Hypocalcemia: A key biomarker in hospitalized COVID-19 patients.

BACKGROUND: At the end of 2019 a new respiratory syndrome emerged in China named Coronavirus disease 2019 (COVID-19) due to SARS-CoV-2 infection. Considering the severity of the disease in adult subjects with one or more chronic pathologies, it was mandatory to find simple and effective biomarkers for negative prognosis of the disease easily available at the admission to the hospital. METHODS: To identify possible parameters showing association with the outcome in COVID-19 patients with pre-existing chronic diseases, blood biochemical profiles of 511 patients, enrolled from March to June 2020, were retrospectively evaluated. The pathological conditions taken into consideration were diabetes, arterial hypertension, chronic kidney disease, cardiovascular diseases, chronic obstructive pulmonary disease, obesity, and cancer. All the data were collected upon admission to the emergency room (ER) during the indicated period. RESULTS: We observed that serum and ionized calcium were prevalently altered in our cohort. We determined that hypocalcemia was a major parameter associated with mechanical ventilation and poor prognosis, correlating also with the presence of comorbidities such as cardiovascular diseases, chronic kidney disease, and cancer. In addition, we found a positive correlation between hypocalcemia and clinical complications during hospitalizations. CONCLUSIONS: Our results strengthen the relevance of serum calcium concentration as a useful prognostic biomarker in hospitalized COVID-19 patients.

Sulfadiazine crystalluria in a patient with lupus nephritis.

Objectives: It is estimated that 29% of patients treated with sulfadiazine ultimately develop acute kidney failure. Diagnosis is based on urine sediment analysis. Case presentation: A 71-year-old woman with loss of visual acuity in the context of a flare of systemic erythematosus lupus (SEL). A diagnosis of acute retinal necrosis was established, pending etiological confirmation. Empirical treatment with sulfadiazine was initiated. Follow-up analyses included urine sediment, which revealed pH 6, 30-50 RBCs/field, urothelial cells and lower tract epithelial cells, hyaline casts, fatty casts or Maltese cross, and abundant sulfadiazine crystals. The finding was reported to the Unit of Nephrology, and treatment was immediately suspended. Conclusions: Sulfadiazine is an antibiotic of the family of sulfamides. Crystalization of sulfadiazine in the renal tubules may cause acute interstitial nephritis. These crystals adopt different shapes according to the metabolite that crystalizes: unaltered forms precipitate into dense, globular crystals, whereas in other cases, as in the case reported in this paper, crystals adopt a fan-shaped, shocks-of-wheat morphology.

CYFRA 21-1 in patients with suspected cancer: evaluation of an optimal cutoff to assess the diagnostic efficacy and prognostic value.

Objectives: Chosen cutoff for cytokeratin 19 fragment antigen (CYFRA 21-1) as a tumor biomarker considerably influences its diagnostic and prognostic usefulness. The aim of the present study is to determine an optimal cutoff value for diagnostic validity of CYFRA 21-1 by Lumipulse ® technology in patients with suspected cancer and also to determine if CYFRA 21-1 levels provide prognostic value. Methods: A consecutive 284 patients suggestive of malignant disease from six hospitals of Madrid were enrolled in a retrospective design. Optimal CYFRA 21-1 cutoff value was obtained by receiver operating characteristic curve and Youden test. The diagnostic validity was evaluated according to sensitivity, specificity, predictive values and likelihood ratios. The prognostic value of CYFRA 21-1 was checked using multiple logistic regression. Thirty-two diagnostic cancers were confirmed. Results: The most optimal cutoff was 3.15 ng/mL. This cutoff showed a better specificity 93.63% (95% confidence interval [CI], 89.66-96.16), positive predictive value 60.98% (95% CI, 44.54-75.38) and positive likelihood ratio 12.65 (95% CI, 7.64-20.95) than the cutoff recommended by Fujirebio® (1.8 ng/mL) (specificity: 73.71% [95% CI, 67.72-78.95], positive predictive value: 29.79% [95% CI, 21.02-40.23] and positive likelihood ratio 3.43 [95% CI, 2.71-4.35]), improving the current diagnostic accuracy. In multivariate analysis, elevated levels of CYFRA 21-1 (>3.15 ng/mL) was confirmed as an unfavorable prognostic factor. Conclusions: The best cutoff for CYFRA 21-1 obtained was 3.15 ng/mL in patients with suspected cancer. This new cutoff decreases the false positive rate and improves the diagnostic efficacy of CYFRA 21-1 as a tumor marker as well as its association with death events.

Sodium set-point in haemodialysis: is it what we see clinically?

BACKGROUND: Natraemia in haemodialysis (HD) patients is considered constant contrary to daily clinical observations. Its relationship with clinical parameters, dialysis parameters and body water (BW) distribution is not clear. OBJECTIVES: The aims of this study were to know 1) the intraindividual variability of natraemia, 2) the relationship between natraemia and clinical and dialysis parameters and 3) the relationship between natraemia and BW distribution by bioimpedance. MATERIAL AND METHOD: Observational retrospective study on 98 chronic HD patients. Clinical, HD and natraemia, glucose and bioimpedance data were collected. RESULTS: We included 63 males and 35 females of 69.6 (21-91) years of age, with a follow-up of 23.2 (10) months. Variability: 1802 sodium measurements: mean natraemia 138 (3.2) mEq/l and corrected for glucose: 139.1 (3.6) mEq/l, p<.0001. Intraindividual coefficient of variation (CV) was 2% (0.8) (range 1-5.6%) and it correlated negatively with natraemia (r=-0.63, p<.0001). Clinical parameters: corrected natraemia was lower in diabetics than in non-diabetics 138 (2.4) compared with 139 (2) mEq/l, p<.003, CV 2.3 (0.9) compared with 1.9 (0.7)% (p<.01) and SD 3.2 (1.2) compared with 2.5 (0.9) mEq/l (p<.04). No differences according to gender, age, HD time, cardiac or liver disease, medication use, residual renal function or mortality were found. HD parameters: a positive relationship was found between natraemia and total dialysate conductivity and it was negative with interdialysis weight gain (IDG). - Bioimpedance: no relationship was found between natraemia and BW distribution. CONCLUSIONS: Natraemia varies in each patient and is related positively with conductivity and negatively with IDG. In diabetics natraemia is lower and CV is higher. There is no relationship between natraemia and BW distribution.