Exploratory Mendelian randomization analysis: The genetic susceptibility of CT examination preference and the risk of hypertrophic cardiomyopathy.

Inverse-variance weighting indicated a statistically significant negative correlation between genetic propensity for CT scan and hypertrophic cardiomyopathy risk.

• The IVW method produced an OR of 2.22 × 10-16 (P = .013)
• The extremely small OR value suggests a negative (protective) directional association
• Genotype data were drawn from the MRC-IEU and FinnGen databases
• SNPs related to the phenotype 'receiving CT scan' were selected as instrumental variables

MR-Egger and weighted median methods yielded non-significant estimates with wide confidence intervals, inconsistent with the IVW result.

• Both MR-Egger and weighted median methods produced non-significant P-values
• Wide confidence intervals were reported for both alternative methods
• The inconsistency across methods reflects 'differences in the sensitivity of different analysis methods to potential biases'
• Results were described as 'inconsistent results across methods'

Sensitivity analyses suggested the set of instrumental variables was statistically robust.

• Funnel plot analysis was used to assess potential pleiotropy and IV robustness
• Leave-one-out analysis was conducted to evaluate stability of the estimated values
• Both analyses suggested the instrumental variable set was 'statistically robust'
• Multiplicity tests were also conducted to evaluate the robustness of the tool variables

A two-sample Mendelian randomization framework was used with CT scan propensity as the exposure and HCM as the outcome.

• SNPs associated with the phenotype 'receiving CT scan' were selected as instrumental variables from MRC-IEU and FinnGen databases
• CT scan propensity based on genetic prediction was treated as the exposure factor
• HCM was treated as the outcome
• Three MR methods were applied: inverse-variance weighting, MR-Egger, and weighted median

The authors concluded that the findings are at an early stage and highlight the complexity of using broad non-biological exposure indicators in Mendelian randomization studies.

• Differences in estimated values across analytical methods indicate 'inherent complexity involved in using broad non-biological exposure indicators'
• The study is described as 'exploratory'
• Authors emphasized 'the importance of using more precise phenotypic definitions in future research'
• The study calls for further research to explore this potential association