Does an Indian Version of the International Classification of Disease Injury Severity Score Predict Mortality in Four Public Hospitals in Urban India?

Introduction

In 2013 trauma was estimated to cause 4,8 million deaths, which is more than HIV/AIDS, tuberculosis, malaria and maternal conditions combined (1). Ninety per cent of these deaths occur in lower-middle income countries (LMIC) and an estimated two million lives could be saved annually by improved quality of care (2,3). India is considered a lower-middle income country with over 1 million annual trauma deaths (1). In 2020 trauma is estimated to be the third leading cause of death in the country (4). Hence, efforts to strengthen trauma care in India are urgently needed.

Trauma patients constitute a heterogeneous population, making trauma research and outcome comparison over time and between contexts difficult but important (5). Accounting for factors such as selection bias, difference in care and case mix is crucial for correct conclusions (6,7).To enable this several tools or scores have been developed including the Injury Severity Score (ISS) and the Trauma and Injury Severity Score (TRISS) (8,9). The use of these scores as part of quality improvement programmes has been associated with improved trauma care (10).

In ISS and TRISS the severity assigned to each injury is based on expert consensus. In contrast, the international classification of disease (ICD) injury severity score (ICISS) was developed using a more data driven approach (9,11). This score is based on survival risk ratios assigned to ICD injury codes to estimate an individual patient's probability of survival. According to a recent systematic review ICISS outperforms ISS derived methods (12), but so far almost all research on ICISS is from high income countries. Therefore, our research question is, does an Indian version of ICISS predict mortality in four public hospitals in urban India?

Study design