Overall, 30-day, 90-day, and 1-year mortality rates were 4%, 9%, and 19%. Readmission rates for the cohort at 30-day, 90-day, and 1-year were 15%, 26%, and 43%. Septic patients had significantly higher mortality at all time points (p < 0.001) and higher readmission rates at 90 days (29% vs 23%; p < 0.001) and 1-year (48% vs 40%; p < 0.001), with similar readmission rates at 30 days (16% vs 14%; p = 0.07) compared with nonseptic patients (Table 2).
Forty-three percent (1,756) of ICU survivors experienced at least one inpatient readmission within 1 year of their index ICU hospitalization. Twenty-four percent of patients with a readmission had one categorized as a preventable admission (ACSC’s) based on the Agency for Healthcare Research Quality definitions (Supplement Table 1, Supplemental Digital Content 1, http://links.lww.com/CCM/E889). The top five ACSC’s diagnoses were congestive heart failure (8%), pneumonia (6%), complicated diabetes (3%), urinary tract infection (3%), and chronic obstructive pulmonary disease (2%).
The proportion of patients with an inpatient admission increased from 29% in the pre-ICU year to 43% in the post-ICU year (p < 0.001) (Supplement Table 2, Supplemental Digital Content 2, http://links.lww.com/CCM/E890). The increase between the pre- and post-ICU year was larger for patients admitted for sepsis (32% vs 48%; p < 0.001) than those admitted to the ICU for other diagnoses (27% vs 40%; p < 0.001).
There were 650 patients (16%) in the cohort who were new healthcare utilizers in that they did not have a hospital admission, ED visit, or outpatient visit in the pre-ICU period but did have at least one in the post-ICU period. Among patients who ever had a hospital admission, 47% had a hospital admission only in the post-ICU year (new inpatient utilizer). Similarly, 38% of patients with ED visits and 21% of patients with outpatient visits were new ED and new outpatient utilizers, respectively, in the post-ICU year. Of the 3,318 patients who survived to 1-year post-ICU discharge, only 472 (14%) had no visits during the post-ICU period.
Among the 3,318 patients who survived to 1-year post-ICU discharge, 1,489 (45%) were increased utilizers according to our definition. There were significant differences in SES, payer status, severity of illness scores, and ICU LOS between increased utilizers and patients with no increase in utilization (Table 3). Neither mechanical ventilation nor having an outpatient visit 2 weeks post hospital discharge was associated with increased utilization. In a sensitivity analysis where the definition of increased utilization included patients who died within 1 year of ICU discharge, age, diagnosis of heart failure, and discharge to home were also associated with increased utilization (data not shown).
Only 305 (8%) of all ICU survivors (primary cohort) received new support from PT/OT or cognitive/mental health clinicians in the post-ICU period. Eighty-eight percent of cognitive and 100% of psychiatric referrals were new in the post-ICU study period. Among the 617 patients who were in the ICU greater than or equal to 5 days and underwent mechanical ventilation, only 30 (5%) had a PT/OT, cognitive, or mental health visit within 90 days after ICU discharge.
A significant increase in the proportion of patients with opioid prescriptions occurred in the post-ICU period (33% in the post-ICU period vs 28% in the pre-ICU period; p < 0.001) and 17% of the cohort had new orders for opioid medication in the post-ICU period.
Among the 1,256 patients admitted to our referral center ICUs, 335 (27%) had heart failure. Patients without heart failure met our definition of increased utilizer significantly more often (24% vs 15%; p = 0.006) than patients with heart failure. However, patients with heart failure had significantly higher 30-day (21% vs 15%; p = 0.01) and 90-day (30% vs 23%; p = 0.01) readmissions compared with those without heart failure (Supplement Table 3, Supplemental Digital Content 3, http://links.lww.com/CCM/E891). A summary of all analyses and denominators is presented for easy reference in Supplement Table 4 (Supplemental Digital Content 4, http://links.lww.com/CCM/E892).
In this study of a large integrated health system in the United States, 1-year, 90-day, and 30-day hospital readmission rates were high. Almost half of patients were readmitted during the year after hospital discharge. One quarter of ICU survivors had a potentially preventable readmission within the first year. The top five ACSC’s readmission diagnoses were congestive heart failure (8%), pneumonia (6%), complicated diabetes (3%), urinary tract infection (3%), and chronic obstructive pulmonary disease (2%). Forty-five percent of ICU survivors had increased healthcare resource utilization after hospital discharge, and 16% of survivors newly began utilizing health services. Lower SES, type of insurance, higher severity of illness, and longer hospital LOS were all associated with an increase in resource utilization after hospital discharge.
