Predictive value of serum creatinine/cystatin C in neurocritically ill patients

To explore the predictive value of serum creatinine (Cr) to cystatin C (CysC) ratio in neurocritically ill patients.

We conducted a retrospectively observational study of adult patients admitted to a neurocritical care unit (NCU) between Jan 2013 and Jan 2017. Patients were excluded if <18 years old, required neurocritical care <72 hr, did operation during hospitalization, had premorbid disability or acute kidney injury (AKI) at admission. The Cr/CysC ratio was obtained at NCU admission. Primary end points were short-term (30-day) mortality and long-term (6-month) poor outcome, with the latter defined as modified Rankin Scale (mRS) of 4-6.

Of 538 eligible patients, the etiology included acute ischemic stroke (N = 193, 35.9%), intracranial hemorrhage (N = 116, 21.6%), encephalitis and/or meningitis (N = 85, 15.8%), and others (N = 144, 26.7%). Serum Cr/CysC ratio was significantly correlated with body mass index (BMI) (r = .161, p < .001), the length of NCU stay (r = -.161, p < .001), duration of mechanical ventilation (r = -.138, p = .001), and risk of tracheotomy (r = -.095, p = .028). During follow-up, 88 (16.4%), patients died within 30 days and 307 (57.1%) patients achieved good outcome at 6 months. In multivariate logistic regression analysis, we identified serum Cr/CysC ratio as an independent predictor of long-term functional outcome (OR: 0.989, 95% CI: 0.980-0.998, p = .015) but not 30-day mortality (p = .513).

Serum Cr/CysC ratio at admission could be used as a predictor of long-term poor prognosis in neurocritically ill patients.