Cost‐effectiveness of hydrophilic‐coated urinary catheters for individuals with spinal cord injury: A systematic review

Abstract Objective To identify and critically evaluate the economic evaluations examining the cost‐effectiveness of hydrophilic‐coated vs uncoated catheters for individuals with spinal cord injury. Methods We searched MEDLINE, the Excerpta Medica database (EMBASE), Cochrane Database of Systematic Reviews, the Cumulative Index to Nursing and Allied Health Literature (CINAHL), and Emcare for studies in English and French. There were no restrictions to the year of publication. Our search strategy included the following key terms: “spinal cord injury,” “catheterization,” and “cost analysis.” Results The search identified 371 studies, of which eight studies met the inclusion criteria. Five studies observed hydrophilic‐coated catheters to be cost‐effective compared to uncoated catheters. Two studies found hydrophilic‐coated catheters to be not cost‐effective compared to uncoated catheters and one study estimated that hydrophilic‐coated catheters reduced the long‐term health‐care costs compared to uncoated catheters. Conclusion The cost‐effectiveness of hydrophilic‐coated catheters was dependent on the comparator used, the consideration of long‐term effects, and the unit cost of treatment. Further studies are needed to explore the short‐term and long‐term effects of hydrophilic‐coated catheter use on urinary tract infections and clarify the impact of hydrophilic‐coated catheter use on long‐term renal function. Overall, our critical evaluation of the literature suggests that the evidence is pointing toward hydrophilic‐coated catheters being cost‐effective, particularly when a societal perspective is applied.

abdomen (supra-pubic) and are left in situ. Urine is collected through an attached drainage bag. 4 After insertion, indwelling catheters can remain in the bladder for an extended period of time and are regularly changed every 4-6 weeks. 5 However, indwelling catheters have been shown to have a higher number of complications, including bladder stones, urinary tract infection (UTI), and decreased bladder capacity, in comparison to intermittent catheters. [6][7][8] Intermittent catheterization is recommended as the gold standard for bladder management for individuals with spinal cord injury and offers several advantages over indwelling catheters. 9,10 Intermittent catheters are inserted via the urethra or the abdomen, similar to indwelling catheters. 4 In contrast to indwelling catheters, intermittent catheters can be inserted by the patient or caregiver in any location and are immediately removed after bladder drainage. 4 Other advantages of intermittent catheters include lower risk of UTI and other complications, increased quality of life and patient autonomy, and fewer social and intimacy barriers. 9,10 Additionally, intermittent catheters have higher rates of patient adherence. A study by Cameron et al found that only 71% of individuals continue to use intermittent catheters 30 years after initial use. 11 Among the different types of intermittent catheters, uncoated and single-use hydrophilic-coated catheters are the most commonly used. Uncoated catheters are often made from medical-grade polyvinyl chloride (PVC) and require manual external gel lubrication prior to insertion. 12 The need to manually self-lubricate may be particularly difficult for individuals with limited upper limb function. 13 Catheterization with uncoated catheters may have a slightly increased risk of bacterial infection and other complications such as hematuria. 14,15 Moreover, hydrophilic-coated catheters are coated with polyvinylpyrrolidone, a polymer that creates a lubricated surface upon exposure to water to facilitate the insertion of the catheter. Therefore, hydrophilic-coated catheters do not require manual lubrication prior to insertion. 16 Moreover, hydrophilic-coated catheters may lead to better health outcomes due to reduced risk of infection.
A previous systematic review and meta-analysis identified a 16% reduction in UTI risk associated with hydrophilic-coated catheter use in comparison to uncoated catheter use. 17 However, the clinical benefits of hydrophilic-coated catheters come at a cost since this the unit cost for this technology is greater than that of uncoated catheters. 4,18 Several studies have examined the cost-effectiveness of hydrophilic-coated vs uncoated catheters. Two reviews on this topic have been conducted. One review was conducted by Health Quality Ontario (HQO) in 2019. 4 This review sought to determine the cost-effectiveness of intermittent catheterization for long-term usage and identified papers published prior to 2016. 4 All five identified studies comparing hydrophilic-coated and uncoated catheters found hydrophilic-coated catheters to be a cost-effective option. 4 Another review was conducted by Saadat et al and identified six papers from 2014 to 2018; they reviewed the cost-effectiveness of single-use vs repeated-use catheters and hydrophilic-coated vs uncoated catheters. This study briefly summarized the results of each included paper but did not make any conclusions on cost the effectiveness of hydrophilic-coated catheters. 19 Neither of these two previous studies critically evaluated the economic evaluations included in the review.
In order to fill the knowledge gaps identified in the existing literature, our systematic review sought to identify and critically evaluate the economic evaluations examining the cost-effectiveness of hydrophilic-coated vs uncoated catheters for individuals with spinal cord injury. The findings of our study can be used to provide information for public health-care payers to determine whether hydrophilic-coated catheters should be publicly funded.

