Poster session: Heart rate variability following combat injury in British miliary servicemen - is there an association?

Abstract

Combat- related traumatic injury (CRTI) can adversely affect psychophysiological well- being. The association between CRTI and short- term heart rate variability (HRV) remains unexamined within a military cohort and was the aim of this study. This study (n=975) undertook the analysis of the first follow- up data from the ArmeD serVices trAuma rehabilitatioN outComE (ADVANCE) cohort study, UK. The participants were frequencymatched (age, rank, role- in- theatre, and deployment period: Afghanistan 2003- 2014) at recruitment and were divided into injured and uninjured groups. HRV data were acquired using a 5- minute electrocardiogram with participants breathing normally in a supine and fullyrested state. Root- mean- square- of- successive- differences (RMSSD) was reported to measure parasympathetic tone (HRV). A multiple regression model was run to report the CRTI- RMSSD association, adjusting for age, rank, and ethnicity. Participants’ median age was 37.5 (IQR 34.2, 41.2) years. Of 975 participants, 469 had CRTI whereas 506 were uninjured. The time since injury/deployment was approximately 11 years. Median RMSSD was significantly lower in injured than uninjured [37.7ms, (IQR 25.3, | ABSTRACT S273 55.9) vs 41.9ms (IQR 27.7, 62.2); p<0.05]. An 8% reduction in the geometric mean of RMSSD was observed relating to CRTI after confounder adjustment (Geometric Mean Ratio: 0.92 (95%CI:0.85,0.99);p<0.05). The findings indicate that even several years past, the CRTI associates with lower parasympathetic tone in injured than uninjured servicemen. Our findings may help understand the recovery pathway following CRTI.