Prevalence and Prognostic Relevance of Isolated Tubular Dysfunction in Patients With Acute Heart Failure

Background: Renal dysfunction includes glomerular dysfunction (GD) and tubular dysfunction (TD); however, there is limited information regarding the prevalence, coexistence, and prognostic relevance of TD and GD among patients with acute heart failure (AHF). Methods and Results: This study reviewed 489 patients with AHF who had undergone testing at the time of their admission to identify GD (estimated glomerular filtration rate <60 mUmin/1.73 m(2)) and TD (urinary beta-2-microglobulin >= 300 mu g/gCr). Patients were grouped according to the presence/absence of GD and TD as having neither condition (n=116), isolated TD (n=101), isolated GD (n=83), or coexisting GD plus TD (n=189). During a median follow up of 466 days (interquartile range: 170-871 days), 107 deaths were observed. Kaplan-Meier curve analysis revealed that, relative to the absence of a GD and TD group, higher mortality rates were observed in the groups with isolated TD, isolated GD, and coexisting GD plus TD (log-rank P<0.001). Similarly, the adjusted Cox regression analyses revealed that significantly higher risks of mortality were associated with isolated TD, isolated GD, and coexisting GD plus TD. Moreover, isolated GD and isolated TD were both independently associated with increased risks of all-cause mortality. Conclusions: As a significant proportion of patients with AHF had isolated TD and an increased risk of mortality, patients with AHF should be screened for TD even if they do not have GD.