Figure 1. Limitations and strategies for NDB studies 1-1: Lack of information on confounders/covariates, outcomes, and other clinical content 1-2: Limitations regarding patients not included in the NDB 1-3: Misclassification of data 1-4: Lack of unique identifiers and register of beneficiaries 1-5: Other limitations *The box on the left shows the limitations, and the box on the right shows the strategies.
