Background: Medical errors are one of the most important factors affecting patient safety and the quality of health care services, and are affected by many factors. Objective: We aimed to investigate the relationship between hospital and medical error types, seasonality, and work shifts with the severity of medical errors (no harm, near miss, and harmful incident) in Iran’s hospitals. Methods: We conducted a cross-sectional study in 39 hospitals in a province of Iran. Data were collected using voluntary reporting forms and analyzed using multiple logistic regressions. Results: Of 10,384 medical errors, 68.4% were no harm. Medical error type and hospital type had a significant relationship with the severity of medical errors. In terms of seasonality, all types of medical errors were more frequently reported during fall and winter as follows: no harm medical errors (28.4% and 28.3%), near miss (28.9% and 28.2%), and harmful incidents (31.0% and 26.5%). The incidence of errors in public non-educational (OR = 0.22, 95% CI: 0.17–0.30, p<0.001) and public educational hospitals (OR = 0.27, 95% CI: 0.21–0.36, p<0.001) has been significantly less as compared to other types of hospitals. Conclusion: Policymakers should pay attention to hospital types and common medical error types when developing evidence-based interventions and policies to decrease the medical error severity in Iranian and similar countries’ context hospitals.
