Administrative
data typically
result in a lower
mortality rate,
because patients
are included,
who did not die
‘of’ sepsis, but
‘with’ sepsis
hospital DRG (diagnosis-related groups) statistics
for the years 2007–2013 were used. 12 Twenty-
seven clinical and pathogen-based ICD-10
(International classification of diseases) codes
for sepsis were used to identify the cases.
The number of patients with sepsis rose
approximately 5.7% per year, corresponding to
an increasing incidence from 256 to 335 cases
per 100,000 persons per year. Sepsis mortality
decreased by 2.7% per year, to 24.3% in 2013.
In total, nearly 68,000 people died of sepsis in
German hospitals (or died of another disease,
but also had sepsis). 12
These two examples nicely demonstrate
the aforementioned dilemma: whereas in the
prospective research project, the selection
criterion was the clinical diagnosis of sepsis
or septic shock for individual patients, which
provides a higher ‘attributed mortality rate’
(40.4%), administrative data typically result in
a lower mortality rate (24.3%) with the problem
that this rate is not clearly ‘attributed’, because
many patients are included, who did not die ‘of’
sepsis, but ‘with’ sepsis (the investigators used 27
different ICD-10 codes to create a large ‘group’ of
sepsis patients). Summarised statistics of hospital
data make it impossible to discriminate between
different clinical courses because it is not allowed
to break to results down to an individual patient’s
level. By contrast, prospective research projects
with voluntary participation (in the first example,
approximately 5% of German hospitals) suffer
from limited validity of data.
Different countries, different epidemiology?
The same investigator group that performed the
German study based on administrative data
(example 2) tried to apply this approach in several
countries with a group of international
investigators. 13 They systematically searched
15 international citation databases for sepsis
incidence and mortality on a population-level in
9
HHE 2018 | hospitalhealthcare.com
adult populations over 36 years using consensus
criteria. A total of 27 studies mainly from
high-income countries were selected for the
analysis. The incidence rate was 288 for all sepsis
cases and 148 for severe sepsis cases per 100,000
inhabitants and year. From lower-income
countries, no sepsis incidence estimates could
be performed, thus limiting the prediction of
incidence and fatality. This paper underlines
the urgent need to implement global strategies
to measure sepsis morbidity and mortality,
particularly in low- and middle-income
countries. 13
Recently, a Spanish group provided
a comprehensive overview for the general trends
in sepsis epidemiology in western countries. 14 The
investigators confirmed that there are differences
in epidemiologic trends in sepsis between
western countries and low-income and middle-
income countries. In US, most of epidemiologic
studies have been based on large, administrative
databases, reporting an increase in the incidence
of severe sepsis over years (as shown in example
2). In general, studies describing epidemiology
of sepsis outside the US use primarily clinical
definitions and ICU observational cohort designs
instead of administrative databases (see example
1). Incidence of sepsis has increased over years,
probably due to older patients, increasing number
of comorbidities, and maybe a more liberal use
of sepsis codification, which leads to the inclusion
of patients with less severity, that is, lower
mortality. Risk factors for sepsis are the young
and old age, male gender, black race, presence
of comorbidities and certain genetic variants. In
most prospective studies, Gram-positive infections
are meanwhile more frequent that Gram-negative
sepsis, and the most common source of sepsis are
respiratory tract infections. 14
Clinical and economic impact of sepsis
For many years, the clinical sequelae of sepsis