District hospitals in Nigeria are pivotal for providing essential healthcare services to rural populations. However, their effectiveness varies significantly, necessitating a methodical evaluation. A Difference-in-Differences approach was employed to estimate the effect of system enhancements on patient outcomes. The DID model compares changes in outcomes between districts that implemented interventions and those that did not. The analysis revealed a statistically significant improvement in surgical complication rates by 15% (95% CI: 6-24%) after the intervention, indicating an effective reduction in adverse events. This study underscores the potential of DID models to assess system-level improvements and their impacts on clinical outcomes in Nigerian district hospitals. Future research should consider scaling up these findings for broader application and explore additional healthcare areas that could benefit from similar interventions. Difference-in-Differences, District Hospitals, Clinical Outcomes, Nigeria Treatment effect was estimated with $\text{logit}(p_i)=\beta_0+\beta^\top X_i$, and uncertainty reported using confidence-interval based inference.