Our data suggest that needs and vulnerability extend across SES. Interestingly, of the non-Medicaid/Medicare (‘private payers”) patients, 13% had an ED visit or an inpatient admission and no outpatient visit in the post ICU period, while in the Medicaid population that the same percent was higher at 22%. Patients with private insurance represent a higher SES (when measured using area deprivation index), and we suspect they have easier access to outpatient services, while patients with Medicaid or no insurance represent a lower SES. Further, the lack of access to established care contributes to ED visits and hospital admissions in the post-ICU Medicaid group and in patients without insurance, but a better clarification of this pattern will require further research particularly in the uninsured. The higher than expected ED and inpatient visit use without outpatient use in the higher SES group suggests that individual factors, especially psychologic and emotional factors, play an important role in use of follow-up resources and healthcare utilization.
Patients in our cohort used costly ED and inpatient resources more than outpatient services such as PT/OT cognitive or mental health visits in the post-ICU period. This observed pattern may derive from clinician lack of awareness of the availability of such services or of relevant patient disability, or from organizational failures in the outpatient follow-up of ICU survivors. The need for specific outpatient care services designed for the post-ICU population is underscored in our data by the lack of association between an outpatient visit within 2 weeks of hospital discharge and increased resource utilization, suggesting that specific ICU aftercare and recovery activities may be needed to provide relevant and timely services to ICU survivors (24243). The low prevalence of outpatient therapy stands in marked contrast to the high prevalence of relevant disabilities among most ICU survivors (3644–47). Herridge et al (18) report that increased healthcare resource utilization continues up to 5 years post-ICU and is an important legacy of patients with acute respiratory distress syndrome (ARDS) admitted to the ICU for greater than 7 days.
ICU survivors often struggle to regain their pre-hospital way of life and to adjust to a new state of physical needs (112643). The increase in opiate prescription use noted in our data are evidence of a new post-ICU circumstance similar to ICU survivors in the United Kingdom and Scotland who often report chronic pain (1622). Given the current opiate epidemic in the United States, our data identifies ICU survivors as a population to target for other pain control interventions. Thus, strategies and interventions designed to optimize healthcare utilization while maintaining adequate support for ICU survivors is an imperative (4849).
This study has several limitations. It is a retrospective investigation. We did not compare resource utilization with a matched non-ICU control group, rather we used the patient healthcare utilization prior to the ICU admission to control for comorbid conditions unrelated to the ICU admission. Due to the large sample size, statistically significant differences in characteristics like severity of illness may not represent clinically meaningful differences. We were unable to identify patients who resided in a long-term healthcare facility prior to the index ICU admission, and therefore, we were not able to include healthcare facility utilization in this study. Our utilization data are likely an underestimation of true healthcare resource utilization for ICU patients. Our population is 92% Caucasian which may limit the generalizability of our data. We defined preventable hospital readmission using AHRQ standard ACSC criteria, and we do not know if they truly represent preventable admissions. Finally, the competing risk of mortality may be a source of bias; however, a sensitivity analysis that included patients who died in the definition of increased utilizer demonstrated robust findings.
Almost half of all ICU survivors within a mixed payer system have increased healthcare resource utilization. An ICU admission alters an individual’s healthcare utilization patterns including increased hospital readmissions and ED visits. Patient factors including lower SES and higher severity of illness are associated with increased resource utilization. A post-ICU aftercare and recovery clinic designed to specifically address these needs may provide personalized medical therapy and anticipatory guidance thereby reducing healthcare resource utilization.
