¹⁸F-FDG PET/CT in inflammation of unknown origin: a cost-effectiveness pilot-study

Patients with increased inflammatory parameters, nonspecific signs and symptoms without fever and without a diagnosis after a variety of diagnostic procedures are a diagnostic dilemma and are referred to as having inflammation of unknown origin (IUO). The objective of this pilot study was to compare the cost-effectiveness of a diagnostic work-up/strategy with and without (18)F-FDG PET/CT in patients with IUO using a published dataset as a reference.

IUO patients without (18)F-FDG PET/CT (group A, 46 patients) and IUO patients referred for (18)F-FDG PET/CT (group B, 46 patients) were selected. IUO was defined as the combination of nonspecific signs and symptoms and a prolonged erythrocyte sedimentation rate (ESR), defined as ≥age/2 in men and ≥(age + 10)/2 in women (ESR in millimetres per hour and age in years), and/or C-reactive protein (CRP) ≥15 mg/l. The costs of all tests and procedures and the number of hospitalization days in each patient to reach a diagnosis were calculated using current Dutch tariffs.

In group A a diagnosis was reached in 14 of the 46 patients. The mean cost per patient of all the diagnostic procedures was 2,051, and including the cost of hospitalization was 12,614. In group B a diagnosis was reached in 32 of the 46 patients. The mean cost per patient of all the diagnostic procedures was 1,821, significantly lower than in group A (p < 0.0002), and including the cost of hospitalization was 5,298.

In IUO (18)F-FDG PET/CT has the potential to become a cost-effective routine imaging technique indicating the direction for further diagnostic decisions thereby allowing unnecessary, invasive and expensive diagnostic investigations to be avoided and possibly the duration of hospitalization to be reduced. However, a prospective multicentre "bottom-up microcosting" cost-effectiveness study is warranted before these preliminary data can be extrapolated to clinical practice.