Table 3
CitationStudy groupStudy type (level of evidence)OutcomeKey resultsComments
Klougart et al (1989)316 otherwise healthy infants (age 2–16 weeks) with symptoms of colic according to well defined criteria, all treated with chiropractic spinal manipulation. Primary evaluation after two weeks of treatment (average of 3 treatment visits). Number of dropouts = 17Prospective single cohort observational study (level 2b)Daily hours of crying using diary completed by parentsMean no. of daily hours crying over 2 days before treatment (retrospective estimate): 5.2. At day 1: 2.5, and at day 14: 0.65 (74% reduction). Unclear whether infants had been treated on day 1Lack of blinding introduces considerable bias. Lack of randomisation and a control group prevents estimates of a placebo effect or natural course of the condition, which is known to improve with age. The study is however important because of the large number of infants recruited
Symptom improvement score estimated by parentsAt day 14; 6% of sample no change or worse, 34% improved, 60% stopped colic symptoms
Mercer and Nook (1999) 30 infants (0–8 weeks) suffering from infantile colic diagnosed by a paediatrician (criteria unclear). 15 infants treated by chiropractic spinal manipulation (experimental); 15 infants treated with a non-functional, de-tuned ultrasound machine (placebo). In both groups, a maximum of 6 treatments over two weeks. No information given on dropoutsRCT (level 1b) Single blinded study. Randomisation unclearSubjective response to treatment by parents before treatment and at each subsequent consultation. Outcomes not definedStatistically significant difference (no data given) in response to treatment between 2 groups (assumed beneficial in experimental group). Complete resolution of symptoms in 93% of infants in (assumed) experimental group. No comparative data for placebo groupThis study was reported in abstract form. The small sample group without well defined inclusion data and the lack of detail in methodology and recorded data seriously undermines the contribution of this study to the evidence base. Nevertheless, it is reported for completeness, and does support the suggestion of a beneficial effect of chiropractic
Wiberg et al (1999)50 objectively healthy infants (age 2–10 weeks) with well defined colic. 25 treated with chiropractic spinal manipulation for two weeks (mean 3.8 treatments) and 16 with dimethicone for two weeks (9 dropouts)RCT (level 1b) Single blinded study. Method of randomisation unclearDaily hours of crying using diary (completed by parents)At 8–11 days, mean change in no. of hours crying: −1.0 (SE 0.4) dimethicone; −2.7 (0.3) spinal manipulation (p=0.004)Parents reporting outcome knew the intervention. Dimethicone has been shown to be no better than placebo treatments. No follow up period after treatment period so unsure whether observed effect is maintained
Olafsdottir et al (2001)100 colicky infants (age 3–9 weeks) meeting strict entry criteria. 50 treated with chiropractic spinal manipulation for 3 visits (over 8 days) and 50 given placebo treatment (holding). (9 infants excluded (failure to meet entry criteria) and 5 drop outs leaving 86 completing trial)RCT (level 1b) Double blinded study. Randomisation by sealed envelopesDaily hours of crying using diary (completed by parents)At third (last) visit (day 8), mean no. of hours crying: 3.1 (SD 2.7) spinal manipulation; 3.1 (SD 2.7) placebo (p=0.982)No results given for follow up period after treatment finished. No CI or RR given in spite of reference to them in the methods
Symptom improvement score 8–14 days after last visit (completed by parents)No difference in symptom scores between spinal manipulation and placebo (p=0.743). NNT = 10 (95% CI 3 to ∞); NNH (95%CI 9 to ∞)No results given for improvement after visits 1 and 2y