Lead toxicity from retained bullet fragments: A systematic review and meta-analysis

BACKGROUND Firearm injury remains a public health epidemic in the United States. A large proportion of individuals with gunshot wounds subsequently have retained bullet fragments (RBF). There are no standard medical guidelines regarding bullet removal and the full extent of the consequences of RBF remains unknown. OBJECTIVE To determine whether there is an association among RBF, elevated blood lead levels (BLL) and lead toxicity in survivors of firearm injury 16 years and older. METHODS PubMed, EMBASE, CINAHL, Scopus, Cochrane Library, and Sociological Abstracts electronic databases were searched for all randomized controlled trials, prospective and retrospective cohort, case-control and cross-sectional studies published in the English language between 1988 and 2018. Quality assessment and risk of bias was evaluated using the Newcastle Ottawa Scale. A meta-analysis was performed using a random-effects model. RESULTS The search yielded 2,012 articles after removal of duplicates. Twelve were included after full article review. Eleven studies supported an association between elevated BLL and RBF. Bony fractures were associated with increased risk of elevated BLL in three studies. A positive relationship between BLL and the number of RBF was also shown in three studies, with one study demonstrating 25.6% increase in BLL for every natural-log increase in RBF (1-228, p < 0.01). Meta-analysis demonstrated BLL significantly higher in individuals with RBF as compared to controls (5.47 μg/dL, p < 0.01). CONCLUSION Patients with bony fractures or multiple RBF, who are at higher risk of elevated BLL, should be monitored for BLL in intervals of 3 months within the first year of injury. For patients who return with BLL above 5 μg/dL, all efforts must be undertaken to remove fragments if there is no potential to worsen the injury. LEVEL OF EVIDENCE Systematic review, Meta-analysis, level III.