Effect of Hospital Readmission Reduction Program on Hospital Readmissions and Mortality Rates
RATIONALE: Although the Hospital Readmission Reduction Program (HRRP) has reduced the 30-day readmission rates for patients with chronic obstructive pulmonary disease (COPD) across hospitals, the effect of HRRP on hospital mortality remains unknown. Therefore, we examined the association between hospital readmissions and mortality rates for patients discharged with acute exacerbation of COPD (AECOPD).
METHOD: The all-cause hospital-specific 30-day risk-standardized mortality rate (RSMR) and the 30-day risk-standardized readmission rate (RSRR) for patients with COPD from 2010 to 2017 were obtained from the Hospital Compare website. Hospital service area (HSA) information was obtained from the Dartmouth Atlas of Healthcare. The longitudinal relationship between the mortality and readmission rates of a hospital was assessed using mixed linear models.
RESULTS: Of the 3,685 hospitals analyzed, the unadjusted mean RSMRs increased from 7.8% to 8.4% during the study period at a yearly rate of 0.13 (95% CI = 0.12 to 0.14; P < .001), whereas the mean RSRRs declined from 20.7% to 19.6%. When examined according to the baseline readmission rate and interaction with time, each 1% higher-than-baseline readmission rate was associated with a smaller increase in mortality rate by 0.015% (95% CI = −0.02 to −0.01; P < .0001). Inclusion of change in readmissions in the model showed that each 1% decrease in readmission rate was associated with 0.04% (95% CI = −0.01 to −0.06; P = .008) increase in mortality.
CONCLUSION: This hospital-level analysis of AECOPD showed that although the 30-day all-cause readmission rates declined, the mortality rates increased. Hospitals with lower readmission rates had higher mortality rates over time.
© 2019 Society of Hospital Medicine
DISCUSSION
As efforts to decrease readmission rates continue as a part of the HRRP implementation by the CMS, our study shows that among hospitals that discharged patients with AECOPD during 2010-2017, the all-cause 30-day RSRR was decreased, whereas the all-cause 30-day RSMR was increased. Of particular concern is that the rate of increase in mortality also increased. We also found that hospitals with higher readmission rates in 2010-2013 had a lower rate of increase in mortality than hospitals with lower readmission rates. In addition, hospitals that had a larger decrease in readmission rates during the study period had a larger rate of increase in mortality than hospitals with a smaller decrease in readmission rates. Our findings were robust to potential confounders such as hospital characteristics and local population characteristics in which hospitals operate.
Our study findings raise the question whether the implementation of the HRRP resulted in unintentional patient harm by forcing hospitals to make changes that may affect overall patient care. This question is particularly important as other studies on hospitalized patients with HF have found similar results.13,14 On the other hand, a similar association between readmission and mortality rates has not been observed in patients with pneumonia or AMI.14 Several possible explanations can be given for the observed discrepancy between the diseases and their effect on the relationship between readmission rate and mortality rate. Both COPD and HF are chronic diseases and characterized by exacerbations, whereas AMI and pneumonia are episodic diseases that are treatable. As the number of patients hospitalized with AECOPD and HF is much larger, hospitals may have a greater focus on reducing the 30-day readmission rates and may attempt to game the process, such as by delaying admissions through the emergency department within the 30-day period or by admitting patients for observation. In fact, a study found a 3% reduction in the within-hospital readmission rate with a concurrent 0.8% increase in observation unit use since the implementation of the HRRP.26 Such approaches to patient care may lead to adverse outcomes.
It is possible that readmissions and mortality act as competing risks and hence hospitals with higher mortality rates are left with fewer patients and thus have fewer readmissions, whereas those with lower mortality rates have more patients and a higher readmission rate.27 Such studies are not possible with hospital-level data, and patient-level studies will be required to examine this competing risk hypothesis. Our study results provide some support to the competing risk hypothesis (hospitals with lower baseline readmission rates had a steeper increase in mortality); however, it is not possible to draw any conclusions due to the high risk of ecological fallacy bias.
This study has important potential implications for healthcare policy, public health, and research. We found that an important national intervention aimed at decreasing readmission rates and improving the quality of care for patients with AECOPD may be associated with higher mortality rates in these patients. There may be a need to redefine measures for determining the performance of an institution. Our study supports research into the underlying mechanisms resulting in an inverse association between readmissions and mortality. In particular, health policy researchers may need to examine how incentives and penalties affect the allocation of resources within hospitals.
This study has several strengths and some potential weaknesses. We used a national dataset to examine readmission and mortality rates that include the majority of hospitals in the United States. We also included data from the local population for each hospital, thus allowing us to examine hospital performance within the context of its target population. One potential limitation is that we used hospital-level data and not patient-level data; however, the readmission penalties are designed for hospitals, which justifies our use of hospital-level data. Furthermore, data were not available for shorter time intervals; data from shorter time intervals may be associated with greater variability. Being an observational study, it is difficult to establish a causal relationship; the longitudinal nature of the study does establish temporality, an important factor in establishing causality.
In conclusion, we found that although the readmission rates decreased, there was an increase in the mortality rate within the 30 days of discharge from the hospital in patients with AECOPD. The rate of increase in mortality was higher in hospitals with lower readmission rates than in hospitals with higher readmission rates. Further research for determining the mechanism responsible for this association is needed. Future health policy interventions may need to consider the potential for adverse outcomes.
