Objectives: Infant colic (IC), with an estimated prevalence of 5% to 25%, has a high impact on health care costs. Furthermore, reported negative sequelae are disturbed parent–infant interaction, increased susceptibility to abdominal pain, and even child abuse. Its etiology remains unknown, leading to a wide variety in interventions. We hypothesize that definitions and outcome measures in studies on IC will be heterogeneous as well. Our objective is to systematically assess how definitions and outcome measures are reported in randomized controlled trials (RCTs) of IC.
Methods: CENTRAL, Embase, and MEDLINE/PubMed were searched from inception to December 2012. English-language systematic reviews (SRs) and RCTs concerning IC in children ages 0 to 9 months were included. Bibliographies of included SRs were searched for additional articles. Quality was assessed using the Delphi list.
Results: A total of 1702 studies were found; 55 articles were included (16 SRs, 39 RCTs). In 39 trials, we found 20 different definitions for IC, 11 different definitions for improvement, 28 different interventions, and 19 different outcomes. Fifty-one percent of the trials were of good methodological quality. All of the trials used parental diaries; only 31% stated that their instrument was validated.
Conclusions: Too many different definitions and outcome measures for IC are used in RCTs. Only a minority of the trials reported parental perception as primary outcome. Uniform definitions, outcomes, and validated instruments are needed to make a comparison between intervention studies possible.