Frequency and progression of azotemia during acute and chronic treatment of congestive heart failure in cats

Abstract

Background: Azotemia is common in cats with congestive heart failure (CHF) and might be exacerbated by diuretic therapy.

Hypothesis/objectives: Determine frequency, risk factors, and survival impact of progressive azotemia in cats treated for CHF.

Animals: One hundred and sixteen client-owned cats with kidney function testing performed at least twice during acute or chronic CHF treatment.

Methods: Serum creatinine (sCr) and electrolyte concentrations were determined at multiple clinical timepoints to detect azotemia and kidney injury (KI; sCr increase ≥0.3 mg/dL). Furosemide dosage between timepoints was calculated. Multivariable modeling was performed to identify predictors of KI, change in serum biochemistry results, and survival.

Results: Azotemia was common at all timepoints, including initial CHF diagnosis (44%). Kidney injury was documented in 66% of cats. Use of a furosemide continuous rate infusion was associated with increased risk of KI during hospitalization (odds ratio, 141.6; 95% confidence interval [CI], 12.1-6233; P = .01). Higher furosemide dosage was associated with increase in sCr during hospitalization (P = .03) and at first reevaluation (P = .01). Treatment with an angiotensin converting enzyme inhibitor was associated with fewer lifetime KI events (P = .02). Age in years was the only variable associated with shorter survival (hazard ratio, 1.1; 95% CI, 1.0-1.1; P = .03). Neither sCr nor KI were associated with long-term outcome.

Conclusions and clinical importance: Azotemia and KI were common in cats during CHF treatment but did not impact survival.

Keywords: acute renal failure; cardiorenal syndrome; cardiovascular; loop diuretics; renal function.

FIGURE 1

Violin plots showing serum concentrations of blood urea nitrogen and creatinine at various clinical timepoints (CTPs) in 116 cats with congestive heart failure. See Table 1 for definitions of each CTP and Table 4 for number of cats with data available at each CTP. Solid circles indicate median, vertical lines indicate interquartile range, height of the violins indicate range, width of the violins indicates density of the distribution, and individual data points are also plotted. Results of pairwise comparisons between CTPs for each analyte are shown in Table S1.

FIGURE 2

Frequency and grade of azotemia at various clinical timepoints (CTPs) in 116 cats with congestive heart failure. Percentage of cats with each grade of azotemia is shown in the bar graph, whereas absolute number of cats is shown in the table. See Table 1 for definitions of each CTP.

FIGURE 3

Frequency and grade of kidney injury at various clinical timepoint (CTP) intervals in 116 cats with congestive heart failure. Percentage of cats with each grade of kidney injury is shown in the bar graph, whereas absolute number of cats is shown in the table. See Table 1 for definitions of each CTP interval.

FIGURE 4

Violin plots showing serum concentrations of electrolytes and bicarbonate at various clinical timepoints (CTPs) in 116 cats with congestive heart failure. See Table 1 for definitions of each CTP and Table 4 for number of cats with data available at each CTP. Solid circles indicate median, vertical lines indicate interquartile range, height of the violins indicate range, width of the violins indicates density of the distribution, and individual data points are also plotted. Results of pairwise comparisons between CTPs for each analyte are shown in Table S1.