| Search strategy and studies identification
We searched MEDLINE, the Excerpta Medica database (EMBASE), Cochrane Database of Systematic Reviews, the Cumulative Index to Nursing and Allied Health Literature (CINAHL), and Emcare. There were no restrictions to the year or to the language of the publication.
Our search strategy included the following key terms: "spinal cord injury," "catheterization," and "cost analysis." The full search strategy is included in Appendix A. We also conducted a bibliographic hand search of all review articles identified in the database search.
Publications were included if they: (1) included a full economic evaluation (eg, cost-effectiveness, cost-utility, or cost-benefit study) of any type of urinary catheter; (2) were conducted for individuals with spinal cord injury; and (3) were written in English or French. We excluded gray literature, conference abstracts, systematic reviews, comprehensive reviews, letters, guidelines, news articles, and policy analyses. We also excluded costing studies and cost comparison analyses.
After the removal of duplicates, titles and abstracts were independently screened by BC and MX using Covidence software. 20 Potentially relevant full-text articles were screened by BC and MX for an inclusion or exclusion decision. Discrepancies during abstract and full-text screening were resolved by BC.

| Data collection and analysis
We evaluated the methodological quality of the included articles using the Drummond checklist. 21 The Drummond checklist has been recommended for assessing the quality of economic evaluation studies and includes four main categories: study design, data collection, analysis, and interpretation of results. We used the Drummond checklist for quality assessment due to its broad applicability to various types of economic evaluation studies and its simple structure. 22,23 The quality assessment was carried out by two reviewers (BC and MX) and discrepancies were resolved through consensus between the two reviewers.
BC and MX extracted data from the included articles. Extracted variables included study characteristics (eg, author, country study design, year of publication, population, time horizon, intervention, and comparator) and outcomes of interest (eg, costs and incremental cost-effectiveness ratio (ICER)). Relevant data were extracted into a Microsoft Excel database.
A meta-analysis of our data could not be conducted due to the heterogeneity in study designs, populations, time horizons, and outcomes of our included studies. Thus, only descriptive analyses were performed.

| Study selection
Our search identified 371 citations. After the removal of 110 duplicates, we screened 261 titles/abstracts for eligibility. After title and abstract screening, 13 articles remained for full-text screening. Of these 13 articles, eight studies fulfilled the study criteria and were included for further analysis. The main reasons for exclusion at the full-text screening stage included wrong study design (n = 4) and wrong comparator used in study (n = 1). Figure 1 describes the process of study inclusion. Table 1 presents the characteristics of the eight included studies. The eight included studies were published between 2013 and 2018 and were conducted in Canada (n = 2), 4,18 the United Kingdom (n = 2), 24,25 Brazil (n = 1), 12 Japan (n = 1), 26 Italy (n = 1), 27 and the United States (n = 1). 28 All studies carried out cost-utility analysis. 4,12,18,[24][25][26][27][28] Three studies also examined cost per life-year gained. 12,26,27 One study also examined cost per UTI avoided per patient. 25 Studies were conducted from the following perspectives:

| Summary of the study methods and results
The results of the included studies are summarized in Table 1.

| D ISCUSS I ON
Our study sought to assess the cost-effectiveness of hydrophiliccoated catheters compared to other types of urinary catheters among the spinal cord injury population. We identified eight studies that reported the cost-effectiveness of hydrophilic-coated catheters in the spinal cord injury population, evaluating seven different types of catheters.
Using ICER per QALY gained as the primary measure of cost-ef-  24 Similarly, in the HQO report, the reference case analysis compared hydrophilic-coated catheters to uncoated catheters reused for a full week. 4 The ICER decreased from $3. Second, the discrepancy in the cost-effectiveness outcomes of our included studies may be related to whether long-term health impacts were considered. The model design for the economic evaluations identified in our systematic review can be separated into two categories: studies that evaluated short-term health effects 4,24,27 and studies that considered the long-term health implications of using different catheter types. 12,18,25,26,28