With reference to intensive care outcomes, discuss the advantages and limitations of each of the following endpoints as a measure of quality of care:
- ICU mortality
- Hospital mortality
- 90 day mortality
- 1 year functional outcome
- simple, single metric
- concrete endpoint which is already available in hospital databases
- death is an important endpoint
- aggregation of a large number of diagnoses with a small number in each increases power to detect variation
- variation over time may reflect institutional and organisational events or characteristics- budget cuts, bed pressure etc. and be able to detect true quality deficiencies
· May be useful when combined as part of an overall quality program
- Definition of ICU is very hospital specific which can influence mortality (e.g. non-ICU stepdown areas in some hospitals)
- As a consequence can be ‘gamed’ e.g. transfers out to die in the ward or other units
- Poor correlation between mortality and quality of care in some diagnoses - alternatives available e.g. diagnosis specific risk models e.g. EuroSCORE for CABG, APACHE SMR, trauma scores. Can mask problems in low volume diagnostic groups
- Difficult to draw hospital comparisons and or allow league table construction
- False conclusions can be drawn unless robust statistical methods used
Compared to ICU mortality, avoids many problems of censoring at ICU discharge. Hospital mortality can often be 50% higher than ICU mortality, and is a reasonable surrogate (90%) for 90 days mortality.
Advantages – gets over differences in definition of ICU and ICU discharge thresholds. Still a simple and robust endpoint which is easy to obtain from exisiting hospital databases.
Disadvantages – can confound intensive care outcomes with deficiencies in ward or other post ICU care. Does not address in any way functional outcomes [so discharge from hospital to a nursing home in a vegetative state is counted as a positive outcome]
90 day mortality
Simple robust endpoint which addresses the issue of ongoing mortality after hospital discharge (though this difference is about 10% relative in recent large trials).
Advantages – simple robust endpoint; data may be available by linkage with external registries (e.g. Births, Deaths and Marriages)
Disadvantages – still an arbitrary time point [while 28 days is clearly inadequate, 90 days may still be insufficient to accurately measure the attributable mortality from an episode of critical illness]. Problems with loss to follow up after ICU discharge. Ethical implications of contacting patients after discharge (especially for research studies).
1 year functional outcome
Advantages – a ‘POEM’ – (patient oriented endpoint that matters). Takes into account disability and true long-term consequences of critical illness.
Disadvantages – no ideal soring tool available – existing tools all have problems; some measure particular functional domains well; problems with face validity. All functional outcome measures are time consuming to apply. Problems with loss to follow up. Time consuming, labour intensive, costly face to face vs. phone vs. mail follow up. Depending on disease may reflect more the natural history of the disease rather than the ICU care per se.
The above answer is used as a backbone of the LITFL article on this topic. A good discussion of "at what point do we measure mortality" can be found at the AIHW statement on Measuring and reporting mortality in hospital patients (page 6, ch. 2.4.2).
As a good guideline for other ICU outcome measures which should be used to assess the outcomes of Phase II trials, ANZICS has published this statement in 2012 (the 2013 update is for some reason not available for free).
A question like this probably lends itself better to a tabulated answer.
|1-year functional outcome||
Caron, Guy, et al. "Submental endotracheal intubation: an alternative to tracheotomy in patients with midfacial and panfacial fractures." Journal of Trauma and Acute Care Surgery 48.2 (2000): 235-240.
Young, Paul, et al. "End points for phase II trials in intensive care: Recommendations from the Australian and New Zealand clinical trials group consensus panel meeting." Critical Care and Resuscitation 15.3 (2013): 211. - this one is not available for free, but the 2012 version still is:
Young, Paul, et al. "End points for phase II trials in intensive care: recommendations from the Australian and New Zealand Clinical Trials Group consensus panel meeting." Critical Care and Resuscitation 14.3 (2012): 211.
Suter, P., et al. "Predicting outcome in ICU patients." Intensive Care Medicine20.5 (1994): 390-397.
Martinez, Elizabeth A., et al. "Identifying Meaningful Outcome Measures for the Intensive Care Unit." American Journal of Medical Quality (2013): 1062860613491823.
Tipping, Claire J., et al. "A systematic review of measurements of physical function in critically ill adults." Critical Care and Resuscitation 14.4 (2012): 302.
Gunning, Kevin, and Kathy Rowan. "Outcome data and scoring systems." Bmj319.7204 (1999): 241-244.
Woodman, Richard, et al. Measuring and reporting mortality in hospital patients. Australian Institute of Health and Welfare, 2009.
Vincent, J-L. "Is Mortality the Only Outcome Measure in ICU Patients?."Anaesthesia, Pain, Intensive Care and Emergency Medicine—APICE. Springer Milan, 1999. 113-117.
Rosenberg, Andrew L., et al. "Accepting critically ill transfer patients: adverse effect on a referral center's outcome and benchmark measures." Annals of internal medicine 138.11 (2003): 882-890.
Burack, Joshua H., et al. "Public reporting of surgical mortality: a survey of New York State cardiothoracic surgeons." The Annals of thoracic surgery 68.4 (1999): 1195-1200.
Hayes, J. A., et al. "Outcome measures for adult critical care: a systematic review." Health technology assessment (Winchester, England) 4.24 (1999): 1-111.
RUBENFELD, GORDON D., et al. "Outcomes research in critical care: results of the American Thoracic Society critical care assembly workshop on outcomes research." American journal of respiratory and critical care medicine 160.1 (1999): 358-367.