Objective Multisymptom illness (MSI) is prevalent in military and veteran cohorts, but little is known about healthcare usage, especially after leaving the armed forces. We investigated health service utilisation and disability claims for MSI cases among Gulf War veterans and a military comparison group 20 years after the 1990–91 Gulf War.

Methods MSI cases were defined using a modified CDC definition and compared with those with no MSI or chronic illness and those with chronic illness among participants in a Gulf War veterans’ health study conducted in 2000–2003 (Wave-1). At follow-up in 2011–2012 (Wave-2), the subjects were linked to the national Medicare and Department of Veterans’ Affairs (DVA) databases to obtain objective data on health service utilisation and disability claims during 2001–2012. Poisson regression was used to assess differences between groups.

Results 82.5% of subjects had discharged by Wave 2. More MSI cases than those without MSI or chronic illness had visited a General Practitioner (risk ratio [RR] = 1.24, 95% CI = 1.11, 1.39) or were hospitalised (RR = 2.01, 95% CI = 1.44, 2.80) in the 12-months preceding Wave-2. In the 10 years prior to Wave-2, significantly more MSI cases than those without MSI or chronic illness had consulted a medical specialist. No significant differences between the MSI and chronic illness group were observed. There were significantly more disability claims among MSI cases (44.3%) than those without MSI or chronic illness (27.2%; RR = 1.54, 95% CI=1.23, 1.93), but not compared to the chronic illness group (37.3%; RR = 1.13, 95% CI = 0.86, 1.47).

Conclusion Health service use and disability claims were significantly higher in the MSI group than the group without MSI or chronic illness but were comparable with a group with chronic illness 20 years after the Gulf War. As most subjects had left military service, these findings have important implications for those caring for ex-military personnel.