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. Author manuscript; available in PMC: 2020 Nov 1.
Published in final edited form as: Epidemiology. 2019 Nov;30(6):861–866. doi: 10.1097/EDE.0000000000001087

Table 1.

Comparison of parameter estimates from the case–crossover and the self-controlled case series designs across all scenarios

Scenarios Case–crossover Self-controlled case series
Log estimatea Bias MSE OR Log estimatea Bias MSE IR
Base case (no violation of assumptions) 0.70 0.01 0.04 2.02 0.70 <0.01 0.01 2.01
Time-varying confounder (prevalence 40%) 0.82 0.12 0.06 2.27 0.80 0.11 0.02 2.22
Time-varying confounder (prevalence 80%) 0.91 0.22 0.09 2.49 0.90 0.21 0.05 2.46
Time trend (linear increase) in precipitant drug exposure prevalence 0.94 0.25 0.10 2.56 0.69 −0.01 0.01 1.98
90-day precipitant 0.70 0.01 0.02 2.02 0.70 <0.01 <0.01 2.00
Precipitant drug with persistent useb 1.05 0.36 0.15 2.85 0.69 <0.01 0.01 1.99
Object drug discontinuation (10%) 0.71 0.01 0.04 2.03 0.70 0.01 0.01 2.02
Object drug discontinuation (50%) 0.71 0.01 0.05 2.03 0.73 0.04 0.02 2.09
Object drug discontinuation (90%) 0.71 0.01 0.04 2.03 0.80 0.10 0.03 2.22
a

True value is 0.69 (OR of 2.0).

b

Among patients exposed to the precipitant drug, 70% were exposed for 30 days and 30% stayed exposed through the end of the study (persistent use). Bias calculated as the mean difference between the log estimate and the true value (averaged across 1,000 iterations); MSE – mean squared error; OR – odds ratio; IR – incidence ratio. Both OR and IR are calculated as exponential of the mean log estimate.