Pica in Sickle Cell Disease: A Systematic Review and Meta-Analysis

Pica, the persistent ingestion of non-nutritive, non-food substances for ≥ 1 month at a developmentally inappropriate age, is regularly observed but understudied in sickle cell disease (SCD). Its prevalence and risk factors are unclear. This systematic review aims to estimate pica prevalence and synthesize evidence on associated characteristics and correlates in SCD. We searched Embase, MEDLINE ALL, Web of Science, Cochrane CENTRAL, PsycINFO and Google Scholar up to 31 October 2025, for studies reporting original data on the prevalence and characteristics of pica in individuals ≥ 2 years with SCD. Risk of bias was assessed using a modified Newcastle-Ottawa Scale. Meta-analysis of prevalence used random-effects models. Data on substances consumed were pooled. Literature on potential correlates was narratively summarized across biological, psychological and social domains. Ten studies (1585 participants) from North America (n = 6), Africa (n = 1), Europe (n = 1), the Middle East (n = 1) and South America (n = 1) were included, with sample sizes ranging from 55 to 395. The pooled prevalence of pica was 34% (95% CI: 24%-46%, I² = 94%). Across four studies, the most commonly ingested materials were clay/dirt (n = 110, 39.3%), paper (n = 60, 21.4%) and fabric (n = 29, 10.4%). Narrative synthesis identified younger age, lower bodyweight, lower haemoglobin levels, higher impulsivity, lower socioeconomic status, lower family satisfaction and a positive family history as potential correlates of pica in SCD. Pica in SCD is highly prevalent. Psychosocial determinants may play a larger role than previously anticipated, alongside biological and disease-related contributors. However, current evidence is limited by small sample sizes, inconsistent findings, and lack of validated assessment tools. To advance understanding of the aetiology of pica, future longitudinal studies integrating biological, psychological, social and neuroimaging measures are needed.