Validation of a modified cow's milk-related symptom score (CoMISS) for screening of lactose intolerance in adults

Lactose intolerance (LI) is the failure to digest foods and beverages containing the lactose present in milk. LI can present by many digestive symptoms.

To validate the modified CoMiSS score for prediction of LI, that was confirmed by a stool acidity test.

A cross-sectional study, was conducted at Ain Shams University Hospitals/Gastrointestinal Clinics, and included one hundred adult participants during the period from December 2018 to December 2019. Enrolled patients had one or more gastrointestinal symptoms and were subjected to a stool acidity test (fecal PH test) as a reference test and modified CoMiSS as an index test.

The mean age of participants was 35.30 ± 10.714 years old; 55% were females, and their mean body mass index (BMI) was 23.08 ± 2.080 kg/m², with no significant relation between LI and patients` gender or BMI. Out of the studied participants 24% had positive stool PH, LI diagnosed according to modified CoMISS was present among 19% of them. The mean value of modified CoMISS Score was significantly higher in positive cases (12.37) compared to negative LI participants (2.33) as p < .001. Area under ROC Curve was 0.998, at the selected cut-off value 8, the sensitivity was 89.5% and specificity was 100% thus, levels of questionnaire scoring of 8 or higher would indicate presence of lactose intolerance.

Modified CoMiSS is a simple, fast, and easy-to-use tool that can predict LI, with a cut-off value of >8, the Area under the ROC Curve was 0.998, sensitivity 89.5%, and specificity was 100%.