Validation study of a diary for use in acute lower respiratory tract infection

Background. Despite lower respiratory tract infection (LRTi) being the most common illness treated by doctors, no validated outcome measure to assess symptom duration and severity has been developed for patient self-completion. Methods. As part of a randomized control trial researching management of acute LRTi, an easy self-completion diary was formulated and validated against the 'measure yourself medical outcome profile 2' (MYMOP2), an instrument previously validated in general practice. Results. Spearman rank correlations of the diary profile versus MYMOP2 profile at baseline (r = 0.62), day 11 (r = 0.81) and change in score over time (r = 0.51) indicate that our diary correlates significantly with MYMOP2. The standardized response mean of the diary profile (mean change/SD change) = 1.48, indicating sensitivity to change. Conclusion. This study shows that a simple symptom diary is internally reliable, valid and sensitive to change for acute LRTi This instrument could be used as a routine measure of LRTi in further research in both primary and secondary care.