This is a critical abstract of an economic evaluation that meets the criteria for inclusion on NHS EED. Each abstract contains a brief summary of the methods, the results and conclusions followed by a detailed critical assessment on the reliability of the study and the conclusions drawn.

This study evaluated the current immunologic assays for diagnosing celiac disease in adults. The authors concluded that tissue transglutaminase antibody test was the appropriate first serologic test but, after that, the decision on whether or not to use a two-step approach (with endomysial antibody test) was subject to individual clinical judgment. The economic component of this study was an afterthought at most and the authors appropriately did not make definitive cost-effectiveness conclusions.

Cost-effectiveness analysis

The aim was to evaluate all current immunologic assays for diagnosing celiac disease in adults undergoing a gastroscopy, and to assess whether tissue transglutaminase (tTG) antibody was a quantitative marker for histological severity.

The four diagnostic strategies compared were to refer the patient for biopsy: only if tTG positive; only if endomysial antibody (EMA) positive; if tTG positive and then EMA positive (two-step); and if either tTG positive or EMA positive.

UK/secondary care (patients referred to an endoscopy department).

Analytical approach:

Effectiveness data:

Monetary benefit and utility valuations:

Measure of benefit:

Cost data:

Analysis of uncertainty:

The prevalence of celiac disease in group 1 was 3.9%.

The results for sensitivity, specificity, positive predictive values (ppv) and negative predictive values (npv), number of patients undergoing biopsy (per 2000), and missed celiac diagnoses (out of 77) were as follows.

For the only tTG positive strategy, sensitivity was 90.9, specificity was 90.9, ppv was 28.6%, npv was 99.6%, biopsy was 245, and missed diagnoses were 7.

For the only EMA positive strategy, sensitivity was 87.0, specificity was 98.0, ppv was 64.4, npv was 99.4, biopsy was 104 and missed diagnoses were 10.

For the two-step strategy, sensitivity was 85.7, specificity was 98.6, ppv was 71.7, npv was 99.4, biopsy was 92 and missed diagnoses were 11.

For the if either tTG positive or EMA positive strategy, sensitivity was 92.2, specificity was 90.3, ppv was 27.6, npv was 99.7, biopsy was 257, and missed diagnoses were 6.

For the only tTG positive strategy, the total costs per 2,000 patients were £28,210 and the cost per celiac diagnosis was £403. For the only EMA positive strategy the total costs were £20,032 and the cost per diagnosis was £299. For the two-step strategy, the total costs were £21,051 and the cost per diagnosis was £319. For the if either tTG positive or EMA positive strategy, the total costs were £42,906 and the cost per diagnosis was £604.

No incremental analysis was reported.

The authors concluded that tTG was the appropriate first serologic test but, after that, the decision on whether or not to use a two-step approach (with EMA) was subject to individual clinical judgment.

Interventions:

Effectiveness/benefits:

Costs:

Analysis and results:

Concluding remarks:

Not stated.