First 24-hour diuresis as a prognostic marker in cardiogenic shock

Background/Introduction

Cardiogenic shock (CS) is associated with high 30d mortality. After the first 24 hours, clinicians may benefit from routinely available bedside variables to inform ongoing clinical decision making and for supporting patient and family counselling.

Purpose

To assess whether 24-hour urinary output is associated with 30-day mortality in cardiogenic shock patients who survive the first 24 hours, and to determine whether a simple clinical model incorporating diuresis, lactate, and age improves 30-day risk discrimination compared with SCAI stage assessed at 24 hours.

Methods

The Multimodal Phenotyping in Patients Referred with Acute Cardiac Failure (MIRACLE) study is an ongoing prospective multicenter cohort of patients with CS, complemented by an accompanying retrospective cohort. For the present analysis, patients with completed in hospital follow up were screened (n=696). Cases with leading triggers of hypoxia, peri interventional complications, unknown cause, infection or sepsis, or ventricular obstruction were excluded (n=26). We then restricted the cohort to patients who survived more than 24 hours and were not discharged from the ICU within 24 hours (n=557).

Diuresis was dichotomised at 1 L/ 24 h. Kaplan Meier analyses and Cox regression were performed overall and in predefined subgroups. Adjustment was done for age, lactate at 24h, and SCAI stage at 24h. Discrimination for 30-day mortality was assessed using ROC curves for a model including age, diuresis, and lactate at 24 hours, and compared with SCAI stage at 24 hours using DeLong testing.

Results

Among 557 day one survivors (median age 69 years, 72% male, 50% AMI CS), median 24-hour diuresis was 1.7 L. Diuresis at least 1 L per 24 hours was associated with lower 30-day mortality (adjusted HR 0.66, 95% CI 0.49 to 0.89). The association was directionally consistent in several subgroups, including male patients (adjusted HR 0.54, 95% CI 0.38 to 0.77), AMI CS (adjusted HR 0.53, 95% CI 0.34 to 0.80), and age 75 years or younger (adjusted HR 0.64, 95% CI 0.42 to 0.97), but was not statistically significant in females (adjusted HR 1.11, 95% CI 0.61 to 2.04) or non-AMI CS (adjusted HR 0.77, 95% CI 0.49 to 1.21). A model including age, 24 hour diuresis, and lactate at 24 hours showed better discrimination than SCAI at 24 hours alone (AUC 0.78, 95% CI 0.74 to 0.82 vs 0.69, 95% CI 0.64 to 0.73; p < 0.001).

Conclusion

In day one survivors of CS, higher 24-hour diuresis was associated with lower 30 day mortality. Subgroup analyses suggested that this relationship may not be uniform across clinical strata, with weaker or non significant associations in female patients and in non AMI-CS. These subgroup differences should be examined in more detail to determine whether they represent clinically relevant implications between patient groups. External validation is warranted.