Predictors Intention to donate blood among eligible population in Ethiopia: Systematic review and meta-analysis based on the theory of planned behavior in Ethiopia

Background Despite its critical role, there remains a global mismatch between the demand for blood and the availability of safe donors, posing a major public health challenge. Objective To systematically review and meta-analyze predictors of blood donation intention among eligible populations in Ethiopia using the Theory of Planned Behavior (TPB). Methods This systematic review and meta-analysis followed the PRISMA 2020 guidelines. Observational studies (cross-sectional, case-control, and cohort) conducted up to 2025 were included. A comprehensive search was performed in PubMed, Epistemonikos, ScienceDirect, Hinari, and Google Scholar. Study selection was illustrated using a PRISMA flow diagram. Methodological quality was assessed with the Newcastle–Ottawa Scale adapted for cross-sectional studies. Data were synthesized using Stata version 17. Correlation coefficients (r) for each TPB construct were pooled using a random-effects model (DerSimonian–Laird method). Heterogeneity was assessed using I², publication bias with funnel plots and Egger’s test, and sensitivity analyses were performed. Results Six studies comprising 3,866 participants across Amhara, Oromia, SNNPR, and Tigray were included. All TPB constructs were significantly associated with intention to donate blood. Perceived behavioral control (PBC) was the strongest predictor (r = 0.52, 95% CI: 0.32–0.72), followed by attitude (r = 0.33, 95% CI: 0.18–0.48), while subjective norm showed the weakest and most inconsistent association (r = 0.23, 95% CI: 0.05–0.41). Subgroup analyses highlighted regional and contextual variation: attitude-intention correlations were stronger in Oromia and Southern Ethiopia; PBC was most influential in Oromia (r = 0.78); and subjective norm was highly predictive in Amhara and SNNPR but negligible or negative in Tigray. Sensitivity analyses confirmed the robustness of these findings. Conclusion Among Ethiopian adults, intention to donate blood is primarily influenced by perceived behavioral control, with attitude contributing moderately and subjective norms playing a minor and inconsistent role. These findings underscore the importance of interventions that enhance individuals’ confidence and ability to donate.