Definitional and methodological inconsistencies in complementary and alternative medicine research for paediatric autoimmune disease: a targeted review

Background: Research on complementary and alternative medicine (CAM) use in paediatric autoimmune diseases (AD) is widespread, but findings cannot be aggregated to provide reliable prevalence estimates. Studies vary in how CAM is defined, which modalities are included, and how time periods of use are measured. These inconsistencies prevent meta-analyses, which are critical for robust prevalence and effectiveness evidence. Methods: This study provides the first targeted analysis of methodological variability in CAM research for paediatric AD. We conducted data extraction and analysis of 42 studies identified through a systematic search of eight databases. A descriptive analysis examined three domains: (1) CAM definitions, (2) products and practices included, and (3) time periods of CAM use. Results: Substantial inconsistency was identified across all domains. Almost half of the included studies (48%) provided no definition of CAM, while 28% referenced the NIH definition and 24% used author-derived definitions; further variation persisted within these categories, particularly in whether and how specific modalities were listed. CAM modalities were typically grouped as products or practices, with the most frequently reported being vitamins (62%), herbal preparations (50%), massage (48%), and homeopathy (45%), with the inclusion of specific modalities varying considerably across studies. Reporting of time periods of CAM use was also highly inconsistent, with the majority of studies providing no timeframe (n = 20), followed by reports of past use within the previous 3–12 months (n = 13) and only one study addressing future CAM use. Conclusions: Methodological inconsistencies prevent the aggregation of prevalence data, comparisons, and meta-analyses. This study provides the first detailed mapping of CAM definitions, modalities, and the timeframe of use reporting in paediatric AD. Standardised definitions and reporting frameworks are needed to enable meta-analyses to better inform clinical care and policy.