF as the sampling unit to account for potential clustering of observations within SNFs. Because of our large sample size, we used a P value of .01 as our threshold for statistical significance; all hypothesis tests were 2-sided. Analyses used Stata version 13.1.
Our sample included 1 530 824 discharges from 3537 hospitals to 14 251 SNFs. The median hospital in our sample discharged patients to 21 SNFs (interquartile range [IQR], 9-40); the median SNF received patients from 7 hospitals (IQR, 4-10). Our sample included 1 150 063 unique patients, with 271 892 (23.6%) having more than 1 hospital discharge to a SNF during the period. Table 1 describes the SNFs included in our sample.
Of 1 530 824 discharges to SNFs, 321 709 were followed by readmission within 30 days (21.0%; 99% CI, 20.9%-21.1%), and 72 472 were followed by a death within 30 days (4.7%; 99% CI, 4.7%-4.8%). The overall rate of 30-day readmission or death was 23.3% (N = 357 752; 99% CI, 23.3%-23.5%).
Compared with other discharges to SNFs in our sample, discharges that led to a readmission or death more often occurred among patients who were older and more likely to be male or black (Table 2). They were also more likely to occur among patients who were hospitalized for a general medical condition, a pulmonary condition or congestive heart failure, or a cardiac or vascular condition; were less likely to have been hospitalized for a neurologic condition or a surgical or gynecologic condition; and were more likely to have common comorbidities such as coronary artery disease, diabetes, and chronic obstructive pulmonary disease.
In unadjusted analyses (Table 3), the risk of readmission or death within 30 days was lower for discharges from SNFs with better staffing ratings—lowest vs highest rating: 64 677 of 253 231 discharges (25.5%; 99% CI, 25.3%-25.8%) vs 26 531 of 134 029 discharges (19.8%; 99% CI, 19.5%-20.1%). The risk was also lower in SNFs with better facility inspection ratings—lowest rating vs highest rating: 68 642 of 275 471 discharges (24.9%; 99% CI, 24.7%-25.1%) vs 35 332 of 164 629 discharges (21.5%; 99% CI, 21.2%-21.7%) and lower rates of new or worsening pressure ulcers (SNFs above the 75th percentile vs SNFs at or below the 25th percentile: 111 116 of 457 429 discharges [24.3%; 99% CI, 24.1%-24.5%] vs 63 166 of 288 664 discharges [21.9%; 99% CI, 21.7%-22.1%]). Rates of readmission or death were paradoxically lower at SNFs that had higher percentages of patients with moderate to severe pain and acute delirium: 92 309 of 434 008 discharges to SNFs with rates above the 75th percentile on the pain measure were readmitted or died within 30 days (21.3%; 99% CI, 21.1%-21.4%) vs 81 990 of 328 252 discharges to SNFs at or below the 25th percentile (25.0%; 99% CI, 24.8%-25.2%). A total of 63 275 of 285 258 discharges to SNFs above the 75th percentile on the delirium measure were readmitted or died within 30 days (22.2%; 99% CI, 22.0%-22.4%) vs 102 210 of 428 349 discharges to SNFs at or below the 25th percentile (23.9%; 99% CI, 23.7%-24.0%).
Table 4 presents our regression results for our primary outcome. In addition to the fully adjusted model (model 3), models with differing degrees of adjustment for SNF performance measures and facility factors are shown for comparison. In our fully adjusted model, which controlled for patient factors, SNF facility factors, and the discharging hospital, SNFs with the best inspection ratings (9.8% of all SNFs) had a slightly lower risk of 30-day readmission or death compared with discharges to the 20.1% of SNFs that were in the lowest category of inspection rating (23.0%; 99% CI, 23.0%-23.1% vs 23.7%; 99% CI, 23.7%-23.7%). Discharges to SNFs with lower rates of new or worsened pressure were associated with a marginally lower adjusted risk of 30-day readmission or death compared to SNFs with worse performance on this measure (25th vs 75th percentile: 23.2%; 99% CI, 23.2%-23.3% vs 23.4%; 99% CI, 23.4%-23.4%). The adjusted risk of readmission or death at 30 days did not differ according to SNF staffing rating or the percentage of patients with delirium.
Several SNF facility characteristics were also associated with 30-day risk of readmission or death in both the unadjusted and adjusted analyses. In our fully adjusted model, we observed independent associations between the predicted risk of readmission or death and SNF ownership status; the predicted risk was lower for discharges to not-for-profit SNFs compared with those to for-profit SNFs (22.8%; 99% CI, 22.8%-22.8% vs 23.7%; 99% CI, 23.6%-23.7%). Discharge to the smallest facilities were associated with a lower adjusted risk of 30-day readmission or death compared with discharges to the largest facilities (≥151 beds [22.7%; 99% CI, 22.7%-22.7%] vs ≤50 beds [23.5%; 99% CI, 23.5%-23.5%]).
We obtained similar results when we repeated our regression models to predict an end point readmission at 30 days, rather than a combined end point of readmission or death (Table 5). When we repeated our analyses in a smaller data set that included only the first available discharge for each patient in the sample, we observed a lower overall rate of 30-day readmission or death (240 771 of 1 173 072 patients; 20.5%; 99% CI, 20.4%-20.6%); however, the adjusted associations between SNF performance measures and facility factors and 30-day outcomes were qualitatively similar to those obtained in our main regression analyses.
