Consider the research question, study design, and data type when selecting the most appropriate analysis for your meta-analysis. odds ratio (OR), relative risk (RR), and hazard ratio (HR) to help you decide:

Odds Ratio (OR)- The ratio of the odds of an event occurring in the exposed group versus the non-exposed group.
Suitable for case-control studies, cross-sectional studies, or when the outcome is binary.
Interpretation: An OR > 1 indicates an increased odds of the event, while an OR < 1 indicates a decreased odds.

Relative Risk (RR) - The ratio of the probability of an event occurring in the exposed group versus the non-exposed group.
Suitable for cohort studies, randomized controlled trials (RCTs), or when the outcome is binary.
Interpretation: An RR > 1 indicates an increased risk of the event, while an RR < 1 indicates a decreased risk.

Hazard Ratio (HR) - The hazard rate (instantaneous risk) ratio of an event occurring in the exposed and non-exposed groups.
Suitable for time-to-event data, such as survival analysis or when the outcome is time-dependent.
Interpretation: An HR > 1 indicates an increased hazard of the event, while an HR < 1 indicates a decreased hazard.

Consider the following when choosing between OR, RR, and HR:

Study design: OR is often used in case-control studies, while RR is used in cohort studies and RCTs. HR is used in survival analysis.
Outcome type: Binary outcomes (e.g., disease presence/absence) are often analyzed using OR or RR, while time-to-event outcomes (e.g., survival time) are analyzed using HR.
Data availability: If you can access individual patient data (IPD), you can calculate HR. Otherwise, OR or RR might be more suitable.

In summary:

- Use OR for case-control studies or binary outcomes.
- Use RR for cohort studies, RCTs, or binary outcomes.
- Use HR for time-to-event data or survival analysis.