Lactose tolerance test shortened to 30 minutes: An exploratory study of its feasibility and impact.

INTRODUCTION: Lactose malabsorption (LM) is a very common condition with a high prevalence in our setting. Lactose tolerance test (LTT) is a basic, affordable test for diagnosis that requires no complex technology. It has been recently shown that this test can be shortened to 3 measurements (baseline, 30 min, 60 min) with no impact on final results. The purpose of our study was to assess the feasibility and benefits of LTT simplification and shortening to 30 min, as well as the financial impact entailed. MATERIAL AND METHODS: A multicenter, observational study of consecutive patients undergoing LTT for LM suspicion. Patients received 50 g of lactose following a fasting period of 12 h, and had blood collected from a vein at all 3 time points for the measurement of blood glucose (mg/dl). Differences between the shortened and complete test forms were analyzed using McNemar´s test. A comparison of blood glucose levels between patients with normal and abnormal results was performed using Student´s T-test for independent mean values. Consistency was assessed using the kappa index. A p < 0.05 was considered to be statistically significant. RESULTS: A total of 270 patients (69.6 % females) were included, with a mean age of 39.9 ± 16 years. LTT was abnormal for 151 patients (55.9 %). We observed no statistically significant differences in baseline blood glucose levels between patients with normal and abnormal LTT results (p = 0.13); however, as was to be expected, such differences were obvious for the remaining time points (p < 0.01). Deleting blood glucose measurements at 60 minutes only led to overdiagnose LM (false positive results) in 6 patients (2.22 %), with a kappa index of 0.95 (95 % CI: 0.92-0.99) (p < 0.001) versus the complete test. Suppressing measurements at 60 min would have saved at least € 7,726. CONCLUSION: The shortening of LTT to only 2 measurements (baseline and 30-min) hardly leads to any differences in final results, and would entail savings in time, materials, and personnel.

Test de tolerancia a la lactosa reducido a 30 minutos: un estudio exploratorio de su factibilidad e impacto / Lactose tolerance test shortened to 30 minutes: an exploratory study of its feasibility and impact

Introducción: la malabsorción a la lactosa (ML) es una patología muy frecuente con alta prevalencia en nuestro medio. El test de tolerancia a la lactosa (TTL) es una prueba básica y económica que permite su diagnóstico sin precisar tecnología compleja. Recientemente se ha demostrado que este test puede reducirse a 3 determinaciones (basal, 30 y 60 min) sin afectar al resultado final. El propósito de nuestro estudio fue el valorar la factibilidad y ventajas de poder acortar y simplificar el TTL a 30 min, así como el impacto económico que conllevaría. Material y métodos: estudio multicéntrico y observacional de pacientes consecutivos a los que se les realiza un TTL ante la sospecha de ML. Los enfermos reciben 50 g de lactosa tras 12 h de ayuno y se les realiza extracción de sangre venosa en los 3 tiempos para la medición de la glucemia (mg/dl). La diferencia entre el test reducido y el completo se analizaron con el test de McNemar. La comparación de los niveles de glucemia entre los pacientes con test normal y patológico fue realizada usando el test t-Student para comparación de medias independientes. La concordancia fue evaluada con el índice Kappa. Se consideró p < 0,05 como estadísticamente significativo. Resultados: se incluyeron 270 pacientes (69,6 % mujeres) con edad media de 39,9 ± 16 años. El TTL fue patológico en 151 casos (55,9 %). No observamos diferencias estadísticamente significativas entre las glucemias basales de los pacientes con TTL normal o patológico (p = 0,13), sin embargo, como cabía esperar, estas diferencias fueron evidentes en los demás tiempos (p < 0,01). La eliminación de la determinación de glucemia a los 60 min tan solo sobrevaloró el diagnóstico de ML (falsos positivos) en 6 enfermos (2,22 %), con índice kappa de 0,95 (IC 95 %: 0,92- 0,99) (p < 0.001) respecto al test completo. Si se hubiera suprimido la determinación de los 60 min, se podría haber ahorrado al menos 7.726 euros. Conclusión: el reducir el TTL a 2 determinaciones (basal y 30 min) no implica apenas cambios en el resultado final del test, sin embargo conllevaría un ahorro de tiempo, material y personal (AU)

Introduction: Lactose malabsorption (LM) is a very common condition with a high prevalence in our setting. Lactose tolerance test (LTT) is a basic, affordable test for diagnosis that requires no complex technology. It has been recently shown that this test can be shortened to 3 measurements (baseline, 30 min, 60 min) with no impact on final results. The purpose of our study was to assess the feasibility and benefits of LTT simplification and shortening to 30 min, as well as the financial impact entailed. Material and methods: A multicenter, observational study of consecutive patients undergoing LTT for LM suspicion. Patients received 50 g of lactose following a fasting period of 12 h, and had blood collected from a vein at all 3 time points for the measurement of blood glucose (mg/dl). Differences between the shortened and complete test forms were analyzed using McNemar’s test. A comparison of blood glucose levels between patients with normal and abnormal results was performed using Student’s T-test for independent mean values. Consistency was assessed using the kappa index. A p < 0.05 was considered to be statistically significant. Results: A total of 270 patients (69.6 % females) were included, with a mean age of 39.9 ± 16 years. LTT was abnormal for 151 patients (55.9 %). We observed no statistically significant differences in baseline blood glucose levels between patients with normal and abnormal LTT results (p = 0.13); however, as was to be expected, such differences were obvious for the remaining time points (p < 0.01). Deleting blood glucose measurements at 60 minutes only led to overdiagnose LM (false positive results) in 6 patients (2.22 %), with a kappa index of 0.95 (95 % CI: 0.92-0.99) (p < 0.001) versus the complete test. Suppressing measurements at 60 min would have saved at least Euros 7,726. Conclusion: The shortening of LTT to only 2 measurements (baseline and 30-min) hardly leads to any differences in final results, and would entail savings in time, materials, and personnel (AU)