Respiratory organ dysfunction: a leading risk factor for hospital mortality in patients with severe sepsis or septic shock

Introduction

In spite of decreasing case fatality attributable to improved clinical management, patients with severe sepsis or septic shock still have a high mortality rate. This study aimed to describe the impact of respiratory and cardiovascular organ dysfunction (OD) on the outcome of patients with severe sepsis or septic shock (SS).

Methods

We conducted a retrospective study based on hospital discharge and charge master information of ~5 million discharges from ~500 hospitals in the USA during 2006 (Premier Perspective™ Database). SS was defined via ICD-9 coding and required infection and organ dysfunction (six systems as defined in [1]). We created four mutually exclusive OD groups by focusing on respiratory (Resp) and cardiovascular (CV) organ dysfunction because of their relative greater reliability in database analysis: (1) both Resp and CV OD (Resp & CV OD); (2) respiratory OD without cardiovascular OD (Resp/noCV), (3) cardiovascular OD without respiratory OD (CV/noResp), and (4) neither OD. Outcome measures include inhospital mortality, use of the ICU, length of hospital stay (LOS), and total costs during hospitalization.

Results

A total of 89,033 cases were identified as severe sepsis or septic shock, resulting in a SS rate of 1.7% discharges. Among all SS cases, hospital mortality was 31.1%, 68.4% were admitted to the ICU, the mean LOS was 14.9 days, and mean costs of hospitalization were $33,000. Each of the four OD groups consisted of 20.4–29.2% SS patients. Among the four OD groups, the hospital mortality and ICU use were greatest in the Resp & CV OD group and least in the neither OD group with the following trend: both Resp & CV OD > Resp/noCV > CV/noResp > neither OD (mortality: 52% > 34% > 26% > 15%; ICU use: 92% > 79% > 68% > 39%) (P < 10^-7 for all pairwise comparisons). The two groups with respiratory OD (that is, both the Resp & CV OD group and the Resp/noCV group) had a similar LOS (mean: 16.7 days and 18.7 days, respectively) and similar costs (mean: $44,000 and $43,000), which were greater than the CV/noResp OD group (LOS: 12.2 days; costs: $26,000) and the neither OD group (LOS: 13.2 days; costs: $25,000).

Conclusion

Respiratory organ dysfunction increases the risk of death and consumption of healthcare resource in patients with severe sepsis or septic shock.