DISCUSSION
We performed an analysis of costs using micro-costing techniques to determine and compare the costs associated with the diagnostic evaluation of ambulatory patients managed at two different quick diagnosis units in Barcelona. Our study showed that the mean cost per patient was moderately but nonsignificantly higher in the unit of the tertiary hospital compared to the unit of the secondary center. However, costs of personnel and indirect costs of the former were significantly higher, and this was true both for the monetary value and the percent contribution of these costs to the mean cost per patient.
Although quick diagnosis units have multiplied across tertiary and secondary Spanish hospitals during the last 15 years, reported investigations about their role as an alternative ambulatory care model to inpatient admission come just from a few centers [6,9,15,18,19]. A recent comparative study between the units reported in this study revealed that the overall clinical efficiency and performance of both in the diagnostic evaluation of patients with predefined referral criteria and suspected serious conditions were similar [15]. In general, observational studies have concluded that the clinical efficiency of quick diagnosis units is similar to that of conventional hospitalization for diagnostic purposes but that the costs associated with the ambulatory management of these patients are lower than the costs applied to the same conditions in the inpatient setting [7,9,11-13,15,20,21]. Two systematic reviews by authors from the United States investigated all reported articles about quick diagnosis units and found that the average savings from fixed costs of hospitalization ranged from \euro1,764 to \euro2,514 per patient in the quick diagnosis unit model compared to inpatient matched controls. Further, an economic saving of 7 to 8.76 inpatient beds per day was reported [5,8]. As far as we can tell, ours is the first study to compare the costs associated with the diagnostic assessment of patients managed at different quick diagnosis units.
Though limited to the Spanish public system, a healthcare model similar to quick diagnosis units was implemented nationally in Scandinavian countries in the early 2010s. The differentiated approach consisted of an urgent referral pathway for patients with unspecific, serious symptoms, who were referred from primary care centers to the so-called ‘diagnostic centre’, a unit staffed with several specialists and equipped with a sort of facilities for diagnostic investigations. Although results from several studies of patients evaluated through this pathway showed high-quality indicators [22,23], no reports analyzing the associated costs have been published.
The differences in the costs of personnel and indirect costs observed in our study must be interpreted considering the similarities and differences of the two units and their respective hospitals. Patients managed at the tertiary hospital are often referred from smaller, secondary hospitals including the second-level hospital reported here. Unlike the latter, the tertiary hospital has a full complement of services, highly specialized staff, and high technological equipment. Although the clinical indications for referral and working procedures of both units are similar, the volume of patients evaluated, the number of staff, and the contribution of staff time in the unit of the tertiary center are considerably greater.
A salient finding of our study was the similarity of the mean cost per visit between the two units (\euro183 for the Tertiary vs. \euro185 for the Secondary Unit). Yet the mean ratio of successive/first visits was significantly higher in the former (3.1 vs. 2.1, respectively). Therefore, although not statistically significant, the reported differences in the mean cost per patient between the Tertiary and the Secondary Unit (577.5 ± 219.6 vs. 394.7 ± 92.58, respectively; P =0.0559) ought to be mainly ascribed to the higher number of total visits in the former. Despite these differences, however, patients from the tertiary center unit needed significantly less days to be diagnosed than those from the Secondary Unit (8 vs. 12 days, respectively; P <0.0001). As previously reported [5,8], time to diagnosis is considered an indicator of high-healthcare quality in quick diagnosis units.
The analysis of clinical data revealed some notable differences. The emergency department was the referral source of 61% of patients from the Tertiary but only 17% of patients of the Secondary Unit and these differences were more pronounced for patients referred for symptoms suggestive of cancer and patients with a diagnosis of cancer, with approximately 65% of them being referred from the emergency department in the Tertiary vs. 16% in the Secondary Unit. Compared to patients from the secondary center unit, those from the Tertiary Unit were more likely to be referred with cancer suggestive symptoms and have a final diagnosis of malignancy. In general, patients from the Secondary Unit presented with less severe and ‘urgent’ conditions than those from the Tertiary Unit including, among others, unexplained tiredness, laboratory test abnormalities, and osteoarticular symptoms. This different pattern was reflected by the fact that primary care centers and not the emergency department were the main source of referral of patients to the unit of the second-level hospital. A former study showed that, with a lower number of total visits and a longer time to diagnosis, patients from this unit required fewer investigations to achieve a diagnosis than patients from the unit of the third level center [15]. Taken together, these results suggest that a greater complexity of the medical disorders evaluated at the tertiary center unit most likely accounted for the differences in the mean ratio of successive/first visits and, consequently, the differences in the mean cost per patient between the two units.