Missing patients in a regional trauma registry: incidence and predictors

Trauma systems have data registries in order to describe and evaluate (the quality of) trauma care. If results between centres and countries (benchmarking) are to be compared, data has to be accurate, reliable and complete. All trauma registries deal with incompleteness. A contributor to incompleteness of the data is failure to include patients that fulfil the criteria; the so-called missing patients. The aim of this study is to assess the number of missing patients in our regional trauma registry and to identify predictors for being missing from the trauma registry. A random sample was taken. Four calendar weeks from 2012 were selected and medical files of all consecutive presentations to the emergency department or trauma room during those weeks were studied. Patients who were already correctly included in the trauma registry were assigned to the 'included' group and patients who should have been but were not to the 'missing' group. Multivariable logistic regression analysis was performed to identify predictors for being missed from the trauma registry. Of a total of 338 patients, 50 (15%) were identified as missing. Characteristics of the missing patients did not differ substantially from the included patients. Transfer to another hospital after initial assessment and presentation in a Level 3 hospital compared to a Level 1 hospital were independent predictors for being missed from the trauma registry, with an adjusted odds ratio of 5.86 (95% CI: 2.08-16.52) and 6.64 (95% CI: 1.86-23.78), respectively. Overall, 15% of the patients who met the inclusion criteria of the trauma registry were not included in the registry. Special attention should be paid to patients who are transferred to other hospitals in the network after initial assessment and to registration in Level 3 hospitals