1. Agboola S, Golas S, Fischer N, et al. Healthcare utilization in older patients using personal emergency response systems: An analysis of electronic health records and medical alert data: Brief description: A longitudinal retrospective analyses of healthcare utilization rates in older patients using personal emergency response systems from 2011 to 2015. BMC Health Serv Res 2017; 17:282
2. Hewner S, Wu YW, Castner J. Comparative effectiveness of risk-stratified care management in reducing readmissions
in medicaid adults with chronic disease. J Healthc Qual 2016; 38:3–16
3. Unroe M, Kahn JM, Carson SS, et al. One-year trajectories of care and resource utilization
for recipients of prolonged mechanical ventilation: A cohort study. Ann Intern Med 2010; 153:167–175
4. Wunsch H. Weighing the costs and benefits of a sedative. JAMA 2012; 307:1195–1197
5. Wunsch H, Angus DC. The puzzle of long-term morbidity after critical illness. Crit Care 2010; 14:121
6. Wunsch H, Guerra C, Barnato AE, et al. Three-year outcomes for Medicare beneficiaries who survive intensive care. JAMA 2010; 303:849–856
7. Elliott D, Davidson JE, Harvey MA, et al. Exploring the scope of post-intensive care syndrome therapy and care: Engagement of non-critical care providers and survivors in a second stakeholders meeting. Crit Care Med 2014; 42:2518–2526
8. Hacker K, Santos P, Thompson D, et al. Early experience of a safety net provider reorganizing into an accountable care organization. J Health Polit Policy Law 2014; 39:901–917
9. Mechanic R. Post-acute care–the next frontier for controlling Medicare spending. N Engl J Med 2014; 370:692–694
10. Kahn JM, Angus DC. Health policy and future planning for survivors of critical illness. Curr Opin Crit Care 2007; 13:514–518
11. Kahn JM, Kramer AA, Rubenfeld GD. Transferring critically ill patients out of hospital improves the standardized mortality ratio: A simulation study. Chest 2007; 131:68–75
12. Kahn JM, Le T, Angus DC, et al.; ProVent Study Group Investigators: The epidemiology of chronic critical illness in the United States*. Crit Care Med 2015; 43:282–287
13. Zimmerman JE, Kramer AA, Knaus WA. Changes in hospital mortality for United States intensive care unit admissions from 1988 to 2012. Critl Care 2013; 17:R81
14. Prescott HC, Langa KM, Iwashyna TJ. Readmission diagnoses after hospitalization for severe sepsis and other acute medical conditions. JAMA 2015; 313:1055–1057
15. Cheung AM, Tansey CM, Tomlinson G, et al. Two-year outcomes, health care use, and costs of survivors of acute respiratory distress syndrome. Am J Respir Crit Care Med 2006; 174:538–544
16. Griffiths J, Hatch RA, Bishop J, et al. An exploration of social and economic outcome and associated health-related quality of life after critical illness in general intensive care unit survivors: A 12-month follow-up study. Crit Care 2013; 17:R100
17. Herridge MS, Cheung AM, Tansey CM, et al.; Canadian Critical Care Trials Group: One-year outcomes in survivors of the acute respiratory distress syndrome. N Engl J Med 2003; 348:683–693
18. Herridge MS, Tansey CM, Matté A, et al.; Canadian Critical Care Trials Group: Functional disability 5 years after acute respiratory distress syndrome. N Engl J Med 2011; 364:1293–1304
19. Needham DM, Dowdy DW, Mendez-Tellez PA, et al. Studying outcomes of intensive care unit survivors: Measuring exposures and outcomes. Intensive Care Med 2005; 31:1153–1160
20. Ruhl AP, Huang M, Colantuoni E, et al. Healthcare resource use and costs in long-term survivors of acute respiratory distress syndrome: A 5-year longitudinal cohort study. Crit Care Med 2017; 45:196–204
21. Ruhl AP, Lord RK, Panek JA, et al. Health care resource use and costs of two-year survivors of acute lung injury. An observational cohort study. Ann Am Thorac Soc 2015; 12:392–401
22. McPeake J, Devine H, MacTavish P, et al. Caregiver strain following critical care discharge: An exploratory evaluation. J Crit Care 2016; 35:180–184
23. Liu V, Lei X, Prescott HC, et al. Hospital readmission and healthcare utilization following sepsis in community settings. J Hosp Med 2014; 9:502–507
24. Prescott HC, Langa KM, Liu V, et al. Increased 1-year healthcare use in survivors of severe sepsis. Am J Respir Crit Care Med 2014; 190:62–69
25. Iwashyna TJ. Survivorship will be the defining challenge of critical care in the 21st century. Ann Intern Med 2010; 153:204–205
26. Iwashyna TJ. Trajectories of recovery and dysfunction after acute illness, with implications for clinical trial design. Am J Respir Crit Care Med 2012; 186:302–304
27. Garland A, Olafson K, Ramsey CD, et al. Distinct determinants of long-term and short-term survival in critical illness. Intensive Care Med 2014; 40:1097–1105
