Incidence of sepsis and associated mortality within the first year after cancer diagnosis in middle aged adults: A US population based study

Abstract

Background: The incidence of sepsis has been rising overall but updated data in cancer patients are lacking. After a cancer diagnosis, incidence of sepsis and overall mortality peak within the first year. However, how much sepsis contributes to mortality remains unclear. We used a multistate model approach to analyze the incidence, risk factors and associated mortality of sepsis within 1 year of cancer diagnosis in middle aged adults.

Methods: Analysis of a large US health insurance claims database (Marketscan) between 2005 and 2014. Patients with a new diagnosis of cancer who received chemotherapy were included. Within a year of diagnosis, we assessed inpatient admissions for sepsis based on ICD-9 codes and survival using hospitalizations, outpatient visits and prescriptions filled. Competing risk and multistate models were used to assess the incidence of sepsis and transition probabilities between cancer, sepsis and death.

Results: 119,379 patients (38.9% males), aged 55 (50-60) years, were included; 2,560 developed isolated sepsis, 477 severe sepsis and 1331 septic shock within 1 year, with associated hospital mortality of 14.8%, 30% and 46% respectively. The probability of sepsis increased between 2005 and 2014; at 1 year, its cumulative incidence was 3.7% with a probability of mortality after sepsis of 35.5% (95% CI 21.6%-50.9%). Age, male gender, Charlson comorbidity index, hematological malignancies and metastases at diagnosis were associated with sepsis and mortality.

Conclusions: Incidence and mortality of sepsis were 3.7% and 35.5% at 1 year after cancer diagnosis and were both associated with baseline patient and cancer characteristics.

Fig 1

Time course over the study period (2006–2014) of unadjusted probability of sepsis within 1 year for patients with a new cancer diagnosis (Fig 1(A)) and unadjusted hospital mortality for the subset of patients admitted with sepsis (Fig 1(B)). Black lines represent the unadjusted probabilities and grey areas represent the 95% confidence intervals.

Fig 2. Cumulative incidence of sepsis within the first year after cancer diagnosis in a cohort of 119,379 patients, with death without sepsis treated as a competing event.

Fig 3. Transition probabilities within the first year after cancer diagnosis between the states « cancer », « sepsis » and « death » based on the multistate model.

Dark lines represent for a patient diagnosed with cancer at day 0 the probability of transitioning from one state to another over time; grey dotted lines represent the 95% confidence intervals. Cancer->death represents the transition from cancer to death without sepsis.