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)

Influencia del tiempo de tránsito orocecal en la percepción de los síntomas de intolerancia a la lactosa / Impact of orocecal transit time on patient’s perception of lactose intolerance

Antecedentes: los síntomas atribuidos a la intolerancia a la lactosa son un importante problema de salud pública. El tiempo de tránsito es un factor implicado en la severidad de los síntomas asociados al consumo de lactosa. Objetivos: elucidar la relación entre el tiempo de tránsito orocecal (TTOC) y los síntomas de intolerancia a la lactosa. Métodos: estudio observacional en pacientes con un test del aliento de hidrógeno con lactosa patológico (excreción de hidrógeno superior a 25 ppm). El TTOC se midió mediante el test del aliento y los síntomas mediante una escala previamente validada. Los síntomas se determinaron dos veces: antes de recibir la lactosa, preguntando acerca de los síntomas en casa cuando se consumen lácteos (“síntomas en casa”), y de nuevo después de completar el test del aliento con lactosa (“síntomas test”). Resultados: se han incluido 161 pacientes. No se observa correlación entre el TTOC y los síntomas en casa (r = -0,1). Cuando el TTOC fue más rápido de 60 minutos, la intensidad de los “síntomas test” fue parecida a la de los “síntomas en casa”. Sin embargo, en los pacientes con TTOC normal o lento, los “síntomas en casa” fueron más intensos que los “síntomas test” (p < 0,05). En casa los síntomas fueron independientes del TTOC mientras que después de la sobrecarga de lactosa los síntomas fueron más intensos cuanto más rápido el TTOC. Conclusiones: los síntomas que refieren las personas con malabsorción de lactosa son más pronunciados en casa que tras una sobrecarga de lactosa. Los síntomas de intolerancia que los pacientes atribuyen al consumo de lactosa en casa no son debidos a un TTOC rápido(AU)

Background: symptoms attributed to the lactose intolerance are an important public health issue because of their prevalence and social relevance. Also because they may cause undue rejection of dairy products consume with potential health consequences. Transit time is a putative factor implied in the severity of symptoms associated with lactose. Objectives: to elucidate the relation between orocecal transit time (OCTT) and lactose intolerance symptoms. Methods: observational study in patients referred to a lactose hydrogen breath test who showed an increase in breath H2 excretion higher than 25 ppm. OCTT was measured with the breath test and symptoms of lactose tolerance with a validated scale. Symptoms were measured twice: before receiving the lactose, inquiring about self perceived symptoms when patients consumed dairy products at home (“home symptoms”), and again after completing the lactose breath test (“test symptoms”). Results: 161 patients were included. There was no correlation between OCTT and home symptoms (r = -0.1). When OCTT was faster than 60 minutes, intensity of “test symptoms” was similar to “home symptoms”. However, in patients with normal or slow OCTT, the “home symptoms” were more intense than the “test symptoms” (p < 0.05). At home, symptoms were independent of OCTT but with the lactose test load the symptoms were proportionately more intense with faster OCTT. Conclusions: in lactose maldigesters, selfreported symptoms of lactose intolerance are more pronounced at home than after a high lactose challenge. Intolerance symptoms that patients attributed to lactose consume at home are due to factors other than fast OCTT(AU)

Comparison of quick point-of-care test for small-bowel hypolactasia with biochemical lactase assay in children.

AIM: The aim of the present study was to compare the Biohit Lactose Intolerance Quick Test (BLIQT) to the criterion standard biochemical duodenal lactase (DL) activity assay in the paediatric population using standard statistical comparative tests. METHODS: Using standard Olympus endoscopes, 2 postbulbar duodenal biopsies were taken from 38 prospective children (0-16 years) from June 2008-May 2009 at a single tertiary paediatric gastroenterology unit. The biopsies were used for the BLIQT and for biochemical disaccharides assay. RESULTS: Thirty-eight children (19 boys) of median age 5.45 years (0.3-14.8 years) underwent the combined BLIQT and disaccharidase testing. We subdivided the group into those who had biopsies with a larger endoscope (XQ, n = 26) and those who had a smaller endoscope (XP, n = 12) and thus a smaller biopsy forcep. When using a larger endoscope, the BLIQT showed a sensitivity of 100%, specificity of 86%, and positive and negative predictive value of 57.1% and 100%, respectively, on comparing it with DL. With a smaller endoscope, the BLIQT had a sensitivity of 100%, specificity of 80%, positive predictive value of 50%, and a negative predictive value of 100%. CONCLUSIONS: As in adult studies, the sensitivity and negative predictive value of the BLIQT was 100%. The specificity too appears to be high but variable, probably because of smaller biopsies obtained, and may warrant the need for 2 biopsies. The high sensitivity, specificity, and negative predictive value of the BLIQT for indicating hypolactasia make it an effective point-of-care test for paediatric hypolactasia.

