Using external data to assess the external validity of a randomised controlled trial

Adi Turjeman*, Muhammad Awwad, Shachaf Shiber, Tanya Babich, Noa Eliakim-Raz, Angela Huttner, Stephan Harbarth, Leonard Leibovici, Dafna Yahav

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

Background: Few studies have addressed external validity of randomized controlled trials in infectious diseases. We aimed to assess the external validity of an investigator-initiated trial on treatment for uncomplicated urinary tract infection. Methods: In the original study, women (n = 513) with urinary tract infection were randomized to nitrofurantoin or fosfomycin treatment in three countries between 2013 and 2017. In the present study we compared women who were screened for enrolment but excluded to women who participated in the trial, both groups in Israel. The primary outcome was the rate of emergency department index visits resulting in hospitalization within 28 days. Results: We compared 127 included to 110 excluded patients. The most common reasons for exclusion were logistic difficulties in recruitment and antibiotic use in the preceding month. Included patients tended to be older [39 (IQR 29–59) vs. 35.5 (IQR 24–56.25 years)], more likely to have history of recurrent infection and had more urinary symptoms. Among excluded patients, 13.6% (15/110) had initial visits resulting in hospitalization compared to 3.1% (4/127) of included participants (p =.003). The rate of emergency department visits within 28 days was similar in both groups. Clinical and microbiological failures were significantly more common in included patients [26% (33/127) vs. 1.8% (2/110), p <.001; 7.9% (10/127) vs. 0% (0/110), p =.003; respectively]. Conclusions: While differences were observed between included and excluded patients, the excluded group did not represent a more ‘complicated’ population. The present study shows the importance of collecting data on patients excluded from randomized controlled trials.

Original languageEnglish
Pages (from-to)325-331
Number of pages7
JournalInfectious Diseases
Volume53
Issue number5
DOIs
StatePublished - 2021

Funding

FundersFunder number
Israel National Institute for Health Policy and Health Services Research
Life Science Health Priority of the Seventh Framework Programme278348
European Commission
Israel National Institute for Health Policy Research2016/80

    Keywords

    • Urinary tract infection
    • exclusion criteria
    • external validity
    • inclusion criteria
    • randomized controlled trial

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