Within-Individual Dependence in Self-Controlled Case Series Models for Recurrent Events

Summary The self-controlled case series model may be used to analyse recurrent events when event times are conditionally independent given fixed or random individual effects. To test the hypothesis of within-individual independence, the model is augmented by an association parameter for diagonal dependence, which provides the focus for a test of independence. Estimation methods are described, and simulations are presented to illustrate the power of the method in relevant scenarios, and to quantify the bias resulting from failure of the independence assumption. The methods are applied to two data sets, relating to a rare bleeding disorder and to myocardial infarction.