Health Care Costs Associated with AKI

Abstract

Background and objectives: An understanding of the health care resource use associated with AKI is needed to frame the investment and cost-effectiveness of strategies to prevent AKI and promote kidney recovery.

Design, setting, participants, & measurements: We assembled population-based cohort of adults hospitalized in Alberta between November of 2002 and March of 2009 without ESRD or an eGFR<15 ml/min per 1.73 m². Outpatient serum creatinine measurements 6 months preceding admission defined baseline kidney function, and serum creatinine during the first 14 days of hospitalization defined Acute Kidney Injury Network stage; kidney recovery defined as serum creatinine within 25% of baseline and independence from dialysis was assessed at 90 days after AKI. Health care utilization and costs (in 2015 Canadian dollars) were determined from inpatient, outpatient, and physician claims datasets during the index hospitalization, recovery period (90 days post-AKI assessment), and 3-12 months post-AKI. A fully adjusted generalized linear model regression analysis was used to estimate costs associated with AKI.

Results: Of 239,906 hospitalized subjects, 25,495 (10.6%), 4598 (1.9%), 2493 (1.0%), and 670 (0.3%) had Acute Kidney Injury Network stages 1, 2, 3 without dialysis, and 3 with dialysis, respectively. Greater severity of AKI was associated with incremental increases in length of stay (+2.8; 95% confidence interval, 1.4 to 4.3 to +7.4; 95% confidence interval, 7.2 to 7.5 days) and costs (+$3779; 95% confidence interval, $3555 to $4004 to +$18,291; 95% confidence interval, $15,573 to $21,009 Canadian dollars) from admission to recovery assessment (3 months). At months 3-12 postadmission, compared with subjects without AKI, AKI with kidney recovery and AKI without kidney recovery were associated with incremental costs of +$2912-$3231 and +$6035-$8563 Canadian dollars, respectively. The estimated incremental cost of AKI in Canada is estimated to be over $200 million Canadian dollars per year.

Conclusions: Severity of AKI, need for dialysis, and lack of kidney recovery are associated with significant health care costs in hospitalized patients and persist a year after admission. Strategies to identify, prevent, and facilitate kidney recovery are needed.

Keywords: Acute Kidney Injury; Alberta; Canada; Cost-Benefit Analysis; Health Care Costs; Inpatients; Investments; Kidney Failure, Chronic; Kidney Function Tests; Length of Stay; Linear Models; Outpatients; Renal Insufficiency, Chronic; acute renal failure; chronic kidney disease; costs; creatinine; dialysis; hospitalization; resource utilization.

Graphical abstract

Figure 1.

Study cohort. Study cohort size per time period as follows: N=239,906 for index hospitalization; N=239,739 for admission to assessment of kidney recovery or 90-day time period (239,906−167) exclusion of migration only; N=238,500 for admission to 1-year time period [239,906−(167+1239)] exclusion of migration only; and N=217,543 for assessment of kidney recovery or 90-day to 1-year time period [239,906−(167+1239)−(11,554+9403)] exclusion of migrations and deaths. AKIN, Acute Kidney Injury Network; SCr, serum creatinine.

Figure 2.

Timeline.

Figure 3.

Costs categories by AKI severity and kidney recovery for all time periods except index hospitalization. (A) Admission to assessment of kidney recovery or 90 days. (B) Admission to 1 year. (C) Assessment of kidney recovery or 90 days to 1 year. AKIN, Acute Kidney Injury Network.