A systematic search of economic evaluation studies for interventions in an SCI population yielded 19 studies. From the results of the base case analyses it would appear that ITB for management of spasticity, transanal irrigation for bowel care and electrical stimulation therapy, negative pressure wound therapy for treatment of pressure injuries, fibrin sealant for surgical treatment of pressure injuries all had better clinical outcomes and lower costs versus conventional treatment. Similar results were observed for sildenafil citrate in treating erectile dysfunction when compared to intracavernous injections of papaverine prostadil, transurethral suppository or surgical implantation of prosthetic and also for duplex ultrasound at admission for screening deep vein thrombosis. Sildenafil citrate had results that would be considered cost effective compared to triple mix and vacuum erectile device. Gel reservoir catheters versus non-coated catheter for bladder management, sacral anterior root stimulation for neurogenic bladder and telephone support with standard pressure injury management were considered cost-effective. However, supported employment did not result in a reduction in cost or gain in outcomes for US veterans compared to standard care. Early decompression for individuals with traumatic cervical SCI and neuroprosthesis implant for cough restoration was associated with lower costs. Older individuals requiring surgical and rehabilitation management had higher costs for individuals with traumatic cervical SCI.

Unfortunately, there are numerous concerns that limit the comparability of economic evaluations. First, the studies were from different jurisdictions that have different health care systems. Each country has a different mix of public/private payment for health care services. Some countries such as Canada and many European nations rely more heavily on the public funding while other countries such as the US rely more on private/third party payment. As well, each health care system has different emphases when providing health care to their citizens. Some countries may focus more on treatment modalities while others may focus more on prevention. Second, all studies have different perspectives in costing. Many of the studies focused on the government payer perspective. Even in the studies that took a government payer perspective, each study took a different bundle of health care costs, ranging from 5-6 different costs to only 1 cost item (clinician time in providing care).

The cost of illness study methods for the included studies varied widely making comparison of results difficult. This is compounded by the difficulty of comparing cost of illness between jurisdictions where different health care systems have different patient care modalities, behaviours, habits and resource limitations. Many of the limitations of interpreting economic evaluation studies apply for cost of illness studies. The results of the cost of illness studies in most cases only represent the health care resource utilization and associated gross costs experienced by an individual with SCI. The absence of a matched non-SCI population in many of the studies does not allow us to understand the additional health care costs attributable to SCI and the additional economic burden that is associated with this injury. The lack of studies exploring net costs in other disease areas in general also does not facilitate a comparison of SCI attributable cost to other diseases.

Despite the limitations in methods in the studies reviewed, limitations in applicability to other jurisdictions and the lack of comparability, this review provides an interesting summary of the state of economic research in SCI. Currently, comparative cost analyses for interventions in the SCI population are sparse with only a few studies identified in the last 15 years. There appear to be a strong interest in understanding the cost-effectiveness of hydrophilic catheters as well as interventions for treating pressure injuries. For cost of illness studies there are over a dozen analyses conducted in the general SCI population in the last 10 years representing 8 different jurisdictions. Both Canada and the US have the highest number of studies. The studies from Canada were based on various data sources. In the US, studies were driven by data from the Model Systems Centre through the National SCI statistical centre. With the limited number of cost of illness studies, many countries are not represented and the cost impact of SCI remains unknown. Despite the relative lack of data, it remains that that there are substantial costs associated with SCI even though it is a relatively low prevalence condition

There is a need for additional economic studies in the area of SCI given the sizable impact of this condition to the health care system and the large number of interventions that an individual with SCI would require throughout their lifetime. Given the substantial health care costs associated with SCI, identifying and implementing cost-effective health care strategies would benefit all parties including the health care recipient, provider and funder. The authors hope that this review will shed light on the state of economic studies in SCI and spark increased interest in researchers to pursue studies in this field.