Dataset Information

Sample size implications of mortality definitions in sepsis: a retrospective cohort study.

ABSTRACT:

Background

Many randomized controlled trials (RCTs) employ mortality at a given time as a primary outcome. There are at least three common ways to measure 90-day mortality: first, all-location mortality, that is, all-cause mortality within 90 days of randomization at any location. Second, ARDSnet mortality is death in a healthcare facility of greater intensity than the patient was in prior to the hospitalization during which they were randomized. Finally, in-hospital mortality is death prior to discharge from the primary hospitalization of randomization. Data comparing the impact of these different measurements on sample size are lacking. We evaluated the extent to which event rates vary by mortality definition.

Methods

This was a retrospective cohort study of 30,691 patients hospitalized at Veterans Affairs (VA) hospitals for sepsis during 2009. 12,727 (41.5%) received care in an ICU setting. For each patient, we measured event rates for three different 90-day mortality outcomes: all-location mortality, ARDSnet mortality, and in-hospital mortality. We also calculated sample sizes necessary to power an example RCT given those event rates.

Results

At 90 days, all-location mortality was 26.4% (95% CI 25.9-26.9%), ARDSnet mortality was 19.2% (95% CI 18.8-19.7%), and in-hospital mortality was 13.4% (95% CI 13.0-13.8%) (p < 0.01 all comparisons). These respective event rates result in different required sample sizes to achieve a 20% relative reduction in mortality with 80% power and a 5% false positive rate. Such a trial of VA sepsis patients would require 2080 patients for all-location mortality, 3080 for ARDSnet mortality, and 4796 for in-hospital mortality. Among sepsis patients mechanically ventilated in an ICU, 2438 experienced all-location mortality (46.2% [95% CI 44.8-47.5%]), 2181 experienced ARDSnet mortality (41.3% [95% CI 40.0-42.6%]), and 1894 experienced in-hospital mortality (36.0% [95% CI 34.7-37.3%]).

Conclusions

Event rates vary substantially in sepsis patients based on the chosen 90-day mortality definition. This could have important implications for RCT design trade-offs.

SUBMITTER: Govindan S

PROVIDER: S-EPMC5870299 | biostudies-literature | 2018 Mar

REPOSITORIES: biostudies-literature

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Sample size implications of mortality definitions in sepsis: a retrospective cohort study.

Govindan Sushant S Prescott Hallie C HC Chopra Vineet V Iwashyna Theodore J TJ

Trials 20180327 1

<h4>Background</h4>Many randomized controlled trials (RCTs) employ mortality at a given time as a primary outcome. There are at least three common ways to measure 90-day mortality: first, all-location mortality, that is, all-cause mortality within 90 days of randomization at any location. Second, ARDSnet mortality is death in a healthcare facility of greater intensity than the patient was in prior to the hospitalization during which they were randomized. Finally, in-hospital mortality is death p ...[more]

PMID: 29587803

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Project description:The Third International Consensus Definitions for Sepsis and Septic Shock (Sepsis-3) present clinical criteria for the classification of patients with sepsis. We investigated incidence and long-term outcomes of patients diagnosed with these classifications, which are currently unknown.We did a retrospective analysis using data from 30?239 participants from the USA who were aged at least 45 years and enrolled in the Reasons for Geographic and Racial Differences in Stroke (REGARDS) cohort. Patients were enrolled between Jan 25, 2003, and Oct 30, 2007, and we identified hospital admissions from Feb 5, 2003, to Dec 31, 2012, and applied three classifications: infection and systemic inflammatory response syndrome (SIRS) criteria, elevated sepsis-related organ failure assessment (SOFA) score from Sepsis-3, and elevated quick SOFA (qSOFA) score from Sepsis-3. We estimated incidence during the study period, in-hospital mortality, and 1-year mortality.Of 2593 first infection events, 1526 met SIRS criteria, 1080 met SOFA criteria, and 378 met qSOFA criteria. Incidence was 8·2 events (95% CI 7·8-8·7) per 1000 person-years for SIRS, 5·8 events (5·4-6·1) per 1000 person-years for SOFA, and 2·0 events (1·8-2·2) per 1000 person-years for qSOFA. In-hospital mortality was higher for patients with an elevated qSOFA score (67 [23%] of 295 patients died) than for those with an elevated SOFA score (125 [13%] of 960 patients died) or who met SIRS criteria (128 [9%] of 1392 patients died). Mortality at 1 year after discharge was also highest for patients with an elevated qSOFA score (29·4 deaths [95% CI 22·3-38·7] per 100 person-years) compared with those with an elevated SOFA score (22·6 deaths [19·2-26·6] per 100 person-years) or those who met SIRS criteria (14·7 deaths [12·5-17·2] per 100 person-years).SIRS, SOFA, and qSOFA classifications identified different incidences and mortality. Our findings support the use of the SOFA and qSOFA classifications to identify patients with infection who are at elevated risk of poor outcomes. These classifications could be used in future epidemiological assessments and studies of patients with infection.National Institute for Nursing Research, National Center for Research Resources, and National Institute of Neurological Disorders and Stroke.

Project description:BackgroundSepsis and acute kidney injury (AKI) are common severe diseases in the intensive care unit (ICU). This study aimed to estimate the attributable mortality of AKI among critically ill patients with sepsis and to assess whether AKI was an independent risk factor for 30-day mortality.MethodsThe information we used was derived from a multicenter prospective cohort study conducted in 18 Chinese ICUs, focusing on septic patients post ICU admission. The patients were categorized into two groups: those who developed AKI (AKI group) within seven days following a sepsis diagnosis and those who did not develop AKI (non-AKI group). Using propensity score matching (PSM), patients were matched 1:1 as AKI and non-AKI groups. We then calculated the mortality rate attributable to AKI in septic patients. Furthermore, a survival analysis was conducted comparing the matched AKI and non-AKI septic patients. The primary outcome of interest was the 30-day mortality rate following the diagnosis of sepsis.ResultsOut of the 2175 eligible septic patients, 61.7% developed AKI. After the application of PSM, a total of 784 septic patients who developed AKI were matched in a 1:1 ratio with 784 septic patients who did not develop AKI. The overall 30-day attributable mortality of AKI was 6.6% (95% CI 2.3 ∼ 10.9%, p = 0.002). A subgroup analysis revealed that the 30-day attributable mortality rates for stage 1, stage 2, and stage 3 AKI were 0.6% (95% CI -5.9 ∼ 7.2%, p = 0.846), 4.7% (95% CI -3.1 ∼ 12.4%, p = 0.221) and 16.8% (95% CI 8.1 ∼ 25.2%, p < 0.001), respectively. Particularly noteworthy was that stage 3 AKI emerged as an independent risk factor for 30-day mortality, possessing an adjusted hazard ratio of 1.80 (95% CI 1.31 ∼ 2.47, p < 0.001).ConclusionsThe overall 30-day attributable mortality of AKI among critically ill patients with sepsis was 6.6%. Stage 3 AKI had the most significant contribution to 30-day mortality, while stage 1 and stage 2 AKI did not increase excess mortality.

Dataset Information

Sample size implications of mortality definitions in sepsis: a retrospective cohort study.

Background

Methods

Results

Conclusions

Publications

Sample size implications of mortality definitions in sepsis: a retrospective cohort study.

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