Quiz Ref IDAmong fee-for-service Medicare beneficiaries who received postacute care at a US SNF, better performance on available measures of postacute care quality was not consistently associated with a lower adjusted risk of readmission or death at 30 days. Although better performance on several available SNF performance measures was associated with improved outcomes in unadjusted analyses, these associations were attenuated substantially after adjustment for patient factors, the discharging hospital, and SNF facility characteristics. In our fully adjusted regression models, SNFs with better facility inspection ratings demonstrated a slightly lower adjusted risk of readmission or death; however, adjusted outcomes did not vary meaningfully across SNFs that differed in terms of staffing ratings or their performance on clinical measures related to pain or delirium.
Past research has suggested that SNF quality may be associated with the risk of hospital readmission10,11,34- 36; however, previous studies have focused on small groups of hospitals10,34 and selected subsets of patients.35 Our study, which takes a comprehensive approach that includes all fee-for-service Medicare beneficiaries admitted to SNFs for postacute care, accords with these past findings insofar as it demonstrates variations in rates of readmission or death according to selected SNF facility characteristics and inspection rating performance.18- 24,28,30- 32 However, because past analyses have not accounted for hospital effects, their comparisons of performance across SNFs could be confounded by differences in the quality of care at discharging hospitals.11,35 By using fixed effects to control for all time-invariant hospital factors, our analysis provides insight into the association between measured SNF performance and clinical outcomes while holding hospital factors constant.
As hospitals seek ways to prevent readmissions, our finding of lower readmission rates at certain types of SNFs may inform hospitals’ approaches to discharge planning. At the same time, our results suggest that preferential discharge to SNFs with better performance on available quality metrics may yield only modest effects on readmission rates after accounting for other factors. In the setting of an average readmission or death rate of 23%, we found that by choosing a SNF in the highest vs the lowest category of facility inspection ratings, hospitals might expect at most an absolute reduction in their readmission rate of 0.7 percentage points, or a relative reduction of just over 3%. Quiz Ref IDSuch a reduction may be meaningful to both the hospital in terms of their finances and the patients whose readmission would potentially be prevented; however, our findings suggest that there is significant remaining variation in rates of readmission across SNFs that is not explained by currently available performance measures.
Quiz Ref IDWe chose to study performance measures that are publicly reported by Medicare and available for virtually all US SNFs because they could be easily incorporated by hospitals into current discharge planning processes. Because these performance measures were developed before recent policy efforts to reduce hospital readmissions, it is unlikely that they were designed to capture aspects of quality directly related to readmission. In particular, the 3 clinical measures of performance that we examined in and of themselves represent important aspects of SNF quality. However, they do not predict clinically meaningful differences in the risk of readmission or death. As such, our work suggests a need for further efforts to develop metrics that influence readmission rates among SNF patients, potentially including care transitions and efforts to avoid unnecessary hospitalizations for changes in clinical status that can be safely managed at a SNF.
Alternatively, publication of risk-adjusted readmission rates among patients receiving postacute care at a given SNF could represent a further policy strategy to aid discharge planning by hospitals and potentially reduce readmissions. At present, hospitals do not have access to information on SNF readmission rates. Although making this information publicly available could improve transparency and motivate SNFs to improve their quality, such a strategy could also lead to unintended negative consequences if it motivated SNFs to differentially accept the healthiest patients, limit postacute care access for sicker patients, or fail to transfer patients to hospitals when medically necessary.
Our work has limitations. Because Medicare Provider Analysis and Review files do not contain information on patients in Medicare health maintenance organizations, our sample included only fee-for-service Medicare patients. As such, our findings may not be generalizable to patients in Medicare health maintenance organizations or patients not enrolled in Medicare, groups that tend to be healthier than patients enrolled in fee-for-service Medicare. Although our models adjusted for an array of potential confounders, our results may still be biased if patients’ severity of illness varied across SNFs in ways that we could not observe in the study database, or if the claims-based algorithms we used for risk adjustment incompletely captured important aspects of patients’ health. However, we followed approaches currently used by the Centers for Medicare & Medicaid Services in the Hospital Readmission Reduction Program to adjust for a wide range of observed patient factors. As a retrospective analysis, our study cannot address whether a causal relationship exists between measured SNF performance and clinical outcomes.
Despite these limitations, our results provide new information to inform the efforts of hospitals, health systems, and insurers to reduce rates of hospital readmission through more effective use of postacute care. Ultimately, although SNF performance measurement plays an important role in promoting transparency and accountability in the US health care system, our findings suggest that in their current form they are unlikely to serve as a sole basis for large-scale reductions in readmissions unless accompanied by other strategies.
Among fee-for-service Medicare beneficiaries discharged to a SNF after an acute care hospitalization, available performance measures were not consistently associated with differences in the risk of readmission or death.
Corresponding Author: Mark D. Neuman, MD, MSc, Department of Anesthesiology and Critical Care, Perelman School of Medicine, University of Pennsylvania, 423 Guardian Dr, 1119A Blockley Hall, Philadelphia, PA 19104 (email@example.com).
Author Contributions: Dr Neuman had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.
Study concept and design: All authors.
Acquisition, analysis, or interpretation of data: All authors.
Drafting of the manuscript: Neuman.
Critical revision of the manuscript for important intellectual content: All authors.
Statistical analysis: Neuman, Werner.
Obtained funding: Neuman, Werner.
Administrative, technical, or material support: All authors.
Study supervision: Neuman, Werner.
Conflict of Interest Disclosures: All authors have completed and submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest and none were reported.
Funding/Support: This work was supported by grants from the National Institute on Aging (grant K08AG043548 to Dr Neuman; grant R01 AG034182 to Dr Werner).
Role of the Funders/Sponsors: The funding agency played no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication.
Additional Contributions: Additional data management and statistical programming was performed by Jianing Yang, BS (University of Pennsylvania). She was compensated for this work.