The use of a faecal calprotectin (FC) test was a cost-effective method of screening adult patients for inflammatory bowel disease (IBD) in the primary care setting, according to the results of a Canadian study published in BMJ Open.
“Recently, the detection of faecal calprotectin, the most extensively studied faecal marker of IBD, has been shown to be an accurate and useful screening tool for identifying patients who need further investigation through endoscopy,” according to study researcher Wei Zhang, of St. Paul’s Hospital, Vancouver, Canada, and colleagues. However, most studies looking at FC testing have been conducted in a secondary care setting.
In this study of a primary care setting, the researchers used a cut-off level of 100 µg/g for FC testing. The cost-effectiveness of FC testing was compared with the standard practice of a blood test. Probabilistic analyses were conducted for the base case and all scenarios.
The researchers used $40 Canadian (~$29.81 US) as the current cost of the FC case in their base case, consistent with the “cost used in previous cost-effectiveness analyses conducted in the UK and the USA.”
FC testing was expected to cost about $21 Canadian (~$15.65 US) more than standard practice blood test ($295.1 Canadian [~$219.90 US] vs. $273.9 Canadian [~$204.10 US]), but yield slightly higher quality-adjusted life years (QALYs; 0.751 vs. 0.750), the study showed. The incremental cost-effectiveness ratio was $20,323.35 Canadian (~$15,144.45 US) per QALY gained.
According to the researchers, delayed diagnosis is common for IBD. Patients tested with an FC screen received an IBD diagnosis almost 40 days faster than those tested with a blood screen alone.
“The average times to IBD diagnosis among patients with IBD were 192.4 days with FC testing and 232.4 days for standard practice,” the researchers wrote. “The time to diagnosis under the standard practice was reasonably consistent with a Canadian study that reported the mean time to diagnosis for Crohn’s disease and ulcerative colitis to be 255.5 and 202.3 days, respectively.”
At a willingness-to-pay threshold of $50,000 Canadian (~$37,195 US) per QALY gained, there was an 81.3% probability that the FC test would be cost-effective.
The researchers noted that one of the limitations of the study was the assumption of 100% patient uptake.
“Given the invasive nature and set of complications associated with colonoscopies, patients may refuse this diagnostic test,” they wrote. “The FC test may also not be widely accepted, with a variable uptake rate between primary and secondary care.”