Incidence and Trends of Sepsis in US Hospitals Using Clinical vs Claims Data, 2009-2014

Abstract

Importance: Estimates from claims-based analyses suggest that the incidence of sepsis is increasing and mortality rates from sepsis are decreasing. However, estimates from claims data may lack clinical fidelity and can be affected by changing diagnosis and coding practices over time.

Objective: To estimate the US national incidence of sepsis and trends using detailed clinical data from the electronic health record (EHR) systems of diverse hospitals.

Design, setting, and population: Retrospective cohort study of adult patients admitted to 409 academic, community, and federal hospitals from 2009-2014.

Exposures: Sepsis was identified using clinical indicators of presumed infection and concurrent acute organ dysfunction, adapting Third International Consensus Definitions for Sepsis and Septic Shock (Sepsis-3) criteria for objective and consistent EHR-based surveillance.

Main outcomes and measures: Sepsis incidence, outcomes, and trends from 2009-2014 were calculated using regression models and compared with claims-based estimates using International Classification of Diseases, Ninth Revision, Clinical Modification codes for severe sepsis or septic shock. Case-finding criteria were validated against Sepsis-3 criteria using medical record reviews.

Results: A total of 173 690 sepsis cases (mean age, 66.5 [SD, 15.5] y; 77 660 [42.4%] women) were identified using clinical criteria among 2 901 019 adults admitted to study hospitals in 2014 (6.0% incidence). Of these, 26 061 (15.0%) died in the hospital and 10 731 (6.2%) were discharged to hospice. From 2009-2014, sepsis incidence using clinical criteria was stable (+0.6% relative change/y [95% CI, -2.3% to 3.5%], P = .67) whereas incidence per claims increased (+10.3%/y [95% CI, 7.2% to 13.3%], P < .001). In-hospital mortality using clinical criteria declined (-3.3%/y [95% CI, -5.6% to -1.0%], P = .004), but there was no significant change in the combined outcome of death or discharge to hospice (-1.3%/y [95% CI, -3.2% to 0.6%], P = .19). In contrast, mortality using claims declined significantly (-7.0%/y [95% CI, -8.8% to -5.2%], P < .001), as did death or discharge to hospice (-4.5%/y [95% CI, -6.1% to -2.8%], P < .001). Clinical criteria were more sensitive in identifying sepsis than claims (69.7% [95% CI, 52.9% to 92.0%] vs 32.3% [95% CI, 24.4% to 43.0%], P < .001), with comparable positive predictive value (70.4% [95% CI, 64.0% to 76.8%] vs 75.2% [95% CI, 69.8% to 80.6%], P = .23).

Conclusions and relevance: In clinical data from 409 hospitals, sepsis was present in 6% of adult hospitalizations, and in contrast to claims-based analyses, neither the incidence of sepsis nor the combined outcome of death or discharge to hospice changed significantly between 2009-2014. The findings also suggest that EHR-based clinical data provide more objective estimates than claims-based data for sepsis surveillance.

Figure 1.. Organ Dysfunction Distribution and Associated Mortality in Patients With Sepsis in 2014 and Associated Mortality by Number of Organ Dysfunction Criteria Met

A, Number of sepsis cases with each organ dysfunction and associated in-hospital deaths were n = 49 400 (16 715 deaths) for vasopressor initiation; n = 45 088 (14 290 deaths) for initiation of mechanical ventilation; n = 92 779 (18 345 deaths) for hyperlactatemia (serum lactate level ≥2.0 mmol/L); n = 75 553 (9664 deaths) for acute kidney injury (doubling in baseline creatinine level or decrease in estimated glomerular filtration rate by ≥50%); n = 26 083 (3717 deaths) for hepatic injury (doubling in baseline total bilirubin level to ≥2.0 mg/dL); n = 21 830 (4869 deaths) for thrombocytopenia (decrease in baseline platelet count by ≥50%, with baseline platelets >100 cells/µL). Further details on organ dysfunction criteria are described in the Box. Total number of sepsis encounters, 173 690. B, Number of sepsis cases meeting the specified number of organ dysfunction criteria and associated in-hospital deaths were n = 173 690 (26 061 deaths) for 1 or more organ dysfunction criteria; n = 88 248 (20 687 deaths) for 2 or more organ dysfunction criteria; n = 50 466 (16 506 deaths) for 3 or more organ dysfunction criteria; and n = 29 161 (11 725 deaths) for 4 or more organ dysfunction criteria. Number of organ dysfunction criteria includes different organ dysfunctions that may have occurred at separate times during hospitalization if surveillance criteria were met more than once.

Figure 2.. Sepsis Trends From 2009-2014: Incidence, In-hospital Sepsis Mortality, and In-hospital Mortality or Discharge to Hospice.

Adjusted rates from 2009-2013 calculated relative to observed 2014 rates. Error bars indicate 95% CIs. “Clinical criteria” indicates blood cultures + antibiotics + concurrent organ dysfunction (Box). “Clinical criteria without lactate” excludes the criterion for lactate level of 2.0 mmol/L or greater. Primary trends assessment was conducted using clinical criteria without lactate levels. “Explicit sepsis codes”: discharge diagnoses of severe sepsis (995.92) or septic shock (785.52). “Implicit sepsis codes”: at least 1 infection diagnosis and 1 organ dysfunction diagnosis. All trends adjusted for hospital characteristics (institution, region, teaching status, bed count, annual admissions) and case mix (median age of hospitalized patients, sex and race/ethnicity distributions, proportion of intensive care unit vs total admissions). Veterans Affairs hospitals not included in the trends analysis. Total number of sepsis cases per year was 30 744 (2009), 35 596 (2010), 34 445 (2011), 36 524 (2012), 144 322 (2013), and 145 236 (2014) for clinical criteria; 28 723 (2009), 32 175 (2010), 30 348 (2011), 32 019 (2012), 120 402 (2013), and 112 355 (2014) for clinical criteria without lactate levels; 50 223 (2009), 61 483 (2010), 65 193 (2011), 76 208 (2012), 275 480 (2013), and 272 679 (2014) for implicit or explicit codes; and 9062 (2009), 12 688 (2010), 12 571 (2011), 15 309 (2012), 61 285 (2013), and 65 176 (2014) for explicit codes.