Background: Acute kidney injury (AKI) is a common complication of renal cell carcinoma or its treatment. It is unclear whether AKI, compared to inpatients with similar clinical and hospital-level characteristics without AKI, is associated with worse clinical outcomes and higher costs. To address this void, our study aimed to evaluate how an AKI diagnosis affects the length of stay (LOS), costs, and in-hospital mortality among adult U.S. inpatients.
Methods: We analyzed the AHRQ Healthcare Cost and Utilization Project (HCUP) Nationwide Inpatient Sample (2014), a dataset encompassing 20% of all United States inpatient hospitalizations. Patients aged 18 years or older with renal cell carcinoma with and without AKI were included. Descriptive analyses were performed with a focus on patient characteristics and comorbidities. Multivariable survey regression methods were used to assess associations between AKI and different outcomes.
Results: There was an estimation of 16315 (19.8%) adult inpatients 18 years of age or older with renal cell carcinoma had an AKI diagnosis (70.4% male, 73.8% white, 13.4% black). Patients with a diagnosis of AKI were older (mean age 68.5 vs. 63.7), more likely to have Medicare insurance (65.5% vs. 51.8%), and higher prevalence of hypertension (74.4% vs. 64.4%), coronary artery disease (26.2% vs. 17.2%), congestive heart failure (23.2% vs. 10.2%), chronic obstructive pulmonary disease (14.9% vs. 11.2%), diabetes mellitus (36.3% vs. 26.9%), hyperlipidemia (41.1% vs. 34.9%). Among all hospitalizations with renal cell carcinoma developed AKI, the inpatient mortality rate was 8.9% (1450). After adjustment, patients with AKI were associated with higher odds of mortality (adjusted odds ratio [aOR] 4.14, 95% confidence interval [CI] 3.44- 4.99, p<0.001). Patients with a diagnosis of AKI were hospitalized a mean 7.7 days (95% CI 7.39- 7.99), compared with 4.5 days (95% CI 4.44- 4.64) among patients without a diagnosis of AKI. Overall mean inpatient care costs were $20,995 (95% CI 19,939–22,050) and $14,597 (95% CI 14,105–15,088) in patients with AKI and without AKI (p < 0.001).
Conclusions: The demographic characteristics, including age, comorbidity, sex, race, payer status were significantly different between two groups of renal cell carcinoma patients with or without a diagnosis of AKI (P < 0.001). Patients with AKI were more likely to die in the hospital, had longer LOS, higher inpatient care costs. Thus, a diagnosis of AKI appears to be an indicator of worse outcomes and higher costs. Clinicians and hospitals should recognize and treat AKI early to reduce the risk of in-hospital mortality.