A re-appraisal of lactose intolerance.

BACKGROUND: Lactose, beta-galactose-1,4-glucose, is hydrolysed by the enzyme lactase. Lactose intolerance occurs when lactase deficiency causes clinical symptoms. AIMS: To provide an overview of lactose intolerance, including definition, aetiology and epidemiology, the clinical symptoms and diagnostic testing and management. METHODS: A literature review was carried out to meet the aims of this paper. This resulted in the analysis of a database of patients tested for lactose intolerance to provide examples of the consequences of problems of terminology identified. CONCLUSIONS: The terminology relating to lactose intolerance is confusing for clinicians and researchers. Clinicians need to ensure that these problematic terms do not cause diagnostic mistakes and inappropriate treatment. Researchers should be aware of inconsistent terminology in studies and resultant problems with the interpretation of results.

Molecularly-defined lactose malabsorption, milk consumption and anthropometric differences in adult males.

BACKGROUND: Lactose malabsorption (LM) may be associated with reduced skeletal calcium content. Diagnosis to date has been based on indirect methods, with a high false-negative rate. Identification of the LCT polymorphism led to development of a PCR-based test. AIM: To evaluate the PCR-based test compared to a combination the hydrogen breath test and the lactose tolerance test, and investigate anthropometrical differences, changes in bone mineral density and oral calcium intake according to LCT polymorphism and milk-drinking habits. METHODS: All participants (n = 278) underwent clinical examination, with measurement of height, weight and bone density (DXA), and were genotyped for LCT polymorphism (LCT CC or LCT TT: CC is associated with LM). A subgroup (n = 51) had a hydrogen breath test and a lactose tolerance test, in addition to genotyping. RESULTS: Detection of LM by LCT polymorphism was highly significant (p = 0.001). The correlation between LCT genotype and self-reported milk-intolerance or dislike of milk with was slight, but the correlation with functional tests was highly significant. Non-milk-drinkers were lighter (-5 kg) and significantly shorter (-4 cm) than milk-drinkers (p = 0.07 and 0.04, respectively). Total calcium consumption was lower among non-milk-drinkers by about 18% (p = 0.03). DISCUSSION: Genotyping is an economic, quick and convenient method for diagnosing lactose malabsorption, with results comparable to existing tests. Sufficient calcium consumption may be relevant to body growth, as milk-drinkers were taller. Negative calcium bone balance may be prevented when provision is made for adequate calcium intake.

Temperature of a test solution influences abdominal symptoms in lactose tolerance tests.

In lactose maldigesters, retarding gastric emptying (food/pharmaceuticals) improves tolerance to lactose. The role of temperature of test solution on the indicators of lactose intolerance was studied. After an overnight fast, 10 lactose maldigesters ingested, in three sessions, 50 g lactose in a randomized cross-over trial. The solutions were at temperatures of 20-21 degrees C (room temperature), 2-3 degrees C (cold) and 55-58 degrees C (hot). Gastrointestinal symptoms and indicators measuring lactose absorption were recorded. Abdominal pain was noticeably increased by the modification of temperature. The cold solution reduced flatulence and abdominal bloating, whereas the hot solution increased bloating and borborygmi. Breath hydrogen excretion tended to be augmented and retarded after cold solution. The temperature of the solution used in a lactose tolerance test affects the gastrointestinal symptoms, but has only minor effects on the other indicators of lactose maldigestion. The constant tendencies observed suggest that a room temperature solution is to be recommended for testing lactose digestion.

