Impaired kidney function (IKF) in adolescent patients with anorexia is common and transiently worsens during hospitalization, according to a recent study.

In a study of 395 recently hospitalized patients with the psychiatric disorder (mean age 14.6 years; 81.6% girls), IKF was present in 146 (36.8%), Evgenia Gurevich, MD, of Schneider Children’s Medical Center of Israel in Petach Tikva, and colleagues reported in JAMA Network Open. The investigators defined IKF as an estimated glomerular filtration rate (eGFR, in mL/min/1.73 m2) less than 90.

Among patients with IKF, the mean eGFR significantly decreased during hospitalization, from 83.0 at admission to a nadir of 79.1 during hospitalization. It rose to 97.7 at the most recent measurement.

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The investigators observed no significant difference in body mass index (BMI) at admission between the patients with and without IKF. The maximal serum creatinine level during hospitalization was significantly higher in the patients with IKF (mean 83 vs 59 mg/dL).

During hospitalization, serum creatinine increased in those with IKF but remained unchanged in those without IKF. “Since proper hydration could be assured during hospitalization, this finding suggests the presence of a unique yet undefined mechanism other than dehydration,” Dr Gurevich and colleagues wrote.

The patients with vs without IKF had a significantly lower mean minimal eGFR (79.1 vs 112) and a significantly higher serum creatinine to BMI ratio (4.9% vs 3.6%).

Minimal heart rate and free triiodothyronine levels, both physiologic parameters of anorexia severity, correlated with eGFR but not with admission BMI, the investigators reported. The median length of hospital stay was significantly longer in the IKF than no-IKF group (13 vs 8 days).

“Results of this case-control study suggest that impaired kidney function may be a better parameter of anorexia nervosa severity than body mass index,” Dr Gurevich and colleagues concluded.

The investigators compared the anorexia group with a control group of 495 age- and sex-matched patients hospitalized during the same period with other diagnoses. The median BMI percentile at hospital admission was significantly lower in the anorexia group compared with the control group (12.3 vs 49). The minimal eGFR was significantly lower in the anorexia than control group (99.8 vs 124). The mean serum creatinine concentration was in the normal range for the anorexia group as a whole, but was higher compared with the control group (0.68 vs 0.54 mg/dL), according to the investigators. The mean serum creatinine level increased significantly during hospitalization and then decreased to a value lower than that at admission in the anorexa group. The level was 0.66 mg/dL at admission, reached a maximum of 0.68 mg/dL during hospitalization, and was 0.60 mg/dL at discharge.


Gurevich E, Steiling S, Landau D. Incidence of impaired kidney function among adolescent patients hospitalized with anorexia nervosa. JAMA Netw Open. 2021;4(11):e2134908. Published online November 22, 2021. doi:10.1001/amanetworkopen.2021.34908