28. Szakmany T, Walters AM, Pugh R, et al. Risk factors for 1-year mortality and hospital utilization patterns in critical care survivors: A retrospective, observational, population-based data linkage study. Crit Care Med 2019; 47:15–22
29. Lone NI, Gillies MA, Haddow C, et al. Five-year mortality and hospital costs associated with surviving intensive care. Am J Respir Crit Care Med 2016; 194:198–208
30. Hua M, Gong MN, Brady J, et al. Early and late unplanned rehospitalizations for survivors of critical illness*. Crit Care Med 2015; 43:430–438
31. Angus DC, Linde-Zwirble WT, Lidicker J, et al. Epidemiology of severe sepsis in the United States: Analysis of incidence, outcome, and associated costs of care. Crit Care Med 2001; 29:1303–1310
32. Iwashyna TJ, Odden A, Rohde J, et al. Identifying patients with severe sepsis using administrative claims: Patient-level validation of the Angus implementation of the international consensus conference definition of severe sepsis. Medl Care2014; 52:e39–e43
34. Singh GK. Area deprivation and widening inequalities in US mortality, 1969–1998. Am J Public Health 2003; 93:1137–1143
35. Knighton AJ, Savitz L, Belnap T, et al. Introduction of an area deprivation index measuring patient socioeconomic status in an integrated health system: Implications for population health. EGEMS (Wash DC) 2016; 4:1238
36. Charlson ME, Pompei P, Ales KL, et al. A new method of classifying prognostic comorbidity in longitudinal studies: Development and validation. J Chronic Dis 1987; 40:373–383
37. Deyo RA, Cherkin DC, Ciol MA. Adapting a clinical comorbidity index for use with ICD-9-CM administrative databases. J Clin Epidemiol 1992; 45:613–619
38. Welch CA, Harrison DA, Hutchings A, et al. The association between deprivation and hospital mortality for admissions to critical care units in England. J Crit Care 2010; 25:382–390
39. Garland EL. Disrupting the downward spiral of chronic pain and opioid addiction with mindfulness-oriented recovery enhancement: A review of clinical outcomes and neurocognitive targets. J Pain Palliat Care Pharmacother 2014; 28:122–129
40. Kramer AA, Higgins TL, Zimmerman JE. Intensive care unit readmissions
in U.S. hospitals: Patient characteristics, risk factors, and outcomes. Crit Care Med 2012; 40:3–10
41. Hill AD, Fowler RA, Pinto R, et al. Long-term outcomes and healthcare utilization following critical illness–a population-based study. Crit Care 2016; 20:76
42. Czerwonka AI, Herridge MS, Chan L, et al. Changing support needs of survivors of complex critical illness and their family caregivers across the care continuum: A qualitative pilot study of towards RECOVER. J Crit Care 2015; 30:242–249
43. McPeake J, Shaw M, Iwashyna TJ, et al. Intensive care syndrome: Promoting Independence and Return to Employment (InS:PIRE). Early evaluation of a complex intervention. PLoS One 2017; 12:e0188028
44. Griffiths J, Fortune G, Barber V, et al. The prevalence of post traumatic stress disorder in survivors of ICU treatment: A systematic review. Intensive Care Med 2007; 33:1506–1518
45. Hennessy D, Juzwishin K, Yergens D, et al. Outcomes of elderly survivors of intensive care: A review of the literature. Chest 2005; 127:1764–1774
46. Sacanella E, Pérez-Castejón JM, Nicolás JM, et al. Functional status and quality of life 12 months after discharge from a medical ICU in healthy elderly patients: A prospective observational study. Crit Care 2011; 15:R105
47. Jackson JC, Hart RP, Gordon SM, et al. Post-traumatic stress disorder and post-traumatic stress symptoms following critical illness in medical intensive care unit patients: Assessing the magnitude of the problem. Crit Care 2007; 11:R27
48. Mehlhorn J, Freytag A, Schmidt K, et al. Rehabilitation interventions for postintensive care syndrome: A systematic review. Crit Care Med 2014; 42:1263–1271
49. Ball C, Kirkby M, Williams S. Effect of the critical care outreach team on patient survival to discharge from hospital and readmission to critical care: Non-randomised population based study. BMJ2003; 327:1014
50. Weinberger M, Smith DM, Katz BP, et al. The cost-effectiveness of intensive postdischarge care. A randomized trial. Med Care 1988; 26:1092–1102
51. Harrison MB, Browne GB, Roberts J, et al. Quality of life of individuals with heart failure: A randomized trial of the effectiveness of two models of hospital-to-home transition. Med Care 2002; 40:271–282
52. Foster EM. Does the continuum of care improve the timing of follow-up services? J Am Acad Child Adolesc Psychiatry 1998; 37:805–814
53. Daly BJ, Douglas SL, Kelley CG, et al. Trial of a disease management program to reduce hospital readmissions
of the chronically critically ill. Chest 2005; 128:507–517