Prevalencia de hipolactasia tipo adulto, en biopsias de tercera porción de duodeno obtenidas por endoscopia en pacientes con indicación clínica de endoscopia digestiva alta

Objetivo: a) determinar la prevalencia de hipolactasa tipo adulto (HTLTA) en biopsias de duodeno obtenidas por endoscopia; b) estandarizar la técnica para determinar actividad de lactasa; compararla con la prueba de tolerancia a la lactosa (PTL) y síntomas de intolerancia; c) establecer la relación entre la HLTA con dispepsia funcional (DF) y síndrome de intestino irritable (SII). Diseño: estudio descriptivo de prevalencia y utilidad diagnóstica. Marco de referencia: muestra consecutiva de pacientes enviados para endoscopia digestiva alta al Hospital San Juan de Dios. Pacientes: 221 de 940 que cumplieron criterios de inclusión. Intervenciones: tres biopsias de tercera porción de duodeno, encuesta estructurada y PTL. Mediciones principales: criterios diagnósticos para DF, SII e intolerancia a la lactosa; actividad duodenal de lactasa; glicemias basal, 30 y 60 minutos postcarga de lactosa. Resultados: el 70.7 por ciento de los sujetos que consumen lácteos presentan sintomas, especialmente expulsión de gases (38.2 por ciento) y 39.4 por ciento presentaban >= dos síntomas. el consumo de lactosa fue equivalente a 290 ml/leche. La actividad de lactasa fue deficiente en el 70.1 por ciento. El consumo de lactosa fue inferior en aquellos con HLTA. La PTL y los síntomas ocacionados por los lácteos no tuvieron utilidad diagbóstica, independiente de la presencia de DF y de SII. Conclusiones: la biopsia de duodeno por EGD es adecuada para la cuantificación de la lactasa intestinal. la prevalencia de HLTA del 70 por ciento fue elevada pero acorde con la literatura; la PTL y la sintomatología ni fueron útiles para su diagnóstico. No se encontró asociación de la HLTA con la presencia de DF y de SII

Poor predictability of lactose malabsorption from clinical symptoms for Chilean populations.

Clinical symptoms and lactose malabsorption may occur in persons intolerant to lactose. To predict malabsorption from symptoms and age, the authors used simple regression, multiple regression, and discrimant analysis on data from 436 Chileans. All individual r2 values from simple regression were less than 0.05. For the best stepwise multiple regression program, R2 was only 0.09, indicating that 91% of the variability in malabsorption was "unexplained" by the five best predictor variables. Because of so much unexplained variability, the authors could detect (using multiple regression) only 56 of 90 (62%) malabsorbers and only 14 of 38 (37%) absorbers. In conclusion, for their Chilean populations the authors poorly predicted malabsorption from symptoms.

[Assessment of the lactose test and its value in detecting intolerance to milk sugar]. / K otsenke laktoznogo testa i ego znacheniia v vyiavlenii intolerantnosti k molochnomu sakharu.

In 109 healthy and sick subjects suffering from diverse affections of the digestive organs the lactase activity in the mucosa of the large intestine was determined and a lactose test set up (1 g of lactose per 1 kg of body weight). In the test the following factors were considered: clinical symptoms, the rate of passage in the intestines (till the appearance of carmine), blood glucose content, pH and sugar in the feces. To appraise the activity of lactase the most accurate indicator in the test appeared to be the estimated degree of the rising blood glucose concentration as against the area of its ascent (23% of erroneous results). Because of a great variability of the test indicators the assessment of the lactase activity by combination of the latter did not increase the total number of correct results. However, in cases when there appeared combinations of indicators most characteristic for different activity of the lactase, the significance of the test results proved much higher (11.5-7% of erroneous results). Since in the lactose tolerance tests it is the total lactase activity, covering the entire surface of the small intestine that is recorded and subject to assessment are also possible changes, adaptive inclusive, of the gastro-intestinal tract motoricity, this test characterizes in the final analysis more correctly the tolerance of food products containing lactic sugar, than does direct determination of the lactase activity.