Table 2.
Simulation results evaluating the performance of mintMR and competing methods in different scenarios
| Number of IVs | Probability of QTL effect being consistent across QTL and GWAS sample | Number of tissues for each exposure | |||||||
|---|---|---|---|---|---|---|---|---|---|
| 15 | 25 | 100 | 0.8 | 0.5 | 0.2 | 5 | 10 | 15 | |
| Power | |||||||||
| mintMR | 0.734 | 0.822 | 0.932 | 0.867 | 0.789 | 0.660 | 0.553 | 0.713 | 0.739 | 
| mintMRoracle | 0.764 | 0.861 | 0.964 | 0.898 | 0.852 | 0.746 | 0.586 | 0.810 | 0.900 | 
| mintMRsingle-gene | 0.547∗ | 0.789∗ | 0.963 | 0.751∗ | 0.712∗ | 0.527∗ | 0.497∗ | 0.538∗ | 0.583∗ | 
| IVW+metaIV | 0.351∗ | 0.352∗ | 0.530 | 0.299∗ | 0.388∗ | 0.399∗ | 0.321∗ | 0.286∗ | 0.281∗ | 
| Egger | 0.236∗ | 0.254∗ | 0.220 | 0.367∗ | 0.289∗ | 0.264∗ | 0.240∗ | 0.180∗ | 0.192∗ | 
| MVMR-IVW | 0.444∗ | 0.774 | 0.969 | 0.682∗ | 0.572∗ | 0.436 | 0.316∗ | 0.302∗ | 0.487 | 
| MVMR-Egger | 0.383∗ | 0.729 | 0.898 | 0.562∗ | 0.495 | 0.407 | 0.266∗ | 0.326∗ | 0.404 | 
| MVMR-Lasso | 0.631∗ | 0.783 | 0.969 | 0.793∗ | 0.679∗ | 0.443 | 0.612∗ | 0.364∗ | 0.493 | 
| MVMR-Median | 0.526∗ | 0.745∗ | 0.920∗ | 0.723∗ | 0.671∗ | 0.500 | 0.418∗ | 0.225 | 0.480∗ | 
| MVMR-Robust | 0.276 | 0.730 | 0.961 | 0.513 | 0.432 | 0.324 | 0.175 | 0.190 | 0.407 | 
| Type I error rate | |||||||||
| mintMR | 0.049 | 0.055 | 0.041 | 0.053 | 0.066 | 0.060 | 0.052 | 0.037 | 0.062 | 
| mintMRoracle | 0.049 | 0.051 | 0.056 | 0.049 | 0.054 | 0.050 | 0.048 | 0.050 | 0.048 | 
| mintMRsingle-gene | 0.115∗ | 0.109∗ | 0.059 | 0.236∗ | 0.152∗ | 0.194∗ | 0.174∗ | 0.235∗ | 0.126∗ | 
| IVW+metaIV | 0.145∗ | 0.144∗ | 0.093 | 0.148∗ | 0.156∗ | 0.168∗ | 0.146∗ | 0.157∗ | 0.125∗ | 
| Egger | 0.134∗ | 0.112∗ | 0.074 | 0.109∗ | 0.110∗ | 0.127∗ | 0.138∗ | 0.124∗ | 0.105∗ | 
| MVMR-IVW | 0.122∗ | 0.064 | 0.055 | 0.122∗ | 0.106∗ | 0.067 | 0.126∗ | 0.122∗ | 0.081 | 
| MVMR-Egger | 0.122∗ | 0.063 | 0.055 | 0.120∗ | 0.098 | 0.064 | 0.126∗ | 0.153∗ | 0.084 | 
| MVMR-Lasso | 0.194∗ | 0.068 | 0.057 | 0.188∗ | 0.129∗ | 0.069 | 0.303∗ | 0.145∗ | 0.081 | 
| MVMR-Median | 0.114∗ | 0.116∗ | 0.100∗ | 0.172∗ | 0.112∗ | 0.069 | 0.135∗ | 0.076 | 0.103∗ | 
| MVMR-Robust | 0.066 | 0.047 | 0.051 | 0.067 | 0.052 | 0.036 | 0.072 | 0.062 | 0.060 | 
When varying the number of IVs, the proportion of variation in outcome explained by UHP effect is 0.1. The causal effects are generated from . The probability of QTL effect being consistent across QTL and GWAS samples is 0.8. Five tissues are generated for each exposure. When decreasing the probability of QTL effect being consistent, the causal effects are generated from . We simulated 15 IVs across 5 tissues for each exposure. When the number of tissues for each exposure increased from 5, 10, to 20, we simulated 15, 25, and 45 IVs, respectively. The probability of consistency is 0.8. Causal effects are generated from . Results are asterisked (∗) for methods unable to control type I error rates (≥0.1).