Background Understanding the role of comorbidity in recovery following injury is an important challenge given known associations between comorbidity and poor outcomes, more complex clinical management, and increased healthcare costs.
Aim To compare rates of recovery over 24 months following injury for those with no pre-existing comorbid conditions, one comorbidity and two or more comorbidities.
Methods The Prospective Outcomes of Injury Study recruited 2856 injured New Zealanders aged 18-64 years. Data sources included participant surveys and administrative data from New Zealand’s no-fault injury compensation insurer, the Accident Compensation Corporation, and the National Minimum Dataset of hospital discharges. Recovery, or lack of, was measured using the WHO Disability Assessment Schedule at 3, 12 and 24 months post-injury. Twenty-one pre-existing chronic conditions were used to identify comorbidity. Analysis involved Generalised Estimating Equations.
Results The distribution reporting none, one comorbidity, or multimorbidity pre-injury was 51%, 27%, and 21% respectively. We estimated no difference (log odds per year 0.05, 95% CI -0.17 to 0.27) between the rate of change of disability for those with one pre-injury comorbidity compared to those with none. Those with pre-injury multimorbidity had significantly slower reduction in disability over time than those with no pre-injury comorbidity (log odds per year 0.27, 95% CI 0.05 to 0.48).
Conclusion This longitudinal analysis of disability outcomes following injury indicates those with pre-existing multimorbidity have significantly slower recovery rates. Given the increasing prevalence of multimorbidity in many countries, greater understanding of the opportunities for intervention to better support injured people with multimorbidity are required.