Potentially preventable readmission diagnoses include pneumonia, hypertension, dehydration, asthma, urinary tract infection, chronic obstructive pulmonary disease exacerbation, perforated appendix, diabetes, angina, congestive heart failure, sepsis, acute renal failure, skin or soft tissue infection, and aspiration pneumonitis. The shaded areas indicate 95% confidence intervals.
Prescott HC, Langa KM, Iwashyna TJ. Readmission Diagnoses After Hospitalization for Severe Sepsis and Other Acute Medical Conditions. JAMA. 2015;313(10):1055-1057. doi:10.1001/jama.2015.1410
Patients are frequently rehospitalized within 90 days after having severe sepsis.1 Little is known, however, about the reasons for readmission and whether they can be reduced. We sought to determine the most common readmission diagnoses after hospitalization for severe sepsis, the extent to which readmissions may be potentially preventable by posthospitalization ambulatory care, and whether the pattern of readmission diagnoses differs compared with that of other acute medical conditions.
We studied participants in the nationally representative US Health and Retirement Study,2 a multistage probability sample of households with adults aged 50 years or older, that is linked to Medicare claims (1998-2010). We identified hospitalizations with severe sepsis using a validated approach that requires International Classification of Diseases, Ninth Revision, Clinical Modification codes for both infection and acute organ dysfunction.3,4 We matched hospitalizations for severe sepsis to hospitalizations for 15 common acute medical conditions (Table) 1:1 by age, sex, postdischarge comorbidity burden (Charlson Comorbidity Index), prehospitalization functional disability (limitations of activities and instrumental activities of daily living), and length of hospitalization using coarsened exact matching.5
We measured the rate and 95% confidence interval of 90-day readmissions. Using the Healthcare Cost and Utilization Project’s Clinical Classification Software, we determined the most common readmission diagnoses. To gauge what proportion of rehospitalizations may be potentially preventable, we measured ambulatory care sensitive conditions (ACSCs), which are diagnoses for which effective outpatient care may reduce hospitalization rates.6 We used ACSCs identified by the Agency for Healthcare Research and Quality,6 and an expanded definition also including sepsis, skin or soft tissue infection, acute renal failure, and aspiration pneumonitis, all of which could plausibly be prevented or treated early to avoid rehospitalization.
We compared readmission rates using McNemar χ2 tests with significance at P < .001 (2-sided) given multiple comparisons. The University of Michigan institutional review board approved this study; patients provided oral informed consent at enrollment and for Medicare linkage.
We identified 3494 hospitalizations for severe sepsis, of which 2843 (81.4%) survived to discharge. Of these, 2617 (92.1%) were matched to hospitalizations for other acute medical conditions. The cohort’s mean age was 78.9 years (SD, 8.9 years), 57.3% were female, and they had some preexisting functional disability (median, 1 limitation; interquartile range [IQR], 0-4 limitations). At discharge, patients had moderate comorbidity burden (median Charlson Index, 6; IQR, 3-8). Median hospitalization length was 7 days (IQR, 4-11 days). Age, sex, comorbidity burden, functional status, and hospitalization length did not differ between severe sepsis and matched acute medical conditions (P > .05 for each).
There were 1115 severe sepsis survivors (42.6%) rehospitalized within 90 days. The 10 most common readmission diagnoses following severe sepsis included several ACSCs (eg, heart failure, pneumonia, chronic obstructive pulmonary disease exacerbation, and urinary tract infection; Table). Collectively, ACSCs accounted for 22.2% (95% CI, 20.3%-24.5%) of 90-day readmissions. Using the expanded definition, ACSCs accounted for 41.6% (95% CI, 39.1%-44.1%) of 90-day readmissions after severe sepsis.
Patterns of readmission differed between survivors of severe sepsis and matched acute medical conditions (Table and Figure). Rates of readmission for sepsis and renal failure were higher and accounted for a greater proportion of the total readmissions after severe sepsis. Readmissions for a primary diagnosis of infection (sepsis, pneumonia, urinary tract, and skin or soft tissue infection) occurred in 11.9% (95% CI, 10.6%-13.1%) of severe sepsis survivors compared with 8.0% (95% CI, 7.0%-9.1%) of matched acute medical conditions (P < .001). Readmissions for ACSCs were more common after severe sepsis (21.6%; 95% CI, 20.0%-23.2%) vs matched acute conditions (19.1%; 95% CI, 17.7%-20.7%) (P = .02) and accounted for a greater proportion of all 90-day readmissions (41.6% [95% CI, 39.2%-44.1%] vs 37.1% [95% CI, 34.8%-39.5%], respectively; P = .009).
Readmissions within 90 days after hospitalization for severe sepsis were common, and 42% occurred for diagnoses that could potentially be prevented or treated early to avoid hospitalization compared with 37% after matched acute medical conditions.
A limitation of the present study is that we inferred the potential preventability of rehospitalizations by measuring readmissions for ACSCs. Whether these diagnoses represent preventable admissions, especially after sepsis, is not clear. Nonetheless, the high prevalence and concentration of specific diagnoses during the early postdischarge period suggest that further study is warranted of the feasibility and potential benefit of postdischarge interventions tailored to patients’ personalized risk for a limited number of common conditions.
Corresponding Author: Hallie C. Prescott, MD, MSc, Department of Medicine, University of Michigan, 2800 Plymouth Rd, North Campus Research Center, Ann Arbor, MI 48109 (firstname.lastname@example.org).
Author Contributions: Dr Prescott 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: Prescott.
Acquisition, analysis, or interpretation of data: All authors.
Drafting of the manuscript: Prescott.
Critical revision of the manuscript for important intellectual content: All authors.
Statistical analysis: Prescott, Iwashyna.
Obtained funding: Iwashyna.
Study supervision: Iwashyna.
Conflict of Interest Disclosures: The 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 T32 HL007749, R01 AG0030155, R21 AG044752, and U01 AG09740 from the National Institutes of Health and grant IIR 11-109 from the Department of Veterans Affairs Health Services Research & Development Service. The Health and Retirement Study is funded by the National Institute on Aging and performed at the Institute for Social Research, University of Michigan.
Role of Funder/Sponsor: The National Institutes of Health and the Department of Veterans Affairs Health Services Research & Development Service had 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.
Disclaimer: The views expressed in this article are those of the authors and do not necessarily reflect the position or policy of the Department of Veterans Affairs or the US government.
Additional Contributions: We appreciate the expert programming of Ryan McCammon, MS, and Vanessa Dickerman, MS, at the University of Michigan, Ann Arbor. They were not compensated for their contributions besides salary.