Evaluation of the usefulness of vitamin D as a predictor of mortality in patients with COVID-19.

INTRODUCTION: One of the functions of vitamin D is to regulate respiratory epithelium inflammatory response; therefore, deficiency of this vitamin in the context of COVID-19 could constitute a predictive biomarker of the disease outcome. OBJECTIVE: To evaluate the usefulness of vitamin D for predicting mortality in patients with COVID-19. METHODS: Observational, retrospective study in which 154 patients diagnosed with COVID-19 were included, out of whom 111 survived and 43 died. Vitamin D concentration was determined in all of them. RESULTS: A log-rank p-value < 0.032 was obtained for survival when vitamin D concentration was used as a categorical variable (≤ 20 ng/mL and > 20 ng/mL). On Cox proportional analysis, age and vitamin D concentration were shown to be risk factors associated with mortality in patients with COVID-19 (age: HR = 1.036, 95% CI = 1.016-1.058, p < 0.001; vitamin D: HR (≤ 20 ng/mL and > 20 ng/mL) = 0.478, 95% CI = 0.237-0.966, p < 0.040). CONCLUSION: Age and vitamin D concentration were predictive factors for mortality in COVID-19-infected patients.

INTRODUCCIÓN: Una de las funciones de la vitamina D es regular la respuesta inflamatoria del epitelio respiratorio; por ello, la deficiencia de esa vitamina en el contexto de COVID-19 podría constituir un biomarcador preditivo del desenlace de COVID-19. OBJETIVO: Evaluar la utilidad de la vitamina D para predecir la mortalidad en pacientes con COVID-19. MÉTODOS: Estudio observacional y retrospectivo en el que se incluyeron 154 pacientes con diagnóstico de COVID-19, de los cuales 111 sobrevivieron y 43 fallecieron. En todos se determinó la concentración de vitamina D. RESULTADOS: Se obtuvo un valor log-rank de p < 0.032 para la supervivencia al utilizar la concentración de vitamina D como variable categórica (≤ 20 ng/mL y > 20 ng/mL). Mediante análisis proporcional de Cox se encontró que la edad y concentración de vitamina D mostraron ser factores de riesgo asociados a la mortalidad en pacientes con COVID-19 (edad: HR = 1.036, IC 95 % = 1.016-1.058, p < 0.001; vitamina D: HR ≤ 20 ng/mL y > 20 ng/mL = 0.478, IC 95 % = 0.237-0.966, p < 0.040). CONCLUSIÓN: La edad y la concentración de vitamina D constituyeron factores predictivos de mortalidad en pacientes infectados por COVID-19.

Evaluación de la utilidad de la vitamina D como predictor de mortalidad en pacientes con COVID-19 / Evaluation of the usefulness of vitamin D as a predictor of mortality in patients with COVID-19

Resumen Introducción: Una de las funciones de la vitamina D es regular la respuesta inflamatoria del epitelio respiratorio; por ello, la deficiencia de esa vitamina en el contexto de COVID-19 podría constituir un biomarcador preditivo del desenlace de COVID-19. Objetivo: Evaluar la utilidad de la vitamina D para predecir la mortalidad en pacientes con COVID-19. Métodos: Estudio observacional y retrospectivo en el que se incluyeron 154 pacientes con diagnóstico de COVID-19, de los cuales 111 sobrevivieron y 43 fallecieron. En todos se determinó la concentración de vitamina D. Resultados: Se obtuvo un valor log-rank de p < 0.032 para la supervivencia al utilizar la concentración de vitamina D como variable categórica (≤ 20 ng/mL y > 20 ng/mL). Mediante análisis proporcional de Cox se encontró que la edad y concentración de vitamina D mostraron ser factores de riesgo asociados a la mortalidad en pacientes con COVID-19 (edad: HR = 1.036, IC 95 % = 1.016-1.058, p < 0.001; vitamina D: HR ≤ 20 ng/mL y > 20 ng/mL = 0.478, IC 95 % = 0.237-0.966, p < 0.040). Conclusión: La edad y la concentración de vitamina D constituyeron factores predictivos de mortalidad en pacientes infectados por COVID-19.

Abstract Introduction: One of the functions of vitamin D is to regulate respiratory epithelium inflammatory response; therefore, deficiency of this vitamin in the context of COVID-19 could constitute a predictive biomarker of the disease outcome. Objective: To evaluate the usefulness of vitamin D for predicting mortality in patients with COVID-19. Methods: Observational, retrospective study in which 154 patients diagnosed with COVID-19 were included, out of whom 111 survived and 43 died. Vitamin D concentration was determined in all of them. Results: A log-rank p-value < 0.032 was obtained for survival when vitamin D concentration was used as a categorical variable (≤ 20 ng/mL and > 20 ng/mL). On Cox proportional analysis, age and vitamin D concentration were shown to be risk factors associated with mortality in patients with COVID-19 (age: HR = 1.036, 95% CI = 1.016-1.058, p < 0.001; vitamin D: HR [≤ 20 ng/mL and > 20 ng/mL] = 0.478, 95% CI = 0.237-0.966, p < 0.040). Conclusion: Age and vitamin D concentration were predictive factors for mortality in COVID-19-infected patients.

Intrahospital correlation of the international normalized ratio.

Background. Monitoring of oral anticoagulant therapy (OAT) is usually accomplished by measuring prothrombin time and the international normalized ratio (INR). However, thromboplastins have different responsiveness and sensitivity to vitamin K-dependent coagulation factors depletion. Several studies have shown INR variation when low sensitive thromboplastins are used. This study compared INR variability between two laboratories using highly sensitive thromboplastins. Methods. A total of 237 plasmas were tested, half of them from patients under OAT. Samples were tested simultaneously in two laboratories: in laboratory A, a Behring Coagulation Timer instrument and a human recombinant thromboplastin (Innovin, Dade Behring) (ISI 1.01) were used. In laboratory B, a Thrombolyzer Compact (Behnk Elektronik) and a rabbit brain thromboplastin (Simplastin Excel S, Organon Teknika) with an ISI of 1.30 were used. Statistical analysis was carried out according to the method of Bland and Altman. Results. Even though high correlation coefficients were obtained when comparing both laboratories, Bland-Altman analysis showed a variation of INR between laboratories ranging from -0.77 to +1.07. After logarithmic transformation of data, these values yielded a variation of the INR either 25% below or 44% above. Conclusions. These results are clearly inadequate for clinical use because such a variation would most probably induce the clinician to make a change in warfarin dose. Standardization of instruments, reagents, and controls is warranted to decrease this variation.